The fundamental unit of life | class 9 science NCERT solutions

Chapter - 5

NCERT Class 9th solutions

Page 59

Ans1.

Robert hooke discovered cells in 1665 while examining a thin slice of cork through a self designed microscope. He saw that the cork resembled the structure of a honeycomb. The small boxes in the comb are called cells.

Ans2.

A cell is capable of independently carrying out all the necessary activities of life. So, they are called structural and functional unit of life.

Page 61

Ans1.
Carbon dioxide moves by diffusion and water move by osmosis through cell membrane.

Ans2.

It is called selectively permeable membrane because it allows the entry and exit of some substances, not all.

Page 63

Ans1. ((Pending))

Page 65

Ans1.

The two organelles which have their own genetic material are -

1) Mitochondria

2) Plastids

Ans2.

The cell will not be able to revive and lysosomes will digest it.

Ans3.

When the cell gets damaged, lysosomes may burst and the enzymes digest their own cell. Therefore, lysosomes are known as suicide bags.

Ans4.

The proteins are synthesized in the ribosomes that are also known as protein factories.

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