Learn 9th biology on itdunya.

[kashibhayya]

Assalam-o-alaikom!
Ab 9th biology sekhie itdunya par. Kaise? Main banunga apka teacher.
Main apko 9th biology asaan aur jame andaaz main sikhaonga aur apko behtareen notes faraham karonga.
Main apko yahan daily kuch topics sikhaonga bas apko daily is thread ko visit karna hai Qk agar topics reh gae to phir recover karna mushkil hai.
wo students jo 9th main achche marks hasil karne ki khwahish rakhte hain unhain mere har topic ko notebook main note karna parega.Qk mujhe yaqeen hai k is se behtar notes apko kahien se bhi nahi milainge.
NOTE:-Ap logon se guzarish hai k apni raaye ka izhar thread main mat kejie Qk is tarah thread bohut zyada lamba ho jaega aur students ka muqarrara topic tak rasaa'ee main bohut time zayaa ho jaega.
agar kisi ne sawal puchna ho to P.M par rabta karne ki koshish karain main har aik ko reply karun ga.
To shuru karte hain Is dua ke saath k Allah mujhe aur apko is kaam ko saheeh tareeqe se sar anjaam dene ki taufeeq dain.

[kashibhayya]

I think 1st chapter main itni mushkilat nahi hain.Isliye2nd chapter se start lete hain.

[kashibhayya]

MICROSCOPE:
"An instrument used to obtain a magnified image of minute objects is called a microscope."
OR
"An instrument which is used for the vission of small objects is called Microscope."
* Following are some kinds of microscope.
{1}:LIGHT MICROSCOPE: It has one convex lens or only an eye piece.
{2}:COMPOUND MICROSCOPE: It has a system of two lenses.
* It can magnify an object 1000 times to the original size.
{3}:ELECTRON MICROSCOPE: In this microscope a beam of electron is passed through the objects to be seen.
* It is the most powerful and modern form of microscope.
* It can magnify an object up to 250000 times of its actual size.
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1}:LIGHT MICROSCOPY: Observation by light or compound microscope is called Light microscopy.
For example: to study cell.
2}:ELECTRON MICROSCOPY: Observation by electron microscope is called Electron microscopy.

[kashibhayya]

CELL:
"The structural and functional unit of living organisms is called Cell."
Structural: All living organisms are made of cell.Therefore,cell is called the Structural unit.
Functional: All the basic functions of living organisms are performed by cells and hence known as the Functional unit.
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DISCOVERY OF CELL:
Cell was discovered by an English scientist Robert Hookein1665.
=> He examined a piece of cork under his own made microscope.
=> He noticed small chambers like honey comb with walls in them.
=> He named those chambers as cells.
=> Another scientist Robert Brown discovered nucleus in Plant cell.
=> A German zoologist Theodor Schwann discovered Animal cell with nucleus.
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CELL THEORY:
Cell theory was formulated by two German scientists named Mathias Schleiden a Botanist in 1838 and Theodor Schwann a zoologist in 1839.
=> Main points of cell theory are:
1}: All living organisms are made of one or more cells.
2}: Cell is the basic unit of structure and function in all living organisms.
3}: New cells arise from pre-existing cells by cell division.
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SHAPE OF CELL:
Cells are different in shape.
=> They may be round,oval,elongated or polygonal.
=> Some cells have irregular shape,e.g. Amoeba.
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SIZE OF CELL:
The cells of animals and plants show great variation in their sizes.
=> The majority of cells are extremely small and can be seen only with the help of microscope.
e.g. Blood cells,bacterial cell etc.
=> The size of few cell may be as large as which can be seen with naked eye.
e.g. Amoeba cell can be seen in the form of white spots on rotten leaves in water.
Note:The smallest cell,a type of bacteria is known as mycoplasma while the largest cell is an egg of Ostrich.
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[kashibhayya]

Q:-> Describe the structure of an animal cell?
Ans: STRUCTURE OF ANIMAL CELL:
A typical animal cell consists of three parts.
{1}. Cell membrane
{2}. Cytoplasm with organelles.
{3}. Nucleus.
1}: CELL MEMBRANE:
Cell membrane or Plasma membrane is the outermost layer of an animal cell.
=> It is two layered,thin,delicate,elastic and semi-permeable.
=> It is composed of protiens and lipids.
=> The lipid layer lying centrally while the protien layer present outerly.
Functions:
1}. It gives shape to animal cell.
2}. It provides protection to the cell.
3}. It controles and regulates the flow of materials from and to the cell.
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2}: CYTOPLASM:
"The translucent,living,viscous substance lying between the nucleus and Cell membrane is called Cytoplasm".
=> It consists of two portions.
{a} Ectoplasm
{b} Endoplasm
{a}. Ectoplasm: It is the outer clear portion.
{b}. Endoplasm: It is the inner granular portion.

Chemical composition of Cytoplasm:-
=> Chemically it is composed of 90% water and 10% vital molecules of life such as protiens,carbohydrates,fats,inorganic salts,waste materials and storage products.

Cytoplasmic organelles:
It contains minute living structures known as Cytoplasmic organelles such as,
{a} Mitochondria
{b} Golgi bodies
{c} Endoplasmic reticulum
{d} Ribosomes
{e} Centrosome
{f} Lysosomes.

Function:
Cytoplasm stores useful substances and is a site of anaerobic respiration.
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{3}: NUCLEUS:
"Nucleus is a spherical structure found in the centre of an animal cell and young plant cell.
=> Structurally nucleus is composed of the following parts.
1}: Nuclear membrane: It is a membrane which surrounds nucleus.
2}: Nucleoplasm: "The part of nucleus inside the nuclear membrane is called Nucleoplasm".
=> The nucleoplasm contains Chromatin network and the nucleolus.
3}: Nucleolus: Nucleoplasm contains one or two rounded structures called Nucleolus.{plural nucleoli}.
4}: Chromatin network: Nucleoplasm contains a network of thin fibres called Chromatin network.
=> This network is converted into chromosomes.
=> The number of chromosomes remains constant in members of the same species.
e.g. 46 in man, 26 in frog, 14 in peas and 48 in potatoes.
Functions:
Following are the functions of nucleus.
1}. Nucleus plays an important role in cell division.
2}. Nucleus activates all the cytoplasmic organelles.
In short, nucleus controles all the activities of cell.Therefore,it is called the heart of the cell.
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[kashibhayya]

Q: Write a comprehensive notes on Cytoplasmic organelles.
Ans: CYTOPLASMIC ORGANELLES:
Cytoplasm contains minute living structures known as Cytoplasmic organelles which are the following.
{1}. Mitochondria
{2}. Golgi bodies
{3}. Endoplasmic reticulum.
{4}. Ribosomes
{5}. Centrosome
{6}. Lysosomes.
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{1}: Mitochondria:
"Mitochondria are small granular or rod shaped or filamentous bodies.
=> Each mitochondria is bounded by a double membrane,an outer smooth membrane and and inner folded membrane.
Function:
Mitochondria release energy for the cell during respiration and hence it is known as Power house of the cell.
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{2}: GOLGI BODIES:
Golgi bodies were discovered by an Italian scientist, Golgi in 1898.
=> They may have the appearance of granules,rods,thread or canals.
Function:
Functionally Golgi bodies play an important role in the production and storage of secretions.
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{3}:ENDOPLASMIC RETICULUM:
"It is a network of interconnected tubules present throughout the cytoplasm.
=> Its one end is attached with cell membrane and other end is attached with nuclear membrane.
=> They are of two types.
{a}. Rough Endoplasmic reticulum: This type E.R are rough because of ribosomal attachement.
{a}. Smooth Endoplasmic reticulum: This type E.R are free from ribosomal attachement and that is why they are smooth.
Functions:
1}. E.R help in transport of materials inside the cell.
2}. E.R contain enzymes.Therefore,help in the metabolism of lipids.
3}. E.R detoxify the harmful drugs.
4}. It helps in the transmission of impulses.
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{4}: RIBOSOMES:
They were discovered by Palade in 1955.
=> They are granular like structures scattered on Cytoplasm or attach with ER.
=> They are also called Ribonucleic Protien because they contain an equal amount of RNA and Protien.
Function:
Ribosomes help in Protien synthesis.
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{5}: CENTROSOME:
" Centrosome is a small round body lies near nucleus.
=> It contains two small rod like structures called Centrioles.
Function:
Centrosome help in Cell division.
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{6}: LYSOSOMES:
They are spherical or hollow organelles.
=> They are filled with enzymes.
Function:
1}. They engulf undesireable particles within the cell and digest these particles. This process is called eating process of the cell.
2}. The enzymes present in them are also involved in Self eating (autophagy}.
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Download a complete video lecture on the Cell.
vuclip.Com/w?cid=465571632&2=1106&frm=s

[haroonsultan]

بہترین کاوش
اللہ آپ کو جرائے خیر عطا کرے۔

[Abid_Majaaz]

بهائيوں آپ سب كو ان كى حوصلہ افزائى كيكۓ كمنٹ كرنے چاہۓ

[zakir_sabir]

bhai next topic tu post kro na

[fahudmah]

very nice sharing good work keep it up

[Arslan WALI]

bhai next topic kaha hy

[ikram haider]

Sir g , Next topic ap kab samjho ga?