Biology Revision

My Biology Revision For Gcse.
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How do hormones reach their target organs?
transported by the bloodstream
All responses must be...
How are impulses transmitted across a synapse?
By chemicals
What is the order of the reflex action diagram?

The image shows the way the reflex happens.
What is FSH?
is made by the pituitary gland and causes the egg to mature and oestrogen to be produced.
What is Oestrogen?
Oestrogen is produced by the ovaries and inhibits the further production of FSH. It stimulates the production of LH and also stimulates the womb lining to develop to recieve the fertilised egg.
What is LH?
Is made by the pituitary gland and stimulates the mature egg to be released.
What effect does the production of Oestrogen have on the production of FSH and LH?
oestrogen inhibits the production of FSH and stimulates the production of LH.
What are the 4 internal conditions that need to be controlled?
water content, ion content, temperature, blood sugar levels.
How do we lose any excess water?
In the urine produced by the kidneys
We must keep our temperature content otherwise
the enzymes in the body will not work properly (or may not work at all)
Why is sugar in the blood important?
it is the energy source for respiring cells
What are the differences between the hormone and nervous systems?
The hormone system relies only on messages being transmitted by chemicals. Impulses in the nervous system are electrical, except at synapses where they are chemical.
Suggest one argument for and one argument against the use of fertility treatment. :)
for: allows parents to have children when they wouldnt otherwise be able to.against: includes cost it is against gods will as not natural. many eggs will be fertilised, many will die
What type of neurone transmits the pulse from a motor to a sensory neurone?
How does the contraceptive pill work?
it contains oestrogen which inhibits the production of FSH
You are ________ if you do not have a balanced diet.
What is your metabolic rate?
is a measure of how quickly your cells are converting food into energy
If it is warm you will need less energy than if it was ____
The amount of energy you need depends on many things for example these five things:
1) Your size2)Your sex3)The amount of exercise you do4)Outside Temperature5)Pregnancy
Suggest why exercise increases the metabolic rate...
you need more energy for the activity. the cells respond by releasing energy from food more quickly. ;)
What are the 4 conditions obese people suffer from?
1) arthritis2)diabetes3)high blood pressure4)heart disease
Fast food can contain too much 1)____ and 2) ______
Too much salt can lead to _____ ______ ________
increased blood pressure
Where is cholesterol made?
by the liver
What are the two types of lipoproteins that carry cholesterol around the body?
low- density lipoproteins (LDLs) bad oneshigh- density lipoproteins (HDLs) good ones
What fats help reduce cholesterol levels?
mono-unsaturated and polyunsaturated. :)
What do lipoproteins do in the body?
transport cholesterol
What was Thalidomide used for and what was it used to prevent in women? What were the bad things about it?
It was used for as a sleeping pill to prevent morning sickness but had serious side effects on the fetuses developing in the womb. ):
What are recreational drugs?what are examples of one
are used by people for pleasure examples are heroin and cocaine, very addictive and illegal, cannabis.
Why can you become addicted to recreational drugs?
Because they affect the nervous system and from pressure from the people you are with, wanting to experiment further.
Why do people say there is a bigger problem with legal, recreational drugs as opposed to illegal recreational drugs?
Many more people take them.
Name one legal drug and one illegal
paracetomol and cannabis
Alcohol slows down your ______ ______ and therefore slows down your reactions. Which causes problems if _______.
nervous systemdriving
Too much alcohol leads to 4 things:
too much leads to loss of self control, to lose consciousness, go into a coma, and use over a long time will damage the liver and brain.
What in the tobacco smoke is addictive?
The nicotine
Tobacco smoke also contains cancer causing chemicals called
The carbon monoxide in tobacco smoke reduces the amount of oxygen the blood can ____
Pregnant women give birth to babies with..
lower birth weights as the babies do not get enough oxygen
What is a pathogen?
An organism that causes an infectious disease
bacteria and viruses reproduce and produce
poisons or toxins that make us feel ill
Semmelweiss discovered that infection could be
transferred from patient to patient in a hospital
White blood cells do 3 things to help us protect ourselves:
1) they can ingest pathogens. This means they can digest and destroy them.2) They produce antibodies to help destroy particular pathogens3) they produce antitoxins to counteract (neutralise) the toxins that pathogens produce
What is a well known antibiotic?
Why are viruses more difficult to kill?
They live inside the cells
If the pathogen changes by __________ or through _________ __________ then it will be very difficult to control.
1) mutating2) natural selection
What does pandemic mean?
When disease can spread quickly across countries.
mutation takes place in an instant whereas natural selection
is a gradual process over many years
Why does it take a long time to develop a medicene?
Drugs have to be tested on volunteers. It can take years for the side effects to develop. Until company are sure there is no side effects , it will not sell the drug. It will cost them a lot of money if it proves to be dangerous.
Argument whether vaccines are safe eg.....
MMR (measles, mumps and rubella)
If bigger animals have smaller surface areas compared to their volume this means that they can conserve heat more easily but it is also more difficult to lose ____
What 3 things do plants compete for?
light, water and nutrients
What 5 things do animals compete for?
water, food, space, mates and breeding sites
The cell nucleus contains.....
Chromosones are made up of ____
How can plants be cloned?2 things
by taking cuttings and tissue culture taking groups of cells and growing them under special conditions
Embryo transplants are used to clone animals in...
What is the process of adult cell cloning?

in the diagram below
Genes are "cut out" of the chromosone of an organism used an
What is Lamarcks theory?
acquired characteristics are passed on to the next generation. eg. if parents went to the gm to build up their muscles this would be passed onto their offspring!!!!!
What is darwins theory?
That small changes took place over time. All organisms vary and therefore some are more likely to survive through natural selection. Those that are best adapted breed and pass on their characteristics.
Weaker members of the population may die from 3 things:
diseaselack of foodvariation in climate
What is natural selection?
The organisms best adapted to their environment survive and breed passing their characteristics onto the next generation
We pollute 3 things
the water with sewage. fertiliser and toxic chemicals
the air with gases such as sulfur dioxide and with smoke
the land with pesticides and herbicides and these can be washed into the water
Burning fuels release what gas?
carbon dioxide
cows and rice fields release which gas?
methane gas
What does sustainable development mean?
means finding ways of reducing the need for more resources.
What are the two indicators of pollution?
Lichens for air pollution and freshwater invertebrates indicate the level of water pollution
How do we know when the organisms represented by fossils were present on Earth?
Fossils are found in rocks, it is possible to date rocks.

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