U3 Key Area 3- Photosynthesis Flashcards
Why is photosynthesis important
Plant change light energy to chemical energy. If plants didnt do this there would be no animals!
What does a plant require for photosynthesis (2)
- sunlight energy
- raw materials from the environment
Photosynthesis word summary
What is photosynthesis
Photosynthesis is a series of enzyme-controlled reactions
What are the two stages photo synthesis occurs
-light reaction
-carbon fixation
What are the steps of light reaction (6)
- The light reaction occurs in the chloroplast. It contains the green pigment chlorophyll which traps light energy.
- Light energy is converted into chemical energy
- Some of this energy is used to split water into hydrogen and oxygen
- Some of the energy id used to product ATP (this stores chemical energy)
- The hydrogen and ATP are required for Stage 2 of photosynthesis
- Excess oxygen diffuse from the cells into the atmosphere.
What are the raw materials of light reaction (2)
- water
- light energy
What are the products of photosynthesis and what are they used for (3)
- oxygen (released as by product)
- hydrogen (used in Stage 2)
- ATP (used in Stage 2)
What is carbon fixation
Carbon fixation is a series of enzyme controlled reactions
What happens in carbon fixation
ATP provides energy to combine carbon dioxide from the sir with hydrogen to produce glucose
What are the raw materials of the carbon fixation stage (3)
- hydrogen (from stage 1)
- ATP (from stage 1)
- carbon dioxide (from the air)
What is the product of carbon fixation
Sugar (glucose)
What are 3 way glucose is used for
Used for respiriation
Stored as starch
Made into cellulose
Describe the procedure which you would carry out in order to test the leaf for starch
Boil leaf in water then alcohol; add iodine
Why would a plant be kept in darkness for 24hrs prior the starch experiment
To destarch the leaves to make sure there is no starch left over
