Biology

revision

HideShow resource information
  • Created by: kasia
  • Created on: 22-01-12 20:58

Hormones

1.FSH

  • produced by the pituitary gland
  • causes the egg to mature in one of the ovaries
  • stimulates the ovaries to produce oestrogen

2.Oestrogen

  • produce in the ovaries
  • causes the pituitary to produce LH
  • Inhibits the further release of FSH

HORMONES are chemical messengares which travel around in your blood to activate target cells.

1 of 6

Cholesterol and Salt

CHOLESTEROL is a fatty substance that is essential for good health its found in every cell

LDLs carry cholesterol from the liver to the body cells they are sometimes called (bad cholsetero.) as any excess can build up in the arteries

HDLs carry cholesterol that isnt needed from the body cells back to the liver for removal from the body

2 of 6

Fighting Diseases

There are two types of Pathogens 

  • BACTERIA
  • VIRUSES

bacteria are small and they make you feel ill by damaging your cells and producing toxins which are poisnous

Viruses are tiny they replicate themselves by invading your cells and using your cell machinery to produce many copies of themselves they make the cell burst which releases new viruses.This cell damage makes us feel ill

WHITE BLOOD CELLS

They travel around in your blood and crawl into every part of you constantly patrolling for microbe,when they come across a microbe they:

  • consume them-engluf foregin cells and digest them
  • Produce antibodies-antibodies lock on to the invading microbe and kill them they are specific to that type of antigen
  • prouce antitoxins
3 of 6

Cloning

CUTTINGS

  • gardeners take cuttings from good parent plant and plant them to produce clones of the parent plant
  • these plants can be produced quickly and cheaply

TISSUE CULTURE

  • This is where a few plant cells are put in a growth medium with hormones and they grow into new plants clones of the parent plant

the disadvantages of two are reduced gene pool

EMBRYO TRANSPLANTS

  • sperm cells taken from bull and egg cells from cow.The sperm are then used to artificially fertilise the egg cell.the embryo that develops splits many times to form clones.
  • these cloned embryos can be inplanted into lots of cows.
  • disadvantage is reduced gene pool
4 of 6

Adult Cell Cloning

  • happens by taking a sheep egg cell and removing its genetic material
  • A complete set of chromosomes from the cell of an adult sheep was inserted into empty embryo which then grew into an embryo.
  • this grew into a genetically identical sheep
5 of 6

Genetic Engineering

  • a useful gene is cut from organisms chromosome using ENZYMES
  • ENZYMES are then used to cut another organisms chromosome and then insert the useful gene.

EVOLUTION

  • Lamorocks theory was that if characteristics were used a lot by an organism it would become more developed and be passed on the next generation.
  • Darwin theory was that organism were born well adapted to their enviroment therefore they standed a better chance of survival and breeding
6 of 6

Comments

No comments have yet been made

Similar Biology resources:

See all Biology resources »See all resources »