Dr. Ehab Aboueladab (PhD in Biochemistry): مارس 2013

1. Which is NOT an end product of eukaryotic cellular aerobic respiration?
A) carbon dioxide.
B) water.
C) ATP.
D) oxygen
E) All of the choices are correct.

Answer: D

2. The correct sequence for aerobic metabolic breakdown of glucose is
A) glycolysis–preparatory reaction–cirtric acid cycle–electron transport system
B) preparatory reaction–glycolysis–electron transport–citric acid cycle
C) electron transport system–citric acid cycle–preparatory reaction–glycolysis
D) light reactions–electron replacement–ATP production–calvin cycle
E) glycolysis–citric acid cycle–electron transport system–preparatory reaction

Answer: A
3. Of the following processes, which does NOT require oxygen to occur?
A) electron transport system
B) preparatory
C) glycolysis
D) citric acid cycle
E) All of these require oxygen

Answer: C

4. The end product of glycolysis
A) is pyruvate in aerobic respiration.
B) can form alcohol and/or lactate if fermentation occurs.
C) nets the cell 2 ATP.
D) nets the cell 2NADH
E) All of the choices are correct.

Answer: E

5. Which is NOT true of the citric acid cycle?
A) Must occur twice for each glucose molecule metabolized.
B) Produces 2 ATP by substrate-level phosphorylation
C) Produces 4 carbon dioxide molecules per glucose molecule.
D) Occurs in the cristae of the mitochondria.
E) Produces 6 NADH per glucose.

Answer: D

6. The electron transport system produces ______ATP from each NADH and/or _________ATP from each flavin mononucleotide entering the system.
A) 4: 2
B) 3: 2
C) 2: 4
D) 2: 3
E) 4: 3

Answer: B

Use the following to answer questions 7-10:

7. Which label is pointing to the stroma?
A) a
B) b
C) c
D) d
E) e

Answer: B

8. Letter “a” is pointing to the location of the
A) citric acid cycle
B) glycolysis reactions
C) calvin cycle
D) electron transport chain
E) generaton of NADH

Answer: D

9. What important process takes place in the area labeled “d”?
A) The reactions of the citric acid cycle.
B) The production of water.
C) The utilization of oxygen
D) The accumulation of protons creating an electrochemical gradient
E) The production of reduced coenzymes for the powering of the electron transport chain

Answer: D

10. What would NOT be found along the membrane marked “a”?
A) the proteins of the electron transport chain
B) ATP synthase channels
C) the enzymes of glycolysis
D) ATP protein channels
E) cytochrome molecules

Answer: C

============

1. About _____ of the energy in the glucose molecule is captured in ATP through the reactions of cellular respiration.
A) 12%
B) 26%
C) 39%
D) 57%
E) 84%

Answer: C

2. Which process must occur before fermentation?
A) the citric acid cycle
B) glycolysis
C) the electron transport system
D) fermentation
E) the preparatory reaction

Answer: B

3. Why would an organism utilize fermentation if it was wasteful of the energy in food molecules and posed the threat of killing itself with high levels of toxic alcohol?
A) The organism can survive short spells of anaerobic conditions and maintain growth and reproduction.
B) If glucose levels are not high, there may be time to disperse the alcohol “waste.”
C) Fermentation can provide a rapid burst of ATP since it does not have to go through the full breakdown cycle.
D) All of the choices are advantages.
E) None of the choices is an advantage; anaerobes only survive where aerobes cannot.

Answer: D

4. The critical factor driving yeasts to use fermentation to metabolize sugar is
A) inability to carry on glycolysis.
B) lack of oxygen.
C) lack of any enzymes.
D) that yeast is intolerant to alcohol.
E) that yeasts can secure 38 ATP molecules from fermentation.

Answer: B
5. Which of these pairs of processes are anaerobic?
A) fermentation and glycolysis
B) fermentation and the citric acid cycle
C) glycolysis and the citric acid cycle
D) the citric acid cycle and the electron transport system
E) glycolysis and the electron transport system

Answer: A

6. The energy stored in 36 ATP molecules produced by aerobic respiration is 39 percent of the energy available in a six-carbon glucose and the other 61% of the glucose bond energy is lost. The respiration of an 18-carbon fatty acid produces 216 ATP. We can expect that
A) the degradation of a fatty acid is totally unrelated to the citric acid cycle.
B) six times as much energy was stored in this molecule but also a similar proportion is lost.
C) because the molecules are so large, fats are an inefficient form of stored energy.
D) this respiration pathway must occur in some cell organelle besides the mitochondrion.
E) None of these statements is true.

Answer: B

7. Degradative reactions
A) cause death.
B) can drive anabolism.
C) tend to be endergonic.
D) include the buildup of products such as complex proteins and nucleic acids.
E) All of the choices are true.

Answer: B

8. For fatty acids to be able to enter the pathways of cellular respiration, they must be
A) deaminated.
B) combined with glycerol.
C) combined with ATP.
D) broken into acetyl groups.
E) be converted into five-carbon sugars.

Answer: D
9. Adult humans cannot synthesize _____ out of _____ amino acids.
A) eleven, twenty
B) nine, eleven
C) nine, twenty
D) any, twenty
E) half, all

Answer: C

10. The amino acids we cannot synthesize are called _____ because we _____ .
A) unnecessary, therefore do not need them
B) limiting, must include them in our diet
C) anabolic, must use alternative amino acids
D) essential, must include them in our diet.
E) superfluous, must survive without them.

Answer: D

=================

1. Some bacteria are strict aerobes and others are strict anaerobes. Some bacteria, however, are facultative anaerobes and can live with or without oxygen. If given the choice of using oxygen or not, which should a facultative anaerobe perform?
A) Use oxygen since aerobic metabolism provides more ATP per molecule of carbohydrate broken down than anaerobic metabolism.
B) Not use oxygen since it is a facultative anaerobe, it doesn’t tolerate oxygen well.
C) Use oxygen because aerobic metabolism is easier.
D) It doesn’t matter; both processes will produce the same results.
E) None of these is correct.

Answer: A

2. Which of the following molecules can be broken down into acetyl and enter the citric acid cycle?
A) proteins
B) amino acids
C) fatty acids
D) pyruvate
E) all of the choices are correct

Answer: E

3. Which of these processes occurs in the cytosol?
A) the citric acid cycle
B) glycolysis
C) the electron transport system
D) the preparation of pyruvate
E) chemiosmosis

Answer: B

4. Complete oxidative breakdown of glucose results in ______ ATP molecules.
A) 2
B) 4
C) 32
D) 36
E) 39

Answer: D

5. The preparatory reaction breaks
A) glucose into pyruvates.
B) pyruvates into glucose.
C) pyruvates into acetyl-CoA and carbon dioxide.
D) pyruvates into acetyl-CoA and water.
E) acetyl CoA into pyruvates and carbon dioxide.

Answer: C

6. The first reaction in the citric acid cycle is binding
A) carbon dioxide to a four-carbon (C4) molecule.
B) carbon dioxide to a five-carbon (C5) molecule.
C) acetyl-CoA to a C4 molecule.
D) acetyl-CoA to a C5 molecule.
E) acetyl-CoA to citric acid

Answer: C

7. Cellular respiration yields about ____ of the energy of glucose in ATP molecules.
A) 2%
B) 15%
C) 28%
D) 39%
E) 50%

Answer: D

8. The process based on the Greek root words for “sugar” and “splitting” is
A) metabolism.
B) glycolysis.
C) phosphorylation.
D) fermentation.
E) chemiosmosis.

Answer: B
9. The first process in breaking down glucose is
A) the citric acid cycle.
B) glycolysis.
C) the electron transport system.
D) fermentation.
E) the preparatory reaction.

Answer: B

10. Which process produces both NADH and FADH2?
A) the citric acid cycle
B) glycolysis
C) the electron transport system
D) fermentation
E) the preparatory reaction

Answer: A

====================

1- Name the major proteins of plasma.

(Albumin, Globulin and Fibrinogen)

2-Name the transport proteins

(Albumin, Lipoproteins, Prealbumin, Transthyretin, Retinol Binding protein, Thyroxin binding Globulin)

3-How many copper atoms can bind to one molecule of ceruloplasmin?

(6-8)

4-What is A: G ratio, what is its range in the normal health?

(1.2:1 to 1.5:1)

5-What is the most significant sign of hypoproteinemia?

(Edema)

6-Almost all proteins except Globulins are synthesized in the liver, True or false?

(True)

7-Name the negative phase proteins

(Albumin, Transthyretin, Transferrin etc.)

8-What are the different types of light chains?

( Kappa and Lambda)

9-Which immunoglobulin is the major antibody of primary immune response

(IgM)

10-What is the function of the secretory piece of the IgA?

(It protects the antibody from proteolytic digestion)

11-What is the actual meaning of Fc and Fab ?

(These are the two portions of immunoglobulins produced after proteolytic cleavage of immunoglobulin. Fc denotes fragment crystallisable and Fab denotes antigen binding fragment)

12-Which form of Ig M – monomeric or polymeric acts as a receptor on the surface of B lymphocytes.

( Monomeric form)

13-Which form (Alpha helical, Beta pleated sheet or triple helical) predominates in the structure of collagen?

(Triple helical)

14-What are the different types of heavy chains present in different types if immunoglobulins?

(α, β,γ,δ, Σ)

15-What types of globin chains are present in Fetal Hemoglobin?

(Two alpha and 2 Gamma)

16-What is methaemoglobin?

( Hb in which iron is in the oxidized form(Ferric form )

17-25 % of the structure of hemoglobin is in the alpha helical form- state true or false?

(False- 75% is in the alpha helical form)

18-Name the beta globulins of biological significance

(Transferrin, Haemopexin, Complement etc)

19-What is the nature of ceruloplasmin?

(Alpha 2 globulin)

20-What is the function of Transferrin?

(Transfer of iron)

21-What is the function of fibrinogen?

(Blood clotting and viscosity)

22-What is the clinical significance of C- reactive protein ?

(Acute phase protein, activates complement, also helps in the formation of haem)

==============

1. The steps of glycolysis between glyceraldehyde 3-phosphate and 3-phosphoglycerate involve all of the following EXCEPT

a. ATP synthesis
b. utilization of Pi.
c. oxidation of NADH to NAD+.
d. reduction of NAD+ to NADH.
e. formation of 1,3 bisphosphoglycerate.

Ans:C

2. When a muscle contracts aerobically, less lactic acid is formed than when it contracts anaerobically because under aerobic conditions

a. muscles cannot convert glucose 6-phosphate to pyruvate.
b. most of the pyruvate generated is oxidized.
c. the lactic acid generated is rapidly converted back to glucose.
d. the major source of energy is the pentose pathway.
e. the major source of energy is creatine phosphate.

Ans:B
3. The conversion of 1 mol of glucose 1-phosphate to 2 mol of pyruvate by the glycolytic pathway results in a net formation of

a. 1 mol of NAD+ and 2 mol of ATP.
b. 1 mol of NADH and 2 mol of ATP.
c. 2 mol of NADH and 2 mol of ATP.
d. 2 mol of NADH and 3 mol of ATP.
e. 2 mol of NAD+ and 3 mol of ATP.

Ans:D
4. Which combination of cofactors is involved in the conversion of pyruvate to acetyl-CoA?

a. NAD+, biotin, and TPP
b. TPP, lipoic acid, and NAD+
c. pyridoxal phosphate, FAD, and lipoic acid
d. biotin, FAD, and TPP
e. biotin, NAD+, and FAD

Ans:B

5. The conversion of 1 mol of pyruvate to 3 mol of CO2 via pyruvate dehydrogenase and the citric acid cycle yields ___mol of NADH, ____mol of FADH2, and ___mol of ATP (or GTP).

a. 3; 2; 0
b. 4; 2; 1
c. 4; 1; 1
d. 3; 1; 1
e. 2; 2; 2

Ans:C
6. An enzymatic reaction that is most similar to the conversion of pyruvate to acetyl CoA is catalyzed by

a. citrate synthase.
b. alpha-ketoglutarate dehydrogenase.
c. succinyl-CoA synthetase.
d. isocitrate dehydrogenase.
e. succinate dehydrogenase.

Ans:B
7. Intermediates of the citric acid cycle are replenished by a reaction converting pyruvate to

a. oxaloacetate.
b. citrate.
c. alpha-ketoglutarate.
d. succinyl-CoA.
e. acetyl-CoA.

Ans:A
8. Which enzyme is used in gluconeogenesis but not glycolysis?

a. Phosphoglucoisomerase
b. Lactate dehydrogenase
c. Glucose 6-phosphatase
d. 3-Phosphoglycerate kinase
e. Aldolase

Ans:C
9. All of the following compounds can serve as the starting material for the synthesis of glucose via gluconeogenesis EXCEPT

a. alanine.
b. oleic acid.
c. aspartic acid.
d. glycerol.
e. pyruvate.

Ans:B
10. Substrates for glycogen synthase are

a. glucose 1-phosphate and the C-4 hydroxyl of primer.
b. UDP-glucose and the C-4 hydroxyl of primer.
c. UDP-glucose and the C-6 hydroxyl of primer.
d. UDP-glucose and the C-1 hydroxyl of primer.
e. glucose 1-phosphate and the C-1 hydroxyl of primer.

Ans:B

=======================

1. In the elongation of glycogen, activated glucosyl units are attached to which hydroxyl of the terminal residue of the growing chain?
a. C-1
b. C-2
c. C-3
d. C-4
e. C-6

Ans:D

2. In the breakdown of muscle glycogen, the predominant product is
a. glucose.
b. glucose 1-phosphate.
c. UDP-glucose.
d. maltose.
e. maltotriose.

Ans:B

3. Which enzyme is activated by direct binding of cAMP to a regulatory subunit?
a. Adenylate cyclase
b. Protein kinase A
c. Phosphorylase kinase
d. Protein phosphatase
e. Phosphorylase

Ans:b

4. Several hours after a meal, when blood glucose levels are approximately 6 mM, the glucokinase activity of the liver is approximately equal to the activity of
a. glucose 6-phosphatase.
b. glucose phosphate isomerase.
c. phoshofructokinase-1.
d. glucose 6-phosphate dehydrogenase.
e. glycogen synthetase.

Ans:A

5. The most important allosteric inhibitor of glycolysis in resting muscle is
a. AMP.
b. H+.
c. ATP.
d. Fructose 2,6 bisphosphate.
e. cAMP.

Ans:C

6. A pathway/step of carbohydrate metabolism that is stimulated by insulin in muscle, but not in liver:
a. Glycolysis
b. Gluconeogenesis
c. Glycogenolysis
d. Glycogen synthesis
e. Glucose transport

Ans:E

7. In most tissues, an increase in the following ratio directly causes an increase in TCA cycle activity:
a. ADP/ATP
b. ATP/ADP
c. GTP/GDP
d. NADH/NAD+
e. NAD+/NADH

Ans:E

8. A 23 year old man is unable to exercise vigorously without developing muscle cramps. Studies of his exercising forearm reveal that during maximal work, he does not produce lactate. This individual most likely has a deficiency of
a. fructose 1,6 bisphosphatase.
b. PEP carboxykinase.
c. pyruvate dehydrogenase.
d. glycogen debranching enzyme.
e. glycogen phosphorylase.

Ans:E

9. In the digestive tract, disaccharides such as sucrose are hydrolyzed to monosaccharides mainly by enzymes located in the
a. saliva.
b. gastric secretions.
c. lumen of the small intestine.
d. brush border of the small intestine.
e. lumen of the large intestine.

Ans:D

10. All of the following are products of the oxidative branch of the hexose monophosphate pathway EXCEPT
a. CO2.
b. ribulose 5-phosphate.
c. NADPH.
d. NADH.

Ans:D

11. The protein that binds and directly reduces the terminal electron acceptor in mitochondrial electron transport is
a. cytochrome oxidase.
b. succinate dehydrogenase.
c. coenzyme QH2
d. NADH:Q reductase.
e. cytochrome bc1.

Ans:A

12. All of the following use coenzyme Q as either substrate or product EXCEPT
a. Complex I
b. Complex II
c. Complex III
d. Complex IV

Ans:D

=================

1. The committed step of the glycolytic pathway is catalyzed by
a. hexokinase/glucokinase.
b. phosphofructokinase-1.
c. aldolase.
d. glycerol 6-phosphate dehydrogenase.
e. pyruvate kinase.
Ans:B

2. The first high energy intermediate produced in the conversion of glucose to pyruvate:
a || b || c || d || e .
Ans:D

3. In the reaction mechanism for the oxidative decarboxylation of pyruvate, which cofactor is required for the decarboxylation step?
a. Thiamine pyrophosphate
b. Lipoic acid
c. FAD
d. NAD+
e. Biotin

Ans:A

4. Lactic acid taken from the blood is a significant fuel for the heart. If 30 ATPs are produced (net yield) by the complete oxidation of glucose, approximately how many ATPs can be produced in the heart by the complete oxidation of 1 lactate molecule?
a. 2
b. 3
c. 6
d. 10
e. 14

Ans:E

5. During aerobic glycolysis in muscle, electrons transferred to dihydoxyacetone phosphate enter the mitochondrial electron transport chain at
a. complex I.
b. complex II.
c. complex III.
d. cytochrome c.
e. coenzyme Q.

Ans:E

6. The protein that binds to and directly reduces complex IV in mitochondrial electron transport is
a. cytochrome aa3.
b. cytochrome bc1.
c. cytochrome c.
d. succinate dehydrogenase.
e. NADH:Q reductase.

Ans:C

7. Barbiturates such as amytal disrupt energy metabolism by blocking the exit of electrons from complex I. This would prevent the oxidation of
a. CoQH2.
b. NADH.
c. FADH2 in complex II.
d. cytochrome c.
d. cytochrome c.

Ans:B

8. In the conversion of 1 molecule of acetyl CoA to carbon dioxide, how many O2 molecules are consumed or produced directly by the reactions of the citric acid cycle?
a. 1 produced
b. 2 produced
c. 1 consumed
d. 2 consumed
e. 0 consumed or produced

Ans:E

9. Which of the following metabolites can NOT be a substrate for gluconeogenesis?
a. Alanine
b. Acetate
c. Glutamate
d. Lactate
e. Succinate

Ans:B

10. An enzyme that is common in both glycolysis and gluconeogenesis:
a. Phosphofructokinase-1
b. Glucokinase
c. Aldolase
d. Fructose bisphosphatase
e. Pyruvate carboxylase

Ans:C

==============

1. The main function of the hexose monophosphate pathway is to
a. supply energy in adipose tissue and liver.
b. provide an additional pathway for production of fructose 6-phosphate.
c. increase the cytoplasmic NADH/NAD+ ratio.
d. replenish TCA cycle intermediates.
e. supply pentoses and NADPH.

Ans:E

2. In a tissue that metabolizes glucose via the hexose monophosphate pathway, C-1 of glucos would be expected to end up principally in
a. glycogen.
b. phosphoglycerate.
c. carbon dioxide.
d. ribulose 5-phosphate.
e. pyruvate.

Ans:C

3. Galactosemia is a genetic error of metabolism associated with a(n)
a. inability to transport galactose into cells.
b. inability to digest lactose.
c. deficiency of galactokinase.
d. deficiency of UDP-glucose: galactose 1-phosphate uridylyltransferase.
e. deficiency of UDP-glucose.

Ans:D

4. The rate-limiting step in glycolysis is
a. the breakdown of glycogen.
b. the phosphorylation of glucose.
c. isomerization of glucose 6-phosphate to fructose 6-phosphate.
d. the phosphorylation of fructose 6-phosphate.
e. formation of ATP from phosphoenolpyruvate.

Ans:D

5. Entry of acetyl-CoA into the citric acid cycle decreases as
a. the ratio of [ATP]/[ADP] increases.
b. [AMP] increases.
c. the ratio of [NAD+]/[NADH] increases.
d. the rate of electron transport increases.

Ans:A

6. Elevated epinephrine levels stimulate all of the following EXCEPT
a. glycogen breakdown in muscle.
b. glycogen synthesis in liver.
c. gluconeogenesis in liver.
d. glycolysis in muscle.
e. fatty acid mobilization in adipose tissue.

Ans:B

7. In the signal transduction cascade leading to glycogen breakdown, the most immediate effect of increasing [cAMP] is
a. activation of protein kinase A.
b. inactivation of glycogen synthase.
c. activation of phophorylase kinase.
d. activation of glycogen phosphorylase.

Ans:A

8. Which fuel can produce the most ATP per second in a working muscle?
a. glycogen
b. glucose
c. glucose 1-phosphate
d. fatty acids
e. creatine phosphate

Ans:E

9. During aerobic glycolysis in muscle, which of the following compounds transfers electrons from the cytosol directly to a flavoprotein on the cytoplasmic face of the inner mitochondrial membrane?
a. lactate
b. NADH
c. glycerol phosphate
d. malate
e. NADPH

Ans:C

10. During anaerobic glycolysis, there is a net production in the cytosol of lactate and
a. NAD+.
b. NADH.
c. CO2
d. ATP.
e. FADH2.

Ans:D

=========

Question 1: Characteristics of Phenylketonuria (PKU)
A) Alpha KG defect
B) Deficiency of phenylalanine hydroxylase
C) Abundance of dihydropteridine reductase
D) Up regulation go phenylalanine hydroxylase

Question 2: Alcaptonuria
A) Homogenistate oxidase hyperactivity
B) Homogenistate oxidase deficiency
C) Clear urine

Question 3: Not part of a treatment for PKU
A) Oral tetrahydrobiopterin (THB)
B) High phenylalanine diet
C) Long term
D) Controlled low phenylalanine diet

Question 4: Creatine
A) Formed nonezymatically, not excreted in urine
B) Formed ezymatically, entirely excreted in urine
C) Formed nonezymatically, entirely excreted in urine

Question 5: Serotonin synthesis
A) Melatonin->serotonin
B) Serine->serotonin
C) Trp->serotonin

Question 6: Tyrosinemia type 2
A) Liver, kidney, peripheral nerve defects. Deficiency of Fumarylacetoacetate hydrolase
B) Eye, skin defects. Deficiency of tyrosine amino acid transferase

Question 7: Coenzyme A synthesis
A) Phosphopantothenate + Cystiene -> Anp + CoA-SH
B) Tryptophan + Cystiene -> Anp + CoA-SH
C) Phosphopantothenate + SAM -> Anp + CoA-SH
D) Phosphopantothenate + Serine-> Anp + CoA-SH

Question 8: Pyriminde biosynthesis requires
A) Aspartate, Glutamine
B) Serine, Aspartate
C) Glycine, Glutamine, Aspartate

Question 9: Polyamines
A) Putrescine, spermidine, spermine. Derived from ornithine and methionine
B) Putrescine , spermidine. Derived from ornithine and methionine
C) Putrescine , spermidine, ornithine. Derived from spermine and methionine
D) Putrescence, spermidine, spermine. Derived from ornithine and methionine

Question 10: NO synthesis
A) Arginine-> Citrulline + NO
B) Arginine-> Citrulline-> NO
C) Serine-> Citrulline + NO

Question 11: SAM synthesis
A) Tryptophan, NAD
B) Serine, Methionine and ATP
C) Methionine and ATP
D) Succinate, co2, glycine

Question 12: Classical albinism caused by
A) Aromatic acid decarboxylase deficiency
B) Tyrosinase deficiency
C) Tyrosinase overabundance

Question 13: E-n-trimethyllysine conversion to
A) Tryptophan
B) SAM
C) NAD
D) Carnitine

Question 14: Catecholamine synthesis
A) Tyr->Dopa->Dopamine->Epi->NE
B) Phe->Dopa->Dopamine->NE->Epi
C) Tyr->Dopa->Dopamine->NE->Epi
D) Tyr->Dopamine->Dopa->NE->Epi

Question 15: Purine synthesis requires
A) Glycine, Aspartate
B) Glycine, Glutamine, Aspartate
C) Serine, Aspartate, Glycine

Question 16: Neonatal tyrosinemia
A) Deficiency of homogenistate oxidase
B) Delay in s-hydroxyphenylpyruvate, typically benign, dietary treatment
C) Delay in p-hydroxyphenylpyruvate, typically benign, dietary treatment
D) Delay in p-hydroxyphenylpyruvate, serious disease, dietary treatment

Question 17: GABA synthesis
A) Glutamate synthase
B) Glutamate decarboxylase
C) Glutamate
D) Glutamate carboxylase

Question 18: Untrue about PKU
A) May be defective biopterin metabolism
B) 97% of children have low IQ
C) Uncommon
D) Toxic to cns

Question 19: Tyrosinemia type 1
A) Eye, skin, cns problems, tyrosine aminotransferase
B) Liver, kidney, peripheral ns problems, Fumarylacetoacetate hydrolase deficiency
C) Liver, kidney, peripheral ns problems, Tyrosine amino transferase deficiency

Question 20: Synthesis of porphyria requires
A) Glutamine
B) Aspartate
C) Glycine

Question 21: How many ATP molecules does it take to produce one GSH
A) 1
B) 3
C) 4
D) 2

Question 22: Melatonin synthesis
A) Trp->serotonin->Melatonin
B) Trp->melatonin
C) Serine->serotonin->Melatonin

Question 23: MSUD maple syrup urine disease
A) Branched chain alpha ketoacid dehydrogenase upregulation
B) Branched chain alpha ketoacid dehydrogenase deficiency
C) Fumarylacetoacetate hydrolase deficiency

Question 24: Melanin synthesis
A) Tryptophan -> dopa quinone-> melanin
B) Tyrosine-> dopa quinone-> melanin
C) Dopa quinone->Tyrosine-> melanin

Question 25: NAD metabolism
A) Tyrosine, PRPP, quinolate phosphoric bosyl transferase
B) Tryptophan, PRPP, quinolate phosphoric bosyl transferase
C) Methionine, ATP, Methionine adenosyl transferase

Question 26: Catecholamines
A) Acetylcholine
B) Norepinephrine
C) Norepinephrine and Epinephrine
D) Epinephrine

Question 27: Histamine synthesis
A) From histidine, requires aromatic acid decarboxylase
B) From tyrosine, requires aromatic acid decarboxylase
C) From histidine, inhibited by aromatic acid decarboxylase

Question 28: Carnotine synthesis requires
A) Fe2+, alpha-kg, o2, SAM
B) Fe2+, alpha-kg
C) Fe2+, alpha-kg, o2
D) Succinate, CO,` glycine

Question 29: Acetylcholine
A) Tyrosine->Choline + acetyl CoA-> acetylcholine (requires SAM)
B) Serine->Choline + acetyl CoA-> acetyl choline (requires SAM)
C) Serine->Choline-> acetyl choline (requires SAM)
D) Serine->Choline + acetyl CoA-> acetyl choline

Answer

=====

1) Characteristics of Phenylketonuria (PKU)
- Alpha KG defect
- Up regulation go phenylalanine hydroxylase
- Abundance of dihydropteridine reductase
Correct answer: Deficiency of phenylalanine hydroxylase

2) Alcaptonuria
- Clear urine
- Homogenistate oxidase hyperactivity
Correct answer: Homogenistate oxidase deficiency

3) Not part of a treatment for PKU
- Controlled low phenylalanine diet
- Oral tetrahydrobiopterin (THB)
- Long term
Correct answer: High phenylalanine diet

4) Creatine
- Formed ezymatically, entirely excreted in urine
- Formed nonezymatically, not excreted in urine
Correct answer: Formed nonezymatically, entirely excreted in urine

5) Serotonin synthesis
- Serine->serotonin
- Melatonin->serotonin
Correct answer: Trp->serotonin

6) Tyrosinemia type 2
- Liver, kidney, peripheral nerve defects. Deficiency of Fumarylacetoacetate hydrolase
Correct answer: Eye, skin defects. Deficiency of tyrosine amino acid transferase

7) Coenzyme A synthesis
- Phosphopantothenate + Serine-> Anp + CoA-SH
- Tryptophan + Cystiene -> Anp + CoA-SH
- Phosphopantothenate + SAM -> Anp + CoA-SH
Correct answer: Phosphopantothenate + Cystiene -> Anp + CoA-SH

8) Pyriminde biosynthesis requires
- Glycine, Glutamine, Aspartate
- Serine, Aspartate
Correct answer: Aspartate, Glutamine

9) Polyamines
- Putrescine , spermidine, ornithine. Derived from spermine and methionine
- Putrescine , spermidine. Derived from ornithine and methionine
- Putrescence, spermidine, spermine. Derived from ornithine and methionine
Correct answer: Putrescine, spermidine, spermine. Derived from ornithine and methionine

10) NO synthesis
- Arginine-> Citrulline-> NO
- Serine-> Citrulline + NO
Correct answer: Arginine-> Citrulline + NO

11) SAM synthesis
- Serine, Methionine and ATP
- Tryptophan, NAD
- Succinate, co2, glycine
Correct answer: Methionine and ATP

12) Classical albinism caused by
- Aromatic acid decarboxylase deficiency
- Tyrosinase overabundance
Correct answer: Tyrosinase deficiency

13) E-n-trimethyllysine conversion to
- SAM
- NAD
- Tryptophan
Correct answer: Carnitine

14) Catecholamine synthesis
- Phe->Dopa->Dopamine->NE->Epi
- Tyr->Dopamine->Dopa->NE->Epi
- Tyr->Dopa->Dopamine->Epi->NE
Correct answer: Tyr->Dopa->Dopamine->NE->Epi

15) Purine synthesis requires
- Glycine, Aspartate
- Serine, Aspartate, Glycine
Correct answer: Glycine, Glutamine, Aspartate

16) Neonatal tyrosinemia
- Delay in p-hydroxyphenylpyruvate, serious disease, dietary treatment
- Delay in s-hydroxyphenylpyruvate, typically benign, dietary treatment
- Deficiency of homogenistate oxidase
Correct answer: Delay in p-hydroxyphenylpyruvate, typically benign, dietary treatment

17) GABA synthesis
- Glutamate carboxylase
- Glutamate
- Glutamate synthase
Correct answer: Glutamate decarboxylase

18) Untrue about PKU
- May be defective biopterin metabolism
- Toxic to cns
- 97% of children have low IQ
Correct answer: Uncommon

19) Tyrosinemia type 1
- Liver, kidney, peripheral ns problems, Tyrosine amino transferase deficiency
- Eye, skin, cns problems, tyrosine aminotransferase
Correct answer: Liver, kidney, peripheral ns problems, Fumarylacetoacetate hydrolase deficiency

20) Synthesis of porphyria requires
- Glutamine
- Aspartate
Correct answer: Glycine
21) How many ATP molecules does it take to produce one GSH
- 1
- 3
- 4
Correct answer: 2

22) Melatonin synthesis
- Trp->melatonin
- Serine->serotonin->Melatonin
Correct answer: Trp->serotonin->Melatonin

23) MSUD maple syrup urine disease
- Fumarylacetoacetate hydrolase deficiency
- Branched chain alpha ketoacid dehydrogenase upregulation
Correct answer: Branched chain alpha ketoacid dehydrogenase deficiency

24) Melanin synthesis
- Tryptophan -> dopa quinone-> melanin
- Dopa quinone->Tyrosine-> melanin
Correct answer: Tyrosine-> dopa quinone-> melanin

25) NAD metabolism
- Methionine, ATP, Methionine adenosyl transferase
- Tyrosine, PRPP, quinolate phosphoric bosyl transferase
Correct answer: Tryptophan, PRPP, quinolate phosphoric bosyl transferase
26) Catecholamines
- Epinephrine
- Norepinephrine
- Acetylcholine
Correct answer: Norepinephrine and Epinephrine

27) Histamine synthesis
- From tyrosine, requires aromatic acid decarboxylase
- From histidine, inhibited by aromatic acid decarboxylase
Correct answer: From histidine, requires aromatic acid decarboxylase

28) Carnotine synthesis requires
- Succinate, CO,` glycine
- Fe2+, alpha-kg, o2, SAM
- Fe2+, alpha-kg
Correct answer: Fe2+, alpha-kg, o2

29) Acetylcholine
- Tyrosine->Choline + acetyl CoA-> acetylcholine (requires SAM)
- Serine->Choline + acetyl CoA-> acetyl choline
- Serine->Choline-> acetyl choline (requires SAM)
Correct answer: Serine->Choline + acetyl CoA-> acetyl choline (requires SAM)

===========

1. In the gut, the generic class of enzymes that convert macromolecules to monomeric units area.
a. hydrolases.
b. phosphatases.
c. dehydrogenases.
d. ligases.
e. isomerases.

2. Enteropeptidase (enterokinase) plays a key role in digestion by directly converting
a. pepsinogen to pepsin.
b. chymotrypsinogen to chymotrypsin.
c. trypsinogen to trypsin.
d. procarboxypeptidase to carboxypeptidase.
e. proelastase to elastase.

3. In a primitive microorganism, compound A is continuously produced by metabolism, and the energy available from conversion of A to B is used directly to pump sodium ions out of the cell. The cell also contains a Na+/H+ antiporter, and the energy is captured in ATP as indicated.
Addition of a specific inhibitor that blocks the A -> B reaction would
a. increase the rate of ATP synthesis.
b. increase the influx of Na+.
c. increase the efflux of Na+.
d. increase the transmembrane sodium ion gradient.
e. decrease the transmembrane proton gradient.

4.A catalyst alters the rate of a chemical reaction by:
A) always providing a surface on which molecules react
B) changing the products formed in the reaction
C) inducing an alternate pathway for the reaction with generallylower activation energy
D) changing the frequency of collisions between molecules

5.Choose the INCORRECT answer. The rate of a chemical reaction:
A) usually is increased when the concentration of one of the reactants is increased
B) is dependent on temperature
C) may be inhibited sometimes by certain catalytic agents
D) will be very rapid if the activation energy is large

7.A catalyst
A) takes part in a reaction and speeds it up
B) appears in the rate equation of a chemical reaction
C) provides an alternate reaction pathway
D) raises the activation energy of a reaction
E) none of the above

8.Which of the following does not determine the rate of a reaction?
A) value of DELTA H0
B) activation energy
C) presence of a catalyst
D) temperature of reactants
E) none of these

9.Which of the following lowers the activation energy of a reaction?
A) adding reactants
B) lowering the temperature
C) removing products
D) adding a catalyst
E) raising the temperature

10. Which of the following is an example of a phosphoryl transfer reaction?
a. glucose + ATP glucose 6-phosphate + ADP
b. glucose 6-phosphate glucose + phosphate
c. glycerol 3-phosphate glyceraldehyde 3-phosphate
d. ADP + Pi ATP
e. glucose 6-phosphate 6 fructose 6-phosphate

==========

1). When glucose is converted to lactate by anaerobic glycolysis, the equivalent of ________ ATPs are derived. When glucose is completely oxidized to CO₂ by glycolysis, Pyruvate dehydrogenase, and the TCA cycle, the equivalent of _______ ATPs are derived.

a) 7; 20

b) 2; 38

c) 7; 32

d)2; 12

e) 7; 25

2).Choose the incorrect statement about the condition ‘When one molecule of glucose is oxidized to 2 molecules of lactate during anaerobic glycolysis’-

a) One molecule of ATP is used by the phosphofructokinase-1 reaction

b)One molecule of ATP is used by either the glucokinase or hexokinase reaction

c) Two molecules of ATP are produced by the Glyceraldehyde -3-P dehydrogenase reaction

d) Two molecules of ATP are produced by the pyruvate kinase reaction

e) No ATP is produced at the level of lactate dehydrogenase reaction.

3). All of the following help to explain some cases of Lactic Acidosis except-

a) High altitude

b) Heart failure

c) Not enough oxygen to satisfy the needs of oxidative phosphorylation

d) Congenital deficiency of liver lactate dehydrogenase

e) Inhibition of the electron transport chain

14) . All of the following are part of the Cori Cycle except-

a) Lactate is the result of anaerobic glycolysis in a number of tissues

b) Lactate is transported to the liver

c) Lactate is converted to glucose in the liver

d) ATP is produced by the conversion of lactate to glucose

e) Glucose is transported from liver to other tissues

5). The ATP/AMP ratio has a major effect upon the rate of ATP production by glycolysis. ATP and AMP bind to allosteric sites on-

a) Hexokinase

b) Glucokinase

c) Phosphofructokinase-1

d) Phosphofructokinase-2

e) 3-phosphoglycerate kinase

6). Which of the following statements about pyruvate kinase is false -

a) Can convert Phosphoenol pyruvate to pyruvate

b) Is regulated by feed forward regulation

c) Is active in the dephosphorylated form

d) Is also involved in gluconeogenesis

e) Deficiency causes haemolytic anemia.

7). Pasteur effect is due to inhibition of glycolysis by high concentration of -

a) Creatine phosphate

b) ATP

c) ADP

d) AMP

e) Pi

8). In the liver, glucagon causes a decrease in the glycolytic pathway by all of the following mechanisms except-

a) Increased binding of GTP to G-protein

b) Activation of the cAMP cascade

c) Increased phosphorylation of enzymes by protein kinase A

d) Activation of fructose-2,6-bisphosphatase and inhibition of phosphofructokinase-2

e) Increased binding of fructose-2,6-bisphosphate to phosphofructokinase-1

9). An increased concentration of insulin after meals causes an increase in the rate of glycolytic pathway by all of the following mechanisms except-

a) Increase uptake of glucose in adipose tissue and muscle

b) Inactivation of the cAMP cascade

c) Increased dephosphorylation of enzymes activated by protein kinase A

d) Activation of fructose-2,6-bisphosphatase and inhibition of phosphofructokinase-2

e) Induction of Glucokinase and PFK-1

10).During fasting state, the insulin to glucagon ratio drops and all of the following occur except-

a) Protein kinase A will phosphorylate pyruvate kinase

b) The pyruvate kinase step will be activated

c) Protein kinase A will phosphorylate phosphofructokinase-2/fructose-2,6-bisphosphatase

d) The concentration of fructose-2,6-bisphosphate will decrease

e)The liver will not be able to synthesize pyruvate from phosphoenolpyruvate.

11) A high concentration of Glucose-6-P is inhibitory to which of the following enzymes ?

a) Hexokinase

b) Glucokinase

c) PFK-1

d) PFK-2

e) All of the above,

Answer

1)-b, 2)-c, 3)-d, 4)-d, 5)-c ,6)-d, 7)-b, 8)-e,9)-d, 10)-b, 11)-a

==============

1) Which of these enzyme reactions is not irreversible in glycolysis?

a) Hexokinase

b) Glucokinase

c) 3-phosphoglycerate kinase

d) Phosphofructokinase-1

e) Pyruvate kinase

2) Which out of the following statements is not true about aerobic glycolysis ?

a) The rate limiting enzyme is phosphofructokinase-1 which converts fructose-6- phosphate to fructose-1,6-bisphosphate

b) The pathway is inhibited allosterically by fructose-2,6-bisphosphate and AMP

c) The pathway takes place in mitochondria of every cell

d) The pathway produces Pyruvate and NADH

e) The pathway begins with glucokinase or hexokinase

3) The first step in the glycolytic pathway in Liver -

a) Is catalyzed by glucokinase

b) Uses ATP and glucose as substrates

c) Produces glucose-6-phosphate and ADP

d) Is an irreversible step

e) All of the above.

4) Phosphoglycerate kinase functions in carbohydrate metabolism to produce ATP via:

a) Oxidative phosphorylation.

b) Substrate level phosphorylation.

c) Oxidative decarboxylation.

d) Phosphorolysis

e) Oxidative deamination

5). The phosphofructokinase-2 enzyme that transfers a phosphate group to fructose-6-phosphate in glycolysis-

a) Is active in the phosphorylated form

b) Catalyzes a reversible reaction

c) Produces fructose-2,6-bisphosphate as a product

d) Is the rate limiting enzyme for glycolysis

e) Produces ATP as a product.

6). The enzyme that produces NADH from a triose phosphate in the glycolytic pathway-

a) Uses NAD⁺ and dihydroxyacetone phosphate as substrates

b)Produces 3-phosphoglycerate and NADH

c) Is reversible

d) Is called 3-phosphoglycerate kinase

e) Uses FADH₂ and glyceraldehyde-3-phosphate as substrates

7). The enzyme that catalyzes first substrate level phosphorylation in glycolysis-

a) Produces 3-phosphoglycerate as a product

b) Produces ADP from AMP

c) Is called glyceraldehyde-3-phosphate dehydrogenase

d) Is called phosphofructokinase

e) Is the rate limiting enzyme of glycolysis.

8). The enzyme that catalyzes the second substrate level phosphorylation of glycolysis-

a) Is called phosphoglyceromutase

b) Produces lactate as a product

c) Uses phosphoenolpyruvate as a substrate

d) Catalyzes a reversible reaction

e) Is stimulated by Glucagon.

9). Which of the following statements about the Lactate dehydrogenase (LDH) reaction is false

a) The enzyme converts pyruvate to lactate

b)The enzyme converts NADH to NAD⁺

c) The reaction is reversible

d) It is the last enzyme reaction in glycolysis

e) The enzyme is highly active under aerobic conditions

10). The two major factors determining whether a cell oxidizes glucose by aerobic glycolysis or by anaerobic glycolysis are-

a) FADH₂ and the number of mitochondria

b) NADH and the ATP/ADP ratio

c) Ca⁺⁺ and AMP

d) Oxygen pressure and the number of mitochondria

e) Presence of low Glucose and high AMP

Answers- 1)-c, 2)- b, c)-e, 4)-b, 5)-c, 6)-b,7)-a, 8)- c, 9)-e, 10)-b,

============

Q.1 – Which of the following substrates derived from adipose tissues contributes to net Gluconeogenesis in mammalian liver?

a) Alanine

b) Glutamate

c) Glycerol

d) Pyruvate ( c )

Q.2 – Which of the following statements is incorrect?

a) Aerobically, oxidative decarboxylation of pyruvate forms acetate that enters the citric acid cycle.

b) In anaerobic muscle, pyruvate is converted to lactate.

c) Reduction of pyruvate to lactate generates a coenzyme essential for Glycolysis.

d) Under anaerobic conditions pyruvate does not form because Glycolysis does not occur.

( d )

Q.3- The steps of Glycolysis between glyceraldehyde 3-phosphate and 3-phosphoglycerate involve all of the following except:

a) ATP synthesis.

b) Catalysis by phosphoglycerate kinase.

c) Oxidation of NADH to NAD⁺.

d) The formation of 1, 3- bisphosphoglycerate. ( c )

Q.4 – The oxidation of 3 mol of glucose by the pentose phosphate pathway may result in the production of:

a) 2 mol of pentose, 4 mol of NADPH, and 8mol of CO₂.

b) 3 mol of pentose, 4 mol of NADPH, and 3mol of CO₂.

c) 3 mol of pentose, 6 mol of NADPH, and 3mol of CO₂.

d) 4 mol of pentose, 3 mol of NADPH, and 3mol of CO₂. ( c )

Q.5 – How many ATP molecules can be derived from each molecule of acetyl CoA that enters the Krebs’ Cycle?

a) 6

b) 12

c) 18

d) 38 ( b )

Q.6 – All of the following vitamins except one participate in the TCA cycle-

a)Pantothenic acid

b)Lipoic acid

c) Folic acid

d)Riboflavin ( c )

Q.7 – Why Phosphofructokinase rather than hexokinase is the pacemaker of Glycolysis?

a) Glucose 6-phosphate is not solely a glycolytic intermediate

b) Hexokinase has low km for glucose

c) Hexokinase is inhibited by feed back inhibition

d) None of the above ( a )

Q.8 - All are correct about pyruvate dehydrogenase complex except one-

a)The formation of acetyl CoA from pyruvate is an irreversible step

b) Pyruvate dehydrogenase is switched off when Acetyl co A is in excess

c)Phosphorylation switches off the activity of the complex.

d) Pyruvate as well as ADP (a signal of low energy charge) inhibits the complex. ( d )

Q.9-Cellular isozymes of pyruvate kinase are allosterically inhibited by:

a) High concentrations of AMP.

b) High concentrations of ATP.

c) High concentrations ofFr1,6 bisphosphate.

d) Low concentrations of acetyl-CoA. ( b )

Q.10 – Which of the followings is not an intermediate of the citric acid cycle?

a) Acetoacetate

b) Citrate

c) Oxalosuccinate

d) Succinyl-CoA ( a )

Q.11 - In an anaerobic system that is metabolizing glucose as a substrate, which of the following compounds would you expect to increase in concentration following the addition of fluoride?

a) 2-phosphoglycerate

b) Glucose

c) Phosphoenolpyruvate

d) Pyruvate ( a )

Q.12 – Which of the following is a coenzyme in the reaction catalyzed by glyceraldehyde 3-phosphate dehydrogenase?

a) ATP

b) Cu²⁺

c) Heme

d) NAD⁺ ( d )

Q.13 - An enzyme used in both glycolysis and gluconeogenesis is:

a) 3-phosphoglycerate kinase.

b)Glucose 6-phosphatase.

C) Hexokinase.

d)Phosphofructokinase-1. ( a )

Q.14 – Which of the following statements about the pentose phosphate pathway is incorrect?

a) It generates 36 mol of ATP per mole of glucose consumed.

b) It generates 6 moles of CO₂for each mole of glucose consumed

c) It is a reductive pathway; it consumes NADH.

d) It provides precursors for the synthesis of nucleotides ( c )

Q.15 – Which of the following enzymes catalyzes a reaction that involves a decarboxylation reaction?

a)Pyruvate dehydrogenase

b) Isocitrate dehydrogenase

c) α-keto glutarate dehydrogenase

d all of the above ( d )

===================

Q.1 -Anaplerotic reactions are those that result in replenishing intermediates in the TCA cycle. Which of the following enzymes catalyzes an Anaplerotic reaction?

a) Malate dehydrogenase

b) Pyruvate carboxylase

c) Pyruvate kinase

d). Citrate synthase ( b )

Q.2- Which statement BEST describes the fate of Propionyl-CoA in mammalian systems?

a) Propionyl-CoA is metabolized via are action sequence that involves vitamin B12 and biotin.

b) Propionyl-CoA is converted to acetyl CoA.

c) Propionyl-CoA and acetyl CoA condense to form a 5 carbon precursor of a TCA cycle intermediate.

d) Propionyl-CoA is oxidized to Malonate and CoA ( a )

Q.3 – It is very important to feed the baby very soon after birth, because during the first few hours after birth the enzyme Phosphoenolpyruvate carboxykinase is present in very low amounts, and this fact compromises:

a) Gluconeogenesis

b) Glucose phosphorylation

c) Glycogenesis

d) Glycogenolysis ( a )

Q.4 – The citric acid cycle is inhibited by which of the following?

a) Fluoroacetate

b) Aerobic conditions

c) Malic acid

d) Fluorouracil ( a )

Q.5 – Which of the following enzymes is associated with Glycogen synthesis?

a) Amylo- (1, 4->1,6) – transglycosylase

b) Phosphorylase

c) Amylo-1,6-glucosidase

d) Glucose-6- phosphatase ( a )

Q.6 – A medical student developed hemolytic anemia after taking the oxidizing Antimalarial drug primaquine. This severe reaction is most likely due to

a) Glucose-6- phosphate dehydrogenase deficiency

b) Concomitant Scurvy

c) Diabetes

d) Glycogen phosphorylase deficiency ( a )

Q.7- Which of the following explains why individuals with hyperlipidemia should minimize their intake of sucrose and high fructose syrup?

a) Fructose metabolism is faster than glucose

b) After initial modification fructose is cleaved by a specific Enolase

c) Fructose is ultimately converted to galactose

d) Fructose can be phosphorylated by hexokinase in adipose cells ( a )

Q.8-The major glycolytic product produced under normal circumstances by erythrocytes required for unloading of oxygen to the peripheral tissues is

a) 2,3bisphosphoglycerate

b) 1,3bisphosphoglycerate

d)Lactate ( a )

c) Pyruvate

Q.9 – Poorly perfused areas exposed to chronic hypoxia have decreased metabolic energy for tissue maintenance and repair an important reason for this is-

a) Increased hexokinase activity owing to increased oxidative phosphorylation

b) Decreased ATP production and increased glucose utilization due to an aerobic mode of glycolysis

c) Increased glucose utilization by HMP pathway on changing from anaerobic to aerobic glycolysis

d) Decreased respiratory quotient on changing from carbohydrates to fats as the major fuel ( b )

Q.10 – Asians and Native Americans may flush and feel ill after drinking a small amount of ethanol in alcoholic beverages. This reaction is due to genetic variation in an enzyme that metabolizes the liver metabolite of alcohol, which is-

a) Methanol

b) Acetone

c) Acetaldehyde

d) Glycerol ( c )

Q.11 – Which one of the following enzymes catalyzes the phosphorylation of the substrate with the use of inorganic phosphate-?

a) Hexokinase

b) Phospho fructokinase

c) Glyceraldehyde-3-phosphate dehydrogenase

d) Phospho glycerate kinase ( c )

===================

Q.1 -Anaplerotic reactions are those that result in replenishing intermediates in the TCA cycle. Which of the following enzymes catalyzes an Anaplerotic reaction?

a) Malate dehydrogenase

b) Pyruvate carboxylase

c) Pyruvate kinase

d). Citrate synthase ( b )

Q.2- Which statement BEST describes the fate of Propionyl-CoA in mammalian systems?

a) Propionyl-CoA is metabolized via are action sequence that involves vitamin B12 and biotin.

b) Propionyl-CoA is converted to acetyl CoA.

c) Propionyl-CoA and acetyl CoA condense to form a 5 carbon precursor of a TCA cycle intermediate.

d) Propionyl-CoA is oxidized to Malonate and CoA ( a )

a) Gluconeogenesis

b) Glucose phosphorylation

c) Glycogenesis

d) Glycogenolysis ( a )

Q.4 – The citric acid cycle is inhibited by which of the following?

a) Fluoroacetate

b) Aerobic conditions

c) Malic acid

d) Fluorouracil ( a )

Q.5 – Which of the following enzymes is associated with Glycogen synthesis?

a) Amylo- (1, 4->1,6) – transglycosylase

b) Phosphorylase

c) Amylo-1,6-glucosidase

d) Glucose-6- phosphatase ( a )

Q.6 – A medical student developed hemolytic anemia after taking the oxidizing Antimalarial drug primaquine. This severe reaction is most likely due to

a) Glucose-6- phosphate dehydrogenase deficiency

b) Concomitant Scurvy

c) Diabetes

d) Glycogen phosphorylase deficiency ( a )

Q.7- Which of the following explains why individuals with hyperlipidemia should minimize their intake of sucrose and high fructose syrup?

a) Fructose metabolism is faster than glucose

b) After initial modification fructose is cleaved by a specific Enolase

c) Fructose is ultimately converted to galactose

d) Fructose can be phosphorylated by hexokinase in adipose cells ( a )

Q.8-The major glycolytic product produced under normal circumstances by erythrocytes required for unloading of oxygen to the peripheral tissues is

a) 2,3bisphosphoglycerate

b) 1,3bisphosphoglycerate

d)Lactate ( a )

c) Pyruvate

Q.9 – Poorly perfused areas exposed to chronic hypoxia have decreased metabolic energy for tissue maintenance and repair an important reason for this is-

a) Increased hexokinase activity owing to increased oxidative phosphorylation

b) Decreased ATP production and increased glucose utilization due to an aerobic mode of glycolysis

c) Increased glucose utilization by HMP pathway on changing from anaerobic to aerobic glycolysis

d) Decreased respiratory quotient on changing from carbohydrates to fats as the major fuel ( b )

a) Methanol

b) Acetone

c) Acetaldehyde

d) Glycerol ( c )

Q.11 – Which one of the following enzymes catalyzes the phosphorylation of the substrate with the use of inorganic phosphate-?

a) Hexokinase

b) Phospho fructokinase

c) Glyceraldehyde-3-phosphate dehydrogenase

d) Phospho glycerate kinase ( c )

=====================

Q.1-Which of the following enzymes is Thiamine dependent and essential for glucose oxidation in the brain?

a) Pyruvate dehydrogenase complex

b) Acetyl co A carboxylase

c) Transaldolase

d) Succinyl-co A Thiokinase ( a )

Q.2- The reaction catalyzed by phosphofructo kinase is -

a) Inhibited by Fructose 2,6 bisphosphate

b) Activated by high concentration of ATP

c) A regulatory step of glycolysis

d) All of the above ( c )

Q.3- Pyruvate carboxylase requires ————— as a coenzyme.

a) FMN

b) Biotin

c) NAD+

d) TPP ( b )

Q.4- In erythrocytes the most abundantly found Phospho ester is-

a) Glucose-6 phosphate

b) Fructose 1, 6 bisphosphate

c) Fructose-6- phosphate

d) 2, 3 bisphosphoglycerate ( d )

Q.5- Formation of Galactose-1-P from Galactose is catalyzed by-

a) Hexokinase

b) Aldolase

c) Galactokinase

d) Galactose-1-P Uridyl transferase ( c )

Q.6- All the following enzymes except one require NADP+ as a coenzyme-

a) Glucose- 6-phosphate dehydrogenase

b) Cytosolic Isocitrate dehydrogenase

c) Malic enzyme

d) Glucose-6-phophatase ( d )

Q.7- Which of the following product of Triglyceride breakdown and subsequent beta oxidation would undergo gluconeogenesis-

a) Propionyl Co A

b) Acetyl CoA

c) Aceto acetate

d) Beta hydroxy butyrate ( a )

Q.8 – Which of the following reactions generates ATP?

a) Glucose to Glucose -6-phosphate

b) Pyruvate to Lactate

c) Phosphoenol pyruvate to Pyruvate

d) Glucose- 6 phosphate to fructose-6 phosphate ( c )

Q.9- Glucose enters muscle cells mostly by:

a) Simple diffusion

b) Facilitated diffusion using a specific glucose transporter

c) Co-transport with sodium

d) Co-transport with amino acids ( b )

Q.10- Which one of the following compounds is common to both the oxidative phase and the non- oxidative phase of the pentose phosphate pathway?

a) Xylulose-5- phosphate

b) Glucose-6-phosphate

c) Ribulose-5-phosphate

d) Glyceraldehyde-3- phosphate ( a )

Q.11- Mc Ardle’s syndrome causes muscle cramps and muscle fatigue with increased muscle glycogen. Which of the following enzyme is deficient?

a) Hepatic hexokinase

b) Muscle Phosphorylase

c) Muscle Debranching enzyme

d) Muscle Hexokinase ( b )

Q.12- During starvation, the major source of blood glucose is-

a) Hepatic Glycogenolysis

b) Gluconeogenesis

c) Muscle Glycogenolysis

d) Dietary glucose from intestine ( b )

Q.13- Hexokinase has a considerably lower km for-

a) Glucose

b) Fructose

c) Galactose

d) Mannose ( a )

Q.14- In the fasting state there is considerable release of———–from the muscles.

a) Glycine

b) Alanine

c) Valine

d) Glutamic acid ( b )

Q.15- A galactosemic child will manifest all except-

a) Hepatomegaly

b) Splenomegaly

c) Cataract

d) Mental retardation ( b )

=================

Q1- – Which one of the following reactions is unique to gluconeogenesis-?

a) Lactate<———–>Pyruvate

b) Oxaloacetate—->Phosphoenol pyruvate

c) Glucose-6-phosphate—– >Glucose

d) Phosphoenol pyruvate–>Pyruvate ( b )

Q2- The main stores of glycogen are found in—

a) Adipose tissues

b) Skeletal muscles

c) Brain

d) Erythrocytes ( b )

Q.3- Succinyl co A is cleaved by-

a) Succinate dehydrogenase

b) Succinate Thiokinase

c) Succinate lyase

d) Succinate Thioesterase ( b )

Q.4- Arsenate binds to-

a) Free amino end of enzyme

b) SH linkages

c) Free carboxyl end

d) Any of the above ( b )

Q.5- All are intermediates of glycolysis except-

a) Glucose-6 phosphate

b) Fructose 1, 6 bisphosphate

c) Fructose-6- phosphate

d) Glycerol – 3- phosphate ( d )

Q.6- The key regulatory enzyme of HMP pathway is-

a) Glucose- 6-phosphate dehydrogenase

b) Transaldolase

c) Transketolase

d) Glucose-6-phophatase ( a )

Q.7- The net production of ATP in glycolysis during anaerobic condition is:

a) 2 from glucose and 3 from glycogen

b) 2 from glucose and 4 from glycogen

c) 3 from glucose and 4 from glycogen

d) 3 from glucose and 2 from glycogen ( a )

Q.8- Which of the followings does not generate free glucose during the enzymatic breakdown of glycogen in skeletal muscles?

a) Phosphorylase

b) α-1-6-amyloglucosidase

c) Debranching enzyme

d) glucose-6-phosphatase ( a )

Q.9- Which of the followings promotes glucose and amino acid uptake by muscle?

a) Adrenaline

b) Insulin

c) Glucagon

d) Cortisol ( b )

Q.10- In a tissue that metabolizes glucose via the pentose phosphate pathway, C-1 of glucose would be expected to end up principally in:

a) Carbon dioxide

b) Glycogen

c) Phosphoglycerate

d) Pyruvate ( a )

=====================

erial No	DNA	RNA
1.	It usually occurs inside nucleus and some cell organelles. (Mitochondria and Chloroplast in plants)	Very little RNA occurs inside the nucleus. Most of it is found in the cytoplasm.
2.	It is double stranded with exception of some viruses (e.g., Øx174)	It is single stranded with exception of some viruses (Reovirus)
3.	DNA contains over a million nucleotides	Depending on the type, RNA contains 70-12,000 nucleotides.
4.	The sugar portion of DNA is 2-deoxyribose	The sugar portion of RNA is ribose
5.	Purine and Pyrimidine bases are in equal in number	There is no proportionality in between numbers of Purine and Pyrimidine bases.
6.	The base present in DNA are adenine (A), guanine (G) ,thymine (T) and cytosine (C)	The base present in RNA are adenine (A), guanine (G) , uracil (U) and cytosine (C)
7.	Hydrogen bonds are formed between complementary nitrogen bases of the opposite strands (A-T, C-G)	Base pairing through hydrogen bonds, occurs in the coiled parts.
8.	DNA is spirally twisted to produce a regular helix.	The strand may get folded at places to produce a secondary helix or pseudohelix.
9.	It replicates to form new DNA molecules	It cannot normally replicate itself.
10.	It occurs in the form of chromatin or chromosomes.	It occurs in ribosomes or forms association with ribosomes.
11.	The function of DNA is to transfer genetic information from one generation to the next.	The function of RNA is to direct synthesis of proteins in the body.
12.	DNA transcribes genetic information to RNA. Its quantity is fixed for cell.	RNA translates the transcribed message for forming polypeptides. The quantity of RNA of a cell is variable.
13.	Renaturation after melting is slow.	It is quite fast
14.	DNA is only two types: intra nuclear and extra nuclear.	Three different types of RNA: m-RNA, t-RNA and r-RNA.
15.	It is long lived	Some RNAs are very short lived while others have somewhat longer life.

===========

1. The pentoses in nucleotides are
a) in β-furanose form
b) in α-furanose form
c) Both
d)none of the above

2. To identify self DNA from non-self DNA, the self DNA may be
a) glycosylated
b) carboxylated
c) phosphorylated
d) methylated

3. Functions of nucleotide includes
a) information storage and transmission
b) storage of chemical energy
c) cell signalling
d) All of the above

4. Choose the best option
a) proteins has catalytic activity
b) Proteins and RNA have catalytic activity
c) Proteins, RNA and antibodies have catalytic activity
d) Proteins, RNA, antibodies and phospholipids have catalytic activity

5. The backbone of DNA is
a) hydrophilic
b) hydrophobic
c) nuetral
d) Both hydrophilic and hydrophobic

6. Which is the most stable form of DNA under normal physiological conditions
a) A-DNA
b) B-DNA
c) Z-DNA
d) H-DNA

7. As far as the absorbance of DNA at 260nm. Which of the following is correct?
a) individual nucleotides>ss DNA>dsDNA
b) dsDNA>ssDNA> individual nucleotides
c) ssDNA>dsDNA> individual nucleotides
d) absorbance remains same

8. Which of the following statement is true?
a) DNA is more stable than RNA in alkaline condition because of the presence of 3’OH
b) DNA is more stable than RNA in alkaline condition because of the presence of 2’ H compared to RNAs 2’OH
c) RNA is more stable than DNA in alkaline condition because of the presence of 2’ and 3’OH compared to DNAs 2’H and 3’OH
d) Both are equally stable in alkaline condition

9. Dehydration of DNA samples may induce the formation of
a) A-DNA
b) B-DNA
c) Z-DNA
d) H-DNA

10. An increase in temperature of a DNA sample causes change in
a) absorbance at 260nm
b) viscosity
c) phosphodiester linkage
d) absorbance and viscosity

11. RNA-DNA hybrids are
a) more stable than DNA-DNA hybrid
b) more stable than RNA-RNA hybrid
c) less stable than RNA-RNA hybrid
d) less stable than RNA-RNA hybrid and DNA-DNA hybrid

12. An increase Tm (melting temperature) for a ds-DNA may be due to high content of
a) A+G
b) A+T
c) C+G
d)none of the above

13. Thymine is present in
a) prokaryotic mRNA
b) mammalian mRNA
c) ribosomal RNA
d) tRNA

14. RNA is genetic material in
a) some virusus and prokaryotes
b) some viruses only
c) some virusus, prokaryotes and some primitive eukaryotes
d) none of the above

15. DNA has
a) autocatalytic function
b) heterocatalytic function
c) both autocatalytic and heterocatalytic function
d) none of the above

Answers:
1- a) in β-furanose form (closed 5-membered ring
2- d) methylated.

3- d) All of the above

4- c) Proteins, RNA and antibodies have catalytic activity.
RNA with catalytic activity: ribozymes
Antibodies with catalytic activity-abzymes

5- a) hydrophilic. The OH group of sugar residue form H-bond with water

6- b) B-DNA

7- a) individual nucleotides>ss DNA>dsDNA

The reason for absorbance (A260 in DNA) is N2 bases. In ss DNA, N2 bases are exposed so more A260 than ds DNA. In free nucleotides, N2 bases are much more exposed and free so high A260 than ss and ds DNA.

8- b) DNA is more stable than RNA in alkaline condition because of the presence of 2’ H compared to RNAs 2’OH

9- a) A-DNA

10- d) absorbance and viscosity

11- d) less stable than RNA-RNA hybrid and DNA-DNA hybrid

12- c) C+G has three H-bonds compared to two in A=T. So more temperature is needed for denaturation.

13- d) tRNA. t RNA has thymine and many unusual bases.

14- b) some viruses only

15- c) both autocatalytic and heterocatalytic function
Autocataytic function: DNA replication
Heterocatalytisc function: directs synthesis of RNA and proteins

==================

1-Give an example of reversible denaturation

(Denaturation of Ribonuclease by urea)

2. Give example of a circular peptide.

(Gramicidin S)

3-What is the difference between Salting in and Salting out?

(Salting in is addition of a pinch of salt to increase the solubility of a protein, while salting out is addition of excess of salt to precipitate it out)

4. Name the proteins containing alpha helical structure predominantly.

(Hemoglobin, Myoglobin etc)

5. Name the super secondary structures

(Greek key, beta meanders, Beta alpha beta)

6. Name the respiratory proteins

(Hemoglobin, Myoglobin, cytochromes)

7. What is the class of Zein protein?

(Poor protein- it lacks Tryptophan and Lysine)

8. Name the contractile proteins

( Actin, Myosin, flageller proteins)

9-What are the features of isoelectric pH?

(Decrease in solubility, electric charge, Electrophoretic migration, loss of biological activity)

10-What is the basis of protein precipitation by organic solvents?

(Decrease in dielectic constant of the medium)

11-What is the difference between flocculum and coagulum?

(Flocculum is a reversible state of denaturation while coagulum is a an irreversible state of denaturation)

12-What are the forces that stabilize the alpha helical structure?

(Hydrogen and Vander waals forces mainly)

13-What is the basis of cauterization by silver nitrate during surgery to control bleeding?

(Silver nitrate is a heavy metal salt and by causing precipitation of proteins seals the oozing points of the blood vessels)

14-What is meant by a domain?

(Domain is a term used to denote a compact globular functional unit of a protein)

15-Why is Glutathione called a pseudo peptide?

(In glutathione instead of alpha carboxyl group, the gamma carboxyl participates in the peptide bond formation)

16-Covalent forces stabilize the tertiary structure in a protein- True or false?

(False- the non covalent forces stabilize the tertiary structure in a protein)

17- Which tests should be carried out for the detection of Tryptophan in a given solution?

(Xanthoproteic and Hopkins Cole test)

18- Which amino acids contribute towards ionic interactions?

(Positively charged amino acids like Arginine , Lysine and negatively charged amino acids like Aspartic acid and Glutamic acid)

19- Which protein is precipitated by full saturation with Ammonium sulphate?

(Albumin)

20- What is the relationship of amount of salt required and the molecular weight of a protein?

(More the molecular weight and lesser is the amount of salt required by the protein and vice versa)

21-What are the functions of proteins?

(Nutritive, buffering, defense, viscosity, osmotic pressure, enzymes, hormones etc)

22-Name mono amino dicarboxylic acids

(Aspartic and Glutamic acid)

23-Name heterocyclic amino acids

(Tryptophan and Histidine)

24-Name the 21st and 22 nd amino acid

(Seleno cysteine and Pyrrolysine)

25-Which amino acids are involved in forming N- Glycosidic linkages?

(Asparagine and Glutamine)

=========================

1-Name the semi essential amino acid

(Arginine and Histidine)

2-Which amino acid acts as the precursor of vitamin Niacin?

(Tryptophan)

3-Name the amino acids with a non polar side chain

(Alanine, Valine, Leucine Isoleucine, Methionine, Phenyl Alanine)

4-Which protein structure determines the relationship of amino acids which are 3-4 residues apart ?

(Tertiary structure)

5-Which test will be negative for a protein lacking tryptophan ?

(Hopkins cole test)

6-Name the essential amino acids

( Valine, Leucine, Isoleucine, lysine, Phenylalanine, Methionine and Threonine)

7-Which amino acid is optically inactive ?

(Glycine)

8-Which amino acid is abundantly present in prolamines ?

(Proline)

9-Which protein is mostly found attached to DNA?

(Histone)

10-Name the amino acids which are both glucogenic as well as ketogenic

(Isoleucine. Phenyl Alanine, Tyrosine and Tryptophan)

11-Name a specific test for the detection of alpha amino acids

(Ninhydrin test)

12-Name a specific test for the detection of cysteine

(Lead acetate test)

13-Covalent bond is formed at which level of protein’s structural organization?

(Primary structure)

14-Name the peptide hormones

(ACTH, TRH, FSH, Glucagon, PTH, ADH, Oxytocin, Secretin, Pancreozymin, Cholecystokinin)

15-What is the effect on the biological activity of a protein when exposed to UV light ?

( It will lose its biological activity since it will be denatured)

16-Give two examples of protein misfolding causing disease?

( Prion’s and Alzheimer disease)

17-What is the class of casein ?

(Class 1- complete protein)

18-What are the forces that stabilize quaternary structure of a protein ?

(Mainly non covalent)

19-Which amino acid acts as the best buffer of the plasma?

(Histidine)

20-What will be the product of decarboxylation of Tyrosine?

(Tyramine)

21-Why can’t albumin and majority proteins acquire the native configuration upon denaturation?

(Chaperones and other proteins assisting proper folding are not there)

22-What are Beta bends?

(Short loops to turn the direction of the beta sheets?

23-What are the forces that stabilize the beta bends?

(Hydrogen and electrostatic)

24-Name a peptide to regulate the volume of urine excreted?

(ADH)

25-Which protein is present in the tendons and cartilages?

(Collagen)

26-Name the storage proteins

Ferritin, ceruloplasmin)

========

1- The proteins with a carbohydrate content > 10 % are called as Mucoproteins- True or false?

(True)

2- The most abundant amino acid in keratin?

(Cysteine)

3- The most abundant amino acid in Collagen—-?

(Glycine)

4- Xanthoproteic test does not specify for—- ?

Tyrosine, Tryptophan, Serine

(Serine)

5- Give the characteristics of a peptide bond in one line-

(Rigid, partial double bond, Trans and stable)

6-Name the branched chain amino acids

(Valine, Leucine, iso Leucine)

7-Choose the hydrophobic amino acid out of the followings-

Aspartic acid, Arginine, Serine, Isoleucine

(Isoleucine)

8-Which amino acid acts as Methyl group donor?

(Methionine)

9- What is the difference between Deamination and Transamination?

(Deamination is the removal of amino group of the amino acid while Transamination is the transfer of amino group from one donor amino acid to an acceptor keto acid for the formation of a new amino acid)

10- Out of the 20 amino acids which amino acids participate in the formation of phosphoproteins

(Serine and Threonine)

11- Formation of carbamino compound for the transportation of carbon dioxide is a property of amino group, carboxyl group or both groups?

(Amino group)

12- Hopkins Cole test is a confirmatory test for which amino acid?

(Tryptophan)

13- How many peptide bonds are there in a tripeptide?

(Two)

14- The alpha helix is right or left handed?

(Right handed)

15- What is the direction of hydrogen bonds in the beta pleated sheet structure?

(Perpendicular to the axis)

16-What is the direction of beta pleated sheets in flavodoxin?

(Parallel)

17-Name the most abundant protein in mammals

(Collagen)

18-Name a defect in the primary structure responsible for the causation of a disease

(Sickle cell disease)

19-What is the defect in Alzheimer disease?

(Protein misfolding leading to formation of insoluble protein aggregates)

20-What is the isoelectric p H of casein?

(4.6)

21- What is the effect on the solubility of a protein upon denaturation?

(Solubility decreases upon denaturation)

22- Name the lipo proteins of biological significance

(Chylomicrons, VLDL, LDL, HDL)

23- Which amino acid is lacking in cereals?

(Cereals lack Lysine)

24- Which amino acid forms disulphide linkages between two polypeptide chains in oligomeric proteins?

(Cysteine)

25- Which peptide is used in clinical practice to induce uterine contractions?

(Oxytocin)

==============================

1- What is the nature of a prosthetic group in a lipoprotein?

(Lipoprotein is a conjugated protein with lipid as a prosthetic group)

2- What is the significance of Sakaguchi test?

(This test is undertaken for the detection of Arginine)

3- What is the distance traveled per turn in an alpha helix?

(0-54 nm)

4- Name an imino acid.

(Proline, hydroxy proline)

5-Choose the chromo protein out of the followings-

Collagen, Keratin, hemoglobin

(Hemoglobin)

6-Carbonic anhydrase is an example of simple or conjugated protein?

(It is a conjugated protein, with metal as th prosthetic group)

7- Name a peptide which acts as an artificial sweetener.

(Aspartame)

8- Name the agents which can bring about denaturation of proteins

(Heat, acids, alkalis, heavy metal salt, UV light, vigorous shaking etc)

9- Name a tripeptide which acts a reducing agent in the tissues.

(Glutathione)

10- Name a peptide which acts as vasoconstrictor

(Angiotensin-II)

11- Name the amino acid which is deficient in pulses

(Methionine)

12- Choose the odd one out- Collagen, Elastin, Keratin, Histones

(Histones- The rest three are scleroproteins)

13- Name two nano peptides

(Oxytocin, Vasopressin)

14- Name two globular proteins

(Hemoglobin, Myoglobin)

15-Which test should be undertaken for the detection of cysteine in a protein solution?

(Lead acetate test)

16-What is the nature of peptide bond- Single, double or partial double bond ?

(Partial double bond)

17- Out of all the primary amino acids which amino acid gives yellow color on Ninhydrin test?

(Proline and hydroxy proline )

18- Histamine is formed from Histidine by-

Deamination, decarboxylation or transamination

(Decarboxylation)

19- Name two non alpha amino acid

(GABA, beta Alanine, Delta amino Levulinic acid)

20- Choose the odd one out-

Aspartic acid, lysine, Arginine, Cysteine

(Cysteine- Amino acid with uncharged side chain at physiological p H

21- Choose the odd one out-

Tyrosine, Tryptophan, Threonine

(Tyrosine- non essential Amino acid from the nutritional perspective or threonine if considered non aromatic amino acid)

22- Name a purely ketogenic amino acid

(Leucine)

23- Name a peptide used as an anticancer drug

(Bleomycin)

24- Name the defense proteins

(Complement, immunoglobulin)

25- Choose the odd one out- Silk fibroin, Hemoglobin, Carbonic anhydrase

(Hemoglobin- The rest are proteins with beta pleated sheet

=============

1. Why are amino acids called as Amino acids?

(Since they have an amino group and an acid group i.e. Carboxyl group which is ionized at the physiological p H and behaves as a proton donor and is thus an acid)

2- What is meant by primary amino acids?

(Those amino acids which have a genetic information on the DNA for their synthesis are called as Primary or standard amino acids)

3- What is the linkage between the amino acids in a peptide?

(The amino acids are linked together by a peptide bond which is an anhydrous linkage between the amino acids)

4- Name the amino acids which are derived or modified after translation but are not incorporated in to the tissue proteins.

(Homocysteine, GABA, Argino succinic acid, Ornithine, Citrulline, etc)

5- Define Denaturation

( It is the loss of secondary , tertiary or quaternary structure( if present ) of a protein on exposure to heat, UV light, acids, alkalies, heavy metal salts or even by vigorous shaking, the primary structure is left intact)

6-What is meant by a complete protein, give an example of a complete protein?

( A Complete protein contains all the essential amino acids in an appropriate amount required for growth, repair and maintenance of body weight. Example -Egg protein)

7- Give an example of a protein with axial ratios >10:1

(Fibrinogen, keratin, collagen )

8-How many amino acids can be accommodated in one turn of alpha helix?

(3.4 amino acids)

9- What are chaperones?

(These are the proteins which participate in the proper folding of the proteins)

10- What is the defect in “transmissible spongiform encephalopathies’?

(These are included under the category of Prion’s diseases and are fatal neurodegenerative diseases characterized by spongiform changes, astrocytic gliomas, and neuronal loss resulting from the deposition of insoluble protein aggregates in neural cells. The protein aggregates are formed of misfolded proteins.)

11-What is the difference between a homodimer and a heterodimer?

(Homodimer contains two copies of the same polypeptide chain, while in a heterodimer the polypeptides differ)

12-What are amphipathic helices?

(The alpha helices having predominantly hydrophobic R groups on one side of the axis of the helix and predominantly hydrophilic ones on the other side are called amphipathic helices)

13-All the amino acids except——- have a chiral centre.

(Glycine)

14-What is meant by isoelectric p H ?

( It is the p H at which amino acid carries no net electrical charge)

15-Proteins contain only D-amino acids, for which a left handed alpha helix is by far the more stable, thus only left-handed helices are present in proteins. True or false?

(False –Proteins contain only L-amino acids, for which a right-handed alpha helix is by far the most stable, and only right-handed alpha helices are present in proteins)

16-Give examples of metalloproteins-

( Alcohol dehydrogenase, glutamate dehydrogenase, Xanthine oxidase etc. are the examples of metalloproteins

17-Give examples of non standard amino acids which are incorporated in to tissue proteins.

( Hydroxy proline, hydroxy lysine )

18– What is meant by zwitterion ?

( It is the form of amino acid present at its isoelectric p H, both positive and negative charges are there but the net charge is zero)

19-Name an indole ring containing amino acid-

(Tryptophan

20- Name the peptides which act as gastro intestinal hormones-

( Secretin, pancreozymin and cholecystokinin)

21- Name the amide group containing amino acids

(Asparagine, Glutamine)

22- What are derived proteins ?

(Proteoses, peptones and peptides etc, the product of digestion and denaturation are called as derived proteins )

23- Give two examples of antibiotic peptides

(Polymyxin, Penicillin, etc )

24-What is the difference between cysteine and cystine ?

( Two cystine residues are joined together by a disulfide bridge to from cystine )

25- What are histones?

( Histones are simple proteins which can bind with DNA to form nucleoproteins, generally they are rich in basic amino acids like Arginine and lysine )

--======================

1- Which amino acid disrupts the alpha helical structure of the proteins ?

( Proline and hydroxy proline )

2- Name the components of Glutathione

(Glutamic acid, cysteine and glycine )

3- Name two proteins with a quaternary structure

( Immuno globulins, Hemoglobin, CPK , LDH etc )

4- What are brain peptides ?

( Met encephalin and Leuencephalin)

5- Name a Phospho protein

(Casein, Ovovitellin)

6-What is the product formed after decarboxylation of an amino acid ?

( Amines are formed after decarboxylation of amino acids- like Tryptamine, histamine Tyramine etc)

7-Name the sulphur-containing amino acids-

(Cysteine, cystine and Methionine)

8-Choose the aromatic amino acid out of the following-

Arginine, Histidine, lysine and Tyrosine —— (Tyrosine)

9-Choose an amino acid that does not participate in the alpha helical formation-

Methionine, tryptophan, serine, cysteine——

( Tryptophan )

10- Millon’s reaction is specific for——- ?

( Tyrosine )

11- Out of the followings which amino acid is not present in the proteins?

β- Alanine, Histidine, Glycine

(β- Alanine)

12- Name a peptide which acts as a smooth muscle relaxant

( Bradykinin)

13- What is the nature of prosthetic group in Ceruloplasmin ?

(Copper- It is metalloprotein)

14- What is a nutritionally poor protein ?Give an example-

( A protein which lacks many essential amino acids is called a poor protein, E.g.- Gelatin

15- Which protein is abundantly present in hair?

(Keratin )

16-What is the significance of Biuret test?

( It is for the detection of proteins and peptides. Dipeptides and amino acids do not give this test positive, more than two peptide bonds are required for this test to be positive )

17- What is the nature of casein, the milk protein?

( It is a Phospho protein- A conjugated protein)

18- What is the axial ratio in fibrous proteins?

( > 10:1)

19- In proteins the alpha helical and beta pleated sheet structures are examples of-

Primary, secondary or tertiary structure ?

( Secondary)

20- Name an Imidazole ring containing amino acid

(Histidine)

21- Name a peptide hormone which prevents diuresis –

( ADH)

22 What is the basis of using raw egg for heavy metal poisoning ?

( Egg protein binds with heavy metal to form metal proteinate complex, which is water-soluble and is excretable, else heavy protein binds with tissue proteins to cause damage)

23- The tertiary structure of a protein describes sequence of amino acids- true or false ?

( False- Tertiary structure describes the folding of the protein )

24- Give two examples of haemoproteins.

(Hemoglobin, Myoglobin, Cytochromes, Catalase, Peroxidase and Tryptophan Pyrrolase)

25- In a protein the disulphide bridges can be broken by–

( Reduction )

====================

1. Aminoacids are
a) building blocks of carbohydrates
b) building blocks of nucleic acids
c) building blocks of lipids
d) building blocks of proteins

2. Amino acids has
a) both amino group and carboxyl group
b) both amino group and keto group
c) amino group only
d) carboxyl group only

3. The simplest amino acid is
a) Proline
b) methionine
c) glycine
d) serine

4. Which of the following amino acid is a ‘α-helix terminator’
a) tryptophan
b) phenyl alnine
c) tyrosine
d) proline

5. The first amino acid in a polypeptide chain is
a) Serine
b) Valine
c) Alanine
d) Methionine

6. Which of the following amino acid has buffering capacity
a) Tryptophan
b) cysteine
c) histidine
d) arginine

7. Which of the following is an α imino acid
a) serene
b) threonine
c) valine
d) proline

8. The naturally occurring form of amino acid in proteins
a) L-amino acids only
b) D-amino acids only
c) both L and D amino acids
d) none of these

9. Sulphur containing amino acids are
a) Cysteine and methionine
b) Methionine and threonine
c) Cysteine and threonine
d) Cysteine and serine

10. Aromatic amino acids include
a) Phenylalanine, tyrosine and tryptophan
b) Phenylalanine, serine and tryptophan
c) Threonine, tyrosine and tryptophan
d) Asparagine, tyrosine and tryptophan

11. Positively charged basic amino acids are
a) Lysine and arginine
b) Lysine and asparagine
c) Glutamine and arginine
d) Lysine and glutamine

12. Acidic amino acids include
a) Arginine and glutamate
b) Aspartate and asparagine
c) Aspartate and lysine
d) Aspartate and glutamate

13. Amino acids with hydroxyl groups are
a) serine and alanine
b) Alanine and valine
c) serine and threonine
d) Valine and isoleucine

14. The 21st amino acid is
a) hydroxy lysine
b) hydroxyl proline
c) selenocysteine
d) citrulline

15. Absorbance at 280nm exhibited by protein is due to
a) aliphatic amino acids
b) all amino acids
c) Non-polar amino acids
d) aromatic amino acids

Answers

1-d	2-a	3-c	4-d	5-d
6-c	7-d	8-a	9-a	10-a
11-a	12-d	13-c	14-c	15-d

================

1. The repeating units of proteins are
a) glucose units
b) amino acids
c) fatty acids
d) peptides

2. Amino acids are joined by
a) peptide bond
b) hydrogen bond
c) ionic bond
d) glycosidic bond

3. The primary structure of protein represents

a) Linear sequence of amino acids joined by peptide bond
b) 3-dimensional structure of protein
c) helical structure of protein
d) sub unit structure of protein

4. Peptide bond is

Peptide Bond
a) rigid with partial double bond character
b) planar, covalent
c) covalent
d) all of the above

5. Enzymes are
a) proteins
b) carbohydrates
c) nucleic acids
d) DNA molecule

6. The first protein sequenced by Frederick Sanger is
a) Haemoglobin
b) myoglobin
c) insulin
d) myosin

7. A dipeptide has
a) 2 amino acids and 3 peptide bonds
b) 2 amino acids and 2 peptide bonds
c) 3 amino acids and 3 peptide bonds
d) 2 amino acids and 4 peptide bonds

8. The most common secondary structure is
a) α-helix
b) β-pleated sheet
c) β-pleated sheet parallel
d) β-pleated sheet non parallel

9. Myoglobin is a
a) protein with primary structure
b) protein with secondary structure
c) protein with tertiary structure
d) protein with quaternery structure

10. Fibrous protein such as silk fibroin consists of polypeptide chains arranged in
a) α-helix
b) β-pleated sheet
c) β-helix
d) none of these

11. α-helix has
a) 3.4 amino acid residues/turn
b) 3.6 amino acid residues/turn
c) 3.8 amino acid residues/turn
d) 3.0 amino acid residues/turn

12. Tertiary structure is maintained by
a) peptide bond
b) hydrogen bond
c) di-sulphide bond
d) all of the above

13. Haemoglobin has

Hemoglobin
a) primary structure
b) secondary structure
c) tertiary structure
d) quaternery structure

14. Disulphide bonds are formed between
a) cysteine residues that are close together
b) cystine residues that are close together
c) proline residues that are close together
d) histidine residues that are close together

15. The 3-D structure of protein can be determined by
a) Nuclear magnetic resonance
b) X-ray crystallography
c) both a and b
d) Spectroscopy

Answers

1-b	2-a	3-a	4-d	5-a
6-c	7-a	8-a	9-c	10-b
11-b	12-d	13-d	14-a	15-c

================

1. The most abundant bio molecule on the earth
a) Nucleic acids
b) proteins
c) lipids
d) carbohydrates

2. The major functions of carbohydrates include
a) structural framework
b) storage
c) both a and b
d) none of these

3. The general formula of carbohydrate is
a) (CH2O)n
b) (C4H2O)n
c) (C6H2O)n
d) (C2H2O)n COOH

4. Carbohydrates are
a) polyhydroxy aldehydes and phenols
b) polyhydroxy aldehydes and ketones
c) polyhydroxy ketones and phenols
d) polyhydroxy phenols and alcohols

5. Structural polysaccharides include
a) cellulose, hemicellulose and chitin
b) cellulose, starch and chitin
c) cellulose, starch and glycogen
d) cellulose, glycogen and chitin

6. Nutritional polysaccharides are
a) starch and glycogen
b) starch and chitin
c) starch and cellulose
d) starch and glucose

7. Glycogen in animals are stored in
a) liver and spleen
b) liver and muscles
c) liver and bile
d) liver and adipose tissue

8. Carbohydrates accounts
a) 30% in plants and 20% in animals
b) 30% in plants and 10% in animals
c) 30% in plants and 1% in animals
d) 50% in plants and 50% in animals

9. Smallest carbohydrates are trioses. Which of the following is a triose?
a) glucose
b) ribulose
c) ribose
d) glyceraldehyde

10. Which of the following is a reducing sugar
a) glucose
b) dihydroxyacetone
c) erythulose
d) none of these

11. Oligosaccharides linked to proteins are called
a) glycoproteins
b) glycolipids
c) galactosides
d) ganglioside

12. In polysaccharides, monosaccharaides are joined by
a) peptide bond
b) glucose bond
c) glycosidic bond
d) covalent bond

13. Sucrose is a
a) monosaccharide
b) disaccharide
c) polysaccharide
d) triose

14. Lactose is a disaccharide consists of
a) glucose and fructose
b) glucose and galactose
c) glucose and sucrose
d) glucose and ribose

15. In lactose, the linkage is
a) β-1-4 linkage
b) β-1-2 linkage
c) α-1-4 linkage
d) α-1-2 linkage

15. Maltose is a disaccharide consists of

a) glucose and fructose
b) glucose and galactose
c) glucose and sucrose
d) glucose and glucose

16. In maltose, the linkage is
a) β-1-4 linkage
b) β-1-2 linkage
c) α-1-4 linkage
d) α-1-2 linkage

17. Starch consists of
a) unbranched amylose and branched amylopectin
b) branched amylose and branched amylopectin
c) unbranched amylose and unbranched amylopectin
d) none of these

18. Cellulose is made up of repeating units of
a) β-1-4 linkage between D-glucose units
b) β-1-2 linkage between D-glucose units
c) α-1-4 linkage between D-glucose units
d) α-1-2 linkage between D-glucose units

19. Amylopectin has
a) β-1-4 and β-1-6 linkage
b) β-1-2 linkage
c) α-1-4 and α-1-6 linkage
d) α-1-2 linkage

20. Chitin consists of
a) N-acetyl muramic acid
b) N-acetyl glucosamine
c) D-glucose units
d) N-acetyl muramic acid and N-acetyl glucosamine

Answers

1-d	2-c	3-a	4-b	5-a
6-a	7-a	8-c	9-d	10-a
11-a	12-c	13-b	14-b	15-d
16-c	17-a	18-a	19-c	20-b

=========

1. Enzymes are basically made of
a)Nucleic acids b)proteins c)Fats d)Vitamins

2. A nucleoside is formed of
a)Pentose sugar, phosphate and nitrogen base b)Phosphate and nitrogen base c)Pentose sugar and phosphate d)Pentose sugar and nitrogen base

3. Which one contains four pyrimidine bases?
a)GATCAATGC b)GCUAGACAA c)UAGCGGUAA d)TGCCTAACG

4. Feedback inhibition of enzyme is influenced by
a)Enzyme b)External factors c)End product d)Substrate

5. Key and lock hypothesis of enzyme action was given by
a)Fischer b)Koshland c)Buchner d)Kuhne

6. Sweetest sugar is
a)Fructose b)Glucose c)Mannose d)Lactose

7. Water is important for the functioning of body as
a)It releases energy b)Provides H+ ions c)Kills microorganisms d)It is a very good solvent

8. ATP is
a)Adenosine D-ribose triphosphate b)Adenosine L-ribose triphosphate c)Adenine D-ribose triphosphate d)Adenine L-ribose triphosphate

9. The following molecule is

a)Galactose b)Glucose c)Fructose d)Lactose

10. Lipids are insoluble in water as they are
a)Hydrophilic b)Hydrophobic c)Zwitter ions d)Neutral

Answer

1b,2d,3a,4c,5a,6a,7d,8c,9a,10b

==============================

1. The simplest amino acid is
a)Glycine b)Lysine c)Tyrosine d)Aspartic acid

2. A source of maximum energy is
a)Carbohydrate b)Fat c)Protein d)Vitamins

3. Besides nucleus, DNA is also present in
a)Mitochondria b)Lysosomes c)Golgi apparatus d)Ribosomes

4. Purines of RNA are
a)Guanine and adenine b)Uracil and thymine c)Adenine and cytosine d)Uracil and guanine

5. Structure of DNA was given by
a)Kornberg b)Nirenberg c)Watson and Crick d)Holley and Nirenberg

6. Cellulose is
a)Hexosan polysaccharide b)Pentosan polysaccharide c)Heptopolysaccharide d)Heteropolysaccharide

7. Proteins were named by
a)Berzelius b)Sanger c)Fleming d)Dujardin

8. Purine bases of DNA are
a)A and G b)A and C c)C and T d)A and U

9. Bond present between two nucleotides of a polynucleotide is
a)Covalent bond b)Hydrogen bond c)Phosphodiester bond d)high energy phosphate bond

10. The protein part of enzyme is
a)Prosthetic group b)Apoenzyme c)Holoenzyme d)Zymogen

Answer

1a,2b,3a,4a,5c,6a,7a,8a,9c,10b

===============

1: Water molecule has characteristics of
(A) Acid
(B) Base
(C) Both acid and base
(D) None of these

2: The amount of heat must be absorbed or lost by 1g of that substance to change its temperature by 1 C°
(A) Specific heat
(B) Heat of vaporization
(C) Both A and B
(D) None of these

3: During the conversion of ATP into ADP __________ energy is released.
(A) 31.81 KJ / mole
(B) 7.3 K.Cal / mole
(C) 61.8 KJ / mole
(D) Both A and B.

4: Molecular formula of Stearin fat is
(A) C57 H110 O6
(B) C57 H98 O6
(C) C57 H104 O8
(D) C57 H104 O6

5: The carbohydrate molecule which yield 2 to 10 monosaccharide molecules on hydrolysis are
(A) Polysaccharides
(B) Oligosaccharides
(C) Monosaccharides
(D) Heterosaccharides

6: It is estimated that a person of average size contains 16 Kg of fat which is equivalent to
(A) 244000 K.Cal of energy
(B) 164000 K.Cal of energy
(C) 144000 K.Cal of energy
(D) 188000 K.Cal of energy

7: The four interconnected rings of steroid molecule have total
(A) 12 carbon
(B) 15 carbon
(C) 16 carbon
(D) 17 carbon

8: ATP is an example of
A) Mononucleotide
(B) Dinucleotide
(C) Polynucleotide
(D) None of these

9: The process of making a polypeptide sequence from the genetic code of mRNA molecule associated with a ribosomes termed as
(A) Transduction
(B) Translation
(C) Transformation
(D) Transcription

10: NAD is an example of
(A) Mononucleotide
(B) Dinucleotide
(C) Coenzyme
(D) Both B and C

Answer
1. C, 2. A, 3. D, 4. A, 5. B, 6. C, 7. D, 8. A, 9. B, 10. D

========================

1: Waxes from protective coating on
(A) Leaves
(B) Fruits
(C) Animal’s skin
(D) All of these

2: The four nitrogenous bases which form the code words for DNA language are
(A) ACTU
(B) UTAC
(C) AGTU
(D) AGCT

3: DNA and RNA differ in
(A) Sugar only
(B) Sugar and purines
(C) Sugar and pyrimindines
(D) Sugar & phosphate

4: A bond formed between carboxylic acid and alcohol is
(A) Ester bond
(B) Amide bond
(C) Phosphate bond
(D) Ionic bond

5: When amino acids in a polypeptide chain are arranged in spiral manner, it is called
(A) Primary structure
(B) Secondary structure
(C) Tertiary structure
(D) Quaternary structure

6: The step of protein synthesis in which the information contained specific segment of DNA is copied into RNA is called
(A) Transduction
(B) Translation
(C) Transformation
(D) Transcription

7: Choose the pair of terms that completes this sentence
Nucleotides are to __________as ____________ are proteins.
(A) Aminoacids______Polypeptides
(B) Genes _______ Enzymes
(C) Nucleic acids _____ Amino acids
(D) Polymers _____ Peptides

8: Which of these terms includes all others in the list
(A) Nucleic acid
(B) Purine
(C) Nucleotide
(D) Nitrogenous base

9 The compounds made up of simple repeating isoprenoid units are called
(A) Neutral lipids
(B) Terpenoids
(C) Waxes
(D) All of these

10: The term Protein was coined by
(A) Berzelius
(B) G.J. Murlder
(C) Bloor
(D) T.H. Morgan

Answer
1. D,2. D,3. C,4. A,5. B,6. D,7. C,8. A,9. B,10. A,

===============

1: Which of these is NOT a function of lipids?
(A) Long term energy storage
(B) Structures in cells
(C) Sex hormones
(D) Enzymes

2: All living things use the same ___ amino acids.
(A) 4
(B) 20
(C) 100
(D) 64

3: Which of these is NOT a nucleotide base found in DNA?
(A) Uracil
(B) Adenine
(C) Guanine;
(D) Thymine

4: ATP consists of the ____________________, ribose sugar, , and phosphate group, PO4-2) plus two otherphosphate groups.
(A) Cytosine base
(B) Guanine base
(C) Thymine base
(D) Adenine base

5: Membrane carbohydrates when linked to lipids are called
(A) Sphingolipids
(B) Glycolipids
(C) Phospholipids
(D) Sterols

6: Lactose is present in
(A) Sugar cane
(B) Fruits
(C) Milk
(D) Egg

7: A disaccharide that gives two molecules of glucose on hydrolysis is
(A) Sucrose
(B) Lactose
(C) Maltose
(D) None of these

8: In sugar cane and sugar beet, the storage product is
(A) Maltose
(B) Sucrose
(C) Lactose
(D) Isomaltose

9: One molecule of glucose and one molecule of galactose form
(A) Maltose
(B) Sucrose
(C) Lactose
(D) Isomaltose

10: Nucleic acids are related with
(A) Respiration
(B) Photosynthesis
(C) Heredity
(D) None of these

Answer
1. D,2. B,3. A,4. D,5. B,6. C,7. C,8. B,9. C,10. C

=================

1: It is an animal storage product that accumulates in the vertebrate liver and muscles.
(A) Cellulose
(B) Chitin
(C) Glycogen
(D) Fructose

2: Asymmetrical lipid molecules with a hydrophilic head and a hydrophobic tail, with a phosphate group in place of one of the three fatty acid chains.
(A) Wax
(B) Terpenoid
(C) Steroid
(D) Phospholipid

3: Triglycerides that are solid at room temperature.
(A) Fats
(B) Oils
(C) Linoleic acid
(D) None of these

4: Triglycerides that are liquid at room temperature.
(A) Fats
(B) Oils
(C) Stearin
(D) All of these

5: A chemical group composed of a central phosphorous bonded to four oxygen.
(A) Carbonyl group
(B) Sulfhydryl group
(C) Carboxylic
(D) Phosphate group

6: Nucleic acids are polymers composed of monomer units known as
(A) Amino acids
(B) Nucleosides
(C) Nucleotides
(D) Nitrogenous bases

7: There are __________ nitrogenous bases.
(A) Four
(B) Five
(C) Six
(D) Three

8: The form of RNA that delivers information from DNA to be used in making a protein is _______________.
(A) messenger RNA
(B) ribosomal RNA
(C) transfer RNA

9: RNA occurs in
(A) Nucleus
(B) Cytoplasm
(C) Both A and B
(D) Nucleoplam

10: The monomer that makes up polysaccharides is
(A) Amino acids
(B) Glucose
(C) Fatty acids
(D) Glycerol

Answer
1. C,2. D,3. A,4. B,5. D,6. C,7. B,8. A,9. C,10. B

===========

1: At about 0 C, most enzymes are

(A) Inactive
(B) Active
(C) Destroyed
(D) Replicated

2: Vitamins are essential to the survival of organisms because vitamins usually function as

(A) Substrates
(B) Nucleic acids
(C) Co-enzymes
(D) Nucleosides

3:When a molecule binds to an area of an enzyme that is not the active site, and changes the shape of the enzyme so that it no longer can work, this is called

(A) denaturation
(B) competitive inhibition
(C) noncompetitive inhibition
(D) substrate delocation

4: What is a coenzyme?

(A) Inorganic ion
(B) Organic molecule
(C) Both A and B
(D) None of these

5: Which statement best expresses the information represented in the graph shown?

(A) The action of enzymes varies with pH
(B) A pH of 7 provides the optimum environment for digestive enzymes
(C) Gastric juice is active at a pH extending from 0 to 12
(D) Acids have a pH greater than 7

6: Which type of inhibitor is shown in this diagram?

(A) Competitive
(B) Non-competitive
(C) Allosteric
(D) Both B and C

7: Which enzyme represents an enzyme functioning in this reaction?

(A) E
(B) C
(C) B
(D) A

Answer key

1.A, 2.C, 3.C, 4.B, 5.A, 6.D, 7.C

======================

1: What is a cofactor?

(A) Inorganic ions
(B) Organic molecules
(C) Both a and b
(D) None of the above

2: Mg+2 is an inorganic activator for the enzyme

(A) Phosophatase
(B) Carbonic anhydrase
(C) Enterokinase
(D) Amylase

3: Zn+2 is an inorganic activator for enzyme.

(A) Carbonic anhydrase
(B) Phosophatase
(C) Chymotrypsin
(D) Maltase

4: Which antibiotic blocks the active site of an enzyme that many bacteria used to make cell-walls.

(A) Amphotericin
(B) Gentamicin
(C) Penicillin
(D) Cephalosporin

5: DDT and Parathion are inhibitors of key enzymes in

(A) Nervous system
(B) Respiratory system
(C) Digestive system
(D) Circulatory system

6: At high temperature the rate of enzyme action decreases because the increased heat

(A) Changes the pH of the system
(B) Alters the active site of the enzyme
(C) Neutralize acids and bases in the system
(D) Increases the concentration of enzymes

7: Which of the following enzymes would digest a fat?

(A) sucrase
(B) protease
(C) Ligase
(D) lipase

8: In the Lock and Key model of enzyme action, the part of the enzyme that recognizes the substrate is known as the

(A) Enzyme-substrate complex
(B) Product
(C) Enzyme-product complex
(D) Active site

9: Which model of enzyme action is represented in this diagram.

(A) Fluid mosaic model
(B) Induce fit model
(C) Lock and key model
(D) Reflective index model

10: A certain enzyme will hydrolyze egg white but not starch. Which statement best explains this observation?

(A) Starch molecules are too large to be hydrolyzed
(B) Enzyme molecules are specific in their actions
(C) Egg white acts as a coenzyme for hydrolysis
(D) Starch is composed of amino acids.

Answer key

1.C, 2.A, 3.A, 4.C, 5.A, 6.B, 7.D, 8.D, 9.C, 10.B

===========

1: Which one is not attribute of enzyme

(A) Specific in nature
(B) Protein in chemistry
(C) Consumed in reaction
(D) Increases rate of reaction

2: Which one inactivates an enzyme by indirectly changing the shape of the active site of an enzyme

(A) Non-competitive inhibitor
(B) Competitive inhibitor
(C) Coenzyme
(D) Activator

3: The enzymes are classified into

(A) Five groups
(B) Three groups
(C) Six groups
(D) Four groups

4: Non-proteinaceous part of holoenzyme is

(A) Prosthetic group
(B) Apoenzyme
(C) Tubulin
(D) None of these

5: Enymes are highly specific for a given substrate which is due to the shape of their

(A) Active site
(B) Allosteric site
(C) Non-competitive site
(D) None of these

6: The name enzyme was suggested in 1878 by the German physiologist

(A) Wilhelm Kuhne
(B) Koshland
(C) Fischer
(D) Paul Filder

7: Proteinaceous part of holoenzyme is

(A) Prosthetic group
(B) Apoenzyme
(C) Lecithin
(D) None of these

8: The “lock and key hypothesis” attempts to explain the mechanism of

(A) vacuole formation
(B) pinocytosis
(C) sharing of electrons
(D) enzyme specificity

9: An enzyme that hydrolyzes protein will not act upon starch. This fact is an indication that enzymes are

(A) hydrolytic
(B) specific
(C) catalytic
(D) synthetic

10: The site where enzyme catalyzed reaction takes place is called?

(A) Active site
(B) Allosteric site
(C) Denatures site
(D) Dead Site

Answer key

1.C, 2.A, 3.C, 4.A, 5.A, 6.A, 7.B, 8.D, 9.B, 10.A

==============

1: A catalyst is a chemical involved in, but not ____________ by, a chemical reaction.

(A) Supported
(B) Changed
(C) Controlled
(D) All of these

2: Many enzymes function by __________________ the activation energy of reactions.

(A) Increasing
(B) Promoting
(C) Lowering
(D) Both A and B

3: An uncatalysed reaction requires a

(A) Higher activation energy
(B) Lower activation energy
(C) Balanced activation energy
(D) All of these

4: It suggests that the binding of the substrate to the enzyme alters the structure of the enzyme, placing some strain on the substrate and further facilitating the reaction.

(A) Lock and Key hypothesis
(B) Induced fit hypothesis
(C) Fischer’s hypothesis
(D) D.D. Wood’s hypothesis

5: They are non-protein organic molecules bound to enzymes near the active site.

(A) Activators
(B) Coenzymes
(C) Holoenzymes
(D) All of these

6: The first step in any reaction catalysed by an enzyme is the formation of a specific association between the molecules called an

(A) Enzyme-product complex
(B) Enzyme-intermediate complex
(C) Enzyme-substrate complex
(D) None of these

7: The function of competitive inhibitors is defined by their ability to interact or bind to

(A) The active site of an enzyme
(B) Regulatory sub-units of an enzyme
(C) Non-competitive inhibitor
(D) Enzyme cofactors

8: If an enzyme solution is saturated with substrate, the most effective way to obtain an even faster yield of products would be

(A) Add more of the enzymes
(B) Add more substrate
(C) Add an allosteric inhibitor
(D) Add a non-competitive inhibitor

9: During _____________ the final product of a metabolic pathway turn off the first step of metabolic pathway.

(A) Positive feed back
(B) Negative feed back
(C) Competitive feed back
(D) Both A and C

10: _____________ occurs when the inhibitory chemical, which does not have to resemble the substrate, binds to the enzyme other than at the active site.

(A) Noncompetitive Inhibition
(B) Competitive Inhibition
(C) Uncatalysed reaction
(D) All A, B and C

Answer Key

1.B, 2.C, 3.A, 4.B, 5.B, 6.C, 7.A, 8.A, 9.B, 10.A

=======================

1: The enzyme minus its coenzyme is referred to as the

(A) Iso-enzyme
(B) Metalloenzyme
(C) Apoenzyme
(D) All of these

2: The “lock and key” model of enzyme action illustrates that a particular enzyme molecule

(A) forms a permanent enzyme-substrate complex
(B) may be destroyed and resynthesized several times
(C) interacts with a specific type of substrate molecule
(D) reacts at identical rates under all conditions

3: Consider this reaction. A + B –> C + D + energy.

(A) This reaction is exergonic
(B) An enzyme could still speed the reaction
(C) A and B are reactants; C and D are products
(D) All of these are correct

4: An inhibitor that changes the overall shape and chemistry of an enzyme is known as a(n)

(A) Auto-steric inhibitor
(B) Competitive inhibitor
(C) Steric inhibitor
(D) Noncompetitive inhibitor

5: Non-protein components of enzymes are known as

(A) Coenzymes
(B) Activators
(C) Cofactors
(D) All A, B, and C

6: The reaction below occurs within the cells to prevent the accumulation of hydrogen peroxide. In this reaction, catalase functions as an

(A) Enzyme in the breakdown of hydrogen peroxide
(B) Enzyme in the synthesis of hydrogen peroxide
(C) Emulsifier in the digestion of hydrogen peroxide
(D) Indicator in the detection of hydrogen peroxide

7: An enzyme is generally named by adding ________ to the end of the name of the ____________.

(A) “-ase”. coenzyme
(B) “-ase”. cell in which it is found
(C) “-ose”. substrate .
(D) “-ase”. substrate

8: The minimum amount of energy needed for a process to occur is called the

(A) Minimal energy theory
(B) Process energy
(C) Kinetic energy
(D) Activation energy

9: A student conducts an experiment to test the efficiency of a certain enzyme. Which would probably not result in a change in the enzyme’s efficiency?

(A) Adding an acidic solution to the setup
(B) Adding more substrate but not enzyme
(C) Increasing temperature of solution
(D)All a, b, & c change enzyme’s efficiency

10: Enzymes function as

(A) Organic catalysts
(B) Inorganic catalysts
(C) Inhibitors
(D) All of these

Answer

1.C, 2.C, 3.D, 4.D, 5.D, 6.A, 7.D, 8.D, 9.D, 10.A

=================

Q:1: The catalytic activity of an enzyme is restricted to its small portion called

(A) Active site
(B) Passive site
(C) Allosteric site
(D) All Choices are correct

Q:2: An activated enzyme made of polypeptide chain and a co-factor is

(A) Coenzyme
(B) Substrate
(C) Apoenzyme
(D) Holoenzyme

Q:3: Koshland in 1959 proposed

(A) Fluid mosaic model
(B) Induce fit model
(C) Lock and key model
(D) Reflective index model

Q:4: Enzymes are largely _________________________ in their chemical nature.

(A) Lipids
(B) Steroids
(C) Proteinaceous
(D) All A, B and C

Q:5: Who proposed “lock and key” model to study enzyme – substrate interaction?

(A) Koshland (1959)
(B) Wilhelm Kuhne (1878)
(C) Fischer (1898)
(D) None of these

Q:6: In human body the optimum temperature for enzymatic activities is

(A) 37oC
(B) 40oC
(C) 25oC
(D) 30oC

Q:7: Optimum pH value for pepsin is

(A) 5.5
(B) 7.4
(C) 4.1
(D) 1.4

Q:8: Competitive inhibitors stop an enzyme from working by

(A) Changing the shape of the enzyme
(B) merging with the substrate instead
(C) blocking the active site of the enzyme
(D) combining with the product of the reaction

Q:9: The enzymes are sensitive to

(A) Changes in pH
(B) Changes in temperature
(C) Both A and B
(D) None of these

Q:10: Enzyme B requires Zn2+ in order to catalyze the conversion of substrate X. The zinc is best identified as a(n):

(A) Coenzyme
(B) Activator
(C) Substrate
(D) Product

Answer key

1.A, 2.D, 3.B, 4.C, 5.C, 6.A, 7.D, 8.C, 9.C, 10.B

==============

Best Wishes: Dr.Ehab Aboueladab, Tel:+201007834123,Email:ehab10f@gmail.com