Cell Structure and Functions class 8 worksheets

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Cell Structure and Functions class 8 worksheets

cell structure and function class 8 chapter 8. Download cell structure and function class 8 pdf worksheet based on the latest CBSE syllabus including fill in blanks, long questions define, identifying and more.

Cell-Structure and Functions class 8 worksheets from chapter 8 of NCERT Textbook

Cell is the basic structural and functional unit of life

In 1838, two german biologists Matthias Schleiden and Theodor Schwann put forward the cell theory of life 

Cell Organelles are the living parts of the cell that have a definite shape, structure and function.

A eukaryotic cell is a cell with a nuclear membrane and a well-defined nucleus

Genes are the unit of inheritance.

Multicellular organisms are made up of two or more cells.

A prokaryotic cell is a cell without a nuclear membrane around the nucleus

Turgidity: Distended or swallow, especially due to high fluid content

Organisms made of more than one cell are called multicellular (multi :many; cellular : cell) organisms. The number of cells is less in smaller organisms does not, in any way, affect the functioning of the organisms. an organism with billions of cells begins life as a single cell which is the fertilised egg. The fertilised egg cell multiplies and the number of cells increases as development proceeds.

The single-celled organisms are called unicellular (uni : one; cellular : cell) A single-celled organism performs all the necessary functions that multicellular organisms perform. A single-celled organism, like amoeba, captures and digests food, respires, excretes, grows and reproduces. Similar functions in multicellular organisms are carried out by groups of specialised cells forming different tissues. Tissues, in turn, form organs.

A white blood cell (WBC) in human blood is another example of a single cell which can change its shape. But while WBC is a cell, amoeba is a full fledged organism capable of independent existence.

size of a cell

The size of cells in living organisms may be as small as a millionth of a metre (micrometre or micron) or may be as large as a few centimetres. However, most of the cells are microscopic in size and are not visible to the unaided eye. The smallest cell is 0.1 to 0.5 micrometre in bacteria. The largest cell measuring 170 mm ×130 mm, is the egg of an ostrich

Cytoplasm

It is the jelly-like substance present between the cell membrane and the nucleus. Various other components, or organelles, of cells are present in the cytoplasm. These are mitochondria, golgi bodies, ribosomes, etc

small coloured bodies in the cytoplasm of the cells of Tradescantia leaf. They are scattered in the cytoplasm of the leaf cells. These are called plastids. They are of different colours. Some of them contain green pigment called chlorophyll. Green coloured plastids are called chloroplasts. They provide green colour to the leaves. You may recall that chlorophyll in the chloroplasts of  leaves, is essential for photosynthesis.

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