Question:

1. Name the part of a cell in which

(i) many chemical REACTIONS occur with the help of enzymes.

(ii) a network of CHROMATIN fibres occurs.

(III) cellulose forms the main component

2. Differentiate between

(i) an organ and an organelle

(ii) a plant cell and an animal cell PERTAINING to the presence of plastids.

Answer:

1. (i) Cytoplasm

It is the jelly - like structure present in all the cells which contains many organelles in it.

(ii) Nucleus

It is the membrane - bound organelle which contains DNA and it also CONTROLS the activities of the cell

(iii) Cell wall

It is only found in the plant cell.

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2. (i) Organ :

• can be found everywhere in the body.
• visible through naked eyes.
• examples : liver, kidney, etc.

Organelle :

• can be found inside the cell.
• not visible through naked eyes.
• examples : mitochondria, ribosomes, etc.

(ii) Plant cell :

• contain plastids.
• types of plastids : Chloroplasts, Chromoplasts, Leucoplasts, etc.

Animal cell :

• don't contain plastids.
• don't contains any form of plastids.