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 biology protectors of biosphere structure of chloroplast plastids photosynthetic pigments

Which of the following processes forms chemical potential energy from electromagnetic energy?

  1. Respiration

  2. Photosynthesis

  3. Decomposition

  4. Nitrogen fixation

  5. Fermentation
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Electromagnetic energy is the same as radiation or light energy. This type of kinetic energy can take the form of visible light waves, like the light from a candle or a light bulb, or invisible waves, like radio waves, microwaves, x-rays and gamma rays. Further, irrespective of where radiation is coming from, it can travel in a vacuum. The electromagnetic energy in plants can be converted to stored chemical energy during photosynthesis. 

Multiple choice biology protectors of biosphere structure of chloroplast plastids photosynthetic pigments

Which of the following is responsible for the red, orange and yellow colour of leaves?

  1. Carotenoids

  2. ATP

  3. Leaf decay

  4. Chlorophyll

  5. Over abundance of water
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Option 'A' is correct.

Carotenoids are responsible for the red, orange and yellow color of leaves. Carotenoids are present with chlorophyll, but in summer the leaves are green because of high levels of chlorophyll. Summer masks the color of carotenoids, During autumn, the color of carotenoids becomes more noticeable because of the degradation of chlorophyll. As the autumn progresses, carotenoids also degrade along with chlorophyll but at a much slower rate. Hence the yellow, orange, red colors become visible.   

Multiple choice biology protectors of biosphere structure of chloroplast plastids photosynthetic pigments

The light is trapped by photosynthetic pigments presents in the 

  1. Stroma

  2. Grana

  3. Quantosomes

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

The chloroplast is the cell organelles present in plant cells that are responsible for initiating the process of photosynthesis. Chloroplasts are double-membrane bound structures. The stroma of chloroplast is the jelly-fluid like structure in which another membrane system is presently called the thylakoids. These thylakoids are stacked upon each other to form the structure called grana. The grana are connected with each other by an extension of thylakoids called stroma lamellae. Thylakoid of grana has the photosynthetic pigments embedded in it that perform the trapping of sunlight and begin the light reaction of the photosynthesis.

A. Stroma is the region where the dark reaction of the photosynthesis occurs.
B. Grana is the region where the light reaction occurs through the trap of light by the photosynthetic pigment.
C. Quantasomes are the photosynthetic units made of pigments and are present in the grana.
D. Periplastidial space is the region between the inner membrane and the outer membrane of the plastids.
Hence, the correct answer is 'Grana'

Multiple choice biology protectors of biosphere structure of chloroplast plastids photosynthetic pigments

Chloroplast stroma contains

  1. Chlorophyll

  2. Light dependent reaction enzymes

  3. Light independent reaction enzymes

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

In photosynthesis, light-independent reactions are known as dark reactions. This process does not depend directly on the presence of light but is dependent on the products of light reaction i.e., ATP and NADPH. The dark reactions occur through Calvin cycle. They take place in the stromal matrix of the chloroplast. Chloroplast stroma contains light independent reaction enzymes which are required for the reaction. Thus, the correct answer is option C.

Multiple choice biology protectors of biosphere structure of chloroplast plastids photosynthetic pigments

Where does the primary photochemical reaction occurs in chloroplast ? Where does the light reaction of photosynthesis taken place?

  1. Stroma

  2. Endoplasmic reticulum

  3. Quantasome or thylakoids (Grana)

  4. Inner membrane of chloroplast
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In the chloroplast, the primary photochemical reactions occur. During photosynthesis, primary reactions like the light-capturing and ATP-generating reactions occur on grana. Grana are stakes of thylakoids. Quantasomes are particles found in grana. During photosynthesis, the light-dependent reactions take place on the thylakoid membranes. The inside of the thylakoid membrane is called the lumen. Light-independent reactions take place in the stroma. 

Thus, the correct answer is 'Quantasome or thylakoids (Grana).'

Multiple choice biology protectors of biosphere structure of chloroplast plastids photosynthetic pigments

Which of the following absorb light energy for photosynthesis : -

  1. Chlorophyll

  2. Water molecule
  3. O$ _{2}$

  4. RUBP
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
A pigment is a compound that absorbs a particular wavelength of visible light. Chlorophyll is a green pigment contained in thylakoid membranes of chloroplasts that are used in photosynthesis by plants. The process of photosynthesis occurs when green plants use the energy of light to convert carbon dioxide (CO2) and water (H2O) into carbohydrates. Light energy is absorbed by chlorophyll, a photosynthetic pigment of the plant, while air containing carbon dioxide and oxygen enters the plant through the leaf stomata.

So, the correct answer is 'Chlorophyll'.
Multiple choice biology protectors of biosphere structure of chloroplast plastids photosynthetic pigments

In which of the following parts of the plant cell does photosynthesis occur?

  1. The chloroplasts

  2. The mitochondria

  3. The nucleus

  4. The endoplasmic reticulum
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The green parts of the plants have the chlorophyll pigment containing chloroplasts. The chloroplast is a type of plastid which plays a major role in the photosynthesis process.

Multiple choice biology protectors of biosphere structure of chloroplast plastids photosynthetic pigments

What percentage of water, proteins, lipids and pigments are present in chloroplasts respectively?

  1. 50, 25, 15 and 10

  2. 90, 5, 2 and 3

  3. 95, 2, 1 and 2

  4. 85, 10, 3 and 2
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The chloroplasts are composed of the carbohydrates, lipids, proteins, chlorophyll, carotenoids (carotene and xanthophylls), DNA, RNA and certain enzymes and co-enzymes. The chloroplasts also contain some metallic atoms as Fe, Cu, Mn and Zn. By chemical analysis, these consist of lipids and proteins basically. Lipids are mainly phospholipid components of the membranes and lamellae. Proteins also contain enzymes, which are fully present in mature plastids. By the chemical analysis, it is observed that chloroplastids contain 90% of water, 5% of proteins, 2% of lipids and 3% of pigments.

Multiple choice biology protectors of biosphere structure of chloroplast plastids photosynthetic pigments

Thylakoids possess photosynthetic units called

  1. Photosystem.

  2. Electron transport system.

  3. Photolysis complex.

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

Thylakoid is a sheet-like membrane-bound structure which is the site of the light-dependent photosynthesis reactions within the chloroplasts and cyanobacteria. Photosystems are then functional and structural units of protein complexes involved in photosynthesis.

The electron transport chain is a series of the proteins and organic molecules which are found in the inner membrane of the mitochondria. Photolysis is the chemical process by which molecules are broken down into smaller units through the absorption of light.

The synthesis of ATP in chloroplasts, promoted by light, is termed as photophosphorylation

So the correct option is A.

Multiple choice biology protectors of biosphere structure of chloroplast plastids photosynthetic pigments

Which pigment absorbs the red and far-red light?

  1. Cytochrome

  2. Phytochrome

  3. Carotenoids

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

Phytochrome is a light sensitive pigment in plants and some bacteria and fungi. It exists in two interconvertible forms- Pr and Pfr. Pfr absorbs far red light of 730 nm wavelength. When it absorbs far red light, it converts to its original form, Pr. Thus Pfr is the active form of phytochrome which inhibits flowering.

Multiple choice biology protectors of biosphere structure of chloroplast plastids photosynthetic pigments

Solarisation is a process in which

  1. Sugars are formed with the help of solar energy

  2. Chlorophyll is formed

  3. Destrution of chlorophyll and ultimate death of protoplasmic compounds occurs

  4. None of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Chlorophyll pigments trap sunlight during the process of photosynthesis but get destroyed on exposure to light of higher intensity. An exposure to high light intensity for even a small duration can be harmful. The destruction of chlorophyll when exposed to light of high intensity is called as solarization. It occurs due to irreversible chemical changes in the structure of chlorophyll molecule.

Multiple choice biology protectors of biosphere structure of chloroplast plastids photosynthetic pigments

Photosynthetic units are referred as

  1. Quantasomes

  2. Oxysomes

  3. Phycobilisomes
  4. $F _{1}$ particles
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Photosynthetic units are referred as quantasomes. Quantasomes are particles found in the thylakoid membrane of chloroplasts in which photosynthesis takes place.

Oxysomes are the structures which are present on the surface of the folded inner membrane of the mitochondria. They are also called as f$ _0$-f$ _1$ particles or ATP synthase. They play an important role in the formation of energy for the functioning of the cell.
The protein complexes attached to thylakoid membranes are known as phycobilisomes. They are made up of phycobiliproteins and help in the transfer of light energy to chlorophyll-a molecule of photosystem-II.
Thus, the correct answer is option A. 

Multiple choice biology protectors of biosphere structure of chloroplast plastids photosynthetic pigments

Isotopes employed to study the process of photosynthesis reaction are

  1. $S^{68}\, and\, P^{32}$
  2. $C^{14}\, and\, O^{18}$
  3. $N^{14}\, and\, Co^{60}$
  4. $N^{14}\, and\, O^{18}$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Photosynthesis is a redox reaction in which carbon dioxide is reduced to sugars in dark reaction and water is oxidised to release oxygen in light reaction of photosynthesis. $C^{14}$ label was used to trace the path of carbon in the dark reaction in $C _3$ plants by Calvin, Benson and Basham. The $O^{18}$ label was used by Rumen and Kamen to experimentally prove that the source of oxygen released during light reaction of photosynthesis is water.

Multiple choice biology protectors of biosphere structure of chloroplast plastids photosynthetic pigments

Phytochrome is found in

  1. Algae.

  2. Virus.

  3. Gymnosperms.

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

The main photoreceptor for photoperiodism and many other light initiated plant responses (such as germination and seedling establishment) is phytochrome. It is a family of about five blue-green pigment proteins, each of which is coded for by a different gene in higher plants, like angiosperms. 

Multiple choice biology protectors of biosphere structure of chloroplast plastids photosynthetic pigments

Which of the following is true about photosynthesis?

  1. Light driven

  2. Photo driven

  3. Anabolic

  4. Enzyme moderated

  5. All of the above
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Option 'E' is true.

Photosynthesis is an anabolic endergonic and reductive process. Photosynthesis is a process of conversion of light energy into chemical energy. Light not only behaves as a wave but also has energy particles called photons which are different for different wavelengths. 
Photosynthesis is important because it is responsible for the release of oxygen by green plants into the atmosphere.