B4: PHOTOSYNTHESIS

Question 1

What is photosynthesis?

Answer 1

the process whereby plants and algae absorb energy from (sun)light to produce glucose

Question 2

Why is photosynthesis an endothermic reaction?

Answer 2

energy is transferred from the surroundings to the chloroplasts by light

Question 3

What is the word equation for photosynthesis?

Answer 3

carbon dioxide + water –> glucose + oxygen

Question 4

What is the symbol equation for photosynthesis?

Answer 4

CO2 + H2O –> C6H12O6 + O2

Question 5

What are the 4 limiting factors of photosynthesis?

Answer 5

-light intensity
-temp
-conc. of CO2
-conc. of chlorophyll

Question 6

Why is water not a limiting factor?

Answer 6

-when water is low stomata closes
-CO2 becomes limiting factor

Question 7

RP - Photosynthesis: method

Answer 7

-set up a boiling tube containing 45 cm^3 of sodium hydrogen carbonate solution (1%). allow the tube to stand for a few minutes and shake to disperse any air bubbles that might form
-cut a piece of the pondweed, Cabomba. the pondweed should be 8 cm long
-use forceps to place the pondweed in the boiling tube carefully. make sure that you don’t damage the pondweed, or cause the liquid to overflow
-position the boiling tube so that the pondweed is 10 cm away from the light source. allow the boiling tube to stand for five minutes
-count the number of bubbles emerging from the cut end of the stems in one minute
-repeat the count five times and record your results
-calculate the average number of bubbles produced per minute
-repeat the experiment at different distances away from the light source

Question 8

RP - Photosynthesis: variables

Answer 8

IV - distance of light source
DV - rate of photosynthesis
CVs - length of pondweed/volume of solution/conc. of solution

Question 9

What is the relationship between light intensity and distance?

Answer 9

light intensity is inversely proportional to distance^2