bioenergetics Flashcards
what is photosynthesis?
an endothermic reaction where light energy is transferred by chloroplasts to produce glucose
what is the word equation for photosynthesis?
carbon dioxide + water –> glucose + oxygen
what is the symbol equation for photosynthesis?
CO2+H2O –> C6H12O6 +O2
where in the plant does photosynthesis take place?
inside chloroplasts in plant cells
do all plant cells have chloroplasts?
no, only the ones that recieve light
which plant cells have the most chloroplasts?
the palisade mesophyll cells in the leaves
what factors affect the rate of photosynthesis?
- light intensity
- carbon dioxide concentration
- temperature
- amount of chlorophyll
why does temperature affect photosynthesis?
photosynthesis is a process that uses enzymes. if the enzymes get warmer, photosynthesis happens at a faster rate, but if the enzymes get too hot, they will denature and photosynthesis will stop
what other organisms photosynthesise?
algae (pondweed and seaweed), as well as some bacteria. if there is chloroplast, it will absorb light energy and photosynthesise
what is the inverse square law?
the light energy reaching a certain point is equal to the inverse square of the distance to that point. we can turn distance into light intensity using 1/(d squared).
why do people care about the rate of photosynthesis?
anyone producing food crops will want to maximise profit. adding light, carbon dioxide, or heat into a greenhouse will give faster growth but may cost more, so may not be worth doing.
what is glucose produced in photosynthesis used for?
respiration by all living cells. also some is converted into starch, fats/oils, cellulose and amino acids
why do plants store glucose as starch?
- starch is insoluble, so doesnt affect osmosis
- more compact, so easier to store large amounts
- used by cells as a source of glucose for respiration
when it is dark
why do plants convert glucose to oils?
seeds have oils stored in them as the energy supply for the new plant to start to grow (germinate)
why do plants convert some glucose to cellulose?
cell walls are made from cellulose. it is strong and helps to support the plant. all plant cells have cell walls.