Biology p1

A HEALTHY DIET

A healthy diet contains the right proportions of nutrients and energy.
people who dont eat a balanced diet become malnourished. this can lead to becoming over and underwieght and type 2 diabetes.
to stay in wieght we need to burn the same amount of energy we take on. the more muscle mass you have the higher your metabolic this is how fast your body burns energy.
muscle mass, amount of exersize and inherited factors effect metabolic rate.

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microorganisms that cause disease are called pathogens. there are bacteria and viruses that multiply inside our bodys to make them ill.
semmelweis was a doctor in the 1800s he noticed that if nurses was there hands befor visting patients there were less deaths. however doctors didnt accpect his ideas because it was unkownen how this worked.
our bodys produce white blood cells to fight pathogens.
they can ingest pathogens to kill them, they also make antibodys to attach to pathogens and destroy them and they can produce antitoxins to stop the pathogens toxins.
the white blood cells have to learn what antibodys to make for each pathogen, this can take some time. however once it knows the type of antibody to produce it remebers it. this is when you become immune.
vaccines are weak\dead versions of pathogens.
viruses work inside cells.
antibiotics are medcine that kill bacteria.

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nerve cells are callled neurons.
receptors are th cells which respond to a stimulant and send a elecrtical signal.
sensory neurons are the first to pass on this impusle to a synapse.
at the synapse(a gap) chemicals are realsed these a picked up by the relay neuronin the spine. they send the impulse to a second synapse.
the motor neuron get the impulse and causes the muscle to contract and move.
the muscle is the effector.

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the menstrual cylcle in women is controlled by hormones.
FSH cause a egg to mature and for the ovaries to produce homrones like oestrogen.
LH causes the egg to realse.
OESTROGEN stops the production of FSH so no more eggs mature that month, the lining of the womb thickens as this happens.
ORAL CONTRACEPTIVES 9 birth control) prevent pregnancy. they contain oestrogen or progesterone which stops FSH so no eggs mature.
FSH and LH can be given to women to increase fertility.
IVF is treatment outside the body.
FSH is given to mature a egg. this is removed and fetilised with a sperm in a test tube once the develope into a embryos there placed back in to the womb.

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plant respond to changes in light, moisture and gravityby changing how they grow.
growth to light is called phototropism.
growth to gravity is called graitropism or geotropism.
auxins are plant hormones that control growth. it is made in the root tips and shoots.
it cause the plant to elongate the cells ( grow) it gathers on the shaded side. this cause the plant to grow towards the light.
acroculture is growing crops in feilds for bussnes.
horticulture is growing in garned s for fun.
in weed killers hormones are used to kill the weeds not other plants.

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