Showing posts with label types of cell. Show all posts
Showing posts with label types of cell. Show all posts

Saturday, June 25, 2011

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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