MALLA REDDY UNIVERSITY

SCHOOL OF ALLIED AND HEALTHCARE SCIENCES

MEDICAL BIOCHEMISTRY (Common Syllabus)
R23 - Regulations
QUESTION BANK
UNIT -I
1. Define Carbohydrates. Discuss the classification and functions of carbohydrates?

[1M+2M+3M+2 M]
2. Define Isomerism? Discuss different types of Isomerism exhibited by monosaccharides.
[1M+2M+5M]

3. Define polysaccharides. Classify them by giving suitable examples. Describe any 3 examples of
homo polysaccharides. [1M+2M+5M]

4. What are Glycosaminoglycans? Discuss about any 3 glycosaminoglycans and their functions
[2M+6M]

5. What are lipids? Classify them by giving suitable examples. [1M+2M+5M]

6. What are phospholipids? Describe the chemistry and functions of phospholipids.

[1M+1M+3M+3M]
7. Discuss the structure, properties and functions of Cholesterol. [2M+3M+3M]

8. Write short notes on

a) Anomers [2M]
b) Epimers [2M]
c) Enantiomers [2M]
d) Mutarotation [2M]
9. Write notes on

a) Ketone bodies [4M]

b) Essential fatty acids [4M]
10. Write notes on

a) Lipoproteins and their functions [4M]

b) Classification of Disaccharides [4M]

UNIT-II
1. Discuss the classification of amino acids with suitable examples.

[2+ 2+ 2 + 1 + 1M]
2. What are proteins? Classify them giving suitable examples in each group.
[1+2+2 + 2+1M]
3. Discuss in detail the different levels of organization of protein structure. [2+ 2+2+2M]

4. Define peptide bond. Discuss about biologically important peptides.

5. Draw the structure of DNA. Write the salient features of double helical structure of DNA. [2+6M]

6. Mention different types of RNA. Discuss the structure of t-RNA with a neat labelled diagram.
[2+4+2M]

7. List out the differences between DNA and RNA.

8. Write short notes on:

a) Denaturation of proteins
b) Essential and Non-essential amino acids
9. Write short notes on

a) Chargaff’s rule [2M]

b) Nucleosides and nucleotides [2M]
c) Purines and Pyrimidines [2M]
d) Functions of Nucleotides [2M]
UNIT-III
1. What are Enzymes? Classify them by giving suitable examples [1M+7×1M]

2. Explain various factors affecting the rate of enzyme catalysis. [8×1M]

3. What is enzyme inhibition? Discuss about various types of enzyme inhibitions.

[2M+2M+2M+2M]
4. What are Isoenzymes? Discuss the clinical significance of LDH, CK and ALP

[2M+2M+2M +2M]
5. Define Vitamins. Classify them with suitable examples. List out differences between fat soluble
and water soluble vitamins. [1M+1M+2M+4M]

6. Write the RDA, sources, functions, deficiency manifestation of B1, B2, B5 and B7.

[2M+2M+2M+2M]
7. Write the RDA, sources, functions, deficiency manifestation of B9 and B12.

[4M+4M]
8. Write the RDA, sources, functions and deficiency of Vitamin A and D.

[4M+4M]
9. Write the RDA, sources, functions and deficiency of Vitamin E and K. [4M+4M]
10. Write short notes on

a) Enzyme specificity [3M]

b) Active site [2M]
c) Functions and deficiency of Vitamin C [3M]
UNIT-IV
1. Write in detail about Embden-Meyerhof pathway (Glycolysis) and its regulation

GLYCOLYSIS/ EMP PATHWAY

Definition: Breakdown of glucose into two pyruvate molecules under aerobic conditions along with the
production of a small quantity of energy.
Glucose Pyruvate + ATP
Site: Cytosol of all the cells.
Significance of Glycolysis: Energy production. Reactions of Glycolysis:
Phase 1: Preparatory phase
Various steps of Glycolysis are :
1. Phosphorylation: Glucose is phosphorylated to glucose-6 phosphate in the presence of ATP, catalyzed
by the enzyme hexokinase.
2. Isomerization: Glucose 6 phosphate is converted into its isomer fructose-6-phosphate, catalyzed by
hexose phosphate isomerase.
3. Phosphorylation: Fructose-6-phosphate is phosphorylated in the presence of ATP to form fructose 1.6
bisphosphate by phosphofructokinase.
4. Cleavage; Fructose 1,6 bisphosphate is split into 2 molecules of triose phosphate namely 3
phosphoglyceraldehyde (G3P or PGAI) and dihydroxyacetone phosphate
(DHAP), This interconvertible reaction is catalyzed by Aldolase.
5. Isomerization: DHAP is converted into another G3P molecule in the presence of Isomerase.

Phase 2: Payoff phase

6. Dehydrogenation: 3-phosphoglyceraldehyde is oxidized to 1,3 bisphosphoglyceric acid with the
reduction of NAD to NADH+H+. This is catalyzed by G-3 P dehydrogenase
7. Dephosphorylation: Phosphoglycerokinase catalyzes the formation of 3 phosphoglyceric acid from 1,3
bis PGA. Two molecules of ATP are produced directly by substrate level phosphorylation
8. Intermolecular shift: 3 phosphoglyceric acid is converted into 2 phosphoglyceric acid in the presence of
phosphoglyceromutase
9. Dehydration: 2 PGA molecules lose water molecules in the presence of Enolase to form PEPA
molecules
10. Dephosphorylation; 2 PGA molecules undergo Dephosphorylation in the presence of pyruvic kinase
to form 2 PA molecules.2 ATP molecules are formed.
Energetics:
1Glucose+2NAD+ 2ADP+ 4Pi = 2Pyruvate+2NADH+H
Total = 9ATP -2ATP= 7ATP
Regulation of glycolysis:
+2ATP
Insulin favours glycolysis while Glucagon inhibits glycolysis.
Glycolysis is regulated by allosteric regulation at 3 irreversible steps catalysed by Hexokinase: (-
Glucose-6-Phosphate) Phosphofructokinase: (- ATP; Citrate
+ AMP; F2,6BP) and Pyruvate kinase: (-ATP)
[1+3+3+1M]
2. Discuss about TCA cycle and it’s regulation. Add a note on its energetics.

[1+3+2+1+1M]
3. Give an account of β – oxidation of saturated fatty acid (Palmitic acid) along with its energetics
[1+3+2+2M]

4. What are ketone bodies? Discuss their formation and utilization. [2+3+3M]

5. Write an essay on Urea cycle and its regulation. [3+3+2M]

6. Write notes on

a) Substrate level phosphorylation [4M]

b) Disorders of urea cycle [4M]
UNIT-V
1. Define Minerals and classify them. Discuss the functions and deficiency of Iron.

MINERALS
Minerals perform several vital functions which are absolutely essential for the very existence of the
organism. These include calcification of bone, blood coagulation, neuromuscular irritability, acid-
base equilibrium, fluid balance and osmotic regulation.

Classification:
The minerals are classified as Macro minerals and Micro minerals (trace elements).

Iron
Biochemical Functions
1. Hemoglobin and myoglobin are required for the transport of 02 and CO2
2. Cytochromes and certain non-heme proteins are necessary lor electron transport chain and
oxidative phosphorylation.
3. Peroxidase, the lysosomal enzyme, is required for phagocytosis and killing of bacteria by
neutrophils
4. lron is associated with effective immunocompetence of the body
Sources
Rich sources - Organ meats (liver, heart, kidney).
Good sources - Leafy vegetables, pulses, cereals, fish, apples, dried fruits, molasses.
Poor sources Milk, wheat, polished rice.
RDA
• Adult man - 10 mg/day
• Menstruating woman - 18 mg/day
• Pregnant and lactating woman - 4O mg/day
•
• lron deficiency anemia : This is the most prevalent nutritional disorder worldover, including
the well developed countries (e.g. USA). Inadequate intake or defective absorption of iron, chronic
blood loss, repeated pregnancies and hookworm infections. lron deficiency anemia mostly occurs in
growing children, adolescent girls, pregnant and lactating women. lt is characterized by microcytic
hypochromic anemia with reduced blood hemoglobin levels

[2+2+2+2M]
2. Describe the sources, RDA, functions and deficiency of sodium & potassium

Sodium
Dietary food sources
The common salt (NaCl) used in the cooking medium is the major source of sodium
The good sources of sodium include bread, whole grains, leafy vegetables, nuts, eggs and milk.
RDA
• Adults - 5 – 10 gm/day
• 5 gm NaCl per day for adults without history of hypertension
• 1gm NaCl per day for adults with history of hypertension
Biochemical Functions
1. ln association with chloride and bicarbonate, sodium regulates the body's acidbase balance.
2. Sodium is required for the maintenance of osmotic pressure and fluid balance.
3. lt is necessary for the normal muscle irritability and cell permeability.
4. lt is necessary for initiating and maintaining heart beat,
Hyponatremia : This is a condition in which the serum sodium level falls below the normal.
Hyponatremia may occur due to diarrhea, vomiting, chronic renal diseases, adrenocortical
insufficiency (Addison's disease)

Potassium
Sources
• Banana, orange, pineapple, potato/ beans, chicken, and liver .Tender coconut water is a rich
source of potassium
RDA
• About 3-4 g/day
• Biochemical functions
• 1. Potassium maintains intracellular osmotic Pressure.
• 2. lt is required for the regulation of acidbase balance and water balance in the cells.
3. Potassium is required for the transmission of nerve impulse.
Hypokalemia
Decrease in the concentration of serum potassium is observed due to overactivity of adrenal cortex
(Cushing's syndrome),

The symptoms of hypokalemia include irritability, muscular weakness, tachycardia, cardiomegaly

and cardiac arrest

[2+2+2+2M]
3. What are the biochemical functions of calcium in the body? Write the sources, RDA and
deficiency of Calcium. [3+2+1+2M]

Biochemical functions
1. Development of bones and teeth : Calcium is required for the formation and physical strength of
skeletal tissue
2. Muscle contraction: Ca2+ interacts with troponin C to trigger muscle contraction. Calcium also
activates ATPase, increases the interaction between actin and myosin.
3. Blood coagulation: Several reactions in the cascade of blood clotting process are dependent on
Ca2+ (factor lV).
Dietary sources
• Best sources - Milk and milk products
• Good sources - Beans, leafy vegetables, fish, cabbage, egg yolk
RDA
• Adult men and women - 800 mg/day
• Women during pregnancy/ lactation and post-menopause -1.5 g/day
• Children (1-18 yrs.) - 0.8-1.2 g/day
• Infants (upto 1year) - 300-500 mg/day

Dietary sources

• Best sources - Milk and milk products

• Good sources - Beans, leafy vegetables, fish, cabbage, egg yolk
Hypocalcemia causes Tetany: neuromuscular irritability, spasms and convulsions in the muscles

4. Describe the sources, RDA, functions and deficiency of phosphorous levels in the body.

[2+2+2+2M]
5. What is urea ? Write its normal range. Name the test to identify urea in the given urine sample.
Write the conditions where it is increased and decreased 1M+1M+3M+3M]
UREA
• It is the end product of protein metabolism.
• It is eliminated in urine.
• Normal range : 15-40 mg/day
• Normal excretion : 20-30 g/day
• Increased urea is called uremia
Decreased urea is called renal dysfunction.
It is Identified by Sodium hypo bromide test & Specific urease test.
6. What is uric acid ? Write its normal range. Name the test to identify uric acid in the given urine
sample. Write the conditions where it is increased and decreased.
[1M+1M+3M+3M]

URIC ACID
• It is end product of purine catabolism.
• Increased uric acid is seen in gout & renal failure.
 Decreased uric acid is due to falconi syndrome or disorder in purine catabolism.
• Normal Uric Acid in blood: 3.5 to 7.2 mg/dL Uric Acid in urine: 0.6- 1 g/day.
It is Identified by Phophotungstic acid reduction test
7. What is Creatinine? Write its normal range. Name the test to identify creatinine in the
given urine sample. Write the conditions where it is increased and decreased.
[1M+1M+3M+3M]

CREATININE:
• It is the anhydrous form of creatine.
• It is synthesized by glycine, methionine, arginine.
• Normal level : 0.5 – 1.5 mg/dl.
• Normal creatinine excretion in urine :1-2g/day
• Creatinine level is increased in renal failure .
Decreased creatinine in urine is due to Muscle loss ,pregnancy, malnutrition
• Useful in assessment of kidney function.
Identified by Jeffe’s Test
8. Write an essay on abnormal constituents of blood and urine samples with their clinical significance
[4+ 4M]

Abnormal Constituents of Urine

On standing, urine undergoes bacterial fermentation. It can be preserved under refrigeration or by
adding chemicals such as toluene or chloroform.
The analysis is carried out with properly preserved 24 hours’ urine specimen. When this is not
possible, the early morning specimen can be used.

Physical Characteristics

1. Appearance: Urine is turbid

2. Odour: Normal urine has aromatic odour, which turns ammoniacal on prolonged storage. Urine
smells sweet for ketone bodies, and maple syrup in maple syrup urine disease.
3. Volume: Urinary output is increased (polyuria) in diabetes and after administration of drugs like
digitalis and salicylates. Diminished urinary excretion (oliguria) occurs in nephritis, fever, diarrhea
and vomiting.
4. Colour: Urine becomes smoky brown when blood is present, yellow when bilirubin is present and
black when melanin is present. Urine turns black on standing in alkaptonuria. Urine becomes milky
in appearance if pus, bacteria, epithelial cells or lipids are present.
5. pH: Urine is significantly acidic in fever, diabetes, ketoacidosis-alkaline tide.
6. Specific gravity: Normal range 1.015 to 1.025. It is increased in acute nephritis and fever, and
decreased in diabetes insipidus.

Abnormal constituents which are routinely analysed in urine include:

Reducing sugars (usually Glucose & in special cases lactose, galactose, pentose
&fructose), by Benedicts test
Ketone bodies (Acetone, Acetoacetic acid & β OH butyrate) By Rothera test
Protein (Albumin & Bence- jones proteins) Heat coagulation test, Sulphosalicylic
acid test
Blood, Benzidine Test
Bile pigments By Fouchets test
and Bile salts. By Hays test

Clinical Significance:
Protien:
 Strenuous excerise
 Pregnancy
 Tuberculosis
Reducing Sugar:
a. Diabetes mellitus.
b. Hyperadrenalism.
c. Renal glycosuria
3.Ketone Bodies
Clinical Interpretation:

• Starvation

• Diabetic Ketoacidosis

• Fevers and severe Anemia

4.Blood
Clinical Interpretation:

• (Conditions of haematuria)

• Injury to Urinary tract or Kidney

• Urinary tract Infection

5.Bile Salts and Pigments
Clinical Interpretation (Bile Pigments in Urine):
• Obstructive Jaundice
• Gallstones
• Carcinoma of head of Pancreas
• Hepatitis

9. Write notes on
a) Bile pigments and their clinical significance [2M]
b) Rothera’s test [2M]
c) Clinical significance of serum creatinine [2M]
d) Inorganic constituents of urine [2M]