4. Bioenergetics

• Photosynthesis is a chemical reaction which takes place in plants
• Photosynthesis coverts carbon dioxide and water into glucose and oxygen
• Photosynthesis uses light to power the chemical reaction, that is absorbed by the green pigment called chlorophyll
• Photosynthesis is an example of an endothermic reaction
• Plants acquire the carbon dioxide via diffusion through the stomata of their leaves
• The water is absorbed from the soil through the roots and transported to the cells via the xylem
• There a three limiting factors that decrease the rate of photosynthesis

  • Temperature
  • Light intensity
  • Carbon dioxide levels
• Uses of glucose from photosynthesis

  • Used for respiration
  • Converted into soluble starch for storage
  • Used to produced fat or oil
  • Used to produce cellulose, which strengthens the cell wall
  • Used to produce amino acids for protein synthesis
• Respiration is a chemical reaction which occurs inside the mitochondria of all living cells to release energy.
• Energy is used for functions like movement, warmth and building larger molecules for growth and repair
• Respiration is an exothermic reaction
• Aerobic respiration uses oxygen
• Anaerobic respiration does not require oxygen
• glucose + oxygen = carbon dioxide + water
• Anaerobic respiration equation

  glucose = lactic acid
• In plants and yeast, anaerobic respiration makes other products

  This reaction is called fermentation that is used in the making of bread and beer

  This equation is

  glucose = ethanol + carbon dioxide
• Metabolism is the combination of all the reactions in a cell or the body
• The heart pumps faster and the breathing rate and breath volume all increases to supply more oxygen to the muscles via the bloodstream
• Anaerobic respiration occurs if there isnt enough oxygen reaching the muscles
• The incomplete oxidation of glucose produces lactic acid, which can build up in our body and damage the tissues.
• After long periods of exercise, the muscles can become fatigued and stop contracting.

  You might experience a pain commonly called a stitch