21. Which of the following is an example of a polar molecule?
a) Carbon dioxide
b) Water
c) Oxygen gas
d) Methane
Answer: b) Water
22. Which of the following is not a function of carbohydrates in cells?
a) Energy storage
b) Structural support
c) Cell signaling
d) Enzyme synthesis
Answer: d) Enzyme synthesis
23. Which of the following is a characteristic of saturated fatty acids?
a) Liquid at room temperature
b) Double bonds between carbon atoms
c) Solid at room temperature
d) Found primarily in plant oils
Answer: c) Solid at room temperature
24. Which of the following is responsible for storing genetic information in cells?
a) DNA
b) RNA
c) Proteins
d) Lipids
Answer: a) DNA
25. What is the role of ribosomes in cells?
a) Protein synthesis
b) Energy production
c) DNA replication
d) Cell division
Answer: a) Protein synthesis
