NEET-UG Biology · Class 11
Factors affecting photosynthesis — NEET & JEE Questions
Factors affecting photosynthesis is a topic in Photosynthesis in Higher Plants, a Class 11 Biology chapter of the NEET-UG syllabus. TestBudy holds 12 published NEET-UG questions on Factors affecting photosynthesis, each with the marking scheme of the real paper.
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Factors affecting photosynthesis MCQs with solutions
10 of the 12 published questions on this topic, exactly as they appear in a test. Answers and worked solutions come with your result rather than on this page.
According to Blackman law of limiting factors, what determines the rate of a process when several factors can affect it?
- A. The factor present in the greatest amount
- B. The factor closest to its limiting minimum
- C. The average value of all factors
- D. Only temperature
How does water shortage commonly reduce photosynthesis before severe dehydration damages the photosynthetic machinery?
- A. It converts C3 plants into C4 plants
- B. It immediately destroys all chlorophyll
- C. It raises internal carbon dioxide sharply
- D. Stomatal closure limits CO2 entry
According to Blackman's law of limiting factors, the rate of photosynthesis is controlled by
- A. the factor nearest its limiting value
- B. the factor present in greatest excess
- C. all factors equally at all times
- D. only chlorophyll concentration
Which environmental factor directly supplies the carbon incorporated into carbohydrates during photosynthesis?
- A. Carbon dioxide concentration
- B. Oxygen concentration
- C. Soil nitrogen alone
- D. Humidity alone
Why may increasing light intensity fail to raise the photosynthetic rate of a well-lit leaf?
- A. Chlorophyll stops absorbing light above low intensity
- B. Light never affects photosynthesis
- C. Another factor, such as CO2, is limiting
- D. The Calvin cycle occurs only in darkness
A plant is supplied with abundant light and suitable temperature, but its photosynthetic rate rises when carbon dioxide concentration is increased. What was most likely limiting initially?
- A. CO2 availability
- B. Light intensity
- C. Temperature
- D. Chlorophyll presence
A leaf is exposed to strong light but very low carbon dioxide. Increasing light intensity further produces little rise in photosynthesis. The most likely limiting factor is
- A. carbon dioxide
- B. light
- C. chlorophyll is absent
- D. oxygen is absent
A plant's photosynthetic rate rises as temperature increases from 15°C to 25°C but falls sharply at 45°C. What best explains the decline?
- A. Photosynthetic enzymes become less effective or damaged at excessive temperature
- B. Light intensity necessarily becomes zero
- C. Carbon dioxide turns into oxygen
- D. Chlorophyll becomes a carbohydrate
At the same high light intensity, a C4 plant maintains a higher photosynthetic rate than a C3 plant under warm conditions and relatively low internal carbon dioxide. What best explains the difference?
- A. C4 plants bypass the Calvin cycle entirely in bundle-sheath cells
- B. C4 CO2 concentration suppresses photorespiration
- C. C3 plants lack chlorophyll a
- D. C4 plants obtain ATP without light
Plant P and Q receive equal light and CO2, but Q closes most stomata during drought. Why is Q's photosynthetic rate likely to fall?
- A. Reduced stomatal opening limits CO2 entry
- B. Closed stomata increase CO2 entry
- C. Stomata directly make glucose
- D. Drought converts chlorophyll to RuBisCO
Common mistakes in Factors affecting photosynthesis
Recorded against questions in this topic that are not shown above, so none of these points at an answer you can see on this page.
- Assuming the same factor must remain limiting throughout an experiment.
- Assumes one factor remains limiting across all environmental conditions.
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