Photosynthesis B1 Flashcards
How does carbon dioxide and water make its way into the leaves for photosynthesis?
Carbon dioxide diffuses into the leaves through the stomata and the water is taken up from the soil by the roots and then transported to the leaves by the xylem.
How can glucose be used by plants?
For respiration, to build complex molecules (cellulose - strengthening cell wall), to make oils and fats to be stored as a future energy source, to make amino acids to combine into proteins, to make starch which is a better store of energy to glucose as it’s compact and insoluble (won’t draw water into cell via osmosis)
What factors affect the rate of photosynthesis?
Light intensity, carbon dioxide concentrations, temperature and chlorophyll in the plant.
What happens to the rate of photosynthesis if chlorophyll levels vary?
Chlorophyll absorbs light energy so less chlorophyll means less sunlight - slower rate. Chlorophyll levels may vary due to diseases such as tobacco mosaic virus, lack of nutrients (water) or environmental stress. Diseases damage chloroplasts so they cannot produce as much chlorophyll.
What happens to rate of photosynthesis as light intensity is changed?
As light intensity increases so does the rate of reaction up to a certain point. Where it plateaus, there is something else limiting the rate.
What does a plateau on a graph tell us?
A plateau tells us that something else is a limiting factor.
How may farmers artificially create conditions to improve the rate of photosynthesis?
Use a greenhouse - traps suns heat = increases temperature, enclosed. Artificial light - photosynthesis occurs continuously l. Paraffin heaters - pump CO2 and heat. Fertilisers - provide plants with essential minerals to grow. Pesticides - to kill unwanted bugs.
