AN INTRODUCTION TO

BIOCHEMEISTRY

          BIOCHEMISTRY VIVA QUESTIONS

By

DR.C.GANESAN M.D.

PROFESSOR OF MEDICINE

 

PREFACE

This preparation is done with a aim to make easy understanding of medical topics by paramedical students of all paramedical courses.

This cover the over all topics materials of biochemistry subjects.

These topics will be useful for the students of all the certificate courses, diploma courses and  degree courses of all paramedical sciences

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AN INTRODUCTION TO

BIOCHEMEISTRY

BIOCHEMISTRY VIVA QUESTIONS

 

1. What is Biochemistry?
Biochemistry is the branch of science that studies the chemical processes occurring in living organisms.
It explains the structure and function of biomolecules such as carbohydrates, proteins, lipids, and nucleic acids.
It forms the basis of modern medicine and molecular biology.

2. Who is known as the Father of Biochemistry?
Carl Alexander Neuberg is regarded as the Father of Biochemistry.
He made significant contributions to the study of enzymes and metabolism.
His work helped establish biochemistry as an independent scientific discipline.

3. What are Biomolecules?
Biomolecules are chemical compounds present in living organisms.
They include carbohydrates, proteins, lipids, and nucleic acids.
These molecules are essential for growth, metabolism, and reproduction.

4. Name the Major Classes of Biomolecules.
The four major classes are carbohydrates, proteins, lipids, and nucleic acids.
Each class has unique structural and functional roles.
Together they maintain life processes and cellular activities.

5. What is a Cell?
A cell is the basic structural and functional unit of life.
It contains cytoplasm, genetic material, and organelles.
All living organisms are composed of one or more cells.

6. What is the Chemical Composition of a Cell?
Cells are mainly composed of water, proteins, lipids, carbohydrates, and nucleic acids.
Water constitutes about 60–70% of cell mass.
Minerals and trace elements are also present in small amounts.

7. What is pH?
pH is a measure of hydrogen ion concentration in a solution.
It indicates whether a solution is acidic, neutral, or alkaline.
The pH scale ranges from 0 to 14.

8. What is the Normal pH of Blood?
The normal blood pH is 7.35–7.45.
It is maintained by buffer systems, lungs, and kidneys.
A deviation from this range can impair cellular function.

9. What is a Buffer?
A buffer is a solution that resists changes in pH.
It maintains acid-base balance by accepting or releasing hydrogen ions.
Bicarbonate is the major physiological buffer.

10. Name the Important Physiological Buffers.
The major physiological buffers are bicarbonate, phosphate, and protein buffers.
Hemoglobin also acts as an important buffer in blood.
These systems help maintain normal blood pH.

11. What is Osmolarity?
Osmolarity is the concentration of osmotically active particles in a solution.
It determines the movement of water across membranes.
Normal plasma osmolarity is about 275–295 mOsm/L.

12. What is Homeostasis?
Homeostasis is the maintenance of a stable internal environment.
It regulates temperature, pH, fluid balance, and metabolism.
It is essential for normal physiological function.

13. What are Electrolytes?
Electrolytes are substances that dissociate into ions in solution.
Examples include sodium, potassium, calcium, and chloride.
They regulate fluid balance, nerve conduction, and muscle contraction.

14. What is Diffusion?
Diffusion is the movement of molecules from a region of higher concentration to lower concentration.
It occurs without the expenditure of energy.
It is important for gas exchange and nutrient transport.

15. What is Osmosis?
Osmosis is the movement of water across a semipermeable membrane.
Water moves from a region of lower solute concentration to higher solute concentration.
It helps maintain cellular fluid balance.

16. What is Active Transport?
Active transport is the movement of substances against a concentration gradient.
It requires energy in the form of ATP.
The sodium-potassium pump is a classic example.

17. What is Facilitated Diffusion?
Facilitated diffusion is passive transport through carrier proteins or channels.
It does not require ATP.
Glucose transport via GLUT transporters is an example.

18. What is a Free Radical?
A free radical is a molecule containing an unpaired electron.
It is highly reactive and can damage cellular components.
Examples include superoxide and hydroxyl radicals.

19. What is Oxidative Stress?
Oxidative stress occurs when free radical production exceeds antioxidant defenses.
It causes damage to lipids, proteins, and DNA.
It is associated with aging and many diseases.

20. What are Antioxidants?
Antioxidants are substances that neutralize free radicals.
They protect cells from oxidative damage.
Examples include vitamin C, vitamin E, and glutathione.

21. What are Carbohydrates?
Carbohydrates are organic compounds composed of carbon, hydrogen, and oxygen.
They serve as the primary source of energy for the body.
Examples include glucose, starch, and glycogen.

22. What is Glucose?
Glucose is the principal monosaccharide used as an energy source.
It is transported in blood and utilized by cells for ATP production.
Normal fasting blood glucose is 70–100 mg/dL.

23. What is Fructose?
Fructose is a monosaccharide commonly found in fruits and honey.
It is the sweetest naturally occurring sugar.
It is metabolized mainly in the liver.

24. What is Galactose?
Galactose is a monosaccharide produced from lactose digestion.
It is converted to glucose in the liver.
It is important for the synthesis of glycolipids and glycoproteins.

25. What are Monosaccharides?
Monosaccharides are the simplest form of carbohydrates.
They cannot be hydrolyzed into smaller sugars.
Examples include glucose, fructose, and galactose.

26. What are Disaccharides?
Disaccharides consist of two monosaccharide units linked by a glycosidic bond.
They are broken down into monosaccharides during digestion.
Examples include sucrose, lactose, and maltose.

27. Give Examples of Disaccharides.
Common disaccharides are sucrose, lactose, and maltose.
Sucrose contains glucose and fructose.
Lactose contains glucose and galactose.

28. What is Lactose?
Lactose is the sugar present in milk and dairy products.
It consists of glucose and galactose.
It is digested by the enzyme lactase.

29. What is Sucrose?
Sucrose is common table sugar.
It is composed of glucose and fructose molecules.
It is hydrolyzed by the enzyme sucrase.

30. What is Maltose?
Maltose is a disaccharide formed by two glucose molecules.
It is produced during starch digestion.
It is hydrolyzed by the enzyme maltase.

31. What are Polysaccharides?
Polysaccharides are complex carbohydrates composed of many monosaccharide units.
They serve as storage or structural molecules in living organisms.
Examples include glycogen, starch, and cellulose.

32. What is Glycogen?
Glycogen is the storage form of glucose in animals.
It is mainly stored in the liver and skeletal muscles.
It serves as a readily available source of energy.

33. What is Starch?
Starch is the storage form of carbohydrate in plants.
It consists of amylose and amylopectin.
It is an important dietary source of glucose.

34. What is Cellulose?
Cellulose is a structural polysaccharide found in plant cell walls.
It is composed of β-D-glucose units.
Humans cannot digest cellulose due to the absence of cellulase.

35. What is Glycolysis?
Glycolysis is the metabolic pathway that converts glucose into pyruvate.
It occurs in the cytoplasm of cells.
It produces ATP and NADH as energy sources.

36. Where does Glycolysis Occur?
Glycolysis occurs in the cytoplasm of all cells.
It does not require mitochondria for its reactions.
It is the first step of glucose metabolism.

37. What is the End Product of Glycolysis?
The end product of glycolysis under aerobic conditions is pyruvate.
Under anaerobic conditions, lactate is formed.
ATP and NADH are also produced during the process.

38. What is Gluconeogenesis?
Gluconeogenesis is the synthesis of glucose from non-carbohydrate sources.
It occurs mainly in the liver and kidneys.
It helps maintain blood glucose during fasting.

39. What is Glycogenesis?
Glycogenesis is the formation of glycogen from glucose.
It occurs primarily in the liver and muscles.
It is stimulated by the hormone insulin.

40. What is Glycogenolysis?
Glycogenolysis is the breakdown of glycogen into glucose.
It provides energy during fasting and exercise.
It is stimulated by glucagon and epinephrine.

41. What is the Cori Cycle?
The Cori cycle is the recycling of lactate between muscle and liver.
Lactate produced in muscles is converted back to glucose in the liver.
It helps maintain energy supply during anaerobic activity.

42. What is the Pentose Phosphate Pathway?
The pentose phosphate pathway is an alternative pathway of glucose metabolism.
It produces NADPH and ribose-5-phosphate.
NADPH is important for fatty acid synthesis and antioxidant defense.

43. What is Blood Glucose?
Blood glucose is the concentration of glucose present in the blood.
It is the primary energy source for many tissues.
Its level is regulated by insulin and glucagon.

44. What is the Normal Fasting Blood Sugar Level?
Normal fasting blood glucose ranges from 70–100 mg/dL.
Levels above this range may indicate diabetes mellitus.
Regular monitoring helps assess metabolic health.

45. What is HbA1c?
HbA1c is glycated hemoglobin formed by the attachment of glucose to hemoglobin.
It reflects average blood glucose levels over the previous 2–3 months.
It is used to diagnose and monitor diabetes mellitus.

46. What is Diabetes Mellitus?
Diabetes mellitus is a metabolic disorder characterized by hyperglycemia.
It results from insulin deficiency or insulin resistance.
Long-term complications affect the eyes, kidneys, nerves, and blood vessels.

47. What is Hypoglycemia?
Hypoglycemia is an abnormally low blood glucose level.
It commonly causes sweating, tremors, and confusion.
Severe hypoglycemia may lead to coma.

48. What is Hyperglycemia?
Hyperglycemia is an abnormally high blood glucose level.
It is commonly seen in diabetes mellitus.
Persistent hyperglycemia causes vascular and organ damage.

49. What is Insulin?
Insulin is a peptide hormone secreted by pancreatic β-cells.
It lowers blood glucose by promoting cellular glucose uptake.
It also stimulates glycogen, fat, and protein synthesis.

50. What is Glucagon?
Glucagon is a hormone secreted by pancreatic α-cells.
It increases blood glucose by stimulating glycogenolysis and gluconeogenesis.
It acts opposite to insulin.

51. What are Lipids?
Lipids are organic compounds that are insoluble in water.
They include fats, oils, phospholipids, and steroids.
They function in energy storage, insulation, and cell structure.

52. What are Fatty Acids?
Fatty acids are long-chain hydrocarbons with a carboxyl group.
They are the building blocks of many lipids.
They serve as an important source of energy.

53. What are Saturated Fatty Acids?
Saturated fatty acids contain no double bonds between carbon atoms.
They are usually solid at room temperature.
Examples include palmitic acid and stearic acid.

54. What are Unsaturated Fatty Acids?
Unsaturated fatty acids contain one or more double bonds.
They are usually liquid at room temperature.
Examples include oleic acid and linoleic acid.

55. What are Essential Fatty Acids?
Essential fatty acids cannot be synthesized by the human body.
They must be obtained from the diet.
They are necessary for growth, cell function, and health.

56. Name Essential Fatty Acids.
The main essential fatty acids are linoleic acid and α-linolenic acid.
Arachidonic acid is conditionally essential in some situations.
They are important for membrane integrity and eicosanoid synthesis.

57. What is Cholesterol?
Cholesterol is a sterol present in animal tissues.
It is a component of cell membranes and a precursor of steroid hormones.
It is synthesized mainly in the liver.

58. What are Triglycerides?
Triglycerides are esters of glycerol and three fatty acids.
They are the major storage form of fat in the body.
They provide a concentrated source of energy.

59. What are Phospholipids?
Phospholipids are lipids containing phosphate groups.
They are major components of cell membranes.
They help maintain membrane structure and function.

60. What are Lipoproteins?
Lipoproteins are complexes of lipids and proteins.
They transport lipids through the bloodstream.
Examples include chylomicrons, HDL, LDL, and VLDL.

61. What are Chylomicrons?
Chylomicrons are the largest lipoproteins formed in the intestinal mucosa.
They transport dietary triglycerides and cholesterol from the intestine to tissues.
They are rich in triglycerides and have the lowest density.

62. What is HDL?
HDL stands for High-Density Lipoprotein.
It transports cholesterol from peripheral tissues to the liver for excretion.
It is known as the "good cholesterol."

63. What is LDL?
LDL stands for Low-Density Lipoprotein.
It transports cholesterol from the liver to peripheral tissues.
Elevated LDL levels increase the risk of atherosclerosis.

64. What is VLDL?
VLDL stands for Very Low-Density Lipoprotein.
It carries endogenous triglycerides from the liver to tissues.
It is converted into LDL after triglyceride removal.

65. What is Ketogenesis?
Ketogenesis is the formation of ketone bodies from fatty acids.
It occurs mainly in the liver mitochondria during fasting.
It provides an alternative energy source for tissues.

66. What are Ketone Bodies?
Ketone bodies are water-soluble compounds produced from fat metabolism.
They serve as alternative fuels during carbohydrate deficiency.
Their levels increase during fasting and diabetes mellitus.

67. Name the Ketone Bodies.
The three ketone bodies are acetoacetate, β-hydroxybutyrate, and acetone.
Acetoacetate and β-hydroxybutyrate are used for energy production.
Acetone is excreted through the lungs.

68. What is β-Oxidation?
β-Oxidation is the breakdown of fatty acids into acetyl-CoA units.
It occurs in the mitochondria of cells.
It generates ATP through energy production pathways.

69. Where Does β-Oxidation Occur?
β-Oxidation occurs primarily in the mitochondria.
Long-chain fatty acids enter mitochondria via the carnitine shuttle.
The process produces acetyl-CoA, NADH, and FADH₂.

70. What is Fatty Liver?
Fatty liver is the excessive accumulation of fat in liver cells.
It may result from alcohol use, obesity, or diabetes mellitus.
Severe cases can progress to liver inflammation and cirrhosis.

71. What are Proteins?
Proteins are polymers of amino acids linked by peptide bonds.
They perform structural, enzymatic, and regulatory functions.
They are essential for growth and tissue repair.

72. What are Amino Acids?
Amino acids are the basic building blocks of proteins.
Each amino acid contains amino and carboxyl groups.
They participate in protein synthesis and metabolism.

73. How Many Amino Acids are Present in Proteins?
Twenty standard amino acids are commonly found in proteins.
They differ in their side-chain structures.
These differences determine protein properties and functions.

74. What are Essential Amino Acids?
Essential amino acids cannot be synthesized in sufficient amounts by the body.
They must be obtained through the diet.
They are necessary for normal growth and metabolism.

75. Name Essential Amino Acids.
Essential amino acids include leucine, isoleucine, valine, lysine, methionine, phenylalanine, threonine, tryptophan, and histidine.
They are required for protein synthesis and tissue maintenance.
Deficiency can impair growth and health.

76. What is a Peptide Bond?
A peptide bond is a covalent bond linking two amino acids.
It forms between the amino group of one amino acid and the carboxyl group of another.
It is the basic linkage in proteins.

77. What is Denaturation?
Denaturation is the loss of a protein's native structure.
It may be caused by heat, acids, alkalis, or chemicals.
Denatured proteins usually lose their biological activity.

78. What are Globular Proteins?
Globular proteins are compact and spherical proteins.
They are generally soluble in water.
Examples include hemoglobin, albumin, and enzymes.

79. What are Fibrous Proteins?
Fibrous proteins are elongated and insoluble proteins.
They provide structural support and strength.
Examples include collagen, keratin, and elastin.

80. What is Collagen?
Collagen is the most abundant protein in the human body.
It provides tensile strength to connective tissues.
It is found in skin, bone, cartilage, and tendons.

81. What is Elastin?
Elastin is a fibrous protein that provides elasticity to tissues.
It allows tissues to stretch and return to their original shape.
It is abundant in ligaments, lungs, and blood vessels.

82. What is Keratin?
Keratin is a structural fibrous protein.
It is the major component of hair, nails, and the outer skin layer.
It provides protection and mechanical strength.

83. What is Albumin?
Albumin is the most abundant plasma protein.
It maintains colloid osmotic pressure and transports various substances.
It is synthesized by the liver.

84. What is Globulin?
Globulins are a group of plasma proteins with diverse functions.
They include transport proteins, enzymes, and antibodies.
They play important roles in immunity and transport.

85. What is the Normal Serum Protein Level?
The normal total serum protein level is approximately 6–8 g/dL.
Albumin and globulins constitute the major fractions.
Abnormal levels may indicate liver, kidney, or nutritional disorders.

86. What is Transamination?
Transamination is the transfer of an amino group from one amino acid to another compound.
It is catalyzed by aminotransferase enzymes.
It is important in amino acid metabolism.

87. What is Deamination?
Deamination is the removal of an amino group from an amino acid.
It results in the formation of ammonia and a keto acid.
It mainly occurs in the liver.

88. What is the Urea Cycle?
The urea cycle converts toxic ammonia into urea.
It occurs mainly in the liver.
Urea is then excreted by the kidneys.

89. Where Does the Urea Cycle Occur?
The urea cycle occurs in liver cells.
Some reactions occur in mitochondria and others in the cytoplasm.
It is the major pathway for ammonia detoxification.

90. What is Nitrogen Balance?
Nitrogen balance is the difference between nitrogen intake and nitrogen loss.
Positive nitrogen balance occurs during growth and pregnancy.
Negative nitrogen balance occurs in starvation and severe illness.

BIOCHEMISTRY VIVA QUESTIONS

91. What is an Enzyme?
An enzyme is a biological catalyst that accelerates chemical reactions.
Most enzymes are proteins, although some RNA molecules act as enzymes.
They increase reaction rates without being consumed.

92. Who Discovered Enzymes?
The term enzyme was introduced by the German scientist Wilhelm Kühne in 1878.
Later studies by many scientists established the catalytic role of enzymes.
Their discoveries laid the foundation of enzymology.

93. What is the Active Site?
The active site is the specific region of an enzyme where the substrate binds.
It contains amino acid residues essential for catalysis.
The enzyme-substrate complex is formed at this site.

94. What is a Substrate?
A substrate is the molecule upon which an enzyme acts.
It binds specifically to the active site of the enzyme.
The substrate is converted into product during the reaction.

95. What is a Cofactor?
A cofactor is a non-protein component required for enzyme activity.
It may be a metal ion or an organic molecule.
Without cofactors, some enzymes remain inactive.

96. What is a Coenzyme?
A coenzyme is an organic cofactor that assists enzyme action.
Many coenzymes are derived from vitamins.
They participate in the transfer of chemical groups during reactions.

97. Give Examples of Coenzymes.
Examples of coenzymes include NAD⁺, NADP⁺, FAD, and Coenzyme A.
They play important roles in oxidation-reduction reactions.
Most are derived from B-complex vitamins.

98. What are Isoenzymes?
Isoenzymes are different molecular forms of the same enzyme.
They catalyze the same reaction but differ in structure and tissue distribution.
They are useful in clinical diagnosis.

99. What is Enzyme Specificity?
Enzyme specificity is the ability of an enzyme to act on a particular substrate.
The active site determines this selectivity.
It ensures accuracy in metabolic reactions.

100. What is Enzyme Inhibition?
Enzyme inhibition is the reduction or loss of enzyme activity by an inhibitor.
The inhibitor interferes with substrate binding or catalysis.
It may be reversible or irreversible.

101. What is Competitive Inhibition?
Competitive inhibition occurs when the inhibitor competes with the substrate for the active site.
It can be overcome by increasing substrate concentration.
Km increases while Vmax remains unchanged.

102. What is Noncompetitive Inhibition?
Noncompetitive inhibition occurs when the inhibitor binds away from the active site.
It reduces enzyme activity regardless of substrate concentration.
Vmax decreases while Km remains unchanged.

103. What is Km?
Km or Michaelis constant is the substrate concentration at which the reaction rate is half of Vmax.
It reflects the affinity of an enzyme for its substrate.
A lower Km indicates higher affinity.

104. What is Vmax?
Vmax is the maximum velocity of an enzyme-catalyzed reaction.
It occurs when all enzyme active sites are saturated with substrate.
It reflects the catalytic capacity of the enzyme.

105. What is Allosteric Regulation?
Allosteric regulation occurs when a molecule binds to a site other than the active site.
This binding alters enzyme activity.
It plays an important role in metabolic control.

106. What is the Lock-and-Key Theory?
The lock-and-key theory states that the substrate fits exactly into the enzyme active site.
The active site is considered rigid and highly specific.
It was proposed to explain enzyme specificity.

107. What is the Induced-Fit Theory?
The induced-fit theory suggests that the enzyme changes shape when the substrate binds.
This improves substrate binding and catalysis.
It better explains enzyme flexibility than the lock-and-key model.

108. What is Turnover Number?
Turnover number is the number of substrate molecules converted into product per enzyme molecule per second.
It measures catalytic efficiency.
A higher turnover number indicates a more efficient enzyme.

109. What are Diagnostic Enzymes?
Diagnostic enzymes are enzymes measured in blood to detect tissue damage.
Their levels increase in specific diseases.
Examples include AST, ALT, CK, and LDH.

110. Name Important Cardiac Enzymes.
Important cardiac enzymes include CK-MB, LDH, and AST.
They are released into the blood following myocardial injury.
They aid in the diagnosis of myocardial infarction.

111. What are Vitamins?
Vitamins are organic compounds required in small amounts for normal body functions.
Most vitamins cannot be synthesized adequately by the body.
They are essential for growth, metabolism, and health.

112. What are Fat-Soluble Vitamins?
Fat-soluble vitamins are absorbed along with dietary fats.
They are stored in the liver and adipose tissue.
They include vitamins A, D, E, and K.

113. Name Fat-Soluble Vitamins.
The fat-soluble vitamins are A, D, E, and K.
They perform diverse physiological functions.
Excess intake may lead to toxicity.

114. What are Water-Soluble Vitamins?
Water-soluble vitamins dissolve readily in water.
They are generally not stored in large amounts in the body.
They include the B-complex vitamins and vitamin C.

115. Name Water-Soluble Vitamins.
Water-soluble vitamins include vitamin C and the B-complex group.
Examples are B1, B2, B3, B6, B9, and B12.
They function mainly as coenzymes.

116. What is Vitamin A Deficiency?
Vitamin A deficiency results from inadequate intake or absorption of vitamin A.
It commonly causes night blindness and xerophthalmia.
Severe deficiency may lead to permanent blindness.

117. What is Vitamin D Deficiency?
Vitamin D deficiency impairs calcium and phosphorus metabolism.
It causes defective bone mineralization.
It results in rickets in children and osteomalacia in adults.

118. What is Rickets?
Rickets is a childhood disorder caused mainly by vitamin D deficiency.
It leads to soft and weak bones.
Bone deformities are common clinical features.

119. What is Osteomalacia?
Osteomalacia is defective mineralization of bone in adults.
It is usually caused by vitamin D deficiency.
Patients commonly present with bone pain and muscle weakness.

120. What is Vitamin E Deficiency?
Vitamin E deficiency leads to increased oxidative damage to cell membranes.
It may cause hemolytic anemia and neurological abnormalities.
The deficiency is uncommon in healthy individuals.

121. What is Vitamin K Deficiency?
Vitamin K deficiency impairs the synthesis of clotting factors II, VII, IX, and X.
It results in prolonged bleeding and hemorrhagic tendencies.
Newborns are particularly susceptible to this deficiency.

122. What is Vitamin C Deficiency?
Vitamin C deficiency results from inadequate intake of ascorbic acid.
It impairs collagen synthesis and wound healing.
Severe deficiency causes scurvy.

123. What is Scurvy?
Scurvy is a disease caused by vitamin C deficiency.
It is characterized by bleeding gums, petechiae, and poor wound healing.
Collagen synthesis is markedly impaired.

124. What is Thiamine Deficiency?
Thiamine (Vitamin B1) deficiency affects carbohydrate metabolism and nerve function.
It may lead to beriberi or Wernicke-Korsakoff syndrome.
Alcoholism is a common risk factor.

125. What is Beriberi?
Beriberi is a disease caused by thiamine deficiency.
Dry beriberi affects the nervous system, while wet beriberi affects the cardiovascular system.
Symptoms include weakness, neuropathy, and edema.

126. What is Riboflavin Deficiency?
Riboflavin (Vitamin B2) deficiency causes cheilosis, glossitis, and angular stomatitis.
It affects energy metabolism due to impaired coenzyme function.
The condition is known as ariboflavinosis.

127. What is Niacin Deficiency?
Niacin (Vitamin B3) deficiency leads to pellagra.
It impairs oxidation-reduction reactions involving NAD and NADP.
The classic features are dermatitis, diarrhea, and dementia.

128. What is Pellagra?
Pellagra is a nutritional disorder caused by niacin deficiency.
It is characterized by the "three Ds"—dermatitis, diarrhea, and dementia.
Untreated cases may progress to death.

129. What is Folic Acid Deficiency?
Folic acid deficiency impairs DNA synthesis and cell division.
It commonly causes megaloblastic anemia.
It is especially important during pregnancy.

130. What is Vitamin B12 Deficiency?
Vitamin B12 deficiency causes megaloblastic anemia and neurological disorders.
It may result from pernicious anemia or malabsorption.
Subacute combined degeneration of the spinal cord is a classic complication.

131. What are Minerals?
Minerals are inorganic elements required for normal body functions.
They participate in enzyme activity, bone formation, and fluid balance.
They are classified as major and trace elements.

132. What is Calcium?
Calcium is the most abundant mineral in the human body.
It is essential for bone formation, muscle contraction, and blood coagulation.
About 99% of body calcium is stored in bones and teeth.

133. What is Phosphorus?
Phosphorus is an essential mineral present mainly as phosphate.
It is important for bone formation, ATP production, and nucleic acids.
It works closely with calcium in skeletal health.

134. What is Magnesium?
Magnesium is an important intracellular cation.
It acts as a cofactor for numerous enzymatic reactions.
It is essential for nerve and muscle function.

135. What is Sodium?
Sodium is the major extracellular cation.
It regulates fluid balance, osmotic pressure, and nerve conduction.
Normal serum sodium is approximately 135–145 mEq/L.

136. What is Potassium?
Potassium is the major intracellular cation.
It is essential for nerve transmission and muscle contraction.
Normal serum potassium is approximately 3.5–5.0 mEq/L.

137. What is Chloride?
Chloride is the major extracellular anion.
It helps maintain osmotic balance and acid-base equilibrium.
It is commonly associated with sodium in body fluids.

138. What is Iron?
Iron is an essential trace element required for hemoglobin synthesis.
It plays a vital role in oxygen transport and cellular respiration.
Iron deficiency is a common cause of anemia.

139. What is Ferritin?
Ferritin is the major intracellular iron storage protein.
It reflects the body's iron stores.
Serum ferritin is commonly measured to assess iron status.

140. What is Transferrin?
Transferrin is a plasma protein that transports iron in the bloodstream.
It delivers iron to tissues and bone marrow.
Its level is useful in evaluating iron disorders.

141. What is Copper?
Copper is a trace element involved in enzyme activity and iron metabolism.
It is necessary for connective tissue formation and antioxidant defense.
Copper deficiency may cause anemia and neurological symptoms.

142. What is Zinc?
Zinc is an essential trace element required for numerous enzymes.
It plays a role in immunity, growth, and wound healing.
Zinc deficiency may cause delayed healing and impaired taste.

143. What is Iodine?
Iodine is a trace element required for thyroid hormone synthesis.
It is essential for normal growth and metabolism.
Deficiency may cause goiter and hypothyroidism.

144. What is Fluoride?
Fluoride is a trace element important for dental health.
It strengthens tooth enamel and reduces dental caries.
Excessive intake may cause fluorosis.

145. What is Selenium?
Selenium is a trace element with antioxidant functions.
It is a component of glutathione peroxidase.
It protects cells from oxidative damage.

146. What is Hypocalcemia?
Hypocalcemia is a decrease in serum calcium concentration.
It may cause tetany, muscle cramps, and seizures.
Common causes include hypoparathyroidism and vitamin D deficiency.

147. What is Hypercalcemia?
Hypercalcemia is an increase in serum calcium concentration.
It may occur in hyperparathyroidism and malignancy.
Symptoms include kidney stones, bone pain, and confusion.

148. What is Hyponatremia?
Hyponatremia is a serum sodium level below 135 mEq/L.
It may result from excessive water retention or sodium loss.
Symptoms include headache, confusion, and seizures.

149. What is Hypernatremia?
Hypernatremia is a serum sodium level above 145 mEq/L.
It usually results from water loss exceeding sodium loss.
Patients may present with thirst, weakness, and altered consciousness.

150. What is Hypokalemia?
Hypokalemia is a serum potassium level below 3.5 mEq/L.
It may cause muscle weakness, cramps, and cardiac arrhythmias.
Common causes include vomiting, diarrhea, and diuretic therapy.

151. What is DNA?
DNA (Deoxyribonucleic Acid) is the genetic material of most living organisms.
It stores and transmits hereditary information from one generation to the next.
It consists of two polynucleotide strands arranged in a double helix.

152. What is RNA?
RNA (Ribonucleic Acid) is involved in the expression of genetic information.
It participates in protein synthesis and gene regulation.
Major types include mRNA, tRNA, and rRNA.

153. What are Nucleotides?
Nucleotides are the building blocks of nucleic acids.
Each nucleotide contains a nitrogenous base, pentose sugar, and phosphate group.
They form DNA and RNA through phosphodiester bonds.

154. What is a Nucleoside?
A nucleoside consists of a nitrogenous base attached to a pentose sugar.
It does not contain a phosphate group.
Addition of phosphate converts a nucleoside into a nucleotide.

155. What are Purines?
Purines are nitrogenous bases with a double-ring structure.
The two purines in nucleic acids are adenine and guanine.
They are components of both DNA and RNA.

156. What are Pyrimidines?
Pyrimidines are nitrogenous bases with a single-ring structure.
Cytosine, thymine, and uracil belong to this group.
Thymine occurs in DNA, while uracil occurs in RNA.

157. What is Replication?
Replication is the process by which DNA makes an identical copy of itself.
It occurs before cell division to ensure genetic continuity.
DNA polymerase is the key enzyme involved.

158. What is Transcription?
Transcription is the synthesis of RNA from a DNA template.
It occurs mainly in the nucleus of eukaryotic cells.
RNA polymerase catalyzes this process.

159. What is Translation?
Translation is the synthesis of proteins using mRNA as a template.
It occurs on ribosomes in the cytoplasm.
Amino acids are assembled according to the genetic code.

160. What is the Genetic Code?
The genetic code is the set of rules by which nucleotide sequences specify amino acids.
It is composed of triplet codons.
The code is nearly universal among living organisms.

161. What is a Codon?
A codon is a sequence of three nucleotides on mRNA.
Each codon specifies a particular amino acid or stop signal.
It directs protein synthesis during translation.

162. What is an Anticodon?
An anticodon is a sequence of three nucleotides present on tRNA.
It pairs complementarily with a codon on mRNA.
This ensures correct amino acid incorporation into proteins.

163. What is a Mutation?
A mutation is a permanent change in the DNA sequence.
It may occur spontaneously or due to environmental factors.
Mutations can be beneficial, harmful, or neutral.

164. What is a Point Mutation?
A point mutation involves a change in a single nucleotide base.
It may result in silent, missense, or nonsense mutations.
Such mutations can alter protein structure and function.

165. What is Gene Expression?
Gene expression is the process by which genetic information produces a functional product.
It includes transcription and translation.
It determines cellular structure and function.

166. What is Recombinant DNA Technology?
Recombinant DNA technology involves combining DNA from different sources.
It allows genetic manipulation for research and medicine.
It is widely used in biotechnology and pharmaceutical production.

167. What is PCR?
PCR (Polymerase Chain Reaction) is a technique used to amplify DNA.
It produces millions of copies of a specific DNA segment.
It is widely used in diagnosis, forensics, and research.

168. What is Electrophoresis?
Electrophoresis is a laboratory technique used to separate molecules by charge and size.
It is commonly used for DNA, RNA, and proteins.
The molecules migrate through a gel under an electric field.

169. What is Southern Blotting?
Southern blotting is a technique used to detect specific DNA sequences.
DNA fragments are transferred to a membrane and probed.
It is useful in genetic analysis and diagnosis.

170. What is Northern Blotting?
Northern blotting is used to detect specific RNA molecules.
It helps study gene expression patterns.
RNA is separated, transferred to a membrane, and hybridized with probes.

171. What is Liver Function Testing?
Liver function testing refers to biochemical tests that assess liver health.
These tests evaluate hepatocellular injury and biliary function.
They include bilirubin, ALT, AST, ALP, and albumin measurements.

172. What are Liver Enzymes?
Liver enzymes are enzymes released into the blood during liver injury.
Common examples are ALT, AST, and ALP.
Their levels help assess liver disease severity.

173. What is Bilirubin?
Bilirubin is a yellow pigment formed from hemoglobin breakdown.
It is processed in the liver and excreted in bile.
Elevated levels cause jaundice.

174. What is Jaundice?
Jaundice is the yellow discoloration of skin and sclera due to hyperbilirubinemia.
It may result from hepatic, hemolytic, or obstructive causes.
Serum bilirubin levels are usually elevated.

175. What is SGOT (AST)?
SGOT or AST (Aspartate Aminotransferase) is an enzyme present in liver, heart, and muscle.
Its blood level rises in tissue injury.
It is used in the evaluation of liver and cardiac disorders.

176. What is SGPT (ALT)?
SGPT or ALT (Alanine Aminotransferase) is an enzyme found mainly in liver cells.
It is a sensitive marker of hepatocellular injury.
Elevated levels suggest liver disease.

177. What is Alkaline Phosphatase?
Alkaline phosphatase (ALP) is an enzyme present in liver, bone, intestine, and placenta.
Its level rises in cholestatic liver disease and bone disorders.
It is an important component of liver function tests.

178. What is Renal Function Testing?
Renal function testing assesses the ability of the kidneys to filter and excrete waste products.
Common tests include serum creatinine, blood urea, and GFR estimation.
These tests help diagnose and monitor kidney disease.

179. What is Serum Creatinine?
Serum creatinine is a waste product derived from muscle metabolism.
It is filtered by the kidneys and excreted in urine.
Its concentration is a useful indicator of kidney function.

180. What is Blood Urea?
Blood urea is the concentration of urea present in blood.
Urea is produced in the liver from ammonia metabolism.
Elevated levels may indicate renal impairment or increased protein breakdown.

181. What is Uric Acid?
Uric acid is the end product of purine metabolism in humans.
It is produced mainly in the liver and excreted by the kidneys.
Elevated levels may lead to gout and kidney stones.

182. What is GFR?
GFR (Glomerular Filtration Rate) is the volume of filtrate formed by the kidneys per minute.
It is the best overall indicator of kidney function.
A reduced GFR suggests impaired renal function.

183. What is Creatinine Clearance?
Creatinine clearance is a measure of the kidneys' ability to remove creatinine from blood.
It is used to estimate glomerular filtration rate.
Lower values indicate reduced renal function.

184. What is Thyroid Function Testing?
Thyroid function testing evaluates the activity of the thyroid gland.
The main tests include TSH, T3, and T4 measurements.
They help diagnose hypo- and hyperthyroidism.

185. What is TSH?
TSH (Thyroid-Stimulating Hormone) is secreted by the anterior pituitary gland.
It stimulates the thyroid gland to produce T3 and T4.
It is the most sensitive screening test for thyroid disorders.

186. What is T3?
T3 (Triiodothyronine) is an active thyroid hormone.
It regulates metabolism, growth, and energy production.
Most circulating T3 is formed from T4 in peripheral tissues.

187. What is T4?
T4 (Thyroxine) is the principal hormone secreted by the thyroid gland.
It serves as a precursor for T3 formation.
It plays an important role in growth and metabolism.

188. What are Cardiac Biomarkers?
Cardiac biomarkers are substances released into blood following myocardial injury.
They assist in the diagnosis and monitoring of heart diseases.
Examples include troponins, CK-MB, and myoglobin.

189. What is Troponin?
Troponin is a regulatory protein present in cardiac muscle fibers.
Its blood concentration rises significantly after myocardial infarction.
It is the most sensitive and specific marker of cardiac injury.

190. What is CK-MB?
CK-MB is an isoenzyme of creatine kinase predominantly found in cardiac muscle.
Its level increases following myocardial damage.
It is useful in diagnosing acute myocardial infarction.

191. What is Metabolomics?
Metabolomics is the study of all metabolites present in a biological system.
It provides information about metabolic pathways and cellular activity.
It is useful in disease diagnosis and biomarker discovery.

192. What is Proteomics?
Proteomics is the large-scale study of proteins in cells and tissues.
It examines protein structure, function, and interactions.
It helps understand disease mechanisms and drug targets.

193. What is Genomics?
Genomics is the study of the complete genetic material of an organism.
It includes gene structure, function, and interactions.
It plays a major role in modern molecular medicine.

194. What is Transcriptomics?
Transcriptomics is the study of all RNA transcripts produced by a genome.
It helps analyze patterns of gene expression.
It provides insights into cellular responses and disease processes.

195. What is Bioinformatics?
Bioinformatics is the application of computer technology to biological data.
It assists in analyzing DNA, RNA, and protein sequences.
It is essential in genomics and precision medicine.

196. What is Systems Biology?
Systems biology studies biological systems as integrated networks.
It combines molecular, cellular, and computational approaches.
It helps understand complex interactions within living organisms.

197. What is Personalized Medicine?
Personalized medicine tailors medical treatment to an individual's characteristics.
It considers genetic, environmental, and lifestyle factors.
It improves treatment effectiveness and reduces adverse effects.

198. What is Precision Medicine?
Precision medicine is an approach that uses genetic and molecular information for targeted therapy.
It aims to provide the right treatment to the right patient at the right time.
It is widely applied in oncology and genetic disorders.

199. What is Stem Cell Biology?
Stem cell biology is the study of stem cells and their properties.
Stem cells can self-renew and differentiate into specialized cells.
They have significant applications in regenerative medicine.

200. What is Nanomedicine?
Nanomedicine is the application of nanotechnology in healthcare and medicine.
It uses nanoscale materials for diagnosis, drug delivery, and therapy.
It offers improved precision and targeted treatment strategies.

201. Explain Glycolysis.
Glycolysis is the breakdown of glucose into pyruvate in the cytoplasm.
It produces ATP and NADH as energy sources.
It is the first pathway of glucose metabolism.

202. Explain the TCA Cycle.
The TCA cycle occurs in the mitochondrial matrix and oxidizes acetyl-CoA.
It generates NADH, FADH₂, and GTP.
These products are used for ATP production.

203. Explain Gluconeogenesis.
Gluconeogenesis synthesizes glucose from non-carbohydrate precursors.
It occurs mainly in the liver during fasting.
It helps maintain normal blood glucose levels.

204. Explain Glycogen Metabolism.
Glycogen metabolism includes glycogenesis and glycogenolysis.
These processes regulate glucose storage and release.
They help maintain energy balance in the body.

205. Explain β-Oxidation.
β-Oxidation is the mitochondrial breakdown of fatty acids.
It produces acetyl-CoA, NADH, and FADH₂.
These products contribute to ATP generation.

206. Explain Cholesterol Metabolism.
Cholesterol is synthesized mainly in the liver from acetyl-CoA.
It is used for bile acids, steroid hormones, and cell membranes.
Excess cholesterol contributes to atherosclerosis.

207. Explain Protein Digestion and Absorption.
Proteins are digested into amino acids by gastrointestinal enzymes.
Absorption occurs mainly in the small intestine.
The absorbed amino acids are used for protein synthesis and metabolism.

208. Explain the Urea Cycle.
The urea cycle converts toxic ammonia into urea in the liver.
It protects the body from ammonia toxicity.
Urea is excreted by the kidneys in urine.

209. Explain Enzyme Kinetics.
Enzyme kinetics studies the rate of enzyme-catalyzed reactions.
It evaluates factors affecting enzyme activity.
Km and Vmax are important kinetic parameters.

210. Explain Oxidative Phosphorylation.
Oxidative phosphorylation occurs in the inner mitochondrial membrane.
It uses electrons from NADH and FADH₂ to generate ATP.
It is the major source of cellular energy.

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