Photosynthesis cognito Flashcards
Give one other way of reducing the negative effects of human activity on our
ecosystems
breeding programmes (for endangered species)
* regeneration (programmes)
* reintroduction of field margins / hedgerows
* awareness raising with politicians / public
* recycling
describe the effect of magnesium ions on the
growth of duckweed.
(more) magnesium gives more growth / more leaves / more duckweed
Whats a better way to measure the growth of a plant rather than counting leaves and why
measure mass because it includes the whole plant
Describe the effect of increasing light intensity on the rate of photosynthesis grapgh
increases up to
levels off at
reaches a maximum of
At a light intensity of 250 arbitrary units, light is not a limiting factor of
photosynthesis.
higher light intensity does not increase rate of photosynthesis and graph levels off
Why does the farmer not use a concentration of carbon dioxide higher than
0.08%?
Because it would cost more money than using 0.08%
1
Because it would not increase the rate of photosynthesis of the tomato
plants any further
Multicellular organisms often have complex structures, such as lungs, for gas
exchange.
Explain why single-celled organisms, like algae, do not need complex structures for
gas exchange.
(cell has) larger SA:volume ratio
short (diffusion) distance
(diffusion) via cell membrane is sufficient / good enough
flow of water maintains concentration gradient
Some students investigated the effect of light intensity on the rate of photosynthesis
in pondweed.
A thermometer was placed in the glass beaker.
Why was it important to use a thermometer in this investigation?
(measure) temperature
* to check that the temperature isn’t changing
* rate of reaction changes with temperature
* temperature is a variable that needs to be controlled
All tools should be washed in disinfectant after using them on plants infected with
TMV.
Suggest why
to kill virus
or
to prevent virus spreading
Suggest how scientists can use this plant to produce many plants with the
TMV-resistant gene.
take (stem) cells from meristem and clone it
Describe how you would test for the presence of glucose in fruit.
use Benedict’s solution
1
glucoses turns solution blue to orange
TMV can cause plants to produce less chlorophyll.
This causes leaf discoloration.
Explain why plants with TMV have stunted growth. (4)
less photosynthesis because of lack of chlorophyll
* therefore less glucose made
so
* less energy released for growth
* because glucose is needed for respiration
and / or
* therefore less amino acids / proteins / cellulose for growth
* because glucose is needed for making amino acids / proteins / cellulose
The gardener wants to make his own compost.
(a) An airtight compost heap causes anaerobic decay.
Explain why the gardener might be against producing compost using this method.
methane is produced
which is a greenhouse gas / causes global warming
Some of the leaves from the gardener’s strawberry plant die.
The dead leaves fall off the strawberry plant onto the ground.
The carbon in the dead leaves is recycled through the carbon cycle.
Explain how the carbon is recycled into the growth of new leaves(6)
statements:
* (carbon compounds in) dead leaves are broken down by microorganisms /
decomposers / bacteria / fungi
* photosynthesis uses carbon dioxide
explanations:
* (microorganisms) respire
* (and) release the carbon from the leaves as carbon dioxide
* plants take in the carbon dioxide released to use in photosynthesis to produce
glucose
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use of carbon in growth:
* glucose produced in photosynthesis is used to make amino acids / proteins /
cellulose
* (which are) required for the growth of new leaves
What causes fruit to decay faster
(storage conditions)
* (at) higher temperature / hotter
* (had) more oxygen
* (had) more water / moisture
* (contained) more microorganisms (that cause decay)
