Biology 1

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Keeping Healthy

KEY WORDS:

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. 
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Nerves, Hormones & Drugs

KEY WORDS:

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
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Interdependence & Adaption

KEY WORDS:

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. 
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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. 
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