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

An association is found between the wavelengths of light absorbed by chlorophyll and wavelengths of length that are associated with the greatest amount of oxygen released by plants. Based on the observation, the function of chlorophyll is

  1. It plays a role in cell respiration.

  2. It plays a role in the light reactions of photosynthesis.
  3. It takes part in $H _2O$ release.
  4. It takes part in $CO _2$ fixation.

  5. It generates energy.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Chlorophyll absorbs sunlight of particular wavelength that causes spitting of water at water splitting complex of photosystem II and oxygen gas is released. PSI absorbs light below 680nm while PS II is activated by light below 700 nm; so plants exhibit maximum amount of oxygen released when illuminated with simultaneous exposure to red and far red light. Fixation of $CO _2$ occurs during the dark reaction. Thus, the correct answer is B.

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

Total amount of dry weight of photosynthate produced by all type of plants per annum is

  1. 1.7 million tonnes

  2. 17 million tonnes

  3. 17000 million tonnes

  4. 170000 million tonnes
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Total amount of dry weight of photosynthate produced by all type of plants per annum is 170000 million tonnes. There are several factors, which limit the formation of dry weight such as reduced nitrogen fixation which will result in reduction of dry weight.

Therefore, the correct answer is option (D).

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

The site of photosynthesis in blue green algae is

  1. Chromatophores

  2. Mitochondria

  3. Chloroplast

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

Blue green algae are prokaryotic orgnanisms and lack membrane bound organelles. Mitochondria and cholroplast are double membrane bound organelles of eukaryotes that serve as site of aerobic respiration and photosynthesis respectively. Chromatophores are the pigment containing membranous structures that serve as site for photosynthesis in BGA. Correct answer is A.

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

Intact chloroplasts can be isolated with the help of

  1. Alcohol

  2. Acetone

  3. Carbon disulphide

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

Intact chloroplast from green leaves can be isolated by the acetone isolation method. The membranes of the chloroplast are proteinaceous in nature so it can be easily isolated by acetone. The samples obtained are loaded to the chromatography apparatus, which shows bands on the chromatogram.

So, the correct option is B. 

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

Number of grana present in a chloroplast is

  1. 10-20

  2. 20-30

  3. 30-40

  4. 40-60
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
  • A thylakoid refers to the membrane-bound internal compartment within the chloroplasts of a plant cell and cyanobacteria.
  • It is a site for light-dependent reactions of photosynthesis. 
  • It is made up of a thylakoid membrane which surrounds the thylakoid lumen.
  • A stack of thylakoid disk is organized to form grana.
  • Within a chloroplast of a plant cell, there are about 40- 60 grana and each granum are composed of 10 to 100 thylakoids.
  • So, the correct answer is '40-60'.
Multiple choice biology protectors of biosphere structure of chloroplast plastids photosynthetic pigments

Particles of thylakoid membranes involved in ATP synthesis are called

  1. Quantasomes
  2. $CF _0-CF _1$

  3. Photosystems

  4. Pyrenoids
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
  • The particles of thylakoid membrane responsible for ATP synthesis is a CF$ _1$ -CF$ _O$-ATP synthase.
  • It is embedded in the thylakoid membrane where the CF$ _1$-part is attached to the stroma. 
  • Therefore, ATP synthesis occurs on the stromal side of the thylakoid where the ATP molecules are required for carrying out the light-independent reactions of photosynthesis.
  • So, the correct answer is 'CF$ _0$−CF$ _1$'.
Multiple choice biology protectors of biosphere structure of chloroplast plastids photosynthetic pigments

Number of thylakoids in a granum is 

  1. 10-100

  2. 5-10

  3. 100-200

  4. 200-500
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
  • A thylakoid refers to the membrane-bound internal compartment within the chloroplasts of a plant cell and cyanobacteria.
  • It is a site for light-dependent reactions of photosynthesis. 
  • It is made up of a thylakoid membrane which surrounds the thylakoid lumen.
  • A stack of thylakoid disk is organized to form grana.
  • There are about  10 to 100 thylakoids within a granum and about 40- 60 grana in a plant cell.
  • So, the correct answer is '10-100'.
Multiple choice biology protectors of biosphere structure of chloroplast plastids photosynthetic pigments

All types of plastids possess essentially the same structure because they

  1. Perform the same function.

  2. Store food materials like starch, fat and protein.

  3. Occur in aerial parts.

  4. Can transform from one form to another.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Plastids are considered as sac-like organelles, generally involved in the formation or storage of food. These are chloroplast, chromoplast and leucoplast and are same in their structure to transform into one another during the requirement.

So the correct option is 'Can transform from one form to another.'.

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

Lipid content of chloroplast is

  1. 20-30%

  2. 5-10%

  3. 4-5%

  4. 1-2%
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
  • Plastids are a pigment containing double membrane-bound organelle which is the site of manufacture and storage of chemical compounds.
  • The chloroplast is a plastid which contains the green coloured pigment called chlorophyll and are present in the green parts of the plants that take part in the process called photosynthesis.
  • The outer chloroplast envelope is made up of lipid (20%-30%).
  • So, the correct answer is '20-30%'.
Multiple choice biology protectors of biosphere structure of chloroplast plastids photosynthetic pigments

The packet of thylakoids in a chloroplast is called

  1. Fret channels

  2. Granum

  3. Stroma thylakoid

  4. Photosynthetic thylakoid
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
  • A stack of thylakoid discs is organized to form grana.
  • A thylakoid refers to the membrane-bound internal compartment within the chloroplasts of a plant cell and cyanobacteria.
  • It is a site for light-dependent reactions of photosynthesis. 
  • There are about  10 to 100 thylakoid discs within a granum and about 40- 60 grana in a plant cell.
  • So, the correct answer is 'Granum'.
Multiple choice biology protectors of biosphere structure of chloroplast plastids photosynthetic pigments

Electron carriers involved in photophosphorylation are located in

  1. Outer chloroplast membrane

  2. Inner chloroplast membrane

  3. Stroma

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

The photophosphorylation reaction involves the conversion of ADP to ATP in the presence of sunlight. This takes place in the thylakoid membrane. The photosystem I and II that involves the electron carriers; are present in the thylakoid membranes of the chloroplast. here the light reaction of photosynthesis takes place.

So, the correct option is 'Thylakoid membrane'

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

Photosynthetic pigments found in the chloroplasts occur in

  1. Thylakoid membranes

  2. Plastoglobules

  3. Matrix

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

Photosynthetic or chloroplasts pigments that are found in the thylakoid membrane constitute grana of chloroplasts are the organic molecules that absorb light of specific wavelengths in the visible region due to the presence of conjugated double bonds and are chlorophyll a and b, carotenoids and xanthophylls.

So the correct option is 'Thylakoid membranes'.

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

Chloroplasts stroma of higher plants contains

  1. Chlorophyll

  2. Light dependent reaction enzymes

  3. Light independent reaction enzymes

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

A) Chlorophyll is located within the thylakoid membrane. But chlorophyll is present in both lower (algae) and higher plants and some bacteria as well.
B) The light-dependent reactions use light energy to make ATP and NADPH. This is also seen in lower plants.

C) Light-independent enzymes RuBisCO and RuBP are present only in higher plants.
D) Lysosomes are usually present in animal cells. They can be present in lower plants.
So the correct answer is 'Light independent reaction enzymes'.

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

In chloroplast, the highest number of protons are found in

  1. Antenna complex

  2. Stroma

  3. Lumen of thylakoids

  4. Inter-membrane space
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

During photosynthetic electron transport, protons (H$^+$) accumulate in the thylakoid space. These protons are released into thylakoid space after each split of water molecule during photooxidation and after each electron transport between PQH$ _2$ to cytochrome-f. Increase in the number of protons in the thylakoid space results in an increase in a proton gradient.

Hence, the correct answer is 'Lumen of thylakoids'.

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

Chlorophyll molecules are located in

  1. Thylakoid membrane

  2. Thylakoid lumen

  3. Stroma

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

A) The green pigment chlorophyll is located within the thylakoid membrane.

B) The thylakoid lumen does not contain chlorophyll.
C) The stroma does not contain any pigments.
D) The inner chloroplast membrane does not contain any pigments.
So the correct answer is 'Thylakoid membrane'.