Tag: plastids

Questions Related to plastids

Lipid content of chloroplast is

biology protectors of biosphere structure of chloroplast plastids photosynthetic pigments

  1. 20-30%

  2. 5-10%

  3. 4-5%

  4. 1-2%

Show answer
Correct Option: A
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%'.

The packet of thylakoids in a chloroplast is called

biology protectors of biosphere structure of chloroplast plastids photosynthetic pigments

  1. Fret channels

  2. Granum

  3. Stroma thylakoid

  4. Photosynthetic thylakoid

Show answer
Correct Option: B
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'.

Electron carriers involved in photophosphorylation are located in

biology protectors of biosphere structure of chloroplast plastids photosynthetic pigments

  1. Outer chloroplast membrane

  2. Inner chloroplast membrane

  3. Stroma

  4. Thylakoid membranes

Show answer
Correct Option: D
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'

Stroma is the ground matrix of

biology protectors of biosphere structure of chloroplast plastids photosynthetic pigments

  1. Lysosomes

  2. Oxysomes

  3. Ribosomes

  4. Chloroplast.

Show answer
Correct Option: D
Explanation:

Stroma, refers to the colourless fluid surrounding the grana within the chloroplast. Within the stroma are grana, stacks of thylakoids, the sub-organelles, where photosynthesis is commenced before the chemical changes are completed in the stroma. The internal space enclosed by the chloroplast double membrane but excluding the thylakoid space. This space, filled with a colorless hydrophilic matrix, contains DNA, ribosomes and some temporary products of photosynthesis also known as chloroplastic stroma.

Match the columns and identify the correct option.

I II
(a) Thylakoids (i) Disc shaped sacs in Golgi apparatus
(b) Cristae (ii) Condensed structure of DNA
(c) Cisternae (iii) Flat membranous sacs in stroma
(d) Chromatin (iv) Infoldings in mitochondria
biology protectors of biosphere structure of chloroplast plastids photosynthetic pigments

  1. a-iv, b-iii, c-i, d-ii

  2. a-iii, b-iv, c-i, d-ii

  3. a-iii, b-i, c-iv, d-ii

  4. a-iii, b-iv, c-ii, d-i

Show answer
Correct Option: B
Explanation:
a) Thylakoid (internal photosynthetic membranes) is a membrane-bound compartment present within the stroma (ground matrix) of the cellular organelle called chloroplast.
b) The inner mitochondrial membrane has folds called cristae which helps in increasing the surface area.
c) The folds of the Golgi apparatus are called cisternae which are called the functional units of this organelle.
d) Chromatin is a viscous, gelatinous substance made up of DNA, RNA, basic proteins called histones or acidic proteins called nonhistones.
So, the correct answer is 'a-iii, b-iv, c-i, d-ii'.

Photosynthetic pigments found in the chloroplasts occur in

biology protectors of biosphere structure of chloroplast plastids photosynthetic pigments

  1. Thylakoid membranes

  2. Plastoglobules

  3. Matrix

  4. Chloroplast envelope.

Show answer
Correct Option: A
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'.

Chloroplasts stroma of higher plants contains

biology protectors of biosphere structure of chloroplast plastids photosynthetic pigments

  1. Chlorophyll

  2. Light dependent reaction enzymes

  3. Light independent reaction enzymes

  4. Lysosomes

Show answer
Correct Option: C
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'.

Dimorphic chloroplasts occur in

biology protectors of biosphere structure of chloroplast plastids photosynthetic pigments

  1. Pea

  2. Mango

  3. Sugarcane

  4. Cotton

Show answer
Correct Option: C
Explanation:

Chloroplast of C4 plants is dimorphic chloroplast because it shows two different types of the chloroplast. 

1). The chloroplast with grana

2). Chloroplast without grana and surrounded to the vascular bundle. 

The chloroplast is of 2 different types hence it's called as the dimorphic chloroplast. And it is best seen among sugarcane of the C4 plants.

So, the correct option is 'Sugarcane'.

Cytochrome $b _6$ and cytochrome f occur in

biology protectors of biosphere structure of chloroplast plastids photosynthetic pigments

  1. Ribosomes

  2. Mitochondria

  3. Chloroplasts

  4. Lysosomes

Show answer
Correct Option: C
Explanation:

The cytochrome b6f complex is an enzyme found in the thylakoid membrane in the chloroplast of plants, cyanobacteria, and green algae, that catalyzes the transfer of electrons from plastoquinol to plastocyanin.


So, the correct option is 'Chloroplast'.

Ground substance of chloroplast is

biology protectors of biosphere structure of chloroplast plastids photosynthetic pigments

  1. Stoma

  2. Stroma

  3. Granum

  4. Cisterna.

Show answer
Correct Option: B
Explanation:
Chloroplast is a double membrane structure which is only present in plants . Chloroplast has fluid which is called stroma it is responsible for dark reaction . There are sac like structure present in it which are called thylakoids which which help in light reaction.

So, the correct option is 'Stroma'.