B8 Photosynthesis Flashcards
what energy type do plants store?
light energy
what is the chemical reaction where plants trap light energy called?
photosynthesis
what type of reaction is photosynthesis?
an endothermic reaction
where does photosynthesis take place?
in the leaves of the plant
they contain chlorophyll which absorbs energy
what is the word equation for photosynthesis?
carbon dioxide + water –light–> glucose + oxygen
what is the chemical formula for photosythesis?
6CO2 + 6H2O –> C6H12O6 + 6O2
how does light intensity affect photosynthesis?
as the light intensity increases, the rate of photosynthesis increases
this is because the plant has more light to carry out the photosynthesis reaction so the reaction gets faster
there is a point where the rate of photosynthesis no longer increases
this means it is no longer the limiting factor. something else is the limiting factor
what does limiting mean?
the reaction of photosynthesis was not as fast as it could have been due to a factor
how do levels of carbon dioxide affect the rate of photosynthesis?
as CO2 increases, so does photosynthesis
at a certain point, the rate of photosynthesis no longer increases so is no longer the limiting factor
(the same as light intensity)
how does the amount of chlorophyll in the leaves affect photosynthesis?
if there is less chlorophyll, the rate of photosynthesis is lower as the leaves cannot trap as much light energy
how does temperature affect the rate of photosynthesis?
as temperature increases, the enzymes work faster so the rate of photosynthesis increases
if the temperature continues to increase, the enzymes denature so the rate falls
how is glucose used in respiration?
to release energy in the mitochondria
why is starch produced?
to store glucose from photosynthesis
it can be converted back to glucose when it is needed
what are fats and oils made from glucose used for?
a storage form of energy
what is cellulose made from?
glucose produced in respiration
what are amino acids used for in plants?
to synthesise proteins
what is used to make amino acids?
glucose from respiration
nitrate ions from the soil
why is an LED light source used to investigate photosynthesis?
they do not release much heat
why is sodium hydrogen carbonate solution used when investigating photosynthesis?
it releases carbon dioxide needed for photosynthesis
what is wrong with counting bubbles in the investigation of photosynthesis?
the bubbles may be too fast to count
the bubbles are not always the same size
how can the issues of counting the bubbles when investigating photosynthesis be resolved?
place the pondweed under a funnel and catch the bubbles in a measuring cylinder
this set-up can be used to measure the volume of oxygen produced
what is the trend for the number of bubbles/minute (or volume of oxygen) and the distance from a lamp? (when investigating photosynthesis)
if the distance is doubled, the number of bubbles falls by a factor of 4
this is the inverse square law
this happens because if the distance is doubled, the light intensity falls by four times. because light is needed in photosynthesis, this causes the number of bubbles to fall by four times
how do farmers increase the rate of photosynthesis in greenhouses?
light and heat the greenhouse
add extra carbon dioxide
what is the problem with farmers altering conditions inside greenhouses?
it is quite expensive so the extra cost has to be justified by the increase in yield
