Photosynthesis

Question 1

What is the word equation for photosynthesis?

Answer 1

carbon dioxide + water -> glucose + oxygen

Question 2

What is the symbol equation for photosynthesis?

Answer 2

6CO2 + 6H20 -> C6H12O6 + 6O2

Question 3

Is photosynthesis endo or exothermic?

Answer 3

Endothermic reaction as energy is transferred from the environment to the chloroplasts by light

Question 4

How does temperature affect the rate of photosynthesis?

Answer 4

Increase in temperature -> Increase in rate of photosynthesis

It increases the kinetic energy of particles, increasing the likelihood of collisions between reactants and enzymes which results in the formation of products

At higher temperatures, however, enzymes that control the processes of photosynthesis can be denatured, this reduces the overall rate

Question 5

How does light intensity affect the rate of photosynthesis?

Answer 5

More light -> faster photosynthesis

Light provides energy needed for photosynthesis.
It will only increases to a certain point, beyond that there will be another limiting factor

Question 6

How does carbon dioxide concentration affect the rate of photosynthesis?

Answer 6

More carbon dioxide -> more photosynthesis
One of the raw materials required for photosynthesis

Increases up to the point there is another limiting factor

Question 7

How does amount of chlorophyll affect the rate of photosynthesis?

Answer 7

More chlorophyll -> more photosynthesis

Chlorophyll absorbs light for photosynthesis

Question 8

How to carry out the pondweed experiment?

Answer 8

1. Pondweed is placed in a test tube full of water
2. Top is sealed with a bung. Capillary tube containing water leads into the test tube, and is attached to a syringe
3. Lamp is placed at a measured distance from the tube
4. As it photosynthesises, oxygen is produced, forming a gas tube in the capillary tube
5. The distance the bubble has moved is measured using a ruler to calculate the volume of oxygen produced

Question 9

Independent variable of the pondweed experiment?

Answer 9

Distance of the lamp being changed

Question 10

What does the pondweed experiment measure?

Answer 10

Measuring the oxygen production of a plant, you can calculate the rate of photosynthesis

Question 11

Dependent variable of the pondweed experiment?

Answer 11

oxygen bubbles produces as photosynthesis occurs

Question 12

Controlled variables of the pondweed experiment?

Answer 12

Time the pond weed is left
Other light sources
Size of pondweed
Volume of water

Question 13

What is the inverse proportion in relation to the light source?

Answer 13

Describes a relationship between 2 factors which involves one increasing while the other decreases.

As the distance between the light source and the plant increases, the light intensity decreases

Question 14

What is the inverse square law?

Answer 14

light intensity = 1 / distance^2

Question 15

Uses of glucose from photosynthesis? (5)

Answer 15

• Used for respiration
• Converted into insoluble starch for storage
• Used to produce fat or oil for storage
• Used to produce cellulose, which strengthens the cell wall
• Used to produce amino acids for protein synthesis.