biogenetic (b4)

• Photosynthesis

  Carbon dioxide + water → Glucose + oxygen
• Photosynthesis


  • Occurs in chloroplasts
  • Endothermic reaction
• Respiration


  Process where glucose is used to transfer energy for the plant's functions and create other substances
• Substances produced from glucose

  • Cellulose
  • Amino acids
  • Fats
  • Starch
• Factors affecting rate of photosynthesis

  • Temperature
  • Light
  • CO₂ concentration
  • Raw materials
• factors affecting rate of photosynthesis - amount of Chlorophyll/chloroplast

  Number of chloroplasts and amount of chlorophyll affect the rate of photosynthesis, more chlorophyll faster rate of photosynthesis
• Greenhouse use

  1. Trap sun's heat

  2. Use artificial light

  3. Use heaters and ventilation

  4. Use fertilisers
• Light intensity

  Inversely proportional to distance
• Photosynthesis experiment

  1. Place boiling tube 10cm from LED lamp

  2. Fill with sodium hydrogen carbonate solution

  3. Add pondweed

  4. Count bubbles produced in 1 minute

  5. Repeat at different distances
• Metabolism


  The sum of all chemical reactions in an organism, regulated by enzymes
• Metabolic processes

  • Glucose joining to form starch, cellulose, glycogen
  • Fatty acids and glycerol forming lipids
  • Glucose and nitrate forming proteins
• Respiration


  1. Transfers energy by breaking down glucose

  2. Exothermic reaction releases thermal energy
• Uses of respiration

  • Keeping warm
  • Maintaining constant body temperature
  • Contracting muscles for movement
  • Building large molecules from smaller ones
• Aerobic respiration


  1. Occurs with oxygen

  2. Most efficient way to release energy

  3. Takes place continuously in mitochondria

  4. Glucose + oxygen → carbon dioxide + water
• Anaerobic respiration


  1. Not enough oxygen

  2. Incomplete oxidation of glucose

  3. Glucose → lactic acid or ethanol + carbon dioxide
• During exercise

  • Muscles contract more, need more energy from increased respiration
  • Breathing rate, breath volume and heart rate increase
  • Anaerobic respiration can occur, leading to muscle fatigue and lactic acid buildup
• Oxygen debt must be repaid to clear lactic acid
• how does temperature affect the rate of photosynthesis

  affects how much kinetic energy particles have
• catalysts of photosynthesis

  chlorophyll

  light
• factors affecting the rate of photosynthesis - temperature 


  as temperature increases rate of photosynthesis increases, this continues until enzymes denature
• factors affecting rate of photosynthesis - co2 concentration

  co2 is needed to make glucose, as concentration of co2 increases the rate of reaction increases
• light intensity is inversely proportional to the square of distance
• uses of glucose from phtosynthesis

  -for respiration

  -converted into insoluble starch for storage

  -to produce fat or oil for storage (in seeds)

  -to produce cellulose to strengthen walls

  -combined with nitrates to form amino acids which produce proteins
• what is oxygen debt 


  it is the amount of extra oxygen the body needs after exercise to remove the Latic acid from cells
• metabolism - GLURP

  Glucose ----> glycogen/ starch/ cellulose

  Lipids from glycerol and 3 fatty acids

  Urea from breakdown of excess protein

  RESPIRATION

  Proteins from amino acids from glucose and nitrate ions
• metabolism - 6 marks

  • metabolism is the sum of chemical reactions in a cell or body
  • glucose molecules joined together to form starch and cellulose in plant cell, or glycogen in animals
  • glycerol and 3 fatty acids join to form a lipid
  • excess protein can be broken down to form urea for excretion
  • respiration happens in all cells - releases energy
  • amino acids are made in plant cells from glucose and nitrate ions, they are joined together to make proteins
• response to exercise

  more energy = respiration increases

  body cells require more oxygen

  breath more frequently and deeper breaths

  heart rate increases to pump oxygenated blood around the body
• Latic acid

  latic acid causes muscle to become fatigued

  stop muscles contracting efficiently

  body has to remove latic acid

  transported in the blood

  taken to liver and converted back to glucose

  reacting with latic acid requires oxygen