Biology

• The leaf is the organ for photosynthesis
• Water + carbon dioxide = glucose + oxygen
• Leaves kept in the dark for 24 hour are destarched
• Testing a leaf for starch:

  1. Boil the leaf to kill it
  2. Decolourise using ethanol
  3. Wash to soften
  4. Test with iodine

  a blue black colour shows presence of starch
• As energy is lost at each tropic level it is more energy efficient to eat the organisms nearer to the start of the food chain
• Pyramids of number - show how many organisms are in each trophic level
• Pyramids of biomass - presents the relative biomass of organisms in a community
• Intensive farming is done by using fertilisers and battery farming and disease control
• Pollution can be measured by oxygen levels ( less oxygen the more pollution ), pH levels ( more acidic the more pollution ), and the presence of heavy metals ( more heavy metals the more pollution )
• Lichens are used to indicate air pollution. Some species will only grow in clean air. Very high levels of pollution no species will grow.
• Carbohydrates are broken down by carbohydrase
• Proteins are broken down by protease
• Lipids are broken down by lipase into glycerol and fatty acids
• Starch becomes glucose
• Protein becomes amino acids
• iodine turns from brown to blue/black when starch is present
• Benedict’s goes from blue to brick red when glucose is present
• biurets turns from blue to violet when protein is present
• Protein builds bodies
• Carbohydrates are for energy
• fats provide energy
• Minerals for iron and haemoglobin in blood
• vitamin c maintains healthy tissue
• Fibre provides bulk
• Water is essential for body processes
• Red blood cells contain haemoglobin for transport of oxygen
• White blood cells defend against infectious disease
• Platelets clot the blood
• Plasma carries dissolved substances and distributes heat
• Anaerobic respiration

  glucose + oxygen = carbon dioxide + water + energy
• Inspiration

  • intercostal muscles contract
  • ribs move up and out
  • diaphragm contracts and flattens
• Expiration

  • intercostal muscles relax
  • ribs move down and in
  • diaphragm relaxes and domes up
• The alveoli are adapted for gas exchange by:

  • good blood supply
  • large surface area
  • thin walls
  • moist lining
• Limewater test for carbon dioxide, if carbon dioxide is present the line water will turn cloudy.
• Cilla move mucus up the trachea to be swallowed
• Smoking paralyses the cilla and cause the mucus to clog
• Enzymes rely on collisions of molecules with a specific region of the enzyme call the active site to work
• Genes are sections of DNA made of many bases codes for an amino acid
• High temperatures change the shape of the active site of the enzyme
• Diffusion is the movement of molecules from an area of high concentration to an area of low concentration.