Photosynthesis Basic Concepts 2 — Questions and Answers
Question 1: Which organelle is the primary site of photosynthesis in plant cells?
- Mitochondria
- Chloroplast (Correct answer)
- Nucleus
- Ribosome
Correct answer: Chloroplast
Chloroplasts contain the pigments and enzymes needed to convert light energy into chemical energy.
Question 2: What color of light is LEAST effective for driving photosynthesis?
- Red
- Blue
- Green (Correct answer)
- Violet
Correct answer: Green
Green light is mostly reflected by chlorophyll, which is why plants appear green.
Question 3: Which of the following is a product of the light-dependent reactions?
- Glucose
- RuBP
- NADPH (Correct answer)
- Carbon dioxide
Correct answer: NADPH
The light-dependent reactions produce ATP, NADPH, and oxygen as their primary outputs.
Question 4: The Calvin cycle takes place in which part of the chloroplast?
- Thylakoid membrane
- Grana
- Stroma (Correct answer)
- Outer membrane
Correct answer: Stroma
The Calvin cycle occurs in the stroma, the fluid-filled space surrounding the thylakoids.
Question 5: How many carbon atoms does a molecule of carbon dioxide (CO₂) contribute to the Calvin cycle?
- 1 (Correct answer)
- 2
- 3
- 6
Correct answer: 1
Each CO₂ molecule contributes one carbon atom, which is incorporated into organic molecules during carbon fixation.
Question 6: What is the role of water in the light-dependent reactions?
- It absorbs light energy
- It is the source of electrons that replace those lost by chlorophyll (Correct answer)
- It combines with CO₂ to form glucose
- It transports ATP to the stroma
Correct answer: It is the source of electrons that replace those lost by chlorophyll
Water is split (photolysis) to donate electrons to chlorophyll P680, releasing oxygen as a byproduct.
Question 7: Which pigment is responsible for capturing most of the light energy used in photosynthesis?
- Carotenoid
- Xanthophyll
- Chlorophyll a (Correct answer)
- Phycoerythrin
Correct answer: Chlorophyll a
Chlorophyll a is the primary photosynthetic pigment that directly participates in the light reactions.
Photosynthesis Basic Concepts 2
Which organelle is the primary site of photosynthesis in plant cells?