Question 1

Based on the yeast experiment described, which temperature resulted in the highest rate of gas production, and what does this suggest about enzyme activity at different temperatures?

Accepted Answer

Flask 2 at 25°C; enzyme activity peaks at moderate temperatures before declining at higher temperatures.

Question 2

A student adds calcium carbonate to a solution containing pepsin and salivary amylase. Given that calcium carbonate increases pH, what will happen to the activity of both enzymes?

Accepted Answer

The activity of pepsin will decrease, and the activity of salivary amylase will increase.

Question 3

Which of the following best explains why the yeast produced less gas at 19°C and 40°C compared to 25°C?

Accepted Answer

Enzyme activity is reduced at both low and high temperatures due to decreased molecular motion and denaturation, respectively.

Question 4

Which component is missing from the membrane transport model if it is to represent active transport across a cell membrane?

Accepted Answer

Movement of solutes through a membrane protein.

Question 5

Which of the following is a base criterion that the model of membrane transport must feature to represent active transport?

Accepted Answer

The model features the use of energy.

Question 6

During which phase of the cell cycle does DNA replication occur?

Accepted Answer

S phase

Question 7

A student is testing the characteristics of living things using a sample of pond water. Which of the following claims is most accurate based on the cell theory?

Accepted Answer

The model should include ribosomes, because all cells synthesize proteins.

Question 8

Based on the experiment with mung beans, which light wavelength resulted in the least seedling growth?

Accepted Answer

Wavelengths 495–570 nm (green)

Question 9

Which of the following is NOT a correct conclusion about the student’s photosynthesis model?

Accepted Answer

Sugar is a key product of the light-dependent reactions.

Question 10

During prophase in mitosis, which of the following events occurs?

Accepted Answer

The chromosomes become visible and the nuclear envelope breaks down.

Question 11

Which type of protein is responsible for catalyzing chemical reactions in living organisms?

Accepted Answer

Enzyme

Question 12

Which of the following best describes the function of messenger proteins in living systems?

Accepted Answer

They transmit signals to coordinate processes between cells, tissues, and organs.

Question 13

If a mutation caused a cell to lack transport/storage proteins, which process would be most directly affected?

Accepted Answer

The cell’s ability to store and move molecules such as oxygen and iron.

Question 14

Which of the following statements about enzymes is correct?

Accepted Answer

Enzymes are proteins that lower the activation energy of reactions.

Question 15

A student observes that the rate of reaction for pepsin is highest at pH 2, while salivary amylase is highest at pH 7. Which equation best represents the relationship between enzyme activity and pH?

Accepted Answer

$$A = k 	imes e$$^{-\frac{(pH - pH_{opt}$$)^2$$}{2\$$sigma^2$$}}$

Question 16

Which process is most directly responsible for the movement of sodium ions across the cell membrane in the model shown?

Accepted Answer

Active transport via membrane proteins

Question 17

Which of the following best explains why green light is least effective for photosynthesis in plants?

Accepted Answer

Green light is reflected by chlorophyll, so less energy is available for photosynthesis.

Question 18

Which of the following is a correct statement about the role of proteins in the human body?

Accepted Answer

Proteins can function as enzymes, messengers, structural components, and transport/storage molecules.

Question 19

Which of the following best describes the relationship between the circulatory and respiratory systems in the human body?

Accepted Answer

The circulatory system delivers oxygen from the lungs to tissues, while the respiratory system exchanges gases with the environment.

General Biology: Enzymes, Cell Structure, Photosynthesis, and Protein Function

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