Biology

Photosynthesis in Plants

1,508 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

Green plants combine carbon dioxide and water in the presence of sun light to form food. This process is known as _________.

  1. photosynthesis

  2. respiration

  3. oxidation

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

Photosynthesis is the process by which green plants use sunlight to convert carbon dioxide and water into glucose (food) and oxygen. Chlorophyll in plant cells captures solar energy to drive this reaction, which is the foundation of most food chains on Earth.

Multiple choice

Which of the following processes is complementary to respiration?

  1. Circulation

  2. Photosynthesis

  3. Osmoregulation
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Photosynthesis and respiration are complementary processes - photosynthesis uses CO2 and water to produce glucose and oxygen (in chloroplasts using light energy), while respiration uses glucose and oxygen to produce CO2, water, and ATP (in mitochondria). They are essentially reverse reactions forming a biological carbon cycle. Circulation and osmoregulation are not complementary to respiration.

Multiple choice

The process of photosynthesis is

  1. reductive, exergonic and catabolic

  2. reductive, endergonic and catabolic

  3. reductive, exergonic and anabolic

  4. reductive, endergonic and anabolic
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Photosynthesis is reductive because it reduces CO2 to carbohydrate (adding electrons/hydrogen). It is endergonic because it requires energy input (light energy to drive the process). It is anabolic because it builds complex glucose molecules from simple CO2, breaking down water in the process. Endergonic reactions always require energy input, unlike exergonic reactions that release energy.

Multiple choice

Rate of photosynthesis is independent of

  1. intensity of light

  2. duration of light

  3. quality of light

  4. temperature
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The rate of photosynthesis (how fast it occurs at any moment) depends on light intensity (brighter light drives faster reactions), quality of light (specific wavelengths are absorbed), and temperature (affects enzyme activity). Duration (how long light is available) affects total photosynthetic output over time but not the instantaneous rate - a plant doesn't photosynthesize 'faster' just because the daylight period is longer.

Multiple choice

Which of the given gases is utilised by plants from atmosphere to prepare carbohydrates during photosynthesis?

  1. Nitrogen

  2. Oxygen

  3. Carbon dioxide

  4. Hydrogen

  5. Carbon monoxide
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Photosynthesis is a process used by plants in which energy from sunlight is used to convert carbon dioxide and water into molecules needed for growth. These molecules include sugars, enzymes and chlorophyll. In this process, green plants and some bacteria change light energy and carbon dioxide gas into usable chemical energy in the form of a sugar called glucose. Carbon dioxide plus water yields glucose and oxygen gas.

Multiple choice

Which of the following is not a property of chromoplasts?

  1. They do not change into other type of plastids.

  2. They are found in unexposed cells.

  3. They are irregular in shape.

  4. They range from brownish to reddish in colour.

  5. They provide colour to the organs.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

This is the correct option as this is not a property of chromoplasts. Chromoplasts are found in both exposed and unexposed cells.

Multiple choice

Why do algae float in water during the day and sink at night?

  1. They require light during day for photosynthesis.

  2. They accumulate food at night and get heavy.

  3. Become buoyant in light due to attachment of oxygen bubbles.

  4. Become light due to consumption of food.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Algae float in water during light and sink at night as during day it releases oxygen while photosynthesizing that makes it buoyant. However, during night it again sinks down at the bottom.

Multiple choice

The dark reaction of photosynthesis or Calvin Cycle refers to the pathway in which the free energy of ATP and reducing power of NADPH are used to fix CO2 to form carbohydrate. The first stable product of the dark reaction of photosynthesis is called _____________.

  1. RuBP

  2. glyceraldehyde-3-phosphate

  3. RuBisCO

  4. phosphoglycolate

  5. 3-Phosphoglycerate
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

3-Phosphoglycerate (PGA), a 3 carbon molecule is the first stable product of dark reaction of photosynthesis. Hence this pathway is also called C3 pathway.

Multiple choice

Match the columns:

 
Name of Element
Specific Role in plants
1. Manganese a. In the transfer of electron to P.S. II
2. Boron b. Catalyses oxidation reduction reactions
3. Copper c. Facilitates translocation of sugars
4. Chlorine d. Required during evolution of O2 in photosynthesis
  1. 1. Manganese d. Required during evolution of O2 in Photosynthesis
    2. Boron c. Facilitates translocation of sugars
    3. Copper b. Catalyzes oxidation reduction reaction
    4. Chlorine a. In the transfer of electrons to P.S.II
  2. 1. Manganese a. In the transfer of electrons to P.S. II
    2. Boron d. Required during evolution of O2 in photosynthesis
    3. Copper c. Facilitates translocation of sugars
    4. Chlorine b. Catalyses oxidation reduction reaction
  3. 1. Manganese b. Catalyses oxidation reduction reactions
    2.Boron c. Facilitates translocation of sugars
    3. Copper d. Required during evolution of O2 in photosynthesis
    4. Chlorine a. In the transfer of electrons to P.S. II
  4. 1. Manganese c. Required during evolution of O2 in photosyntesis
    2. Boron b. Catalyses oxidation reduction reactions
    3. Copper d. Required during evolution of O2 in photosynthesis
    4. Chlorine a. In the transfer of electrons to P.S. II
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

This is the correct match.