Sunday 6 October 2013
Structures and functions of CELL.
Cell membrane or Plasma membrane;
Cell membrane is present in all prokaryotic and eukaryotic cells and this membrane is thin and elastic type cell membrane.It works like a semipermeable barrier and allowing a very few molecule in it.Cell membrane maintain the internal composition of cell.Cell membrane can also sense chemical message and can identify other cell.Fluid mosaic model is the model in which there is a lipid bilayer and protein molecule are collect strongly in it.This lipid bilayer gives fluidity and elasticity to membrane.In eukaryotic cell ,cholastrol also present in lipid bilayer.In eukaryotic cell many organelles for example, Mitochondria, Chloroplast, Golgi apparatus are also bounded by cell membrane.
Cytoplasm;
Cytoplasm is a semi-viscous and semi transparent substance and present between plasma membrane (cell membrane) and nuclear envalop (a double membrane by which nucleus is bounded ).It contains water in which many organic molecules (like proteins carbohydrates and lipids ) and inorganic salts are completely or partially dissolved.Cytoplasm provides space for the proper functioning of organelles and also act as the various biochemical (metabolic) reaction.For example, Glycolysis (break down of glucose during cellular respiration) occurs in cytoplasm.
Cytoskeleton;
Cytoskeleton is a network of microfilaments and microtubules. Microtubules are made of tubulin protein and are used by cells to hold their shapes.They are also the majer components of cilia (moves back and forth) and flagella (latin word meaning whip). Microfilaments are thinner and are made of actin protein. They help cells to change their shapes.
Cell organelles;
Organelles are small structure with in cells that perform dedicated functions. There are about the dozen types of organelles commonly founds in eukaryotic cells.Some important organelles are present below;
- Nucleus: A prominent nucleus occurs in eukaryotic cells. In animal cells it is present in the center while in mature plant cells, due to the formation of large central vacuole, it is pushed to side. Nucleus is bounded by double membrane is nucleur envelope. inside nucleur envelope granular fluid like nucleoplasm is present. Nucleoplasm contain one or two nucleoli and chromosomes.
- Ribosomes : Ribosomes are tiny granular structures that are either floating freely in cytoplasm or are bound to endoplasmic reticulum . Ribosomes are not bound by membranes and so are found in prokaruotes. Ribosomes are the protien synthesis.
Minerals and their roles in body.
Minerals
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Role in body
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Major minerals
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Sodium
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Fluid balance in the body
Helps in absorption of other nutrients
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Important for muscle Contraction, nerve impulse transmission, heart function and
blood pressure
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Potassium
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Fluid balance in the body
Acts as cofactor for enzymes
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Chloride
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Fluid balance in the body
Component of hydrochloric acid
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Calcium
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Development and maintenance of bone and teeth
Blood clotting
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Magnesium &
Phosphorus
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Development and maintenance of bones and teeth
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Trace minerals
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Iron
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Oxygen transport and storage
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Act as enzyme
cofactors
Support immune
function
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Zinc
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Aids
insulin action
Helps in growth and reproduction
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Copper
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Act as enzyme cofactor
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Chromium
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Helps in insulin action
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Fluoride
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Stabilizes bone minerals and hardens tooth enamel
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Iodine
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Essential for
normal thyroid function
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Structure and keys of keyboard.
There are different types of keys available on the keyboard.
- Alphabets (Upper and lower case letters A, B, C----, a, b, c -----)
- Numeric (0 to 9)
- Function keys ( F1 to F12)
- Special character (!, $, #, ^etc.)
- Editing keys (Ctrl, Alt, Del, Enter, Back Space,etc)
- Cursor moment keys (Arrows, Pg-up, Pg-down, home, end)
- Command keys (Ctrl, Alt, Del, Shift)
Structure of keyboard;
Abraham Lincon
Abraham lincon is 16th president of united states.He was the son of woodcutter but soon he become a president and it is the result of his efforts.He was born in february 12,1809 in united states.His height may be 1.93m and he married with marry todd lincon.He assassinated in april 15,1865.Robert todd lincon,William wallace lincon,Tad lincon,Edward baker lincon all of these his children.William wallace lincon is the third son abraham lincon he was died at the age of 11 due to illness.
ABRAHAM LINCON
Born: february 12,1809
Assassination: April 15,1865
COMPUTER abbreviation.
- C _stand for calculation
- O_stand for of
- M_stand for many
- P_stand for program/problem
- U_stand for under
- T_stand for the
- E_stand for electronic
- R_stand for resource
COMPUTER stands for calculation of many program/problem under the electronics resource.
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