1. The primary function of carbohydrates is to:
(A) Store genetic information
(B) Provide energy
(C) Catalyze reactions
(D) Serve as structural components only
2. Proteins are composed of:
(A) Nucleotides
(B) Monosaccharides
(C) Amino acids
(D) Fatty acids
3. Lipids are primarily:
(A) Hydrophilic
(B) Hydrophobic
(C) Polar molecules
(D) Nucleic acids
4. Enzymes function as:
(A) Catalysts
(B) Structural proteins
(C) Hormones only
(D) Storage molecules
5. The bond linking amino acids in a protein is called:
(A) Peptide bond
(B) Hydrogen bond
(C) Glycosidic bond
(D) Phosphodiester bond
6. The basic building block of nucleic acids is:
(A) Nucleotides
(B) Amino acids
(C) Monosaccharides
(D) Fatty acids
7. The double helix structure of DNA was proposed by:
(A) Mendel and Morgan
(B) Franklin and Wilkins
(C) Hershey and Chase
(D) Watson and Crick
8. The main storage form of glucose in animals is:
(A) Glycogen
(B) Starch
(C) Cellulose
(D) Chitin
9. The main storage form of glucose in plants is:
(A) Glycogen
(B) Starch
(C) Cellulose
(D) Glucose-6-phosphate
10. Saturated fatty acids:
(A) Contain double bonds
(B) Contain single bonds only
(C) Are liquid at room temperature
(D) Are hydrophilic
11. Unsaturated fatty acids:
(A) Are always solid at room temperature
(B) Contain only single bonds
(C) Contain one or more double bonds
(D) Do not contain carbon
12. Cholesterol is a type of:
(A) Carbohydrate
(B) Lipid
(C) Protein
(D) Nucleic acid
13. The primary structure of a protein is:
(A) Sequence of amino acids
(B) 3D folding of protein
(C) Arrangement of alpha helices and beta sheets
(D) Association of multiple polypeptide chains
14. The secondary structure of a protein includes:
(A) Peptide bond sequence
(B) Alpha helices and beta sheets
(C) Tertiary folding
(D) Quaternary assembly
15. The tertiary structure of a protein refers to:
(A) Linear sequence of amino acids
(B) Beta sheets only
(C) Alpha helices only
(D) 3D folding of a single polypeptide
16. The quaternary structure of a protein refers to:
(A) Folding of a single polypeptide
(B) Only beta sheets
(C) Primary sequence
(D) Association of multiple polypeptides
17. Glycolysis occurs in:
(A) Nucleus
(B) Endoplasmic reticulum
(C) Mitochondrial matrix
(D) Cytoplasm
18. The end product of glycolysis is:
(A) Glucose
(B) Pyruvate
(C) Acetyl-CoA
(D) Lactate only
19. Citric acid cycle occurs in:
(A) Mitochondrial matrix
(B) Cytoplasm
(C) Nucleus
(D) Golgi apparatus
20. The final electron acceptor in the electron transport chain is:
(A) NAD+
(B) FAD
(C) Oxygen
(D) Pyruvate
21. ATP is produced primarily by:
(A) Electron transport chain and oxidative phosphorylation
(B) Glycolysis only
(C) Fermentation only
(D) Beta-oxidation only
22. NAD+ and FAD function as:
(A) Energy storage molecules
(B) Enzymes
(C) Structural components
(D) Electron carriers
23. Essential amino acids:
(A) Can be synthesized by the body
(B) Cannot be synthesized by the body and must be obtained from diet
(C) Are not used in protein synthesis
(D) Are only in plants
24. Non-essential amino acids:
(A) Cannot be synthesized by the body
(B) Are toxic
(C) Can be synthesized by the body
(D) Are not incorporated into proteins
25. Lipoproteins transport:
(A) Lipids in the blood
(B) Glucose
(C) Amino acids
(D) Nucleotides
26. The major energy currency of the cell is:
(A) GTP
(B) NADH
(C) ATP
(D) FADH2
27. Enzyme activity can be affected by:
(A) pH
(B) Temperature
(C) All of the above
(D) Substrate concentration
28. Competitive inhibitors:
(A) Increase enzyme activity
(B) Bind to another site and change enzyme shape
(C) Bind to the active site and prevent substrate binding
(D) Degrade the enzyme
29. Non-competitive inhibitors:
(A) Bind to the active site
(B) Enhance enzyme activity
(C) Bind to allosteric site and inhibit activity
(D) Only affect cofactors
30. Vitamins often act as:
(A) Enzymes
(B) Inhibitors
(C) Substrates
(D) Coenzymes
31. Minerals act as:
(A) Cofactors for enzymatic reactions
(B) Enzymes
(C) Substrates
(D) Inhibitors
32. DNA is composed of:
(A) Amino acids
(B) Ribose, phosphate, and nitrogenous bases
(C) Deoxyribose, phosphate, and nitrogenous bases
(D) Fatty acids
33. RNA differs from DNA because it:
(A) Has deoxyribose
(B) Is double-stranded only
(C) Has uracil instead of thymine
(D) Cannot be transcribed
34. The peptide bond is formed between:
(A) Two hydroxyl groups
(B) Carboxyl group of one amino acid and amino group of another
(C) Phosphate and sugar
(D) Nitrogen and phosphate
35. Enzyme-substrate complex is formed:
(A) Randomly
(B) Only in absence of cofactors
(C) Only during denaturation
(D) When substrate binds to enzyme’s active site
36. The Michaelis constant (Km) represents:
(A) Enzyme concentration
(B) Maximum velocity
(C) Substrate concentration at half-maximal velocity
(D) Inhibitor concentration
37. Glycogen phosphorylase catalyzes:
(A) Conversion of glucose to pyruvate
(B) Synthesis of glycogen
(C) Breakdown of glycogen to glucose-1-phosphate
(D) Fatty acid oxidation
38. Lipase catalyzes:
(A) Carbohydrate metabolism
(B) Synthesis of triglycerides
(C) Breakdown of proteins
(D) Breakdown of lipids to glycerol and fatty acids
39. Transamination reactions are important for:
(A) Amino acid metabolism
(B) Nucleotide synthesis
(C) Glycolysis
(D) Fatty acid oxidation
40. The main product of beta-oxidation is:
(A) Pyruvate
(B) Glucose
(C) Amino acids
(D) Acetyl-CoA
41. Ketone bodies are synthesized in:
(A) Liver
(B) Muscle
(C) Brain
(D) Kidney
42. Lipids include:
(A) Triglycerides
(B) Phospholipids
(C) Steroids
(D) All of the above
43. The enzyme amylase hydrolyzes:
(A) Proteins
(B) Lipids
(C) Starch
(D) Nucleic acids
44. The major site of protein digestion in humans is:
(A) Mouth
(B) Stomach and small intestine
(C) Large intestine
(D) Liver
45. The major site of lipid digestion is:
(A) Mouth
(B) Stomach
(C) Small intestine
(D) Large intestine
46. Hormones like insulin regulate:
(A) Blood glucose levels
(B) Fatty acid metabolism
(C) All of the above
(D) Protein synthesis
47. ATP consists of:
(A) Cytosine, ribose, and phosphate
(B) Guanine, ribose, and two phosphate groups
(C) Adenine, deoxyribose, and phosphate
(D) Adenine, ribose, and three phosphate groups
48. Oxidation of glucose to CO₂ and H₂O produces approximately:
(A) 2 ATP
(B) 4 ATP
(C) 30-32 ATP
(D) 10 ATP
49. Coenzyme A is derived from:
(A) Vitamin B1
(B) Vitamin B12
(C) Vitamin C
(D) Vitamin B5 (Pantothenic acid)
50. Glycoproteins are:
(A) Nucleotides only
(B) Lipids with sugar groups
(C) Proteins only
(D) Proteins with carbohydrate groups attached