Type of Cell

Cell is the structural & functional unit of living organism.

Type of cell:

On the basis of the structure of nucleus cell is of two types –

1. Prokaryotic cell (e.g Bacteria)
2. Eukaryotic cell (e.g Human cell)

On the basis of physiological function cell is of two types -

1. Somatic cell (Body cell)
2. Sex cell (Reproductive cell)

Function of a cell: 

1. Function & assimilation – the process by which food substances are taken into the cells of the body after they have been digested & absorbed.

2. Growth & repair – Development & regeneration of organs.

3. Metabolism – the sum of all the chemical & physical changes that takes place within the body.

4. Respiration – the process of gaseous exchange.

5. Excretion - elimination of wastes product from the body.

6. Irritability & conductivity – Response to stimuli & communication with other cell.

Organelles (components) of cell:

A cell consists of –

1. Cell membrane – a semi-permeable membrane covering protoplasm. It protect the cell organelles.

2. protoplasm – it consist of Cytoplasm & Nucleus.

3. Cytoplasm – Except nucleus the rest of cell body is called Cytoplasm.

Organelles of Cytoplasm :

1. It consist of-
2. mitochondria: Rod-lide structure & is called power house of cell. Energy stored as ATP (Adenosine Triphosphate).
3. Endoplasmic Reticulum: It is a system of interconnecting membrane bound channels within the cytoplasm. Participate in protein synthesis.
4. Golgy body : Canal – like structure that helps in synthesis of carbohydrate cell membrane.
5. Lysosome:  Are tiny granules composed of RNA (Ribo Nucleic Acid) (65% & Protein (35%). It consists of subunits: Large – 50s & Smaller – 30s. Synthesize cytoplasmic protein.

Nucleus:

Centrally located a round mass is called nucleus. It is separated from cytoplasm gy a nuclear membrane. It contains 46 chromosomes of which 23 from mother & 23 from father that contain genes. Genes are composed of DNA (Deoxyribo Nucleic Acid – double helix structure of (chromosomes).

Chromosome:

There is some chromatin threads present in
the nucleus, called chromosome.
Chromosomes are the vital to the
everyday activities of the cell &
responsible for determining the hereditary
characteristics of the human body.

Functions of Nucleus:

1. It produces Ribosome.
2. Synthesize RNA & protein.
3. It inherits the character to the offspring through genes.
4. It influences growth & initiates divisions or reproduction of cell.

Parts of nucleus

1. Nuclear membrane
2. Nucleoplasm
3. Nucleolus
4. Nuclear reticulum or chromatin.

Structure of a cell

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Organ

Definition

Collection of tissues united together to perform a particular function is called organ.

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