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

How is photosynthesis similar in C4 and CAM plants?

  1. In both pathways, only photosystem I is used.

  2. Both types of plants make sugar without Calvin cycle.

  3. In both cases, RUBISCO is not used to fix carbon initially.

  4. Both types of plants make most of their sugar in the dark.

  5. In both cases. thylakoids are not involved in photosynthesis.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In both plants, initial carbon is fixed by PEP carboxylase.

Multiple choice

Which of the following processes is most directly driven by light energy?

  1. Creation of a pH gradient by pumping protons across thethylakoid membrane

  2. Carbon fixation in the stroma

  3. Reduction of NADP molecules

  4. Removal of electrons from chlorophyll molecules

  5. ATP synthesis
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Chlorophyll absorbs a photon of light molecule causing the electrons to become excited and move to a higher energy level.

Multiple choice

Which process is most directly driven by light energy?

  1. Creation of a pH gradient by pumping protons across thethylakoid membrane

  2. Carbon fixation in the stroma

  3. Reduction of NADP-molecules

  4. Removal of electrons from chlorophyll molecules

  5. ATP synthesis
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Chlorophyll absorb a photon of light molecule, causing the electrons to become excited and move to a higher energylevel.these high energy level can flow along one of two pathways giving cyclic electron flow or noncyclic electron flow

Multiple choice

In plants, the transcription of Cab genes has been previously shown to be regulated by a circadian oscillator coupled to the red light-absorbing plant photoreceptor. Which among the following types of oscillating gene present in plants regulates the expression of CAB?

  1. Kai genes

  2. The CCA1 gene

  3. Frq gene

  4. The LHY gene

  5. Toc1 gene
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Toc1 gene, also known as Timing of CAB Expression 1 gene, is an oscillating gene found in the plants that is known to control the expression of CAB. It has been shown to affect the period of circadian rhythms through its repression of transcription factors. This was found through mutations of toc1 in plants that had shortened period of CAB expression.

Multiple choice

The nitrogen gets converted into its oxides during

  1. lightening

  2. transpiration

  3. decomposition

  4. photosynthesis
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Lightning provides the enormous energy needed to break the strong triple bond in atmospheric nitrogen (N2). This allows nitrogen to react with oxygen, forming nitrogen oxides like NO and NO2.

Multiple choice

In which of the following processes oxygen is not used up?

  1. Combustion

  2. Respiration

  3. Formation of oxides

  4. Photosynthesis
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Photosynthesis produces oxygen as a byproduct, it does not consume it. Combustion and respiration both use oxygen to produce energy, while oxide formation involves oxygen reacting with other elements.

Multiple choice

Which of the following gases is used up in respiration and released during photosynthesis?

  1. Nitrogen

  2. Carbon dioxide

  3. Oxygen

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

Oxygen is consumed during cellular respiration as the final electron acceptor in the electron transport chain, producing water and ATP. During photosynthesis, oxygen is released as a byproduct when water molecules are split to provide electrons for the light-dependent reactions. This reciprocal relationship sustains atmospheric oxygen levels.

Multiple choice

Which of the following processes converts atmospheric carbon into glucose molecules?

  1. Transpiration

  2. Fossilization

  3. Decomposition

  4. Photosynthesis
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Photosynthesis is the process where plants, algae, and some bacteria use sunlight to convert atmospheric carbon dioxide (inorganic carbon) into glucose (organic carbon). This occurs through the Calvin cycle where CO2 is 'fixed' into carbohydrate molecules. Transpiration is water loss, fossilization forms fossils, and decomposition breaks down organic matter.

Multiple choice

What do plants take in during day time?

  1. Take CO2 and give O2

  2. Take O2 and give O2

  3. Take CO2 and give CO2

  4. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

During daylight, plants perform photosynthesis, taking in carbon dioxide (CO2) and releasing oxygen (O2) as a byproduct. At night, they primarily respire, taking in O2 and releasing CO2. Options B and C incorrectly state the gas exchanges, and D is wrong because photosynthesis does occur during the day.

Multiple choice

Which of the following occurs both during cyclic and non-cyclic modes of photophosphorylation?

  1. Formation of ATP

  2. Release of O2

  3. Formation of NADPH

  4. Involvement of both PS-I and PS-II
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Both cyclic and non-cyclic photophosphorylation produce ATP. However, only non-cyclic photophosphorylation produces NADPH and releases oxygen (involving both Photosystem I and II). Cyclic photophosphorylation only involves Photosystem I and generates ATP without producing NADPH or oxygen.

Multiple choice

Which of the following statements is/are false about photosynthesis?

  1. It causes absorption of light energy by chlorophyll molecules.

  2. Water molecules are splitted into H2 and O2 atoms.

  3. ATP is formed in this process.

  4. The reaction of CO2 takes place to form carbohydrates.

  5. Options (2) and (4)
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

 The reaction of CO2 takes place in this process.