key area 6;photosynthesis Flashcards
(22 cards)
what is photosynthesis?
it is a chemical reaction
what is the word equation for photosynthesis?
Carbon Dioxide + Water =oxygen + Glucose
what are the 2 things needed for photosynthesis?
light and chlorophyll
where does photosynthesis happen?
it happens in the leaves of a green plant
what is the pigment in green plants called?
chlorophyll
where is chlorophyll found?
in the chloroplasts
what are the 2 stages of photosynthesis?
the light reactions and carbon fixation
what does stage 1 of photosynthesis involve?
the splitting of water and the release of oxygen
what does stage 2 of photosynthesis involve?
it involves the combining of carbon dioxide and hydrogen to make glucose
explain stage 1 in more detail
the light energy from the sun is trapped by chlorophyll in the chlorplasts.here it is converted into chemical energy which is used to generate atp.this atp is used to split into hydrogen and oxygen
what happens to the oxygen after stage 1?
it diffuses from the cell as it is not needed
what happens to the hydrogen and the atp after stage 1?
they move onto stage 2
explain stage 2 in more detail
carbon fixation is a series of enzyme controlled reactions which use hydrogen and atp (produced by light reactions) with carbon dioxide to produce glucose
what are the fates of glucose
storage,respiration and structural
explain the storage fate of glucose
glucose can be converted into an insoluble carbohydrate called starch for storage
explain the respiration fate of glucose
glucose can be used as a substrate for respiration
explain the structural fate of glucose
glucose can be converted to cellulose and used to build cell wall
how can we test a leaf for starch?
you can use iodine to test for starch
how do we know if starch is present?
if the iodine goes from an orange colour to a blue/black colour starch is present
what is starch?
starch is a molecule that plants store their glucose as
what is a limiting factor?
a limiting factor slows down or stops the rate of photosynthesis because it is in short supply
what are 3 limiting factors of photosynthesis?
temperature ,carbon dioxide concentration and light intensity
