Question

Give important points or summary of the Chapter "Cell - The basic unit of Life" Of Class 9th.
(Second time)

Answer 1

Hey dear...

Here's your answer...

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CELL-THE BASIC UNIT OF LIFE:

Structure

Cells are the smallest units of living things. They are too small to be seen with the naked eye, so we need to use microscopes to see their structures.

Cells have a cell membrane, cytoplasm and a nucleus. Plant cells also have a cell wall, and oft en have chloroplasts and a large vacuole containing cell sap.

The cell membrane is partially permeable, and it controls what enters and leaves the cell.

The cytoplasm is a jelly-like solution of many different substances in water. It is the site of many different metabolic reactions.

The nucleus contains the chromosomes, which are made of DNA. This is the genetic information and it controls the activities of the cell.

The cell wall of a plant cell is made of criss-crossing fibres of cellulose. It is fully permeable. It helps to support the cell, and prevents the cell bursting if it absorbs a lot of water.

The vacuole of a plant cell contains cell sap, which is a solution of sugars and other substances in water.

Chloroplasts contain the green pigment chlorophyll, which absorbs sunlight for photosynthesis. There may be starch grains inside the chloroplasts, which are the form in which plants store the food that they make in photosynthesis.

A tissue is a group of similar cellswhich work together to carry out a particular function. Tissues are grouped into organs, and organs are grouped into organ systems

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@Rêyaañ11

Answer 2

HEYA!!!!

Here is your answer Rehan Bhai :
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Important points of the chapter :
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>> Cell was first discovered by Robert hooke in 1665.

>> Robert brown was the first to discover Nucleus of the cell.

>> The cell is the basic and structural unit of the cell. It helps in functioning of all processes like respiration, reproduction, excretion etc..

>> Every living thing is composed with many cells. There are crores of Cells present in the living bodies.

>> Cells are mostly in the spherical in shape.

>> Schleiden and Schwann proposed the cell theory.

ORGANELLES OF CELL :
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Cell wall : Cell wall is made up of cellulose. Cell wall is present in the plant cell. Most of the cell walls are erect.

Cell membrane or plasma membrane : Plasma membrane is composed with lipids and protiens. It is semi permeable in nature. It helps in containing the cytoplasm.

Nucleus : Nucleus is the control room of the cell. It is filled with fluid called Nucleoplasm. Nucleus controls all the functions of cell. Nucleus contain chromosomes which are useful in cell division.

Mitochondria : Mitochondria is called as power house of the cell. It helps in the cellular respiration.

Endoplasmic reticulam : It is in eshk like structure. They are two types. Rough and smooth. It helps in the transportation of substances in the cell.

Golgi body : Golgi body is composed with many structures. It helps in the packing of the substances of the cell.

Lysosomes : These are small like structures with some enzymes. They burst out to remove the poisonous substances. So, they are called as Suicidal bags of the cells.

Ribosomes : These are the small dot like structures which are responsible for the protein synthesis.

Plastids : Plastids are present in the plant cells. They are similar to the mitochondria. Plastids are responsible for storing foods.

Chloroplast : These are present in plant cells. This contains a green pigment called Chlorophyll which is essential for the photosynthesis process.

Vacuoles : These are fluid filled chambers. They are big in plant cells. As only one vacuole is present in vacuole.


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