1. What is the primary function of enzymes in biochemical reactions?
a) Provide energy
b) Speed up reactions
c) Store genetic information
d) Transport molecules
Answer: b) Speed up reactions
2. Which type of bond links amino acids together in a protein?
a) Hydrogen bond
b) Ionic bond
c) Covalent bond
d) Van der Waals bond
Answer: c) Covalent bond
3. What is the basic unit of carbohydrates?
a) Amino acid
b) Nucleotide
c) Monosaccharide
d) Fatty acid
Answer: c) Monosaccharide
4. Which molecule is considered the “energy currency” of the cell?
a) DNA
b) ATP
c) RNA
d) NADH
Answer: b) ATP
5. What is the role of ribosomes in a cell?
a) Protein synthesis
b) DNA replication
c) Lipid metabolism
d) Carbohydrate storage
Answer: a) Protein synthesis
6. Which of the following is a pyrimidine base found in DNA?
a) Adenine
b) Guanine
c) Cytosine
d) Thymine
Answer: c) Cytosine
7. What is the primary function of lipids in the body?
a) Provide immediate energy
b) Store genetic information
c) Serve as a long-term energy source
d) Act as enzymes
Answer: c) Serve as a long-term energy source
8. Which vitamin is essential for the synthesis of collagen?
a) Vitamin A
b) Vitamin B12
c) Vitamin C
d) Vitamin D
Answer: c) Vitamin C
9. What is the process by which glucose is broken down to produce ATP?
a) Photosynthesis
b) Glycolysis
c) Citric acid cycle
d) Beta-oxidation
Answer: b) Glycolysis
10. Which molecule carries genetic instructions from DNA to the ribosome?
a) tRNA
b) rRNA
c) mRNA
d) DNA
Answer: c) mRNA
11. What type of reaction involves the addition of water to break down molecules?
a) Dehydration synthesis
b) Hydrolysis
c) Condensation
d) Oxidation
Answer: b) Hydrolysis
12. Which organelle is responsible for ATP production in eukaryotic cells?
a) Endoplasmic reticulum
b) Golgi apparatus
c) Mitochondrion
d) Lysosome
Answer: c) Mitochondrion
13. What type of bond is formed between the phosphate groups in ATP?
a) Ionic bond
b) Hydrogen bond
c) Phosphoanhydride bond
d) Covalent bond
Answer: c) Phosphoanhydride bond
14. What is the primary function of the endoplasmic reticulum?
a) Protein and lipid synthesis
b) Cellular respiration
c) Genetic material storage
d) Waste removal
Answer: a) Protein and lipid synthesis
15. Which of the following is a monosaccharide?
a) Sucrose
b) Lactose
c) Glucose
d) Maltose
Answer: c) Glucose
16. What is the role of chaperone proteins in cells?
a) Provide energy
b) Assist in protein folding
c) Transport molecules
d) Synthesize DNA
Answer: b) Assist in protein folding
17. What is the end product of the citric acid cycle (Krebs cycle)?
a) Glucose
b) Pyruvate
c) Carbon dioxide and ATP
d) Lactic acid
Answer: c) Carbon dioxide and ATP
18. What type of macromolecule is an enzyme?
a) Carbohydrate
b) Lipid
c) Protein
d) Nucleic acid
Answer: c) Protein
19. What is the primary function of nucleotides?
a) Store energy
b) Store genetic information
c) Act as enzymes
d) Provide structural support
Answer: b) Store genetic information
20. Which amino acid contains a sulfur atom and forms disulfide bonds?
a) Cysteine
b) Glutamine
c) Lysine
d) Arginine
Answer: a) Cysteine
21. What is the primary role of the Golgi apparatus in a cell?
a) DNA replication
b) Protein modification and sorting
c) Lipid synthesis
d) Cellular respiration
Answer: b) Protein modification and sorting
22. Which process converts light energy into chemical energy in plants?
a) Cellular respiration
b) Photosynthesis
c) Fermentation
d) Glycolysis
Answer: b) Photosynthesis
23. What is the function of the nucleolus?
a) DNA replication
b) rRNA synthesis
c) Protein synthesis
d) Lipid metabolism
Answer: b) rRNA synthesis
24. Which lipid molecule is a major component of cell membranes?
a) Triglyceride
b) Phospholipid
c) Steroid
d) Glycolipid
Answer: b) Phospholipid
25. What is the name of the process by which proteins are synthesized from mRNA?
a) Transcription
b) Translation
c) Replication
d) Translation
Answer: b) Translation
26. Which type of RNA carries amino acids to the ribosome?
a) mRNA
b) rRNA
c) tRNA
d) DNA
Answer: c) tRNA
27. What is the primary function of the mitochondrion?
a) Protein synthesis
b) ATP production
c) Lipid metabolism
d) DNA replication
Answer: b) ATP production
28. What is the primary component of cell membranes?
a) Proteins
b) Carbohydrates
c) Lipids
d) Nucleic acids
Answer: c) Lipids
29. What is the role of ATP synthase in the mitochondrion?
a) DNA replication
b) Protein folding
c) ATP production
d) Lipid synthesis
Answer: c) ATP production
30. What type of chemical bond is found in the double helix of DNA?
a) Ionic bond
b) Covalent bond
c) Hydrogen bond
d) Metallic bond
Answer: c) Hydrogen bond
31. Which vitamin is crucial for the synthesis of coenzyme A?
a) Vitamin A
b) Vitamin B5
c) Vitamin C
d) Vitamin D
Answer: b) Vitamin B5
32. What is the main function of the rough endoplasmic reticulum?
a) Lipid synthesis
b) Protein synthesis
c) DNA replication
d) Detoxification
Answer: b) Protein synthesis
33. What is the role of coenzymes in biochemical reactions?
a) Act as enzymes
b) Provide energy
c) Assist enzymes by carrying chemical groups
d) Store genetic information
Answer: c) Assist enzymes by carrying chemical groups
34. What molecule serves as a signaling molecule in cells?
a) DNA
b) RNA
c) Hormones
d) Enzymes
Answer: c) Hormones
35. What is the main function of glycoproteins?
a) Provide structural support
b) Act as enzymes
c) Participate in cell-cell recognition and communication
d) Store genetic information
Answer: c) Participate in cell-cell recognition and communication
36. What is the role of ribozymes in cellular processes?
a) Catalyze biochemical reactions
b) Provide structural support
c) Store genetic information
d) Transport molecules
Answer: a) Catalyze biochemical reactions
37. Which of the following is a polysaccharide?
a) Glucose
b) Fructose
c) Starch
d) Sucrose
Answer: c) Starch
38. What is the role of the cytoskeleton in a cell?
a) Provide energy
b) Maintain cell shape and enable movement
c) Store genetic information
d) Produce ATP
Answer: b) Maintain cell shape and enable movement
39. What is the primary function of the lysosome?
a) DNA replication
b) Cellular digestion
c) Protein synthesis
d) Lipid metabolism
Answer: b) Cellular digestion
40. Which process involves the conversion of pyruvate to acetyl-CoA?
a) Glycolysis
b) Citric acid cycle
c) Oxidative phosphorylation
d) Pyruvate decarboxylation
Answer: d) Pyruvate decarboxylation
41. What is the primary role of chlorophyll in plants?
a) Absorb sunlight for photosynthesis
b) Store energy
c) Facilitate respiration
d) Transport nutrients
Answer: a) Absorb sunlight for photosynthesis
42. What is the name of the process that synthesizes glucose from non-carbohydrate sources?
a) Glycolysis
b) Gluconeogenesis
c) Fermentation
d) Krebs cycle
Answer: b) Gluconeogenesis
43. Which molecule is involved in the transfer of electrons during cellular respiration?
a) NADH
b) ATP
c) FADH2
d) Glucose
Answer: a) NADH
44. What is the main component of cell walls in plants?
a) Cellulose
b) Chitin
c) Peptidoglycan
d) Lignin
Answer: a) Cellulose
45. Which enzyme is responsible for DNA replication?
a) DNA polymerase
b) RNA polymerase
c) Ligase
d) Helicase
Answer: a) DNA polymerase
46. What is the main function of cholesterol in cell membranes?
a) Provide rigidity and fluidity
b) Act as an energy source
c) Store genetic information
d) Facilitate digestion
Answer: a) Provide rigidity and fluidity
47. What is the role of the enzyme amylase?
a) Break down proteins
b) Digestion of carbohydrates
c) Synthesis of DNA
d) Lipid metabolism
Answer: b) Digestion of carbohydrates
48. What molecule is produced as a byproduct of fatty acid oxidation?
a) Acetyl-CoA
b) Glucose
c) Lactic acid
d) Ethanol
Answer: a) Acetyl-CoA
49. Which molecule is the primary carrier of genetic information?
a) RNA
b) DNA
c) Protein
d) Carbohydrate
Answer: b) DNA
50. What is the main function of the endoplasmic reticulum in lipid synthesis?
a) Transport lipids to the Golgi apparatus
b) Synthesize lipids and hormones
c) Degrade lipids
d) Store genetic material
Answer: b) Synthesize lipids and hormones