CXC - Caribbean Examinations Council Biology: Photosynthesis and Respiration Questions and Answers

Question 1

Which of the following is the correct balanced chemical equation for photosynthesis?

Accepted Answer

6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂

Answer

C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + ATP

Answer

C₆H₁₂O₆ → 2C₂H₅OH + 2CO₂

Answer

6O₂ + C₆H₁₂O₆ → 6H₂O + 6CO₂

Question 2

A student places a destarched plant in a sealed, transparent container under a bright light. After several hours, which TWO gases would be expected to show a net change in concentration inside the container?

Accepted Answer

Carbon dioxide decreases, Oxygen increases

Answer

Nitrogen increases, Oxygen decreases

Answer

Carbon dioxide increases, Oxygen increases

Answer

Nitrogen decreases, Carbon dioxide increases

Question 3

Which of the following statements correctly distinguishes between aerobic respiration and photosynthesis?

Accepted Answer

Respiration releases energy from glucose, while photosynthesis stores energy in glucose.

Answer

Respiration occurs only in animals, while photosynthesis occurs only in plants.

Answer

Respiration produces oxygen, while photosynthesis consumes oxygen.

Answer

Respiration occurs only in the dark, while photosynthesis occurs only in the light.

Question 4

In the absence of oxygen, yeast cells undergo anaerobic respiration. What are the main products of this process?

Accepted Answer

Ethanol and carbon dioxide

Answer

Lactic acid and ATP

Answer

Carbon dioxide and water

Answer

Glucose and oxygen

Question 5

A scientist is growing a water plant in a beaker of water with hydrogencarbonate indicator. The setup is placed under a lamp. Initially, the indicator is red. After one hour, it turns purple. What is the MOST likely limiting factor for photosynthesis at this point? (Indicator colours: Yellow = high CO₂, Red = normal CO₂, Purple = low CO₂)

Accepted Answer

Carbon dioxide concentration

Answer

Light intensity

Answer

Water availability

Answer

Temperature

Question 6

In which organelles do photosynthesis and aerobic respiration primarily occur within a typical plant cell, respectively?

Accepted Answer

Chloroplast; Mitochondria

Answer

Mitochondria; Chloroplast

Answer

Cytoplasm; Mitochondria

Answer

Nucleus; Chloroplast