Question

which structure of a plant cell is non- living and what are its functions?

Answer 1

Non living1) Chromoplasts:

It contains the pigments other than chlorophyll, e.g. Phucoxanthin, phycocyanin etc.

2) Vacuole:

Plant cells have one or more vacuoles of variable size. The material contained in vacuole is called as cell sap.

3) Cell sap:

Cell sap is relatively less dense than the surrounding cytoplasm. It contains sugars, salts, proteins and phenols as well as some specific pigments e.g. anthocyanin.

4) Cell wall:

Plant cell is surrounded by a non-living and rigid coat called cell wall. The main function of the cell wall is to pro­vide plant cell a definite shape and mechanical support and strength to tissues and organs.

Types of organism:

There are two types of organism; prokaryotes and eukaryotes. There differences are given below.

Prokaryotes:

a. Prokaryotes have small cells (< 5 mm)

b. They are always unicellular

c. No nucleus or any membrane- bound organelles, such as mitochondria

d. DNA is circular, without proteins

e. Ribosomes are small (70S)

f. No cytoskeleton

g. Motility by rigid rotating flagellum made of flagellin

h. Cell division is by binary fission

i. Reproduction is always asexual

j. Huge variety of metabolic pathways

Eukaryotes:

a. Eukaryotes have larger cells (> 10 mm)

b. They are often multicellular

c. Always have nucleus and other membrane-bound organelles

d. DNA is linear and associated with proteins to form chromatin

e. Ribosomes are large (80S)

f. Always has a cytoskeleton

g. Motility by flexible waving undulipodium, made of tubulin

h. Cell division is by mitosis or meiosis

i. Reproduction is asexual or sexual

j. Common metabolic pathways