1. What is the difference between DNA and RNA?

- A) DNA is double-stranded and RNA is single-stranded.

- B) DNA has thymine and RNA has uracil.

- C) DNA is found in the nucleus and RNA is found in the cytoplasm.

- D) All of the above.

- Answer: D. All of the statements are true. DNA and RNA are both nucleic acids that store genetic

information, but they have different structures and functions.

2. What are the four types of tissues in the human body?

- A) Epithelial, connective, muscle, and nervous.

- B) Epidermal, cartilage, skeletal, and neural.

- C) Endothelial, collagen, cardiac, and glial.

- D) None of the above.

- Answer: A. Epithelial tissue covers the body surfaces and lines the cavities and organs.

Connective tissue supports and binds other tissues. Muscle tissue contracts and produces

movement. Nervous tissue transmits electrical impulses and coordinates activities.

3. What is the role of enzymes in biochemical reactions?

- A) They increase the rate of reactions by lowering the activation energy.

- B) They decrease the rate of reactions by raising the activation energy.

- C) They change the direction of reactions by altering the equilibrium constant.

- D) They change the products of reactions by modifying the substrate molecules.

- Answer: A. Enzymes are biological catalysts that speed up reactions by lowering the activation

energy, which is the amount of energy needed to start a reaction. Enzymes do not change the

direction or the products of reactions.

4. What are the three stages of cellular respiration and where do they occur in the cell?

- A) Glycolysis in the cytoplasm, Krebs cycle in the mitochondria, and electron transport chain in

the plasma membrane.