GCSE AQA Additional Biology all units

Osmosis = movement of water

• random, requries no energy
• through/across semi-permeable membrane
• dilute solution --> more concentrated solution
  • larger difference of concentration, faster rate of osmosis

Water needed to 

• support cells

Chemical reaction take place in SOLUTION

RIBOSOMES

synthesised proteins made here

MITOCHONDRIA

where energy is released during aerobic respiration

Plant roots take up

(1) Nitrates

• used to make amino acids
• too little nitrate = stunted growth

(2) Magnesium Ions

• used to produce chlorophyll
• no chlorophyll = yellow leaves

There is energy loss between EACH STAGE of a foochain

not all energy taken by organism = growth

energy --> used up not lost

energy used in

• faeces (poo)
• respiration
• movement
• keeping temperature constant (homeostasis)

plants AND animals respire

energy released in respiration:

• builds large molecules from small ones
• enables muscle contraction in animals
• keeps contant body temp. (in mammals+birds)
• allows sugars, nitrates + nutrients to turn into amino acids then into protein

Respiration

glucose + oxygen --> CO2 + water [+energy]

mostly takes place in MITOCHONDRIA

returns CO2 to atmosphere

Photosynthesis

carbon dioxide + water (+light energy) --> glucose + oxygen

removes CO2 from atmosphere

lack of light       > 

cold weather     >  slows down photosynthesis

too little CO2    >

Glucose

• used for respiration
• combines with nutrients by plants = make new materials
• stored by some plants as insoluble starch  --> no effect on osmosis

carbon dioxide = taken in by leaves 

water = taken in by roots

chlorophyll = traps energy needed for photosynthesis

oxygen = given off as a waste gas

glucose sugar = made by/during photosynthesis

Animal cells            mnemonic for help remembering

nucleus                      nude

cytoplasm                  cyclists

cell membrane            cycle

mitochondria               my

ribosomes                   road

Plant cells            mnemonic for help remembering

nucleus                      nude

cytoplasm                  cyclists

cell membrane            cycle

mitochondria               my

ribosomes                   road

cell wall                      casually

chloroplasts                colouring

permanent vacuole       pavements

Decay organisms = micro organisms

(types of worm)       (bacteria and funghi)

decay = fast if warm and wet

ALL materials from waste + dead organisms are recycled

stem cells = unspecialised cells

develop into specialised cells

stem cells found in 

• embryo
• adult bone marrow

stem cells from adult bone marrow = limited use

as different types of specialised cells = limited

embryonic stem cells researched on from:

• aborted embryos
• 'spare' fertility treatment embryos

ethical issues and debate over

destroying life for research

Genes = short lengths of DNA

Alleles = genes controlling the SAME characteristic

SOME amino acids we take in = not used up

not used up = converted to UREA in LIVER

excreted by KIDNEYS in URINE

Water and ion content of cells = carefully controlled

if not

too much or too little = water movement in OSMOSIS

homeostasis is processes in your body that maintain a constant internal environment

Core temp. rises

blood vessels near skin surface dilate 

more blood flows through skin capillaries

heat = lost via radiation

sweat glands make more sweat

Core temp. falls

blood vessels near skin surface constrict

less blood flows through capillaries keeping internal organs warm

heat = LESS loss via radiation

'shivering' = muscles contracting quickly

Pancreas monitors and controls blood sugar level

blood sugar too high = insulin produced

when insulin produced = excess insulin stored in LIVER as glycogen

Enzymes = biological catalysts 

Enyzmes ---> large proteins = different shape each

area where other molecules fit called active site

conditions too hot?

denatured enzymes --> change shape

enzymes = sensitive to pH levels

too high/too low = denatured enzymes

optimum temp. = temp. enzymes work best as

enzymes

• catalyses build up of SMALL molecules into LARGE molecules
• break down of LARGE molecules into SMALL molecules

enzymes LOWER energy needed for reaction

this energy = activation energy

Protease made in

stomach

pancreas

small intestine

catalyses proteins into amino acids in stomach and small intestine

works best in acidic stomach

Lipase made in

small intestine 

pancreas

catalyses lipids (fats and oils) into fatty acids and glycerol

works best in slightly alkaline small intestine

Amylase made in

small intestine 

pancreas

salivary glands

catalyses starch into sugars in mouth and small intestine

works best in slightly alkaline small intestine

Bile

• made by liver
• stored in gall bladder 

carbohydrases = make starch into sugar syrup --> use in foods

protease = pre-digests proteins in some baby foods

pyramids of biomass are more accurate than a food chain

as they present MASS not quantity