PRACTICE QUESTIONS WITH ANSWERS

TOPIC: INTRODUCTION TO BIOCHEMISTRY

SET 1.

1. Which of the following best describes biochemistry?

a) The study of chemical processes in rocks
b) The study of the structure and function of biomolecules
c) The study of chemical elements in the air
d) The study of chemical reactions in non-living systems
Answer: b)

2. What are the main classes of bioorganic substances?

a) Carbohydrates, lipids, proteins, nucleic acids
b) Water and inorganic salts
c) Enzymes and hormones
d) Vitamins and minerals
Answer: a)

3. Which of the following is NOT a function of lipids?

a) Forming cell membranes
b) Catalyzing biochemical reactions
c) Serving as an energy source
d) Acting as chemical messengers
Answer: b)

4. What is the primary function of enzymes in biochemical reactions?

a) To store genetic information
b) To catalyze and accelerate chemical reactions
c) To serve as structural components
d) To provide energy for cells
Answer: b)

5. Which molecule is considered the powerhouse of the cell?

a) Nucleus
b) Ribosome
c) Mitochondria
d) Chloroplast
Answer: c)

6. In which organelle does protein synthesis primarily occur?

a) Nucleus
b) Mitochondria
c) Ribosome
d) Lysosome
Answer: c)

7. What is the role of nucleic acids in the cell?

a) Providing energy
b) Storing genetic information and directing protein synthesis
c) Structuring cell walls
d) Catalyzing enzymatic reactions
Answer: b)

8. What is the primary purpose of the cell membrane?

a) To synthesize proteins
b) To separate the internal environment from the external environment
c) To generate energy
d) To transport DNA
Answer: b)

9. Which of the following best defines metabolism?

a) The process of cell division
b) The synthesis of nucleic acids
c) The set of life-sustaining chemical reactions in organisms
d) The formation of organelles
Answer: c)

10. Which organelle is involved in packaging and distributing proteins?

a) Ribosome
b) Nucleus
c) Golgi apparatus
d) Lysosome
Answer: c)

11. Which type of biomolecule is primarily responsible for catalyzing chemical reactions in cells?

a) Proteins
b) Lipids
c) Carbohydrates
d) Nucleic acids
Answer: a)

12. Where does photosynthesis occur in plant cells?

a) Mitochondria
b) Ribosomes
c) Chloroplasts
d) Lysosomes
Answer: c)

13. What is the function of lysosomes?

a) To produce ATP
b) To digest unwanted materials in the cell
c) To synthesize lipids
d) To store genetic material
Answer: b)

14. What is the main function of the endoplasmic reticulum?

a) Protein and lipid synthesis
b) Energy production
c) Digestion of macromolecules
d) Transport of genetic material
Answer: a)

15. What does the nucleus of a cell contain?

a) Lipids and proteins
b) Enzymes and ribosomes
c) Genetic material (DNA)
d) Carbohydrates and RNA
Answer: c)

16. Which of the following describes the structure of the cell membrane?

a) A rigid carbohydrate layer
b) A bilayer of phospholipids
c) A protein-only membrane
d) A single layer of nucleic acids
Answer: b)

17. What is the function of peroxisomes in the cell?

a) Energy production
b) Protein synthesis
c) Breakdown of hydrogen peroxide
d) Genetic information storage
Answer: c)

18. Which element is NOT one of the most common in living organisms?

a) Carbon
b) Oxygen
c) Nitrogen
d) Calcium
Answer: d)

19. What happens in oxidation-reduction reactions in metabolism?

a) Energy is stored in ATP
b) Electrons are transferred between molecules
c) Water is broken down into hydrogen and oxygen
d) Proteins are synthesized from amino acids
Answer: b)

20. Which cellular organelle is known as the "information center"?

a) Endoplasmic reticulum
b) Nucleus
c) Golgi apparatus
d) Lysosome
Answer: b)

SET 2.

1. Which of the following molecules is most abundant in living cells?

a) Lipids
b) Carbohydrates
c) Proteins
d) Water
Answer: d)

2. Which type of bond connects the nucleotides in a DNA strand?

a) Hydrogen bonds
b) Peptide bonds
c) Glycosidic bonds
d) Phosphodiester bonds
Answer: d)

3. What is the primary role of carbohydrates in cells?

a) To store genetic information
b) To provide energy
c) To catalyze reactions
d) To synthesize proteins
Answer: b)

4. Which of the following macromolecules acts as the main structural component of cell membranes?

a) Proteins
b) Carbohydrates
c) Lipids
d) Nucleic acids
Answer: c)

5. What is the primary storage form of glucose in animals?

a) Starch
b) Glycogen
c) Cellulose
d) Sucrose
Answer: b)

6. Which of the following is NOT a property of enzymes?

a) They are reusable
b) They lower the activation energy of a reaction
c) They are consumed during the reaction
d) They are specific to their substrates
Answer: c)

7. What type of molecule is ATP?

a) Carbohydrate
b) Lipid
c) Nucleotide
d) Protein
Answer: c)

8. Which process involves the breakdown of glucose to produce energy?

a) Photosynthesis
b) Glycolysis
c) Protein synthesis
d) DNA replication
Answer: b)

9. In which cellular organelle does oxidative phosphorylation occur?

a) Nucleus
b) Ribosome
c) Mitochondria
d) Chloroplast
Answer: c)

10. Which of the following best describes an amino acid?

a) A component of DNA
b) A building block of proteins
c) A storage form of glucose
d) A type of lipid
Answer: b)

11. What is the role of RNA in protein synthesis?

a) To store genetic information
b) To transport amino acids to ribosomes
c) To catalyze biochemical reactions
d) To provide energy
Answer: b)

12. Which of the following structures is found in plant cells but not in animal cells?

a) Cell membrane
b) Nucleus
c) Mitochondria
d) Cell wall
Answer: d)

13. Which part of the enzyme binds to the substrate?

a) Active site
b) Inhibitor
c) Coenzyme
d) Allosteric site
Answer: a)

14. What is the main function of chloroplasts?

a) ATP production
b) Protein synthesis
c) Photosynthesis
d) DNA replication
Answer: c)

15. Which molecule carries the genetic code from the nucleus to the ribosome for protein synthesis?

a) DNA
b) mRNA
c) tRNA
d) rRNA
Answer: b)

16. What is the backbone of a protein molecule composed of?

a) Sugar-phosphate
b) Amino acids
c) Fatty acids
d) Nucleotides
Answer: b)

17. Which of the following molecules is primarily involved in long-term energy storage in animals?

a) Glucose
b) Fatty acids
c) Amino acids
d) Ribose
Answer: b)

18. What is the function of the Golgi apparatus in the cell?

a) Synthesizing proteins
b) Modifying and packaging proteins
c) Producing ATP
d) Storing genetic information
Answer: b)

19. Which of the following is NOT a function of nucleic acids?

a) Storing genetic information
b) Providing cellular energy
c) Directing protein synthesis
d) Transmitting genetic information
Answer: b)

20. What is the role of cholesterol in cell membranes?

a) To catalyze reactions
b) To maintain membrane fluidity
c) To transport molecules across the membrane
d) To store energy
Answer: b)

TOPIC: CARBOHYDRATES

1. What are carbohydrates chemically classified as?

a) Hydrocarbons
b) Polyhydroxyaldehydes or polyhydroxyketones
c) Amino acids
d) Proteins
Answer: b)

2. Which of the following is NOT a function of carbohydrates?

a) Providing energy
b) Structural components of DNA and RNA
c) Storing genetic information
d) Forming part of cell membranes
Answer: c)

3. What is the empirical formula of carbohydrates?

a) CnH2nOn
b) CnHnOn
c) CnH2n+1On
d) CnH2n-2On
Answer: a)

4. Which of the following is the simplest form of carbohydrates?

a) Disaccharides
b) Polysaccharides
c) Monosaccharides
d) Oligosaccharides
Answer: c)

5. Glucose is classified as a(n):

a) Ketose
b) Aldohexose
c) Pentose
d) Disaccharide
Answer: b)

6. Which disaccharide is found in milk?

a) Maltose
b) Sucrose
c) Lactose
d) Fructose
Answer: c)

7. What is the linkage type found in cellulose?

a) α-1,4-glycosidic
b) β-1,4-glycosidic
c) α-1,6-glycosidic
d) β-1,6-glycosidic
Answer: b)

8. Which of the following is the sweetest sugar?

a) Glucose
b) Galactose
c) Fructose
d) Sucrose
Answer: c)

9. What is the function of glycogen in animals?

a) Immediate energy source
b) Long-term energy storage
c) Structural component
d) Genetic material
Answer: b)

10. The primary structural polysaccharide in plants is:

a) Glycogen
b) Starch
c) Cellulose
d) Chitin
Answer: c)

11. Which sugar is a component of RNA?

a) Glucose
b) Ribose
c) Fructose
d) Galactose
Answer: b)

12. Which molecule is known as blood sugar?

a) Sucrose
b) Glucose
c) Fructose
d) Galactose
Answer: b)

13. Which reaction forms a glycosidic bond between two monosaccharides?

a) Hydrolysis
b) Oxidation
c) Condensation
d) Phosphorylation
Answer: c)

14. What is the reducing disaccharide found in beer and germinating grains?

a) Lactose
b) Sucrose
c) Maltose
d) Cellobiose
Answer: c)

15. Which of the following is NOT a reducing sugar?

a) Maltose
b) Lactose
c) Sucrose
d) Glucose
Answer: c)

16. What polysaccharide gives a blue color when treated with iodine?

a) Glycogen
b) Starch (amylose)
c) Cellulose
d) Chitin
Answer: b)

17. In what form is glucose stored in the liver and muscle of animals?

a) Amylopectin
b) Glycogen
c) Starch
d) Cellulose
Answer: b)

18. What type of glycosidic bond is found in sucrose?

a) α-1,4-glycosidic
b) β-1,4-glycosidic
c) α-1,2-glycosidic
d) β-1,6-glycosidic
Answer: c)

19. Which of the following is a homopolysaccharide?

a) Hyaluronic acid
b) Starch
c) Heparin
d) Chondroitin sulfate
Answer: b)

20. What is the repeating unit in cellulose?

a) D-glucose
b) D-fructose
c) D-galactose
d) Ribose
Answer: a)

21. Which of the following is NOT true about amylopectin?

a) It is a branched polysaccharide
b) It has α-1,4-glycosidic bonds
c) It contains β-1,4-glycosidic bonds
d) It has α-1,6-glycosidic bonds
Answer: c)

22. What enzyme is responsible for the digestion of starch in humans?

a) Lactase
b) Amylase
c) Maltase
d) Sucrase
Answer: b)

23. Which polysaccharide is found in the exoskeleton of arthropods?

a) Starch
b) Chitin
c) Glycogen
d) Cellulose
Answer: b)

24. What is the name of the sugar derivative that results from the reduction of glucose?

a) Glucitol (Sorbitol)
b) Gluconic acid
c) Glucose-6-phosphate
d) Glucuronate
Answer: a)

25. Which polysaccharide serves as a lubricant in joints?

a) Cellulose
b) Hyaluronic acid
c) Chitin
d) Amylopectin
Answer: b)

26. In the structure of D-glucose, what is the name of the anomer where the OH group on the anomeric carbon is below the plane of the ring?

a) β-D-glucose
b) α-D-glucose
c) L-glucose
d) β-D-fructose
Answer: b)

27. Which of the following is a trisaccharide?

a) Raffinose
b) Sucrose
c) Lactose
d) Maltose
Answer: a)

28. Which polysaccharide contains a mixture of α-1,3 and β-1,4-glycosidic linkages?

a) Starch
b) Amylose
c) Carageenan
d) Glycogen
Answer: c)

29. Which sugar is involved in cell recognition processes?

a) Fructose
b) Glucose
c) Galactose
d) Mannose
Answer: d)

30. What is the common term for invert sugar?

a) Glucose
b) Maltose
c) Hydrolyzed sucrose
d) Amylose
Answer: c)

31. Which enzyme is deficient in individuals with lactose intolerance?

a) Amylase
b) Sucrase
c) Lactase
d) Maltase
Answer: c)

32. Which disaccharide contains a β-1,4-glycosidic bond between glucose and galactose?

a) Maltose
b) Lactose
c) Sucrose
d) Cellobiose
Answer: b)

33. Which polysaccharide can humans not digest?

a) Glycogen
b) Amylose
c) Cellulose
d) Amylopectin
Answer: c)

34. Which sugar alcohol is commonly used as a sweetener in chewing gum?

a) Sorbitol
b) Fructose
c) Galactose
d) Ribose
Answer: a)

35. Which polysaccharide plays a structural role in cartilage?

a) Starch
b) Glycogen
c) Chondroitin sulfate
d) Amylopectin
Answer: c)

36. Which enzyme breaks down sucrose into glucose and fructose?

a) Sucrase
b) Lactase
c) Amylase
d) Maltase
Answer: a)

37. What is the general role of glycoproteins?

a) Energy storage
b) Catalyzing metabolic reactions
c) Cell-cell recognition and communication
d) Serving as structural components
Answer: c)

38. What is the source of dietary fiber in food?

a) Digestible carbohydrates
b) Starch
c) Indigestible carbohydrates
d) Protein
Answer: c)

39. What is the consequence of a lack of dietary fiber?

a) Soft stools
b) Increased plaque formation
c) Decreased cholesterol levels
d) Weight loss
Answer: b)

40. What glycosaminoglycan is used as an anticoagulant?

a) Hyaluronic acid
b) Heparin
c) Chondroitin sulfate
d) Glycogen
Answer: b)

TOPIC: LIPIDS

1. What defines a lipid?

a) A molecule that contains nitrogen
b) A water-soluble organic compound
c) An organic compound insoluble in water but soluble in non-polar solvents
d) A compound made up of amino acids
Answer: c)

2. Which of the following is NOT a classification of lipids based on their biochemical function?

a) Energy storage lipids
b) Membrane lipids
c) Vitamins
d) Emulsification lipids
Answer: c)

3. What is the primary function of triacylglycerols?

a) Membrane formation
b) Energy storage
c) Hormone production
d) Cell signaling
Answer: b)

4. Which of the following lipids is involved in membrane structure?

a) Triacylglycerols
b) Phospholipids
c) Eicosanoids
d) Steroid hormones
Answer: b)

5. Which of the following is a saturated fatty acid?

a) Oleic acid
b) Linoleic acid
c) Stearic acid
d) Arachidonic acid
Answer: c)

6. What does the term "polyunsaturated" mean in relation to fatty acids?

a) The fatty acid has no double bonds
b) The fatty acid has one double bond
c) The fatty acid has two or more double bonds
d) The fatty acid is fully hydrogenated
Answer: c)

7. What are omega-3 fatty acids known for?

a) Their ability to synthesize proteins
b) Their role in heart health and inflammation reduction
c) Their high saturation level
d) Their function as enzymes
Answer: b)

8. Which type of lipid is the main component of biological membranes?

a) Steroid hormones
b) Triacylglycerols
c) Phospholipids
d) Waxes
Answer: c)

9. What is the key structural feature of a phospholipid?

a) One fatty acid attached to glycerol
b) Two fatty acids and a phosphate group attached to glycerol
c) A single long-chain alcohol and a fatty acid
d) Four fused carbon rings
Answer: b)

10. Which lipid is classified as a steroid?

a) Cholesterol
b) Stearic acid
c) Lecithin
d) Triglyceride
Answer: a)

11. What is the function of bile acids in lipid digestion?

a) Breaking down proteins into amino acids
b) Emulsifying dietary fats
c) Synthesizing fatty acids
d) Storing energy in adipocytes
Answer: b)

12. Which of the following is an essential fatty acid?

a) Palmitic acid
b) Linoleic acid
c) Stearic acid
d) Oleic acid
Answer: b)

13. What is the primary role of cholesterol in cell membranes?

a) Catalyzing biochemical reactions
b) Providing energy
c) Stabilizing membrane fluidity
d) Serving as a precursor for vitamins
Answer: c)

14. Which molecule is known as a "bad cholesterol" because of its association with cardiovascular disease?

a) LDL (Low-Density Lipoprotein)
b) HDL (High-Density Lipoprotein)
c) VLDL (Very-Low-Density Lipoprotein)
d) Chylomicrons
Answer: a)

15. What are eicosanoids derived from?

a) Triacylglycerols
b) Cholesterol
c) Arachidonic acid
d) Phospholipids
Answer: c)

16. Which of the following is NOT a function of eicosanoids?

a) Regulating blood pressure
b) Inducing labor
c) Producing ATP
d) Mediating inflammatory responses
Answer: c)

17. What is a major function of steroid hormones?

a) Energy storage
b) Regulating reproduction and secondary sex characteristics
c) Forming cell walls
d) Enzyme activity regulation
Answer: b)

18. Which type of fat is considered beneficial and is recommended for consumption in a balanced diet?

a) Saturated fats
b) Monounsaturated fats
c) Trans fats
d) Hydrogenated fats
Answer: b)

19. Which of the following is an artificial fat substitute used in foods?

a) Lecithin
b) Olestra
c) Stearic acid
d) Cholesterol
Answer: b)

20. What lipid-soluble vitamin is involved in blood clotting?

a) Vitamin A
b) Vitamin D
c) Vitamin E
d) Vitamin K
Answer: d)

21. Which lipid is primarily responsible for transporting cholesterol from the liver to cells?

a) HDL
b) LDL
c) VLDL
d) Chylomicrons
Answer: b)

22. What lipid class does wax belong to?

a) Triacylglycerols
b) Steroids
c) Biological waxes
d) Eicosanoids
Answer: c)

23. Which process converts oils into solid fats by adding hydrogen?

a) Hydrolysis
b) Saponification
c) Hydrogenation
d) Esterification
Answer: c)

24. What is the primary difference between fats and oils?

a) Fats are unsaturated, while oils are saturated
b) Fats are solid at room temperature, while oils are liquid
c) Fats contain cholesterol, while oils do not
d) Fats are found in plants, while oils are found in animals
Answer: b)

25. What is the function of lipoproteins?

a) Catalyzing lipid digestion
b) Transporting lipids in the blood
c) Storing lipids in adipose tissue
d) Synthesizing lipids from carbohydrates
Answer: b)

26. Which lipid is a precursor for all steroid hormones?

a) Cholesterol
b) Palmitic acid
c) Lecithin
d) Oleic acid
Answer: a)

27. What type of lipid forms a protective coating on the leaves and fruits of plants?

a) Phospholipids
b) Waxes
c) Triacylglycerols
d) Cholesterol
Answer: b)

28. Which vitamin is known as the "antioxidant vitamin" and protects lipids from oxidation?

a) Vitamin A
b) Vitamin D
c) Vitamin E
d) Vitamin K
Answer: c)

29. What is the primary cause of lipid rancidity?

a) Hydrolysis of lipids
b) Oxidation of unsaturated fatty acids
c) Hydrogenation of fats
d) Saponification of fatty acids
Answer: b)

30. Which class of lipids is involved in cellular signaling and immune responses?

a) Eicosanoids
b) Phospholipids
c) Steroids
d) Triacylglycerols
Answer: a)

31. What lipid is essential for the production of vitamin D in the skin?

a) Cholesterol
b) Sphingomyelin
c) Stearic acid
d) Triacylglycerol
Answer: a)

32. Which lipid is involved in the emulsification of fats during digestion?

a) Phospholipids
b) Cholesterol
c) Bile acids
d) Triacylglycerols
Answer: c)

33. What lipid disorder is characterized by high levels of LDL in the blood?

a) Hypolipidemia
b) Hypercholesterolemia
c) Fatty liver disease
d) Lipid peroxidation
Answer: b)

34. Which lipid is important for the formation of the myelin sheath in neurons?

a) Sphingomyelin
b) Cholesterol
c) Triacylglycerol
d) Lecithin
Answer: a)

35. Which of the following lipids is known to promote inflammation and allergic responses?

a) Thromboxanes
b) Prostaglandins
c) Leukotrienes
d) Cholesterol
Answer: c)

36. What is the product of the saponification of triacylglycerols?

a) Cholesterol
b) Glycerol and fatty acid salts
c) Glycerophospholipids
d) Sphingolipids
Answer: b)

37. Which lipoprotein is known as "good cholesterol"?

a) LDL
b) HDL
c) VLDL
d) Chylomicrons
Answer: b)

38. What lipid forms the backbone of triglycerides?

a) Glycerol
b) Fatty acids
c) Cholesterol
d) Phospholipids
Answer: a)

39. What is the major role of biological waxes in plants and animals?

a) Storing energy
b) Acting as emulsifiers
c) Providing protection and waterproofing
d) Regulating body temperature
Answer: c)

40. Which type of transport requires energy to move lipids across cell membranes?

a) Passive transport
b) Active transport
c) Facilitated transport
d) Diffusion
Answer: b)

TOPIC: PROTEINS

1. What are proteins made up of?

   • A) Nucleotides

   • B) Amino acids

   • C) Lipids

   • D) Sugars
     Answer: B

2. What percentage of a cell's mass do proteins account for after water?

   • A) 10%

   • B) 50%

   • C) 15%

   • D) 5%
     Answer: C

3. Which element is not commonly found in proteins?

   • A) Carbon

   • B) Hydrogen

   • C) Nitrogen

   • D) Silicon
     Answer: D

4. What type of protein contains only amino acid residues?

   • A) Conjugated protein

   • B) Simple protein

   • C) Fibrous protein

   • D) Globular protein
     Answer: B

5. Albumin belongs to which class of proteins?

   • A) Structural proteins

   • B) Transport proteins

   • C) Simple proteins

   • D) Conjugated proteins
     Answer: C

6. Which of the following is a fibrous protein?

   • A) Hemoglobin

   • B) Albumin

   • C) Collagen

   • D) Immunoglobulins
     Answer: C

7. What is the function of myoglobin?

   • A) Transport oxygen in blood

   • B) Store oxygen in muscles

   • C) Breakdown fats

   • D) Fight infections
     Answer: B

8. What kind of protein is insulin?

   • A) Catalytic protein

   • B) Transport protein

   • C) Messenger protein

   • D) Structural protein
     Answer: C

9. Which amino acid is essential and must be obtained from the diet?

   • A) Glycine

   • B) Lysine

   • C) Alanine

   • D) Proline
     Answer: B

10. Which protein is responsible for oxygen transport in the blood?

    • A) Myoglobin

    • B) Collagen

    • C) Hemoglobin

    • D) Albumin
      Answer: C

11. Which protein stores iron in the body?

    • A) Myoglobin

    • B) Ferritin

    • C) Insulin

    • D) Albumin
      Answer: B

12. Which of the following proteins assists in movement?

    • A) Myosin

    • B) Hemoglobin

    • C) Insulin

    • D) Casein
      Answer: A

13. What kind of bond links amino acids in a protein?

    • A) Ionic bond

    • B) Hydrogen bond

    • C) Peptide bond

    • D) Disulfide bond
      Answer: C

14. Which of the following is not a type of secondary protein structure?

    • A) Alpha-helix

    • B) Beta-pleated sheet

    • C) Tertiary coil

    • D) Random coil
      Answer: C

15. What type of bond holds the alpha-helix structure together?

    • A) Covalent bonds

    • B) Hydrogen bonds

    • C) Ionic bonds

    • D) Disulfide bonds
      Answer: B

16. Which of the following proteins contains a prosthetic group?

    • A) Simple protein

    • B) Conjugated protein

    • C) Fibrous protein

    • D) Globular protein
      Answer: B

17. Which amino acid is achiral?

    • A) Glycine

    • B) Alanine

    • C) Phenylalanine

    • D) Serine
      Answer: A

18. Which structure represents the sequence of amino acids in a protein?

    • A) Primary structure

    • B) Secondary structure

    • C) Tertiary structure

    • D) Quaternary structure
      Answer: A

19. What percentage of collagen makes up the body’s total protein?

    • A) 10%

    • B) 50%

    • C) 30%

    • D) 5%
      Answer: C

20. What is the main type of bond involved in the tertiary structure of proteins?

    • A) Peptide bonds

    • B) Disulfide bonds

    • C) Hydrogen bonds

    • D) Covalent bonds
      Answer: B

21. Which amino acid is most commonly found in collagen?

    • A) Glycine

    • B) Proline

    • C) Lysine

    • D) Histidine
      Answer: B

22. The isoelectric point is the pH at which the amino acid:

    • A) Has a net negative charge

    • B) Has a net positive charge

    • C) Has no net charge

    • D) Denatures
      Answer: C

23. Which of the following is an example of a conjugated protein?

    • A) Collagen

    • B) Myoglobin

    • C) Hemoglobin

    • D) Albumin
      Answer: C

24. Which amino acid is a precursor for serotonin?

    • A) Tyrosine

    • B) Tryptophan

    • C) Glycine

    • D) Cysteine
      Answer: B

25. Which protein structure involves multiple polypeptide chains?

    • A) Primary structure

    • B) Secondary structure

    • C) Tertiary structure

    • D) Quaternary structure
      Answer: D

26. What is the primary structural difference between a fibrous and a globular protein?

    • A) Shape

    • B) Size

    • C) Composition

    • D) Charge
      Answer: A

27. Which protein structure is most important in determining function?

    • A) Primary structure

    • B) Secondary structure

    • C) Tertiary structure

    • D) Quaternary structure
      Answer: C

28. In proteins, which bond is responsible for stabilizing secondary structures?

    • A) Peptide bond

    • B) Hydrogen bond

    • C) Ionic bond

    • D) Disulfide bond
      Answer: B

29. Which amino acid forms disulfide bonds?

    • A) Methionine

    • B) Cysteine

    • C) Proline

    • D) Histidine
      Answer: B

30. What is the main role of lipoproteins?

    • A) Transport lipids

    • B) Store oxygen

    • C) Break down proteins

    • D) Fight infections
      Answer: A

31. Which protein is important in forming blood clots?

    • A) Albumin

    • B) Prothrombin

    • C) Myoglobin

    • D) Hemoglobin
      Answer: B

32. Which of the following amino acids is polar?

    • A) Valine

    • B) Serine

    • C) Leucine

    • D) Glycine
      Answer: B

33. What is the main role of structural proteins?

    • A) Store energy

    • B) Regulate metabolism

    • C) Provide mechanical support

    • D) Catalyze reactions
      Answer: C

34. Which amino acid is involved in protein synthesis but not used in standard proteins?

    • A) Selenocysteine

    • B) Proline

    • C) Tyrosine

    • D) Histidine
      Answer: A

35. What kind of molecule is an enzyme?

    • A) Lipid

    • B) Carbohydrate

    • C) Protein

    • D) Nucleic acid
      Answer: C

36. Which protein forms the hard protective covering of nails and hair?

    • A) Myosin

    • B) Keratin

    • C) Albumin

    • D) Globulin
      Answer: B

37. What is the storage form of glucose in animals?

    • A) Glucagon

    • B) Glycogen

    • C) Starch

    • D) Cellulose
      Answer: B

38. Which type of protein transports molecules like oxygen in the blood?

    • A) Structural protein

    • B) Transport protein

    • C) Regulatory protein

    • D) Enzymatic protein
      Answer: B

39. What is the primary structure of a protein determined by?

    • A) Sequence of amino acids

    • B) 3D shape

    • C) Number of peptide bonds

    • D) Polarity
      Answer: A

40. Which amino acid contains sulfur?

    • A) Glycine

    • B) Cysteine

    • C) Tyrosine

    • D) Alanine
      Answer: B