AQA Biology - Core - Revision Cards in GCSE Biology

Co-ordination and Control

Control of the body's functions and responses involves hormones (chemical) and the nervous system (electircal impulses)
relflex actions are responses that are rapis and automatic
reflex actions do not involve the brain
the cycle takes 28 days with ovulations about 14 days into the cycle
the cycple is controleed by three hormones - FSH, Oestrogen and LH
the contraceptive pill contains oestrogen that prevents pregnacy
FHS can be given to a women to help her to produce eggs
It is very important that the internal conditions of the body are kept within certain limits
water and ion content, as well as temperature and blood sugar level, are all carefully controlled

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a healthy diet is made up from the right balance of the differnt foods that you need
you are malnourished if you do not have a balanced diet
if you take in more energy that you need you may become fat, and this may result in health problems
if you eat more food than you need you will put on weight
if you are very fat you are said to be obese
'fast food' is food that has already been prepared. It often contains too much fat and salt
too much fast food is likely to result in health problems

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all drugs can cause problems whether they are illgal or legal
many drugs are addictive. If you try to stop taking them this can result in severe withdrawal symptoms
there are both legal and illegal drugs
there are both medicinal drugs and recreational drugs
some legal drugs can be used illegally
alcohol is a legal drug that can be bought by those over 18 years old in th UK
alcohol does cause erious health problems for some that use it
alcohol is recreational drug
smoking tobacco is legal
the use of tobacco causes a range of health problems and will prbably lead to an early death

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pathogens are microoganisms that cause infectious disease
it is best to stop pathogens getting into your body in the first place, e.g. having no cuts on the skin or trapping pathogens in the mucus in your nose
if pathogens do get in, then the white blood cells help us to defend ourselves
antibiotics can be used to kill bacteria
it is much more difficult to kill viruses
if a pathogen chanages by mutating or through natural selection, then it will be very difficult to control
a new medicine must be effective, it must be safe and it must be able to be storsed for a period of time
new medicine are tested in labs to see if they are toxic and on human volunteers to see if they work
you can be immunised to help stop you getting a disease

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if animals were not adapted to survive in the areas they live in, they would die
plants must be adapted to live in a variety of climates, including deserts
plants must be able to survie being eaten by animals
animals compete with each other in amny different ways
the most successful ones survie and pass on their genes to the nest generations
plants compete for a number of resources
successful plants have structures and habits that allow health growth

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information from parents is passed to the offspring in the genes
they are two types of reproduction - sexual and asexual
there are very important difference between sexual and asexaul reproduction
Asexual does not involve the fusion of sex cells
and sexual does
individuals identiacal to their parents are known as clones
it is much more difficult to clone animals than it is to clone plants
- this is beacuse embroyo tanspnats are used to clone animals. In this process, embroyo are split into smaller groups of cells than each group is allowed to develop in a host animal
scientists can clone animals using fusion cell cloning and adult cell cloning
there are benefits and risks associated with animal cloning
genetic engineering is used to ensure that organisms have desires characteristics
new or altrenative genes are added to the chromosomes
genetic engineering is the subject of much debate

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we are unsure of when life began on Earth
However fossils help us to decide when life began, although it is proving very difficuly to find any really good evidence
there are two main theories of evolution. They are those of Lamarck and darwin
- Lamarck - acquired chararcteristics can be passed on to the nest generation
- Darwin's theorgy - small changes took place over time (natural selection)
Much evidence now points to the theory of Dawin being the correct one
Organisms of a species all vary from one another
Some organisms are more likely to survive and breed as they have 'better' charateristics. This is known as 'natural selection'
Many species have evolves and then become extinct in the life of the earth
'Extinction'means that all of the species has been wiped out
There are a number of changes that can cause a species to become extinct

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the human population is increasing rapidly. So we use up more resources and produce more waste and pollution
Sulfur dioxide is mostly responsible for acid rain
clouds blow across countries, so those producing acid rain often cause problesm for someone else
It is now widely beleives that the atmosphere on the planet is warming up due to our activites
it is also agreed we should do something about it. However not everyone agrees
if we continue to use up the Earth's resources then they will run out
lichens are indicators of level of pollution in the air. Freshwater invertebrates are indicators of pollution in freshwater
- the more lichens the cleaner the air
- Freshwater invertebrates work in the same way
in the development of new housing for increases in the population it is importance to use, as fully as possible, areas that have already been used for building and redevelop them.
this helps is making development sustainable

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