Bioenergetics

• What’s the equation for photosynthesis?

  carbon dioxide + water -> glucose + oxygen
• How do plants use glucose?

  for respiration, making cellulose (strong plant cell walls), making amino acids which are then made into proteins, stored as oils or fats - turned into lipids for storing in seeds, stored as starch - stored in roots, stems and leaves for when photosynthesis isn’t happening.
• What are the limiting factors for photosynthesis?

  Light intensity, carbon dioxide concentration, temperature and amount of chlorophyll.
• What’s the inverse square law?

  Light intensity is inversely proportional to distance squared
• What type of reaction is respiration?

  Exothermic - transfers energy to the environment
• What is respiration?

  The process of transferring energy from the breakdown of glucose
• What are the two types of respiration?

  Aerobic - uses oxygen, transfers more energy

  Anaerobic - without oxygen
• Whats the equation for

  aerobic website?

  Glucose + oxygen -> carbon dioxide + water
• What’s the equation for anaerobic respiration in muscles?

  Glucose -> lactic acid
• What’s the equation for anaerobic respiration in plants and yeast cells?

  Glucose -> ethanol + carbon dioxide
• What’s anaerobic respiration in yeast cells called?

  Fermentation- has economic importance in the manufacturing of bread and alcohol
• What is energy used for?

  To allow muscles to contract, keep body temperature steady and build up large molecules from smaller ones
• What’s metabolism?

  The sum of all the reactions in a cell / or the body
• Examples of larger molecules that are made from smaller ones:

  Glucose -> starch ->glycogen + cellulose

  Lipid molecules are made from a molecule of glycerol and three molecules of fatty acids

  Glucose is combined with nitrate ions -> amino acids -> proteins
• Examples of larger molecules broken down into smaller ones:

  Glucose -> respiration

  Excess protein -> urea - which is excreted in urine
• Metabolism;

  -in a cell there’s lots of chemical reactions happening at the same time, which are controlled by enzymes.

  • many of these are linked together to form bigger reactions
  • In some of these reactions, larger molecules are made from smaller ones
  • In other reactions, larger molecules are broken down into smaller ones
  • The sum of these reactions is the metabolism
• What’s the body’s response to exercise?

  breathing rate and breath volume increase to get more oxygen into the blood, heart rate increases to get oxygenated blood around the body faster.
• Why do muscles need energy?

  To contract, when you exercise some of your muscles contract more frequently than normal so you need more energy - from increased respiration. The increase in respiration means you need more oxygen to your cells.
• What’s the effect of vigorous exercise?

  The body can’t supply oxygen to your muscles quickly enough, so they start to respire anaerobically.
• What can anaerobic respiration in muscles cause?

  Lactic acid buildup - painful.

  Long periods of exercise can cause muscle fatigue - stops the muscles from contracting efficiently.
• What’s oxygen debt?

  Oxygen debt is the amount of oxygen your body needs to react with the build up of lactic acid to remove it from the cells. Oxygen reacts with the lactic acid to form a harmless CO2 and water.
• What’s another way the body can cope with high levels of lactic acid?

  The blood that enters your muscles transports the lactic acid to the liver, where the lactic acid is converted back into glucose.