Biology GCSE (1)

the Nervous systems are :- brain, spinal cords/spinal nerves, receptors 

- info passes from receptors along the neurones(nerve cells) to the brain

3 neurones:- motor, sensory, relay.

-adapted cells carry a electrical signal, which is a nerve impulse.

connections between neurones. there is a small gap called a synapse.

Receptors:- light/eyes, sound/ears, change of position/ in the ears, taste/tounge, smell/nose, touch/pressure/pain/temp- skin.

- reflex actions speeds up response 

-spinal cord - coordinator and passes impules.

-Body temp- 37*C- temp increased by shivering/ temps decreased by sweating

-water content - gained by drinking and lost by lungs and sweating, pee 

-ion content- gained, eating and drinking. loast by sweating and pee

-bloody sugar (glucose) - provides cells with a constant supply of energy, gained- eating and drinking 

conditions controlled

-hormaones (coordinated) chemical substanes produced by glands, moved by bloodstream.

hormones and fertility 

-pituitary gland and ovaries - make lining of womb thicker

-follice stimulating hormone (fsh)- pituitary gland makes ovaries produce oestrogen and eggs mature

-oestrogen- ovaries inhibts production of fhs and production of lutesining hormone (LH)

-LH- pituarity gland- stimulates release of ehh in middle of menstrual cycle 

*******-all chemical ractions in the cells of the body are carried out

- more exercise- MR increases and stays same for a while 

-proportion of fat to muscle in your body / could be from family history

- less exercise- the warmer it is, less food you need

-cholesterol, salt

-cholesterol- made in liver, found in blood.

                  -carried by body in chemicals called Lipoproteins (made from fat/lipid and protein)

-low density Lipoproteins - can cause heart disease 

-high density Lipoproteins- are good cholesterols 

-emphysema- alveoli due to coughing

-bronchitis- increaded infection to mucus production

-pregnace- carbon monoxide, reduces oxygen carrying capacity of blood which can deprive a fetus of oxygen and lead to a low birth mass

-arterial and heart disease, lung cancer

bacteria and viruses

-microorganisms that cause diseases that are called pathogens

-white blood cells that form part of the bodys immune system 

-antibiotics used against bacteria 

-a person can be immunte to a perticular disease by being vaccinoted

Alchol

-depressant- cause reactions to slow down

-lead to a lack of self control

-excess can lead to unconsciousness and even coma or death

-liver damage, brain damage

-organisms compete with each other for space/light, food and water

-population is the total number of individuals of the same species

-a community is all the organisms in a particular area.

adaptations 

-adaptations are special features of behavior. which make an organism particular well suited to it environment.

genetic

-nucleas of a cell contains chromosomes which are made up if a substance called DNA

-a section of a chromosome is called a gene

virartation 

-differences between individuals of the same are called a variation. 

healthy diets

-carbohydrates, fats, protein, fibre, vitamins, minerals, water

-person mahourished diet not good blance

-poor diet = fat/thin, scurvy caused by VC

un healthy

uk/usa -arthritis, diabetes, high blood pressure, heart diease 

africa/asia- reduced resistance to infection, irregular periods in women

-Evolution is the change in a population over a large number of generations that may result in the formation of a new species, the members of which are better adapted to their environment. 

fossils

-fossils are the remains of plants or animals from many years ago which are found in rock. they provide evidence of how organisms have changed over time. 

darwins theory

-charles darwin :- there is much variation in a species

-more offspring are produced than the environment can support (food and breading ares) 

-only the ones best suited or adapted will survive and breed. this i known as natural selection or 'survial of the fittest' 

-those that survie passs their genes onto their offspring. eventually the species which is less suited will become extinct.

Dawins theory was accepted because :- religion had an important place in society. - it is difficult to prove. - many scientists didn't accept the theory. -attempts to demonstrate evolution through tests have failed.

-sexual reproduction is when a sperm from a male fuses with a egg, when that happens genes are mixed

-asexual reproduction means no variation happens at all, unless it is due to environmental causes. 

cloning 

-take the egg out, remove the nucleus and put the DNA of another donor in where the nucleus has and then implant into the uterus.   

evolution

-all living things which exist today and many more that are now extinct, evolved from simple life forms which first developed 3 billion years ago.