Photosynthesis

Question 1

what is photosynthesis?

Answer 1

the process by which plants make their own glucose from sunlight

Question 2

what type of reaction is photoysnthesis?

Answer 2

endothermic so energy is transferred from the environment to the chloroplasts by light

Question 3

what effect does temperature have on photosynthesis?

Answer 3

• an increase in temperature increases the rate of photosynthesis
• controlled by enzymes
• this happens until a certain temperature is reached and the enzyme starts to denature and the rate decreases

Question 4

what effect does light intensity have on photosynthesis?

Answer 4

for most plants, more light intensity means a faster rate of reaction

Question 5

what effect does the carbon dioxide concentration have on photosynthesis?

Answer 5

an increase in CO2 means faster photosynthesis, it is needed to make glucose

Question 6

what effect does the amount of chlorophyll have on photosynthesis?

Answer 6

chlorophyll converts light energy into food and is essential, less chlorophyll means a slower rate of photosynthesis

Question 7

what are the 5 uses of glucose for photosynthesis?

Answer 7

• for respiration
• converted into insoluble starch for storage (roots, stem and leaves)
• to produce fat or oil for storage (seeds)
• to produce cellulose to strengthen cell walls
• combine with nitrates to form amino acids which produce proteins

Question 8

what is the formula for photosynthesis?

Answer 8

carbon dioxide + water —-> glucose + oxygen

Question 9

how is knowing the limiting factor useful for farmers?

Answer 9

they can use it to enhance the conditions in the greenhouse for a greater rate of photosynthesis (more growth = more profits)

Question 10

what is inverse proportion?

Answer 10

the relationship between two factors which involves one increasing and the other decreasing

Question 11

give an example of the inverse square law

Answer 11

• as the distance between the light source and pondweed increases, the light intensity decreases
• the light intensity is ow inversely proportional to the square of the distance

Question 12

what is the independent variable in the pondweed practical?

Answer 12

the light intensity (how close the light is)

Question 13

what is the dependent variable in the pondweed practical?

Answer 13

the number of oxygen bubbles (rate of photosynthesis)

Question 14

what are the controlled variables in the pondweed practical?

Answer 14

• the volume of water
• the size of pondweed
• the temperature

Question 15

what is a limiting factor?

Answer 15

factors that restricts an increase in the rate of photosynthesis, despite an increase in other factors

Question 16

how can you spot a limiting factor in a graph?

Answer 16

if one line levels off

Question 17

what is the formula for the inverse square law?