B8 Photosynthesis Flashcards
What is the equation of photosynthesis?
Carbon dioxide+ Water—-> Glucose+ Oxygen
6CO2+ 6H2O—-> C6 H12 O6 + 6O2
Describe the process of photosynthesis
Light energy is harnessed by the chloroplasts. The light energy is used to convert carbon dioxide and water into glucose. This essentially converts light energy into chemical energy in the form of glucose. Oxygen is released as a by product. Because this requires an input of energy, it is classed as an endothermic reaction.
How are leaves adapted for photosynthesis?
Most leaves are broad, giving them a big surface area for light to fall on
Most leaves are thin so diffusion distances for the gases are short
They contain chlorophyll in the chlorplasts to absorb light
They have veins, which bring plenty pf water in the xylem to the cells of the leaves and remove the products of photosynthesis in the phloem
How does carbon dioxide reach the cells which are photosynthesising?
The carbdon dioxide diffuses up through the guard cells and through the stomata, it diffuses through the spongy mesophyll and eventually diffuses into the palisade mesophyll. This is where there is the most chloroplasts and where most photosynthesis takes place
How does water reach the cells which are photosynthesising?
Water reaches the palisade mesophyll by moving up the xylem vessel following the tranpsiration system.
The xylem vessel is a part of the vascular bundle. The water once reaching the palisade mesophyll then leaves the leaf via osmosis
How does the plant use Glucose?
To provide energy for the cells in respiration
Plants build glucose into complex carbohydrates such as cellulose for cell walls and starch
Glucose may also be stored
Make amino acids (combine glucose with nitrates)
To then make proteins
Make lipids/fats and oils for an energy store
Describe and explain the relationship between light intensity and photosynthesis?
Light intensity is a limiting factor for photosynthesis, with higher light intensity increasing the rate of the photosynthesis until a point where it is no longer a limiting factor, where the rate will remain the same as carbon dioxide concentraion/temperature limits it.
