Photosynthesis Chloroplast Structure 2 — Questions and Answers
Question 1: Which chloroplast membrane system contains the photosynthetic pigments?
- Outer membrane
- Inner membrane
- Thylakoid membrane (Correct answer)
- Tonoplast
Correct answer: Thylakoid membrane
Photosynthetic pigments like chlorophyll are embedded in the thylakoid membrane.
Question 2: The fluid-filled space surrounding the thylakoids inside the chloroplast is called the:
- Cytosol
- Stroma (Correct answer)
- Matrix
- Lumen
Correct answer: Stroma
The stroma is the aqueous phase of the chloroplast where the Calvin cycle reactions take place.
Question 3: How many membrane systems does a chloroplast have in total?
- One
- Two
- Three (Correct answer)
- Four
Correct answer: Three
Chloroplasts have three membrane systems: the outer envelope, the inner envelope, and the thylakoid membrane.
Question 4: Stacked thylakoid discs within a chloroplast are collectively called a:
- Stroma lamella
- Granum (Correct answer)
- Cristae
- Vesicle
Correct answer: Granum
A granum (plural: grana) is a stack of thylakoid discs connected like a pile of coins.
Question 5: What is the primary function of the thylakoid lumen?
- Houses the Calvin cycle enzymes
- Stores CO2 for fixation
- Maintains a proton gradient for ATP synthesis (Correct answer)
- Stores chlorophyll precursors
Correct answer: Maintains a proton gradient for ATP synthesis
Protons pumped into the thylakoid lumen create a concentration gradient that drives ATP synthase.
Question 6: Which of the following is found in the stroma of chloroplasts but NOT in the thylakoid membrane?
- Chlorophyll
- RuBisCO (Correct answer)
- Photosystem I
- ATP synthase
Correct answer: RuBisCO
RuBisCO is a stromal enzyme responsible for carbon fixation in the Calvin cycle.
Question 7: The space between the outer and inner chloroplast envelope membranes is called the:
- Stroma
- Lumen
- Intermembrane space (Correct answer)
- Periplasm
Correct answer: Intermembrane space
The intermembrane space lies between the two envelope membranes of the chloroplast.
Photosynthesis Chloroplast Structure 2
Which chloroplast membrane system contains the photosynthetic pigments?