Quiz: Photosynthesis and Respiration — 11 questions

1. Which sequence best describes the main stages of photosynthesis?

A. Glucose absorbs sunlight, water releases carbon dioxide, and oxygen is converted into hydrogen

B. Chlorophyll absorbs solar energy, water splits, energy becomes chemical, and carbon dioxide forms glucose

C. Carbon dioxide splits first, oxygen becomes chemical energy, and water produces chlorophyll

D. Water forms glucose, chlorophyll releases oxygen, and carbon dioxide supplies solar energy

Answer: (B)

Explanation

Photosynthesis begins with chlorophyll absorbing solar energy, followed by water splitting and conversion of that energy into chemical energy used to form glucose from carbon dioxide. The other sequences reverse or misidentify the substances and transformations involved.

2. What substances are used as the reactants in photosynthesis to produce glucose and oxygen?

A. Glucose and oxygen

B. Carbon dioxide and water

C. Oxygen and water

D. Carbon dioxide and glucose

Answer: (B)

Explanation

Green plants use carbon dioxide and water, powered by sunlight, to make glucose and oxygen. Glucose and oxygen are products of photosynthesis rather than its reactants.

3. What role does chlorophyll play in photosynthesis?

A. It converts oxygen into carbon dioxide

B. It stores glucose produced in the leaf

C. It releases oxygen from the leaf

D. It absorbs sunlight energy for the process

Answer: (D)

Explanation

Chlorophyll captures sunlight energy, allowing photosynthesis to occur in green leaves. Glucose is produced during photosynthesis, but it is not the pigment that absorbs the light.

4. A green leaf is exposed to bright sunlight. Which change reflects the products and gas movement associated with photosynthesis?

A. Carbon dioxide is produced, oxygen enters, and glucose is broken down

B. Oxygen is produced, glucose enters, and carbon dioxide leaves

C. Glucose is produced, carbon dioxide enters, and oxygen leaves

D. Water is produced, oxygen enters, and glucose leaves

Answer: (C)

Explanation

In bright sunlight, photosynthesis produces glucose and oxygen; carbon dioxide is absorbed while oxygen is released from the leaf. Glucose is a manufactured food product, so it does not enter the leaf as the starting material in this process.

5. What are the primary inputs and products of photosynthesis?

A. The inputs are glucose and water, and the products are carbon dioxide and oxygen.

B. The inputs are glucose and oxygen, and the products are carbon dioxide and water.

C. The inputs are carbon dioxide and water, and the products are glucose and oxygen.

D. The inputs are sunlight and oxygen, and the products are glucose and carbon dioxide.

Answer: (C)

Explanation

Photosynthesis uses carbon dioxide and water as inputs to produce glucose and oxygen as outputs. The process is driven by sunlight absorbed by chlorophyll, which enables the plant to synthesize glucose and release oxygen.

6. What are the main products formed during photosynthesis?

A. Glucose and oxygen

B. Carbon dioxide and water

C. ATP and glucose

D. Ethanol and carbon dioxide

Answer: (A)

Explanation

The primary products of photosynthesis are glucose and oxygen, which are produced when chlorophyll absorbs sunlight to convert carbon dioxide and water. Ethanol and carbon dioxide are products of anaerobic respiration, not photosynthesis.

7. What is the primary purpose of respiration in cells?

A. To store energy as starch or sucrose

B. To convert glucose into oxygen and carbon dioxide

C. To absorb sunlight and produce glucose

D. To produce ATP that provides energy for cellular activities

Answer: (D)

Explanation

The main purpose of respiration is to produce ATP, which supplies energy for various cellular processes. The other options describe processes related to photosynthesis or storage, not respiration.

8. During which time period did the understanding that aerobic respiration produces 38 ATP molecules from glucose become established?

A. In the mid-20th century, around 1950-1960.

B. In the 21st century, after 2000.

C. In the late 19th century, around 1880-1890.

D. In the early 20th century, around 1920-1930.

Answer: (D)

Explanation

The detailed understanding that aerobic respiration yields approximately 38 ATP from glucose was established through research in the early 20th century, particularly in the 1920s and 1930s. Earlier studies recognized the process but did not quantify ATP production as precisely.

9. How do photosynthesis and respiration differ in their use of glucose and their production of gases?

A. Photosynthesis produces glucose and consumes carbon dioxide, while respiration breaks down glucose to produce ATP and releases carbon dioxide.

B. Photosynthesis breaks down glucose to produce ATP and releases oxygen, whereas respiration produces glucose and consumes oxygen.

C. Photosynthesis consumes oxygen and produces glucose, while respiration uses glucose to produce oxygen and carbon dioxide.

D. Photosynthesis and respiration both produce glucose, but only respiration releases oxygen.

Answer: (A)

Explanation

Photosynthesis uses sunlight to produce glucose and absorbs carbon dioxide, releasing oxygen, whereas respiration breaks down glucose to generate ATP and releases carbon dioxide. The key difference is in their purpose and gas exchange: photosynthesis builds glucose and removes CO2, respiration breaks down glucose and releases CO2.

10. Who is credited with proposing the role of stomata as the primary structures facilitating gas exchange in plant leaves?

A. Stephen Hales

B. Jan Ingenhousz

C. Theodor Schwann

D. Joseph Priestley

Answer: (A)

Explanation

Stephen Hales is credited with proposing the role of stomata in gas exchange because of his pioneering work on plant physiology, including how gases like carbon dioxide and oxygen move through leaf pores. The other scientists contributed to different areas of biology or chemistry, but not specifically to the discovery of stomata's function.

11. What is the primary effect of the opening of stomata on a leaf's gas exchange during photosynthesis?

A. It prevents water loss by closing the pores.

B. It allows carbon dioxide to enter and oxygen to leave the leaf.

C. It increases the absorption of sunlight by chlorophyll.

D. It reduces the rate of transpiration in the plant.

Answer: (B)

Explanation

The opening of stomata permits carbon dioxide to enter the leaf and oxygen to exit, which is essential for photosynthesis. Closing stomata would limit gas exchange and reduce photosynthetic efficiency.