Cell and Its Types: Biology Notes With Key Points
Definition:
Cell is a smallest unit of life. It is the basic & structural unit of all living organisms.
Some vital information about Cell:
- The term ‘Cell’ introduced by Robert Hooke.
- First living cell was discovered by Leeuwenhoek.
- Study of cell is called – Cytology.
- The smallest cell – Mycoplasma gallisepticum.
- The biggest cell-Ostrich egg cell (dia-170-125mm).
- Biggest cell of human body – female ovum cell.
- Smallest cell of human body – Granule cell or red blood cell.
- Longest human cell – nerve cell.
Types of Cell:
Mainly cells are three types:
1. Prokaryotic Cell:- size of these cell is small, nucleus is not incondite and present in cytoplasm. Its contain 70s type chromosome, other membrane like mitochondria, Golgi bodies, ribosome etc. are also absent in this cell.
Example: Bacteria, Virus cell etc.
2. Eukaryotic Cell: nucleus present, size of cell basically large, membrane bounded nucleus, mitochondria, lysosome etc. Its contain 80S type ribosome.
Example: all animal and plant cell.
3. Mesokaryotic cell: its contain both characteristics of Prokaryotic Cell and Eukaryotic Cell, real nucleus present.
Example: peyridinium.
Structure of cell organs, there position and function:
Cell organs
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Position
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Functions
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Cell wall discovered by Robert Hooke
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Outer surface of cell, which is non living, rigid and made by cellulose, hemicelluloses and pectin.
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It’s giving the structure of cell, like oval, rectangle, square etc. and protects the living cell.
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Cell membrane
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Each and every living cell, outer side of protoplasm, made by protein & Lipid, double layer, elastic and thin.
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Protect Protoplasm, shape controller of cell, participate internal Diffusion and Osmosis work in cell.
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Nucleus discovered by Robert Brown.
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In protoplasm most dense, double layer membrane, almost circle part is called nucleus, nucleolus is stay in nucleus.
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It controls synthesis process so it’s called “control room” of cell.
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Cytoplasm
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Cytoplasm is free of nucleus and situated in protoplasm (discovered by Purkenje) , like jelly, the living organs present in cytoplasm are mitochondria, Golgi bodies,centrosome,plastid etc.
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Protect internal cell organs.
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Mitochondria discover by kolliker
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This are stay in Cytoplasm of living plant an animal, mitochondria surrounded by double layer membrane, rod shaped, in inner membrane founded many fold which is called “crisate”.
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Controlling creebs cycle at the time of respiration, energy compound ATP synthesize in mitochondria so it is called “Power house of Cell”
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Golgi Bodies discovered by Camilo Golgi
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Single membrane covering near to nucleus, circular shaped, parallel distribution in every living animal and plant cell is called Golgi bodies.
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Function of Golgi bodies store of protein & Lipid, merge and distribution which is produce in endoplasmic reticulum
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Plastid
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Found in plant cell, double layer membrane, stay in cytoplasm. It is two types: 1.chromoplast, (colour full) 2.leucoplast.(colour less) found in root.
Chloroplast also four types: a)chloroplast (green colour, involve in photosynthesis, is called “kitchen of the cell”) b) Fioplast (buff colour, found in fruit, seed) c) Redoplast (red colour, found in fruit, seed). d) Janthoplast (yellow colour, found in fruit, seed). |
Produced colour, take part in photosynthesis and store food.
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Endoplasmic reticulum discovered by Porter
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In cytoplasm there found network of tubules which spread from nucleus to cell membrane is called Endoplasmic reticulum; it has two parts 1.tubules 2.vesicols.
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Mainly established structure of Cytoplasm, chemical reaction different each other in cell.
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Ribosome, discovered by Robinson in Plants and Palade in animal.
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Granules made by ribonucleico protein attached to cytoplasm or Endoplasmic reticulum are called Ribosome.
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Protein synthesis
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Lysosome discovered by De Duve
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in cytoplasm in animal cell, covering by membrane like bladders.
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Digest extracerculler material which entre from outsource by enzyme, so it’s called “suicidal bag”
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Vacuole
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In cytoplasm, full of liquid like a vacuum, large in plant cell, small in animal cell.
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Difference types of material store in there.
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Deoxyribonucleic acid (DNA):
1. DNA discovered by James D Watson and Francis Crick.
2. It is two strands of double helix chain type.
3. Nucleotide has three components
a. Phosphate group: dioxiribose sugar and phosphoric acid.
b. Nitrogen base: Purins and pyrimidins,.
c. Sugar base:
4. Nucleoside: Sugar and Nitrogen base.
5. Pyrimidin base: Thymin and Cytosine.
6. Purins Base: Adinine and Guanine.
Ribonucleic acid (RNA):
1. it also a long chain of nucleotides.
2. Pyrimidin base: Urasil and Cytosine
3. Purins Base: Adinine and Guanine.
Three types of RNA:
a. Ribosomal RNA (r RNA)
b. Transfer RNA (t RNA)
c.Messenger RNA (m RNA)
NOTE: 70S or 80S here “S” as per name Scientist Svedberg, it is called unit of Svedberg.
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