Question

3.1.9 - 12.g the overall reactions for photosynthesis and cellular respiration are opposite of each other. select two statements that describe the two processes.
a. photosynthesis uses carbon dioxide from the atmosphere and produces oxygen.
b. cellular respiration uses carbon dioxide from the atmosphere and produces oxygen.
c. photosynthesis uses oxygen to release energy from food and produces carbon dioxide as a by - product.
d. cellular respiration uses oxygen to release energy from food and produces carbon dioxide as a by - product.
a and b
b and c
c and d
a and d

Explanation:

• Statement A: Photosynthesis is the process where plants use carbon dioxide ($CO_2$) from the atmosphere, water ($H_2O$), and light energy to produce glucose ($C_6H_{12}O_6$) and oxygen ($O_2$). The chemical equation is \(6CO_2 + 6H_2O+light

ightarrow C_6H_{12}O_6 + 6O_2\). So, this statement is correct.

• Statement B: Cellular respiration is the process where cells break down glucose in the presence of oxygen to release energy. The reactants are glucose and oxygen, and the products are carbon dioxide, water, and energy. The chemical equation is \(C_6H_{12}O_6+6O_2

ightarrow 6CO_2 + 6H_2O+energy\). It does not use carbon dioxide from the atmosphere to produce oxygen. So, this statement is incorrect.

• Statement C: Photosynthesis does not use oxygen to release energy from food. As mentioned above, it uses light energy, carbon dioxide, and water to produce glucose and oxygen. So, this statement is incorrect.
• Statement D: As per the cellular respiration equation \(C_6H_{12}O_6+6O_2

ightarrow 6CO_2 + 6H_2O+energy\), cellular respiration uses oxygen to release energy from food (glucose) and produces carbon dioxide as a by - product. So, this statement is correct.

Answer:

A. Photosynthesis uses carbon dioxide from the atmosphere and produces oxygen.
D. Cellular respiration uses oxygen to release energy from food and produces carbon dioxide as a by - product.
So the answer is A and D.