Biology Module 3 notes

Condensed version of the AQA CPG revision guide (higher tier) with bullet-pointed and numbered sections and fewer pages.....was intended basically for me to get the revision guide into my head more by typing it up and rewording it a bit, but felt like uploading it as it may be useful for some people, especially those without revision guides :) Good luck!

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  • Created on: 12-05-11 12:21
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Biology
Unit 3 (i) Life Processes 2
Gas and Solute Exchange
Substances move by diffusion, active transport and osmosis
1) Life processes need gases / dissolved substances. E.g. photosynthesis needs CO2
and water, respiration needs glucose + oxygen. Waste needs to leave the cell so
organisms can get rid of…

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Breathing IN:
1) Intercostal muscles + diaphragm
contract
2) Thorax volume increases
3) Decrease of pressure, drawing air
in.

Breathing OUT:
1) Intercostal muscles + diaphragm
relax
2) Thorax volume decreases
3) Air is forced out

Diffusion through Cell Membranes
Gas exchange happens in the lungs

Lungs use alveoli to…

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Active Transport
Root hairs are specialised for absorbing water & minerals
1) Cells on surface of plant roots grow into long "hairs", sticking out into the soil
2) Gives plant a big surface area for absorbing water & mineral ions from the soil
Root hairs take in minerals using active…

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Red blood cells:
1) Carry oxygen from the lungs
2) Doughnut shape with a large surface area to absorb oxygen
3) No nucleus ­ more room for oxygen
4) Contain haemoglobin
5) In lungs, haemoglobin becomes oxyhaemoglobin after combining with oxygen. In
body tissues, the reverse occurs.
Plasma:
Pale liquid…

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Kidneys





Nephrons are filtration units in a kidney.
Ultrafiltration:
1) High pressure is built up, pushing water, urea, ions and sugar out of the blood into
the Bowman's capsule.
2) Membranes between blood vessels and Bowman 's capsule act like filters ­
proteins and blood cells are too big to…

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1) This has to be done regularly, keeping concentrations of dissolved substances at
normal levels and removing waste substances from the blood.
2) In the machine, blood flows along a selectively permeable barrier surrounded by
dialysis fluid. This is permeable to ions and waste substances, but not large
molecules like…

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5) Moulds are added to blue cheese to give colour and taste.
Yoghurt is made from bacteria:
1) Bacteria are used to clot milk during yoghurt making
2) Milk is heat treated to kill off bacteria, then cooled
3) A starter culture of bacteria is added. This ferments the lactose…

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Mycoprotein
1) Mycoprotein ­ protein from fungi. A type of singlecelled protein
2) It is used to make meat substitutes like QuornTM
3) Fusarium, a fungus, is the main source of mycoprotein
4) It is grown in fermenters, using glucose syrup as food which is obtained by
digesting maize starch…

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2) Different microorganisms are used to produce this, fermenting plant and animal
waste containing carbohydrates. Sludge waste eg from sewage works or sugar
factories is used to make biogas on a large scale
3) It is made in a digester / generator ­ a simple fermenter
4) Biogas generators need…

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4) The raw material is readily available and cheap
5) The digested material is a better fertiliser than undigested dung
6) Women have to spend hours collecting wood for fuel in rural communities ­ biogas
saves them from doing this.
7) Generators act as a waste disposal system, getting rid…

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