Bioenergetics

• Define photosynthesis

  A chemical reaction in which energy is transferred from the environment as light to the leaves of a plant, this is an endothermic reaction.
• What absorbs light energy?

  Chlorophyll
• Limiting factors for photosynthesis

  Temp

  C02 concentration

  Light intensity

  Amount of chlorophyll
• Word equation for photosynthesis

  carbon dioxide + water -> glucose + oxygen
• Balanced symbol equation for photosynthesis

  6CO(2) + 6H(2)O -> C(6)H(12)O(6) + 6O(2)
• What is the main function of chloroplasts

  Photosynthesis
• What type of energy is used in photosynthesis

  Light energy
• Define the term limiting factor

  Anything that limits the rate a reaction happens when it is in short supply
• Describe how light intensity affects the rate of photosynthesis

  Light intensity increases = photosynthesis increases

  until another factor becomes the limiting factor

  Photosynthesis will stop if there is little or no light
• Describe how CO2 concentration affects rate of photosynthesis

  CO2 concentration increases = photosynthesis increases

  Until another factor becomes the limiting factor

  Carbon dioxide is often the limiting factor in photosynthesis
• Describe how temp affects the rate of photosynthesis

  Temperature increases = photosynthesis increases

  Because enzymes gain kinetic energy, leading to more frequent collisions between enzymes and substrates

  until optimum temp

  then enzymes denature and photosynthesis plummets
• How do plants use the glucose produces in photosynthesis

  Respiration

  Convert to insoluble starch

  Produce fat or oil (lipids)

  Produce cellulose

  Produce amino acids for protein synthesis
• Aerobic respiration

  Respiration with oxygen

  Complete oxidation of glucose: large amount of energy is released
• Anaerobic respiration

  Respiration without oxygen

  Incomplete oxidation of glucose: much less energy is released than aerobic respiration
• What type of reaction is cellular respiration?

  Exothermic
• Define cellular respiration

  Series of reactions that occur continuously in mitochondria of living cells to release energy from glucose
• What do organisms need energy for (3)

  Chemical reactions

  Muscle contraction

  Keeping warm
• Word equation for aerobic respiration

  Glucose + oxygen -> CO2 + water + energy
• Word equation of anaerobic respiration in muscles

  Glucose -> lactic acid
• What is anaerobic respiration in plant and yeast cells called?

  Fermentation
• Word equation for anaerobic respiration in plant and yeast cells

  glucose -> ethanol + CO2
• What changes during exercise?

  Heart rate. breathing rate, breath volume increase, to supply the muscles with more oxygenated blood
• What substance builds up during anaerobic respiration

  Lactic acid
• What happens to muscles during long periods of activity

  Muscles become fatigued and stop contracting effictively
• How is lactic acid removed from the body

  Lactic acid in muscles ->

  Blood transports to the liver ->

  Lactic acid converted back to glucose
• Metabolism

  Sum of all the reactions in a cell or the body

  The energy released by respiration is used for the continual enzyme-controlled processes of metabolism
• Balanced symbol equation for aerobic respiration

  C(6)H(12)O(6) + 6O(2) -> 6CO(2) + 6H(2)O
• Balanced symbol equation for anaerobic respiration in muscles

  C(6)H(12)O(6) -> 2C(3)H(6)O(3)
• Oxygen debt: The amount of oxygen needed to react with the lactic acid to remove it from cells
• Metabolic processes include the synthesis and breakdown of

  Carbohydrates

  Proteins

  Lipids
• Metabolic processes: Carbohydrates

  Synthesis of larger carbohydrates from sugars (starch, glucose, and cellulose)

  Breakdown of glucose in respiration to release energy
• Metabolic processes: Proteins

  Synthesis of amino acids from glucose and nitrate ions

  Amino acids used to form proteins

  Excess proteins broken down to form urea for excretion
• Metabolic processes: Lipids

  Synthesis of lipids from one molecule of glycerol and 3 molecules of fatty acids