Plastids

Question 1

Introduction to Plastids

Answer 1

Plastids are double membrane bound organelle, found in plants and euglanoides

Question 2

About Plastids

Answer 2

Plastids contain certain pigments which imparts specific colours to the plant

Question 3

Based on type of pigments present, the plastids can be classified into?

Answer 3

Chloroplast
Chromoplast
Leucoplast

Question 4

Chloroplast

Answer 4

The chloroplast contains a green pigment known as chlorophyll, it also contains cartenoid pigments as well.
these pigments are responsible for trapping light energy which is important for photosynthesis

Question 5

Chromoplast

Answer 5

Chromoplast contain fat, soluble, cartenoid pigments such as carotene and xanthophylls which gives red, yellow, orange colour to the plant

Question 6

Leucoplast

Answer 6

colourless plastids which stores nutrient

Question 7

on the basis of what type of nutrients are stored, the plastids are classified into

Answer 7

Amyloplast: which stores carbohydrates
Elaioplast: stores oils and fats
Alueroplast: stores proteins

Question 8

Where are chloroplast found in plant body?
describe their shapes as well?

Answer 8

they are found in the mesophyll region of the leaves.
they are
- oval spherical
- discoid
- ribbon like organelle

their length (5 - 10)
width (2 - 4)

Question 9

How does the number of chloroplast present in chlamydomonas and chloroplast present in mesophyll differ

Answer 9

the number varies 1 per cell of chlamydomonas to a green alga to 20 - 40 per cell in mesophyll

Question 10

Describe about the inner membrane of chloroplast?

Answer 10

inner membrane of chloroplast is less permeable
The space limited by inner chloroplast membrane is known as stroma

Question 11

What are thylakoids?

Answer 11

A number of membranous flattened sacs in stroma are known as thylakoids

• membrane of thylakoids enclose a space called lumen

Question 12

What are grana?

Answer 12

when these thylakoids are arranged as stacks of coins these are known as grana or integral thylakoids.

Question 13

What is stroma lamellae?

Answer 13

they are flattened membranous tubules connecting the thylakoids of different grana are known as stroma lamellae

Question 14

More about stroma

Answer 14

The stroma of inner chloroplast membrane contains enzyme for the synthesis of proteins and carbohydrates.

It contains small double stranded DNA and Ribosomes
Ribosomes are lesser( 70S) than the cytoplasmic ribosomes (80S)