photosynthesis

Question 1

what Do plants use for their source of energy

Answer 1

light, water, gases in the air
to make glucose
glucose which is a form of sugar that plants need to survive

Question 2

what is the reaction that plants use to trap this light energy called

Answer 2

photosynthesis

Question 3

why is photosynthesis an example of an endothermic reaction

Answer 3

because photosynthesis takes in energy

Question 4

where does photosynthesis take place in a plant?

Answer 4

the leaves of a plant

Question 5

what do the leaves contain to absorb light energy?

Answer 5

chlorophyll

Question 6

what happens in the first stage of photosynthesis?
second stage
third stage

Answer 6

1.the plant takes carbon dioxide and water into the leaf like this
light
carbon dioxide + water —————>
chlorophyll

2.light energy is absorbed by chlorophyll and used to covert the carbon dioxide and water into the sugar glucose

                                      light carbon dioxide + water —————>glucose
                                    chlorophyll

3.In this reaction oxygen is then produced
so the full word equation for photosynthesis would be

                                      light carbon dioxide + water —————>glucose+
                                    chlorophyll oxygen

Question 7

write the word equation and the chemical formulas for photosynthesis

Answer 7

carbon dioxide + water —> glucose + oxygen +
 it can be written as 
CO2+H2O —>C6H12O6+O2
or 
6CO2 + 6H2O —> C6H12O6 + 6O2.

Question 8

as we increase the light intensity, what happens to the rate of photosynthesis
why?

Answer 8

the rate of photosynthesis increases

because the plant now has more light energy to carry out the photosynthesis reaction so the reaction gets faster

Question 9

a limiting factor in photosynthesis could be

Answer 9

the light intensity
photosynthesis isnt always as fast as it could be because there wasn’t enough light

level of carbon dioxide
photosynthesis isnt always as fast as it could be because the level of carbon dioxide wasn’t enough

Question 10

if we keep increasing the light intensity there comes a point where the rate of photosynthesis no longer increases. and the graph levels off.
Why?

Answer 10

at this point light intensity is no longer the limiting factor
something ELSE is now in short supply eg the level of carbon dioxide in the air

Question 11

how do we know if something is a limiting factor

Answer 11

the more we increase it, the faster the rate of photosynthesis

until it levels off on a graph meaning it stopped increasing which tells us that carbon dioxide is no longer the limiting factor

Question 12

how do we know if something is NO LONGER a limiting factor

Answer 12

until it levels off on a graph meaning it stopped increasing which tells us that it is no longer the limiting factor

Question 13

the 4 limiting factors are

Answer 13

amount of chlorophyll in a leaf

level of carbon dioxide

intensity of light

temperature

Question 14

explain how the amount of chlorophyll is a limiting factor in the rate of photosynthesis

Answer 14

some leaves can trap less light energy than normal leaves making them have a lower rate of photosynthesis

Question 15

explain how temperature is a limiting factor in the rate of photosynthesis

Answer 15

as we increase the temperature, the enzymes involved in photosynthesis work faster so the rate increases.

however if we keep increasing the temperature, the enzymes will denature and the rate of photosynthesis falls to zero.

Question 16

what happens when we keep increasing the temperature of a plant

Answer 16

the enzymes will denature and the rate of photosynthesis will drop