AQA Biology GCSE Unit 1 revision notes

This contains all the notes that I made for my Unit 1 exam for AQA biology at GCSE.

I hope this helps you!

There are 18 pages in total. Each 'section' (e.g. 11.2) is clearly underlined and in bold so you can easily find each 'section'

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  • Created by: Katie
  • Created on: 02-11-09 22:50
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Biology Revision:
Topic 11.1 ­ How do humans bodies respond to changes
inside them and to their environment?
Explain what a stimulus is by highlighting examples and what organs they
Describe how a nervous response is brought about by stimuli, including the roles
of receptors, sensory neurones, the coordinator and motor neurones.
(Light bulb) -> Receptor (Eye) -> impulse travels along the
sensory neurone to -> Coordinator (Brain) -> impulse travels along
the motor neurone to -> Effector (Eye muscle) -> Response
Neurone= A single nerve
Describe a reflex action and the role of the relay neurone in this action.
Receptor (Finger) -> impulse travels along sensory neurone -> comes
to synapse -> goes onto the relay neurone -> to synapse -> along the
motor neurone -> Effector (Arm muscle)
Synapse = gaps
between the
end of a neurone and the
start of another or an
Axon = the end of a neurone.
Explain that four internal
conditions controlled by the body
include water content, ion
content, body temperature and
blood sugar. Describe, in very
broad outline, how they are
Ion content leaves body 1) in sweat 2) excess lost via kidneys in
The water content of body leaves body 1) in breath 2) as sweat 3)
xcess is lost via kidneys in urine.
emperature -> maintain temperature
at which enzymes work best.
ood sugar levels -> to provide
the cells with a constant supply of
Describe hormones as chemicals which coordinate reactions in the body and that
are secreted by glands and reach their target organs via the blood stream.
tary glands -> FSH and LH.
Biology Revision (Year 9/10) 2008

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­ egg
mature + oestrogen to be
thickens uterus lining + inhibits
ng hormone) ­ egg is released
from ovary + stimulates
Describe how hormones control both the monthly release of an egg and the
varying thickness of the lining.
Recall the location of the pituitary gland and the ovaries and that they are the
main hormone glands for the release of the menstrual cycle hormones.…read more

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Explain that in the developed world the abundance of food leads to weight gain
which causes the following diseases arthritis, diabetes, high blood pressure,
heart disease.
Discuss the problems associated with the lack of food in the developing world that
include reduced resistance to infections and irregular periods in women.
Recall that cholesterol is a substance made by the liver and found in the blood.
Explain that cholesterol levels in the blood are dependent on both inherited
factors and diet.…read more

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Notice a wider range of taste in food as taste buds adjust to having less salt.
Cholesterol is a substance made in the liver. It is found in the blood stream. The
amount of cholesterol produced by the liver depends on a combination of diet and
genes. High levels of cholesterol in the blood increases the risk of disease of the
heart and blood vessels.
Cholesterol is carried around the body by two types of lipoproteins.…read more

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During the 1940s and 1950s the number of deaths from lung cancer prompted
scientists to investigate the cause.
Possible causes?
- Pollution?
- Wet tar?
- Smoking?
Sir Richard Doll was commissioned by the Medical Research Council to investigate a
possible link between smoking tobacco and lung cancer.
He visited 2000 people suspected of having lung cancer and found that those who had
the disease were heavy smokers.…read more

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Infectious diseases:
Good hygiene (washing hands)
Sterilization (radiation/heat)
Antiseptic (for living tissue)
Disinfectant (for non-living tissue)
Good diet
Ignaz Semmelweis
He noticed that in a normal hospital, where doctors delivered babies, the
mortality rate was higher (10%) compared to in a maternity hospital where maternity
nurses delivered babies (1%).…read more

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What are the different types of immunity?
Natural Passive
o Mother to child through placenta or milk
Natural Active
o Occurs during infection. It is active because your body fights an invading
pathogen with antibodies
Artificial Passive
o Used during potentially fatal diseases. Injection of readymade antibodies
provides an instant temporary response. Eg tetanus and rabies
Artificial Active
o Injecting or taking dead pathogens by mouth.…read more

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Will these notes still cover the 2014 syllabus?

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