Biology AS AQA Unit 1 Cells and Movement in and out of them

Made these notes for my year 12 summer exam to revise and read over. There are spelling mistakes in most of my files but due to the busy exam schedule I had no time to correct them (sorry).

Most files have more information than what is needed but I feel it helps you feel more confident walking into the exam if you have a greater knowledge background and may help when having to apply knowledge to questions. Good luck :)

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  • Created by: Chelcie
  • Created on: 02-09-13 12:34

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Cells and movement in and out of them
MAGNIFICATION

Magnification = size of image
Actual size of object


Kilometre km
Metre m
Millimetre mm
Micrometre m
Nanometre nm


x 10-3 when going down table

RESOLUTION: The minimum distance apart two objects can be in order for them to appear separate.…

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TRANSMISSION ELECTRON MICROSCOPE
An electron gun produces a beam of electrons from below which are focused onto the specimen by
a condenser electromagnet.
The beam passes through a thin section of the specimen. The parts of the specimen that absorb
electrons appear dark.
An image is created called a photomicrograph.…

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Nuclear pores
Allow passage of large molecules, such as RNA, out of nucleus.

Nucleoplasm
Granular, jelly like material that makes up the bulk of the
nucleus.

Chromatin
Is the DNA inside the nucleoplasm. This is the diffuse form that chromosomes take up when the cell
is not dividing.

Nucleolus
Small…

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LYSOSOMES
Formed by Golgi apparatus. It is an organelle containing enzymes e.g. protease and lipase.
Lysosomes isolate potentially harmful enzymes from the cell.
Its functions are to:
Break down material ingested by phagocytic cells
Exocytosis - release enzymes to the outside of the cell (to destroy material outside cell)
Autolysis-…

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Insoluble in water
Soluble in organic solvents
Main groups are triglycerides (fats and oils), phospholipids and waxes.

ROLEOFLIPIDS
The main role of lipids is plasma membranes.
Phospholipids contribute to the flexibility of membranes and transfer of lipid soluble
substances across them.
Lipids are an energy source
Waterproofing
Insulation
Protection

Triglycerides…

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MOSAIC: because the proteins embedded in the phospholipid bilayer vary in shape, size and pattern.
MODEL: because it's only a theory.



DIFFUSION
Diffusion is the net movement of molecules or ions from a region where there is a high
concentration to a low concentration.

DYNAMIC EQUILIBRIUM: Where the number of…

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The cell membrane will break, bursting the cell.

OSMOSIS AND PLANT CELLS
Water potential is higher than plant cell, water enters and the protoplast swells which makes the
plant turgid.
If same water potential, there is no osmosis and the protoplast is in an incipient plasmolysis state,
where the protoplast…

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where glucose diffuses inside the small intestine to the blood. Glucose is constantly used by cells
during respiration. This helps to maintain concentration gradient.

The villis muscles that contract and relax mix the contents of the small intestine, hence keep the
concentration gradient.

ROLE OF ACTIVE TRANSPORT IN ABSORPTION ­…

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Vibrio cholerae is transmitted by ingestion of water, or food, that has been contaminated with faecal
material containing pathogen.

1. Most of pathogen is killed in stomach acid however a few survive
2. Surviving bacterium reach small intestine and use flagella to propel them through mucus
lining of intestinal wall.…

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