AQA Biology Unit 2 Revision Notes

Notes are in simple note form and are my adapted notes from the notes I found on this website: http://www.madeleyhigh.org/images/docs/scienceresources/y10aprilnjb2/B2%20Summary%20Notes%20-%20Sets%201-5.pdf

All topics from Unit 2 AQA Biology.  

There may be spelling mistakes and it also isn't in proper sentences. 

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  • Created on: 13-06-16 14:41
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Biology Unit 2

Cells & Cell Structures
All living things made up cells. Structure different type's cells relates function. Get in/out cells
dissolved substances cross cell membrane. Cell smallest unit life.
Cells
Human & Plant Cells:

Nucleus ­ controls activity cell
Cytoplasm ­ most chemical reactions take place
Cell membrane…

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Greater difference concentration faster rate diffusion

Tissues, Organs & Organ Systems
Cells multicellular organisms differentiate & adapt specific functions. Tissues lots similar cells.
Organs lots tissues doing specific functions. Organs organised in organ system work together form
organism.
Multicellular organisms
Large multicellular organisms develop system exchange materials
During development multicellular…

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During:

Light energy absorbed green substances ­ chlorophyll in chloroplasts
Energy used converting CO (from air) & water (from soil) to sugar (glucose)
Oxygen release byproduct
Carbon dioxide + water glucose + oxygen

Where it happens:
Leaves ­ main site
Mesophyll cells ­ place occurs
Cells contain lots chloroplasts
Chloroplasts…

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Affect rate organism's metabolism
Organisms can't maintain constant high body temperature
Can't tolerate extreme temperatures
Organisms maintain constant high body temperature also struggle survive extreme
temperature
Availability nutrients
E.g. nitrates essential growth plants & microorganisms
Low concentrations nutrients organism struggle grow & survive
Amount light
Plants require light energy source…

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Change distribution population organisms 2 neighbouring habitat
Method:
Choose start ­ end position of transect
Determine direction & length transect
Lay down tape/string mark out transect
Sample organisms along line
Take recording factors could influence distribution along line
Types transects:

Record organisms touching line suitable regular intervals
Place quadrat start…

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Enzymes structure & function:
Enzymes biological catalysts increase rate chemical reaction
Enzymes ­ protein molecules made long chain amino acids
Long chains folded produce special shape enable molecules fit in enzyme
Shape vital enzymes function
Only 1 type enzyme (substrate) fit in enzyme
Active site part enzyme substrate fit in…

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Wall stomach muscular & churns food
Food remains stomach few hours
Food leaves stomach small squirts to small intestines

Digestive & absorption small intestines

2 mains jobs:
Complete digestion food
Absorb soluble products digestion in blood

Digestion small intestines
3 juices released:

Bile:
Produced liver
Stored gall bladder
Released in…

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Supplying heat expensive ­ enzymes used industry processes cheaper
Disadvantages:
Enzymes sensitive temp. & pH change
Temp. & pH need carefully monitored expensive

Respiration
Respiration cells take place aerobically/anaerobically energy released used variety ways. Human
body needs react increased demand energy during exercise.

Respiration
Process transferring energy from food molecules…

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All changes increase blood flow to muscles & increase supply sugar & oxygen & increase rate
removal CO
Glycogen

Glucose stored glycogen in muscles increase amount glucose can respired

Anaerobic respiration
During exercise insufficient oxygen reaching muscles use anaerobic respiration to get energy
It is incomplete breakdown glucose producing lactic…

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Cell divide 2 form 2 genetically identical cells
Cells undergo cell division again & again
Cells carry out function the die

Asexual reproduction

Cells offspring produced mitosis from parent cells
Contain same genes as parents ­ genetically identical

Cell differentiation

Differentiation results some genes turned on some turned off
Once…

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