Biology

Photosynthesis in Plants

1,492 Questions

Photosynthesis is the biological process by which plants convert light energy into chemical energy. This page contains practice questions covering essential topics like chlorophyll, light reactions, and the pathways specific to plants. This material is crucial for medical entrance exams and academic assessments.

Chlorophyll and pigmentsLight reactionsCalvin cycleCAM plantsElectron transportPhotosynthesis factors

Photosynthesis in Plants Questions

Multiple choice

During light reaction of photosynthesis, which of the following happens?

  1. Polysaccharides are generated in pyrenoid.

  2. Carbohydrates are synthesised from CO2 and water.

  3. Photons from sunlight are trapped to produce ATP and O2.

  4. All of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Photons from sunlight are trapped to produce ATP and O2. The light reaction of photosynthesis is also called Hill reaction. This is the first step of photosynthesis where light energy from the sun is absorbed by chlorophyll and hydrolyses H2O to produce O2 and H+ ions. This H+ further reduces NADP to NADPH which finally produces ATP from ADP and Pi. This total step is called photophosphorylation.

Multiple choice

Which of the following is an abnormal and hazardous process for biological systems?

  1. Chemosynthesis

  2. Photorespiration

  3. Photo-oxidation

  4. Decolouration
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Photo-oxidation is the degradation of a polymer surface in the presence of oxygen or ozone. The effect is facilitated by radiant energy, such as UV or artificial light. This process is the most significant factor in weathering of polymers. Proteins, carbohydrates, fats and nucleic acids are all polymers.

Multiple choice

Amongst chlorophyll-a (C55H72O5N4Mg) and chlorophyll-b (C55H70O6N4Mg), which one has –CHO group and which has –CH3 group at C-3 position, respectively?

  1. CHO in Chl-a and CH3 in Chl-b

  2. Chl-a has both CHO and CH3 groups

  3. CH3 in Chl-a and CHO in Chl-b

  4. No CHO in Chl-b and CH3 in Chl-a
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Both the chlorophylls have similar structures but they do differ in their compositions, which cause the adaptability in different scenarios. From the given formula, it can be estimated that Chl-a has two more H and an O less than Chl-b. Therefore, CHO is present in Chl-b.

Multiple choice

How does photosynthesis reduce global warming?

  1. Photosynthesis gives out O2.

  2. Photosynthetic plants absorb toxins from air.

  3. It decreases the concentration of CO2.

  4. Photosynthetic plants bring rain.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Photosynthesis decreases the concentration of CO2 which is being added to the atmosphere by the respiration of organisms and burning of organic fuels. The reduction in the concentration of CO2 reduces global warming.

Multiple choice

Chloroplast cannot arise from

  1. pre existing chloroplast

  2. proplastids

  3. leucoplasts

  4. mitochondria

  5. both proplastids and leucoplasts
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Chloroplast cannot arise from mitochondria. So, this is right answer.

Multiple choice

The plastids are green due to the presence of

  1. chlorophyll

  2. haemocyanin

  3. carotenoids

  4. haemoglobin

  5. both chlorophylls and haemocynin
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The plastids are green due to the presence of carotenoids. So, this answer is right.