Biology

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Bunch 1
Pg 22 Insulin & Diabetes
2 hormones : 
  Insulin (reduces blood sugar level) - makes liver turn glucose into glycagon
  Glucagon (increases blood sugar level) - makes liver turn glycagon into glucose

Pg 27 Drugs
Types

(1)Depressants - decrease brain activity, increasing reaction times (e.g. alchohol)
(2)Stimulants - increase brain activity (e.g. caffeine, nicotine)
(3)Pain Killers - e.g. Morphine.  Work in different ways, morphine blocks the nerve impulses in the brain.
(4)Hallucinogens - e.g. LSD - distort perception by altering the pathways that nerve impulses pass along.

Pg 36 ...to pg 38 Nitrogen cycle etc


                           n2
-----------------------------------------------------
 |                  ^
 |                  |           \/  --> Animal --> poo/death
nitrogen fixing  denitrifying   ||                  |
bacteria         bacteria       ||                 decomposer bact 
 |                  |           ||                  |
 |                  |           ||                 ammonia
 |                  |           || (plant)          |
 V                  |           ||                 nitrifying bact
-|--------------------------------------------------| 
  \---------------> nitrates in soil <--------------/

Pg 42 Protein Synthesis
Pg 71 Kidneys
Pg 93 Plant Communication
Pg 98 Fermentation
Pg 102 Genetically modifying organisms

Bunch2

Pg 8 Classification
A 'key' is the flowchart that allows you to narrow down what group an organism belongs to.

Pg 19 Hormones & Nerves
Body temperature is controlled by the hypothalamus.
Hormones are chemicals produced in the endocrine glands.
Hormones are slow to act, travelling at the speed of blood.  Their effect is slow to disappear (for same reason).

Neurones are nerve cells.
Nerves transmit information far quicker than hormones (electrical pulses) and their effect is very short-lived.
 
Pg 20 Nervous System
Pg 21 Reflexes
stimulus -> receptor -> sensory -> relay neurone -> motor  -> effector -> response
                        neurone    (in CNS)         neurone


Pg 23 Plant Growth Hormones
Plants respond to stimuli (light, grav, moist) by regulating growth.
A growth response is called a tropism.

Auxin hormone stimulates the stem tips to grow.
Gibberellin hormone stimulates the plant stems and flowers to grow.

Shoots grow towards the light (positively phototropic)
Roots grow towards gravity (positively gravitropic)

Uses for Plant Hormones 

(1) selective weedkillers - affecting only broad-leaf plants, so can be used in cereal fields, where only broad-leaf plants are weeds.
(2) Helping to grow from cuttings - put a cutting from a plant in soil enriched with growth hormone and you get more/better growth.
(3) Ripening fruit - transport fruit when not ripe (it will be hard and not easy to bruise) then apply growth hormone when near the shop and the fruit will quickly ripen for sale.
(4) Seedless Fruit - apply growth hormone to unpollinated flowers and the fruit will grow but the seeds won't.

Pg 29 Infectious Diseases

Caused by pathogens (microbes that cause disease).  Pathogens are spread in different ways - FABWAC:

Food e.g. salmonella
Air e.g. flu
Body fluids e.g. blood, breast milk, semen
Water e.g. cholera
Animal vectors e.g. malaria
Contact e.g. athlete's foot

Barriers - 2 types, physical and chemical:

Physical- skin, respiratory system
Chemical - lysozyme in tears, HCl in stomach. 

Plants can produce chemicals to defend themselves from pathogens, e.g. Tea Tree produces an oil that kills bacteria.

Antiseptic - used outside the body to kill bacteria (e.g. TCP on wounds, bathroom cleaning products)
Antibiotics - used inside the body to kill bacteria or fungus.  Two types:
antibacterial (e.g penicillin) and antifungal (e.g. nystatin)

Pg 40 Cells & Microscopy
Pg 41 DNA
Pg 47 Mitosis & Meiosis
Pg 54 Photosynthesis
Pg 57 Water uptake/loss in plants
Pg 61 Evidence for evolution

Evidence to support evolution - 2 types of evidence:
DNA
- closely-related organisms have very similar DNA
- less closely related organisms have more dissimilar DNA
- from this we understand that over time organsims DNA changes, so those that diverged more recently should have similar DNA, and those that diverged a long time ago should have more different DNA.  This is what has been found e.g. humans and chimps.

Resistant Organisms
- Poison (warfarin) was used to kill rats
- a particular gene gives rats immunity to it
- these are the rats that survive to breed, so over time rats evolve immunity to warfarin. 
  
Pg 63 Circulatory System
Pg 66 Digestive System
Pg 74 Menstrual Hormones
Pg 81 Monoclonal Antibodies
Pg 84 Daily Rhythmns
Pg 86 ..pg 89 Behaviour
Pg 94 Human evolution
Pg 100 Using enzymes