biology topic 1- cell biology

• where does photosynthesis take place?

  chloroplasts
• factors impacting rate of photosynthesis

  temperature

  light intensity

  carbon dioxide concentration

  chlorophyll concentration
• increasing yield in farming via photosynthesis

  -lighting and heating greenhouses increases the rate of photosynthesis

  -this means that crops grow faster with a larger overall yield
• drawbacks of increasing yield in farming via photosynthesis

  -if lighting and heating are expensive, then it might not be possible to spend that amount on a greenhouse

  -farmers must evaluate the trade-offs between costs of lighting and heating and possible rate of photosynthesis
• uses of glucose in plants


  converted into insoluble starch and stored

  converted into cellulose used to strengthen cell walls

  fats and oils stored in seeds

  proteins needed for growth and repair
• reasons that organisms need energy

  for growth (making large molecules from small molecules)

  for muscle contraction

  to keep the body at constant temperature
• symbol equation for aerobic respiration


  C₆H₁₂O₆ + 60₂ → 6H₂0 + 6CO²
• equation for anaerobic respiration in animals

  glucose --> lactic acid + energy
• equation for anaerobic respiration in plants

  glucose --> ethanol + carbon dioxide
• metabolism definition


  sum of all chemical reactions in a cell or organism
• the body's responses to exercise

  increased heart rate to deliver more blood to muscles

  increased breathing rate to increase rate of gas exchange in lungs

  increased breath volume to increase gas exchange rate

  blood vessels dilate to ensure more blood reaches muscles
• lactic acid


  toxic by-product of anaerobic respiration

  buildup in muscles leads to muscle fatigue and pain

  also stops muscles contracting effectively
• oxygen debt


  extra oxygen needed after exercise to oxidise lactic acid and remove from cells
• how is oxygen debt repayed?

  -blood transports lactic acid to the liver, where it reacts w/ oxygen to produce carbon dioxide and water

  -heavy breathing post-exercise helps to repay oxygen debt by taking more oxygen into the lungs