Chapter 4

• How does photosynthesis use energy?

  Photosynthesis uses energy to change carbon dioxide and water into glucose and oxygen
• Where does photosynthesis happen?

  In chloroplasts in green plant cells - they contain pigments like chlorophyll that absorb light
• What type of reaction is photosynthesis?

  endothermic - energy is transferred to the environment
• What is respiration?

  A reaction where energy is released
• What type of reaction is respiration?

  It is an exothermic reaction
• What does breathing supply for respiration?

  Oxygen
• What does respiration use to release energy?

  Food or photosynthesis
• What are the body processes requiring energy?

  • Building larger molecules (e.g., proteins)
  • Muscle contraction for movement
  • Maintaining body temperature
  • Digesting food
  • Breathing
• What does aerobic respiration require for energy?

  Oxygen and glucose
• What occurs during anaerobic respiration?

  It occurs in the absence of oxygen
• How does anaerobic respiration compare to aerobic respiration?

  Anaerobic transfers less energy than aerobic
• What happens to glucose during respiration?

  Glucose is oxidised, losing electrons
• What does CO2 represent in respiration?

  Carbon dioxide
• What does H2O represent in respiration?

  Water
• What does C6H12O6 represent in respiration?

  Glucose
• What does O2 represent in respiration?

  Oxygen
• What is anaerobic respiration in yeast called?

  Fermentation
• How is fermentation of yeast used in baking?

  It makes bread rise
• How is fermentation of yeast used in drinks?

  It produces alcoholic drinks using ethanol
• What happens to respiration rate during exercise?

  It increases to supply more energy
• Why do cells need more oxygen during exercise?

  To support increased aerobic respiration
• What happens to breathing rate during exercise?

  Breathing rate rises to increase oxygen
• What happens to heart rate during exercise?

  Heart rate increases to deliver oxygen
• What can lead to anaerobic respiration during exercise?

  Insufficient oxygen delivery to muscles
• What is the result of anaerobic respiration?

  Less energy is produced
• What is produced during yeast fermentation for alcoholic drinks?

  Ethanol
• What happens to respiration rates during exercise?

  They increase to supply more energy
• Why do breathing rate and volume increase during exercise?

  To supply more oxygen to the blood
• What happens to heart rate during exercise?

  It increases to deliver oxygen
• What can intense exercise lead to in terms of respiration?

  Anaerobic respiration
• What is a consequence of anaerobic respiration during exercise?

  Build-up of lactic acid
• What does the build-up of lactic acid cause?

  Pain and 'stitch'
• What is oxygen debt?

  Additional oxygen needed to remove lactic acid
• What happens to heart and breathing rates after exercise?

  They stay high to deliver oxygen
• Where is lactic acid transported after exercise?

  To the liver
• What happens to lactic acid in the liver?

  It is converted back into glucose
• What can prolonged exercise lead to?

  Muscle fatigue
• How is heart rate measured?

  By pulse at the wrist
• How is breathing rate measured?

  By counting chest rises
• What is the procedure to investigate the effect of exercise on heart and breathing rates?

  1. Measure HR and BR at rest
  2. Do 10 star jumps, measure again
  3. Do 50 star jumps, measure again
  4. Measure after 3 minutes of rest
  5. Repeat with more individuals
  6. Plot mean values on a bar chart
  7. Analyze oxygen debt