METABOLIC RATE: the speed at which energy is used in the body to carry out chemical reactions.
ANTIBIOTICS: are drugs which kill bacteria.
LDL: bad cholestral
HDL: good, removes cholestral from the wall of the arteries.
- To lose mass you need to use more enegy than you take in: eat less exersize more.
- High blood cholestral can lead to the blockage of arteries. Cholestral levels can be influenced by inherited factors and by diet.
- Some bacteria are becoming resistant to antibiotics an example is MRSA.
- White blood cells attack pathogens via phagocytis, antibodies and antitoxins.
- Vaccination encourages white blood cells to make antibodies against a pathogen. If the person is later infected, the antibodies will be made more quickly. We say thay are immune.
Nerves, Hormones & Drugs
SENSORY NUERONS: carry electrical impulses to the CNS from receptors.
MOTOR NUERONS: carry impulses from the CNS to the effectors (muscles and glands)
- Conditions surrounding cells must be kept constant: water, sugar and salt (concentration) and temperature.
- Sweating is a mechanism the body uses to reduce temp when it rises above 37 degrees.
- Plant hormones called auxins cause their shoots to grow towards the light (POSITIVE PHOTOTROPISM) & roots to grow towards gravity (POSITIVE GRAVITOPISM). Artificial hormones can be used as rooting powder & herbicide.
- Hormones control the mensural cycle: FSH (causes an egg to mature & the ovary to secrete oestrogen). Oestrogen (causes the uterus lining to thicken and stops the production of FSH). LH (causes ovulation)
Interdependence & Adaption
ADAPTION: the characteristics that organisms have to survive in their environment.
- The better the adaption of the organism the more likely the organism will win the competition and get the chance to reproduce.
- Decay by microorganisms is an important way to recycle nutrients. The carbon cycle shows how nutrients is moved around the planet.
- Energy is wasted at each stage in a food chain, which results in less biomass at each level. This is repfresented as a pyramid of biomass.
- Pollution levels can be monitored by measuring factors such as temp and pH; or by studyin the distribution of living pollution indicators; such as lichens to show air pollution indicators and invertabrates to show water pollution.
Genes & Evolution
- Organsims vary because of the genes they inherit from their parents.
- Asexual reproduction produces clones.
- The offspring from sexual reproduction are different from their parents.
- Clones can be created by taking cuttings and carrying out tissue culture, embryo transplants and adult cell cloning.
- Genetic engineering means taking a gene from one organism, and putting into another: used to make human incillin and GM (GENETICALLY MODIFIED) crops.
- Scientist believe that all life on earth evolved from single celled organisms that lived 3.5 billion years ago.
- Darwin's ideas bout evolution: living things evolved due to variation & survival of the fittest. Many people did not believe this till 50 years after his ideas were published.