Cell -Structure and functions
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Transcript of Cell -Structure and functions
CELL- STRUCTURE AND FUNCTIONS
INDEX1. Introduction2. Basic structure of cell3. Discovery of cell4. Cell theory5. Unicellular & Multicellular organism6. Different size of cells7. Different shapes of cells8. Structure of cell 8.1Cell membrane 8.2 Cytoplasm 8.3 Nucleus 8.4 Cell organelles
(i)Vacuole(ii) Mitochondria(iii) Ribosomes(iv) Golgi Bodies
9. Prokaryotic and Eukaryotic cells10. Comparison between plant and animal cell Video Did you know Recapitulation Home Assignment
Students things around us are either living or non –
living –do you ever imagine how these living things made from, what is the
basic unit which composed the living organism.
1.INTRODUCTION Cell is the basic unit of any living
system.
Like ,Brick is the basic structure unit of a house, Same as like Cell is the basic structural unit of a human body.
Onion peel cells under the microscope.
Grouped to form
Grouped to form
Organized into
And make up the complete
Do you know?
Systematic Organization of human body.
2.Basic structure of cell
3.DISCOVERY OF CELLWho discovered cell and how?
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4.CELL THEORY
1.All living cell
things are composed of
cell.
2.Cells are made
up of pre-existing cells.
3.Cell is the
structural and functional unit
of life.
Do you know –Organisms show Variety
In Cell Number Shape Size
5.Classification of Organisms according to no. of cells
1. Unicellular 2.Multicellular
Amoeba , the single cell organism.
Animals, the multicellular organisms.
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6.Size of cellThe size of cells in living organisms maybe as small as a millionth of a meter (micrometer or micron) or may be as large as a few centimeters.
Largest cell
The smallest cell is 0.1 to0.5 micrometre in bacteria. The largest
cell measuring 170 mm ×130 mm, isthe egg of an ostrich.
Do you know?
7.Shapes of cellDifferent cells have different shapes .The shape of a cell is related to its functions and locations.
Round elongated shape
Spindle shape with pointed ends.
8.STRUCTURES OF CELL
8.1Cell membrane/plasma membrane
Cell wall(an outer thick layer in cells of plantscalled cell wall.)
Plasma membrane
FunctionThis additional layersurrounding the cell membrane isrequired by the plants for protection.Plant cells need protection againstvariations in temperature, high windspeed, atmospheric moisture, etc.
Function• It forms the outer
boundary of cell which is thin and delicate
membrane and gives the shape and size to the cell.• It allows only certain selected substance to
enter and leave the cell.
8.2CytoplasmVarious other components, ororganelles, of cells are present in thecytoplasm. These are mitochondria, golgibodies, ribosomes, etc.
Mitochondria
Golgi bodies
Nucleus
Ribosomes
Cell organelles
8.3NucleusI am the oval shaped body floating in the cytoplasm. I am responsible for the vital
functioning of the cells.
I consist of nuclear membrane, nucleoplasm, nucleolus, chromosomes
and genes.
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8.4Cell organelles
These are components, small cytoplasmic bodies, or
organelles, of cells that present in thecytoplasm. These are mitochondria, golgibodies, ribosomes, etc.Mitochondria
LysosomesEndoplasmic reticulum
Golgi Apparatus/bodies
Ribosomes Cell Organelles which are embedded
in the cytoplasm.
More cell organelles and their functions:- (i) Vacuole
I resides only in the plant cells. The blank-looking structure in the cytoplasm is called vacuole. Largevacuoles are common in plant cells.Vacuoles in animal cells are muchsmaller.
(ii)MitochondriaI am
powerhouse of the cell. I store
energy in the form of ATP.
(iii) Ribosome
It helps in protein synthesis.
Protein factory of cell
(iv)Golgi bodies
Its function is the packaging of proteins .
It helps in the synthesis of food (photosynthesis)due to the presence of chlorophyll. Green coloured plastids are
called chloroplasts. They provide greencolour to the leaves.
9.On the basis of nucleus ,cells are of two types:-
Prokaryotic cells
Eukaryotic cells
prokaryotes(pro :primitive; karyon : nucleus) The cells havingnuclear material without nuclearmembrane are termed prokaryoticcells.. E.g.are bacteria and blue green algae.
Eukaryotes(eu :true; karyon: nucleus) that contain well organised nucleus. E.g. are animal and plant cells.
flagella
Nuclear material without nuclear membrane
cytoplasmRibosome's
Difference between Prokaryotes & Eukaryotes
10.Comparison between plant and animal cell
Let’s summarize through the Video
. The cells in the outermost layer of our skin are dead. An averageadult carries around about 2 kg of dead skin. Billions of tinyfragments of the skin are lost every day. Every time you run yourfinger on a dusty table, you shed a lot of old skin.
DID YOU KNOW?
RECAPITULATIONGive the one word answer.
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PracticeLETS PLAY A CROZZ WORD PUZZLE
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HOME ASSIGNMENT1.A cell requires water, minerals and
other nutrients to survive. It is covered with a membrane. How do these things reach inside the cell ?
2.Why are chromosomes called heredity vehicle?
THANK YOU!
Congratulations, you just finished it.
QUIT
ROBERT HOOK IN 1665 OBSERVED
SLICES OF CORK IN MICROSCOPE
Robert took thin slices of cork and observed them under a microscope. He noticed partitioned boxes or
compartments in the cork slice. These boxes appeared like a honeycomb. He also noticed that one box was
separated from the other by a wall or partition. Hooke coined the term ‘cell’ for each box.
Unicellular(uni : one; cellular :
cell)
•Consist of only one cell.•A single-celled organism, like amoeba, captures and digests food, respires, excretes, grows and reproduces. Similar
Multicellular(multi :
many; cellular : cell)
•Consist of cells numbering from few to billions.•Multicellular organisms like human beings carried out functions by groups of specialized cells forming different tissues.
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Inside the nucleusNuclear membrane-It surrounds
the nucleus that controls passage of selected material in and out of
the nucleus.Nucleoplasm-Dense fluid in the
nucleus.Nucleolus-It’s a spherical body that contain RNA( Ribo nucleic
acid).Chromosomes- these a have
thread like structure which are composed of DNA( Deoxyribo
nucleic acid ) which carry genes(the basic units of
hereditary ).
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References NCERT science textbook for class VIII Google gif Animated Images hhttps://www.google.co.in/search?
q=animated+gif+images+of+living+cell&biw=1366&bih=657&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjxiJ3F2v7KAhVDA44KHWJQDuwQ_AUIBigB#tbm=isch&q=animated+gif+images+of+plant+cell&imgrc=7OEmzGogX3b-eM%3Aook im,age
Video- www.makemegenius.com