Biology year 10

• Ways to reduce eutrophication

  • Farmers should be very conservative with the amounts of fertiliser they use
  • Build some sort of barrier between the field and body of water
• NPK Fertiliser


  Nitrogen Phosphorus Potassium
• Food chain


  A sequence of who eats whom in a biological community
• The animal at the top of the food chain has no natural enemies
• Food web


  A web of who eats whom in a biological community
• How would primary consumer 3 benefit from an increase in the population of primary consumer 4?

  There would be more of primary consumer 4 for the tertiary consumer and secondary consumer 2 to eat, so less of it is eaten
• Nitrogen Cycle


  1. Nitrogen fixation

  2. Feeding

  3. Decomposition

  4. Denitrification
• Eutrophication is a process that occurs when too many nutrients enter the water in a river or lake, usually when fertiliser runs off into the water
• Types of Pollution


  • Air
  • Water
  • Land
  • Sound/Noise
• Carbon Cycle


  1. Photosynthesis

  2. Respiration

  3. Fossilisation

  4. Combustion
• Nitrates going into water causes algae to grow, competition for light and food causes plants to die, dead plants are decomposed by bacteria which use up oxygen in the water, causing animals to die
• The animal at the end of the food chain has no natural enemies
• Pesticides like DDT and dieldrin are very persistent, meaning they remain in the environment for a long time and can build up in the bodies of animals
• The poisons can be passed along the food chain, becoming more concentrated as the food chain goes on
• Resistance means the poison does not kill the organism, it just builds up in their bodies
• Enzymes


  Biological catalysts
• Enzymes


  • They increase the rate of chemical reactions without themselves being consumed or permanently altered by the reaction
  • They increase reaction rates without altering the chemical equilibrium between reactants and products
• Optimum temperature


  The temperature that enzymes work best at. If it is too hot, the enzyme is denatured
• Optimum pH


  The pH that enzymes work best at. If it is too acidic or too alkaline, the enzyme is denatured
• Lock and key model

  The substrate is complementary to the active site of the enzyme
• Denaturation


  When the active site changes shape and the substrate cannot bind. It is irreversible.
• Bile


  Helps the digestion of fat by emulsifying it, breaking it down into small droplets and increasing the surface area
• Increasing the surface area of a substrate accelerates the rate of reaction, leading to more collisions
• Pathogen


  Microorganisms that cause disease
• Transmission of pathogens


  • Cough or sneeze
  • Water
  • Animals
  • Contact
• Ways to stop the spread of pathogens

  • Cover your mouth when coughing/sneezing
  • Boil water
  • Wear bug repellent
  • Wash hands regularly
• Pathogens can enter the body through the mouth, nose, cuts, eyes and bites
• Antibiotics


  Used to cure bacterial infections
• Vaccination


  Giving small amounts of dead or inactive pathogens to stimulate the body's immune system to produce antibodies
• How vaccines work


  • The antigens in the vaccine stimulate white blood cells to make antibodies
  • The antibodies stick to the antigens on the surface of the pathogens and cause them to clump together
  • Memory cells are retained, allowing a faster and bigger immune response next time the pathogen is encountered
• Male reproductive system structures

  • Scrotum
  • Testes
  • Sperm tube
  • Glands
  • Penis
• Female reproductive system structures

  • Ovary
  • Oviduct
  • Uterus
  • Cervix
  • Vagina
• Parts involved in pregnancy

  • Placenta
  • Umbilical cord
  • Amniotic sac
• What happens during birth

  1. Uterus wall contracts

  2. Cervix dilates

  3. Amniotic sac ruptures
• Contraception methods


  • Surgical
  • Mechanical
  • Chemical
  • Natural
• Photosynthesis


  The process used by plants to make food
• Chlorophyll


  The green substance in plants used to trap light for photosynthesis
• Nutrients/Minerals


  The chemicals needed for plants to grow healthily
• Xylem


  The thin vessels in a plant that carry water from the roots to the leaves
• Phloem


  The pores on the leaf surface needed for gas exchange and transpiration