AQA Biology 1A

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  • Created on: 18-08-11 14:47
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Biology 1A
Nervous system
You have five sense organs:
They all contain receptors. (Receptors a sensitive to stimulus)they change stimulus energy e.g light
energy into electrical impulses.
A stimulus can be
Change in position
Or temperature
The central nervous system coordinates a response and is where all the information from the sense
organ is sent and where reflexes and actions are coordinated the CNS consist of a brain and spine.
The sensory neurones transmit the information as electrical pulses to and from the CNS. The
instruction from the CNS is sent to the effectors which response accordingly.
The reflex arc
Reflex arc goes through the unconscious part of the brain
1. The stimulus e.g. a bee stings.
2. Detected by the receptor an impulses sent along the sensory neurone to the CNS
3. Then the message is sent through another relay neurone
4. Relay neurone relay impulse to a motor neurone
5. Then the impulse travels along the motor neurone to the effector
6. Muscle contract and move the hand.
Stimulus receptor sensory neurone relay neurone motor neurone effector response
The connection between the neurone is called the synapses which the nerve signals is transferred by
chemicals which diffuse across the gap which set of the chemical signal in the next neurone.

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Biology 1A
Hormones are chemical released directly in blood by only affect particular cells called target cells.
Hormones control things in the organ and cells. Hormones travel at the speed of blood. Also has long
lasting effects.…read more

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Biology 1A
99% effective at stop getting pregnant
Reduce risks of getting cancer
Isn't 100% effective
Has side effect
Don't protect against STI's
FSH can be taken by women who have that have Low FSH to stimulate the egg protection in the
Help people to get pregnant
Doesn't work all the time
Too many eggs released causing less likely for a baby to survived
IVF is when eggs are taken from the women ovaries and fertilize them in…read more

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Biology 1A
Water is lost through sweat breathing urine. On a cold day you not exercising you don't sweat the
urine is dilute. On a hot day when you are exercising you sweat a lot so the urine will be
Body temperature, the brain act like a thermostat, it's sensitive to blood and skin temperature
Sugar level- maintains the right level glucose into the blood you need to add and remove glucose this
is the role of the hormone insulin.…read more

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Biology 1A
Surveys can be done however it still depends on how you collect your data
Cholesterol and Salt
High cholesterol level increase risk problems because the blood vessels get clogged up with fatty
cholesterol deposits which cause heart problems
The liver control the amount of cholesterol and makes and removes cholesterol depending
of your diet
Cholesterol can be carried around the body by high density lipoproteins and low density
lipoproteins (lipoproteins mean fat attached)
HDL is good cholesterol because the cholesterol isn't need for…read more

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Biology 1A
People use drugs because of the users background or personal life which influence them choosing to
use drugs
Cannabis is a stepping stone-the effect of cannabis creates a desire to try harder drugs
Cannabis is a gateway-cannabis use brings people into contact with drug dealers
Down to genetics-certain people are more likely to take drugs
Main products available to stop smoking
Nicotine gums and patches- gradually decrease the dose nicotine.…read more

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Biology 1A
But antibodies actually kill the bacteria except viruses because they are made from your own blood
Bacteria can come resistant to antibiotic as the antibiotics don't manage to kill all bacteria therefore
allowing the others to evolve to become resistant this is natural selection.…read more


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