Photosynthesis

• Photosynthesis


  Photosynthesis is the process by which green plants make their own food using light energy.
• Why is photosynthesis important?

  Photosynthesis releases oxygen that most living organisms need for respiration.

  Photosynthesis also removes carbon dioxide from the atmosphere. This ensures that carbon is constantly recycled.
• Role of carbon dioxide in photosynthesis

  Carbon dioxide diffuses in from the atmosphere, through the stomata of the leaves. The stomata are the pores on the leaf for gas exchange.
• Role of water


  Water is absorbed by osmosis from the soil by the plant root hairs. The water is then carried up the stem to the leaf, through the xylem tissue.
• Role of sunlight


  Sunlight is the natural source of energy for photosynthesis. This energy is necessary for the reaction to occur.
• Role of chlorophyll


  Its role is to trap or absorb the sunlight's energy.
• Role of glucose


  Carbon dioxide and water are combined to form glucose and oxygen. This glucose is used in respiration to make energy for the plant. It also has a structural role, as it can be used to make cellulose for cell walls.
• Role of oxygen


  Carbon dioxide and water are combined to form glucose and oxygen. This oxygen is either used by the plant for respiration or released into the atmosphere.
• Where does the light stage occur?

  Grana of the chloroplast where chlorophyll is located
• What are the three products of the light stage?

  ATP, NADPH, Oxygen
• What happens when light energy is absorbed?

  The electrons within the chloroplast become energized. The energy from these is used to generate ATP
• What happens when the energized electrons leave the chloroplast?

  Picked up by electron acceptor molecule and are brought to the electron transport chain
• How is ATP formed?

  The released energy adds a phosphate to ADP to form ATP
• Why is this pathway regarded as cyclic?

  The electrons that are now low in energy are returned to the chloropyll molecule
• Why is ATP essential for the dark stage to occur?

  ATP is used to form NADPH which provides electrons and protons
• Dark stage is controlled by

  Enzymes
• Where does the dark stage occur?

  The stroma, liquid part of the chlorplast
• What happens after carbon dioxide enters from the air?

  The NADPH carries in the energized electrons and protons to combine and form glucose
• Which products from the dark stage are recycled?

  The NADP+, ADP, and phosphates
• Products of photosynthesis


  Oxygen, glucose