Part I: Definition/10:

Define the following terms or phrases and write your answers on the space provided for you.

1. Heteropolysaccharides
A polysaccharide that contains different types of monosaccharides e.g GAGS

2. Isoenzymes
Isoenzymes are variations of an enzyme that perform the same reaction but have different
structures and properties, enabling specific regulation in various tissues.

3. Peptide
A peptide is a short chain of amino acids connected by peptide bonds, typically consisting of 2 to
50 amino acids, and can act as hormones or signaling molecules.

4. Cori’s Cycle
Cori's cycle is the metabolic process where lactate from anaerobic glycolysis in muscles is sent
to the liver, converted back to glucose, and returned to the muscles for reuse.

2. Uncouplers
Normal flow of electrons, Increased Oxygen Consumption but No formation Proton
Gradient /Heat Dissipitated and No oxidative phosphorylation / No ATP synthesis
(At least two key words for full marks)

Part II: Multiple Choice Questions/30:

Choose the correct answer and write your answer on the space provided to you in the answer
sheet booklet.
1. A 10-year-old boy presents with vomiting, sweating, drooling, and a decreased heart rate. His
friends state that he was in a corn field when it was sprayed by a crop duster. The chemical being
sprayed was an organophosphate derivative that covalently binds to acetylcholinesterase and
inactivates the enzyme. What type of inhibition is being displayed?
A. Competitive. C. Irreversible.
B. Noncompetitive. D. Feedback

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2. A newborn becomes progressively lethargic after feeding and increases his respiratory rate. He
becomes virtually comatose, responding only to painful stimuli, and exhibits mild respiratory
alkalosis. Suspicion of a urea cycle disorder is aroused and decreased of a semi-essential serum
amino acid levels is initiated. The production of which of the following amino acids will be
decreased?
A. Glycine. C. Arginine.
B. Glutamine. D. Methionine.

3. An 8-year-old boy presents with orange colored tonsils, a very low HDL level, and an
enlarged liver and spleen and is diagnosed with Tangier disease. Which of the following
statements best describes HDL?
A. It is produced in skeletal muscle.
B. It scavenges cholesterol from cell membranes.
C. Its major protein is apo E.
D. It is formed when VLDL is digested by lipoprotein lipase.

4. Sickle cell disease results in abnormal hemoglobin formation because of a point mutation in
DNA that leads to the insertion of which amino acid into β-globin?
A. Glutamate. C. Tyrosine.
B. Glutamic acid. D. Valine.

5. Which one of the ketone bodies is not utilizes in the absence of glucose by human brain?
A. Acetone C. β-hydroxyl butyric acid
B. Acetoacetate D. Glycerol
6. Dietary triacylglycerols are absorbed from the intestinal lumen after hydrolysis mainly as:
A. Fatty acids and glycerol
B. Fatty acids and two monoacylglycerol
C. Fatty acids and α, β-diglyceride
D. Acyl-CoA and glycerol
7. One of the following is not a plasma lipids.
A. Triacyl glycerol (TG) C. Cholesterol
B. Phospholipids (PL) D. Acetone
8. The end product of fatty acid synthase anabolic process is:
A. Stearate C. Linoleate
B. Palmitate D. Arachidonat

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9. A 40-year-old woman presents with pain in her legs that is elicited upon walking and relieved
by rest. Imaging reveals that diffuse atherosclerosis is causing her leg pain. She is found to have
no functional apoprotein C-II. Which of the following will be elevated in this patient’s blood?
A. Cholesterol esters C. LDL
B. Chylomicrons D. HDL
10. The number of ATP produced in the oxidation of 1 molecule of NADPH in oxidative
phosphorylation is :
A. Zero C. 3
B. 2 D. 4
11. Activity of cytochrome oxidase is inhibited by:
A. Sulphite C. Arsenite
B. Sulphate D. Cyanide
12. A 53-year-old man presents with xanthomas under his eyes, hepatomegaly, and a triglyceride
level almost 8 times the upper limit of normal at 1500 mg/dL. He is diagnosed with type V
hyperlipidemia. In which tissue are triacylglycerols primarily synthesized?
A. Skeletal muscle C. Liver
B. Heart muscle D. Spleen
13. Which of the following glucose transporter is associated with insulin?
A. SGLT 1 C. GLUT 4
B. GLUT 2 D. GLUT 5
14. The cellular location of glycolytic enzymes is:
A. Mitochondrial fraction C. Cytosomal fraction
B. Nuclear fraction D. Lysosomal fraction
15. The end product of anaerobic glycolysis is :
A. Pyruvate C. Acetyl CoA
B. Lactate D. Carbon monoxide
16. Assuming each NADH and FADH produce 3 and 2 molecules of ATP respectively. What is
the net yield of ATP molecules per one molecule of glucose during anaerobic glycolysis?
A. 40 C. 4
B. 38 D. 2
17. Which of the following lacks the Kreb’s cycle enzymes :
A. Pancreatic cells C. Liver cells
B. Red blood cells D. D. Brain cells

18. Which of the following monosaccharides is not an aldose?

A. Glucose C. Glyceraldehyde
B. Fructose D. Erythrose

C. ____________________
Name: Registration number :___________ Group :_________
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 A. Lipids C. Carbohydrates
B. Proteins
19.Which of the following molecules or substances doesn’t D. derived
Amino Acids
from fatty acids?
23. 65-year-old man expresses his concern about developing colon cancer to his physician and
A. Glycerophospholipids
recommends a diet low in fat and high C. Sphingolipids
in fiber. The doctor explains that studies have shown a
B. Triacylglycerols
decreased D. Inulin.
risk for colon cancer with insoluble fiber consumption. Which of the following glycosidic bonds
20.. α-helix structure of a protein is stabilized by which of the following?
prevents
A. Peptide
humans bonds
from completely C. Hydrogen
digesting fiber? bonds
B.
A. Ionic
α (1-4)bonds
glycosidic D. Disulfide bonds C. β (1-4) glycosidic bond
B. α (1-6) glycosidic bond D. γ (1-4) glycosidic bond
21. Which of these statements about enzyme-catalyzed reactions that obey Michaelis-Menten
24. Which of the following is NOT an essential fatty acid?
kinetics is false?
A. Linolenic acid C. Arachidonic acid
A. At saturating levels of substrate, the rate of an enzyme-catalyzed reaction is proportional
B. Linoleic acid D. Oleic acid
to the enzyme concentration.
25. Which of the following is a significant characteristic of glucokinase?
B. If enough substrate is added, the normal Vmax of a reaction can be attained even in the
A. It has high Km to glucose in the blood
presence of a competitive inhibitor.
B. It is expressed in many tissues
C. The rate of a reaction decreases steadily with time as substrate is depleted.
C. Its activity is stimulated in response to fructose 2,6-bisphosphate
D. The activation energy for the catalyzed reaction is the same as for the uncatalyzed
D. Its activity is inhibited by glucose 6-phosphate
reaction, but the equilibrium constant is more favorable in the enzyme-catalyzed
26. In which one of the following scenarios would one expect to observe an increase in liver
reaction
fructose 2, 6- bisphosphate levels?
22. A.
Patient’s withrelease
After the limited
of blood flow are immediately started on heparin to further prevent the
epinephrine
clotB.
from
In enlarging.
an individualHeparin is anjust
who had example of running
finished which ofa the following?
marathon
C. In a patient exhibiting diabetic ketoacidosis
D. After the consumption of a large bowl of ice cream
26. If glycolysis converts glucose to pyruvate and then pyruvate to lactic acid this is an example
of:
A. Anaerobic metabolism.
B. Anabolic metabolism.
C. Aerobic metabolism
D. Amphibolism
27. When a muscle contracts aerobically, less lactic acid is formed than when it contracts
anaerobically because:
A. Glycolysis does not occur to significant extent under aerobic conditions.
B. Muscle is metabolically less active under aerobic than anaerobic conditions.
C. Under aerobic conditions most pyruvate is oxidized by the citric acid cycle rather than
reduced to lactate.
D. the major energy-yielding pathway in muscle is the pentose phosphate pathway, which
does not produce lactate

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28. A scientist is studying oxidative phosphorylation, and carefully isolated mitochondria. The
scientist then adds a compound that greatly enhances the rate of oxygen consumption. This
compound is most likely to be which one of the following?
A. Rotenone C. Cyanide
B. Carbon monoxide D. Dinitrophenol
29. Energy that is released from oxidation of fuel molecules during respiration but not
transferred to ATP bonds can be detected as
A. H 2 O C. Turgor Pressure
B. CO 2 D. Heat

30. Which of the following enzymes is active in adipocytes following a prolonged fasting?
A. Glycogen phosphorylase
B. Glycerol kinase
C. Hormone-sensitive triacylglyceride lipase
D. Glucose-6-phosphatase

Name: ____________________ Registration number :___________ Group :_________

Part III. Matching/10:

Choose the best answer from the items listed under column B and match to those under
column A and write your answers on the answer sheet booklet.
A B
_B______1. Hetereopolysaccharides A. Leucine
_A______2. Essential amino acid B. Cellulose
__D_____3. Haemoglobin C. Blood clotting factor
_C______4. Heparin D. Iron
_E______5. Amphibolism E. TCA cycle

Part IV. Short answer questions: Give brief and clear answers for the following questions
and your answers on the space provided for you in the answer on the space provided (5
marks).

1. State TWO functions of essential fatty acids (2.5 Marks)

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-Lipotrophic factor (reduces cardiovascular morbidity)
-Fluidity of cell membrane (component of phospholipids)
-Production of eicosanoids (prostaglandins and leukotrienes from arachidonic acids)
-Proper development and functioning of brain and nervous system (myelination of the nerves)
-Supports healthy skin and hair

2. Explain why FADH2 gives less ATP than NADH in the Electron Transport chain and
Oxidative phosphorylation reaction. (2.5 marks)

FADH2 gives its electrons to Complex II which is Non-proton driven pump ( No proton
gradient) and No ATP synthesis associated to Complex II. Hence less ATP
OR
NADH gives its electrons to Complex I which is Proton driven pump ( Formation of proton
gradient) and ATP synthesis associated to Complex I. Hence more ATP
(Either one of the explanation deserves full marks)

### 2. Decreased Production of Amino Acids in Urea Cycle Disorder

- **C. Arginine**

In urea cycle disorders, the production of arginine is decreased due to impaired conversion of ammonia to urea.

### 3. Characteristics of HDL in Tangier Disease

- **B. It scavenges cholesterol from cell membranes.**

HDL is responsible for removing excess cholesterol from tissues.

### 4. Amino Acid Insertion in Sickle Cell Disease

- **D. Valine**

A point mutation in the β-globin gene leads to the substitution of valine for glutamic acid.

### 5. Ketone Bodies Not Utilized by the Brain

- **A. Acetone**

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 Acetone is not utilized by the brain as a fuel source in the absence of glucose.

### 6. Absorption of Dietary Triacylglycerols

- **B. Fatty acids and two monoacylglycerol**

Triacylglycerols are hydrolyzed and absorbed mainly as free fatty acids and monoacylglycerol.

### 7. Not a Plasma Lipid

- **D. Acetone**

Acetone is not classified as a plasma lipid.

### 8. End Product of Fatty Acid Synthase

- **B. Palmitate**

The primary end product of fatty acid synthesis is palmitate (C16:0).

Here are the answers to your questions:

### 9. Elevated Substance in Blood Due to Apoprotein C-II Deficiency

- **B. Chylomicrons**

Lack of functional apoprotein C-II impairs chylomicron metabolism, leading to their accumulation.

### 10. ATP Produced from NADPH in Oxidative Phosphorylation

- **A. Zero**

NADPH is not directly involved in ATP production during oxidative phosphorylation.

### 11. Inhibition of Cytochrome Oxidase

- **D. Cyanide**

Cyanide inhibits cytochrome oxidase, blocking electron transport.

### 12. Tissue Primarily Synthesizing Triacylglycerols

- **C. Liver**

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 The liver is the primary site of triacylglycerol synthesis.

### 13. Glucose Transporter Associated with Insulin

- **C. GLUT 4**

GLUT 4 is the glucose transporter that is insulin-responsive.

### 14. Cellular Location of Glycolytic Enzymes

- **C. Cytosomal fraction**

Glycolytic enzymes are located in the cytosol of the cell.

### 15. End Product of Anaerobic Glycolysis

- **B. Lactate**

The end product of anaerobic glycolysis is lactate.

### 16. Net Yield of ATP During Anaerobic Glycolysis

- **D. 2**

The net yield of ATP from anaerobic glycolysis is 2 ATP molecules.

### 17. Lack of Kreb’s Cycle Enzymes

- **B. Red blood cells**

Red blood cells lack mitochondria and thus do not have Kreb's cycle enzymes.

### 18. Non-Aldose Monosaccharide

- **B. Fructose**

Fructose is a ketose, not an aldose.

Here are the answers to your questions:

### 19. Molecule Not Derived from Fatty Acids

- **D. Inulin**

Inulin is a carbohydrate and not derived from fatty acids.

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### 20. Stabilization of α-Helix Structure

- **C. Hydrogen bonds**

The α-helix structure of proteins is stabilized by hydrogen bonds between the backbone amide groups.

### 21. False Statement About Michaelis-Menten Kinetics

- **D. The activation energy for the catalyzed reaction is the same as for the uncatalyzed reaction, but the equilibrium

constant is more favorable in the enzyme-catalyzed reaction.**

The activation energy is lower for the catalyzed reaction compared to the uncatalyzed reaction.

### 22. Heparin Classification

- **C. Carbohydrates**

Heparin is a glycosaminoglycan, which is a type of carbohydrate.

### 23. Glycosidic Bond in Fiber

- **C. β (1-4) glycosidic bond**

β (1-4) glycosidic bonds in cellulose prevent humans from fully digesting fiber.

### 24. Non-Essential Fatty Acid

- **D. Oleic acid**

Oleic acid is a monounsaturated fatty acid and is not considered essential.

### 25. Significant Characteristic of Glucokinase

- **A. It has high Km to glucose in the blood**

Glucokinase has a high Km, making it less active at low glucose concentrations, which is typical for its role in the liver.

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