The form of energy that directly powers the synthesis of ATP in chloroplasts is: MCQ with Answer and Explanation

The form of energy that directly powers the synthesis of ATP in chloroplasts is:
A. Proton gradient (chemiosmosis)
B. Chemical energy of glucose
C. Light energy
D. Electric current
Answer: Option A
Solution (By JKSSB Mock Tests)
In both mitochondria and chloroplasts, ATP synthase uses the energy stored in a proton gradient across a membrane (thylakoid membrane in chloroplasts, inner mitochondrial membrane) to drive the synthesis of ATP from ADP and Pi. This process is chemiosmosis, proposed by Peter Mitchell.

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Practice More Biology Questions

Question #1
Which of the following is an algal biofertilizer used in rice fields?
A. Rhizobium
B. Azospirillum
C. Nostoc
D. Trichoderma

Correct Answer: Option C


Explanation:
Nostoc is a cyanobacterium (blue-green alga) that fixes atmospheric nitrogen and is used as a biofertilizer in rice paddies. Anabaena azollae with Azolla is also common. Rhizobium is bacterial biofertilizer for legumes, Azospirillum is a free-living nitrogen-fixing bacterium. Trichoderma is a fungal biocontrol agent. BGA biofertilizers increase organic nitrogen in soil.

This question belongs to: Science Biology
Question #2
Consider statements about environment: 1. The greenhouse effect is entirely unnatural. 2. Deforestation contributes to global warming. 3. Ozone depletion causes skin cancer. Which are correct?
A. 1, 2 and 3
B. 1 and 2 only
C. 2 and 3 only
D. 1 and 3 only

Correct Answer: Option C


Explanation:
The greenhouse effect is a natural process that keeps Earth warm; the problem is the enhanced greenhouse effect due to human activities. Deforestation reduces the number of trees absorbing CO2, increasing atmospheric greenhouse gases and contributing to global warming. Ozone layer depletion allows more harmful UV-B radiation to reach Earth, significantly increasing the risk of skin cancers. Thus, statements 2 and 3 are correct.

This question belongs to: Science Biology
Question #3
The genetic material in a retrovirus is:
A. Double-stranded RNA
B. Double-stranded DNA
C. Single-stranded DNA
D. Single-stranded RNA

Correct Answer: Option D


Explanation:
Retroviruses (e.g., HIV) possess two copies of single-stranded RNA and the enzyme reverse transcriptase, which transcribes the RNA into DNA upon infection. This DNA integrates into the host genome. Other viruses may have dsDNA, ssDNA, or dsRNA, but the defining feature of retroviruses is the RNA genome and reverse transcription.

This question belongs to: Science Biology