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Table of Contents

Cells ............................................................................................................................................ 2
Magnification ......................................................................................................................... 2
Organelles............................................................................................................................... 3
Cell Fractionation ................................................................................................................... 5
Lipids....................................................................................................................................... 6
Plasma Membranes ................................................................................................................ 6
Movement .............................................................................................................................. 7
Diseases .................................................................................................................................. 9
The Immune System ................................................................................................................ 10
Risk Factors........................................................................................................................... 10
Pathogens ............................................................................................................................. 10
Defence ................................................................................................................................ 11
Immunity .............................................................................................................................. 12
Artificial Immunity ................................................................................................................ 13
Monoclonal Antibodies…

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Cells

Magnification

Size of image
Magnification =
Size of object

Magnification is number of times bigger the size of the image is compared to the size of the
object. Resolution is the minimum distance for two objects to be identified as separate.

The disadvantages of light microscopes are that the…

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Organelles

Eukaryotic cells have a distinct nucleus and membrane-bound organelles. Eukaryotic cells
have a cell membrane, a cytoplasm and ribosomes. Eukaryotic cells also have a nucleus,
mitochondria, smooth endoplasmic reticula, rough endoplasmic reticula, Golgi apparatus,
lysosomes and microvilli. The mitochondria are thin. This decreases the diffusion pathway
and increases the…

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Prokaryotic cells do not have a distinct nucleus and do not have membrane-bound
organelles. Prokaryotic cells have a cell membrane, a cytoplasm and ribosomes. Prokaryotic
cells also have a capsule, a cell wall, a chromosome, plasmids and a flagellum.

The ribosomes (i.e. smaller and less dense 70S ribosomes) have a…

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Cell Fractionation

Tissue is homogenised in a cold, isotonic, buffer solution. The cold reduces and prevents
enzyme activity (e.g. autolysis). The isotonic prevents osmosis. This prevents the organelles
from shrivelling or bursting. The buffer prevents the proteins from damage. Organelles can
be separated by cell fractionation because different organelles have…

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Lipids

Triglycerides are made of one glycerol molecule and three hydrophobic fatty acid
tails joined by condensation reactions to release three water molecules to form ester
bonds. Saturated fatty acid chains do not have carbon-carbon double bonds between
carbon atoms. This causes saturated fatty acid chains to be saturated with…

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Movement

Osmosis is the net movement of water molecules from an area of high water
potential down the water potential gradient to an area of low water potential
through a partially-permeable membrane. Osmosis is a passive process so does not
require energy.
Diffusion is the net movement of molecules from…

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Water moves through the phospholipid bilayer from a higher water potential to a lower
water potential down the water potential gradient by osmosis through water channels (i.e.
aquaporins). Small, non-polar, lipid-soluble molecules move through the phospholipid
bilayer from a higher concentration to a lower concentration down the concentration
gradient by…

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Diseases

Cholera

Cholera bacteria produce and release toxins which open the chloride channel proteins. This
causes the chloride ions to move into the small intestinal lumen by diffusion. This decreases
the water potential of the small intestinal lumen. This causes water to move into the small
intestinal lumen by osmosis.…

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The Immune System

Risk Factors

Risk factors are something that increase the probability. Changing lifestyle reduces the risk
of the development of some diseases but does not prevent the development of these
diseases.

Risk factors of coronary heart disease include age, sex, genes and obesity. Other risk
factors include smoking,…

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