Photosynthesis

Question 1

What is the equation for photosynthesis

Answer 1

water + carbon dioxide —- light—–> glucose + oxygen

6H2O + 6CO2 —————-Light——> C6H12O6 + 6O2

Question 2

How does a plant use glucose

Answer 2

It uses it to create biomass (grow)
It can store it as starch

Question 3

Where does photosynthesis occur?

Answer 3

In the chloroplasts in the leaf of the plant

Question 4

What is chlorophyll?

Answer 4

A green pigment found in the chloroplasts in plants, it uses sunlight to make glucose and is essential for photosynthesis.

Question 5

What are the reactants in photosynthesis

Answer 5

Carbon dixoide and water

Question 6

Identify the factors plants need for photosynthesis

Answer 6

1. carbon dioxide
2. water
3. sunlight
4. chlorophyll

Question 7

Identify the minerals that plants need for growth

Answer 7

Nitrogen N
Phosphorus P
Potassium K
NPK fertilizer

Magnesium- this is part of chlorophyll

Question 8

Explain how plants take in nutrients from the soil

Answer 8

Roots have specialised cells called root hair cells. They have thin walls so that they are good at absorbing water and minerals from the soil.

Question 9

Identify the products from photosynthesis?

Answer 9

glucose and oxygen

Question 10

Describe the test for starch

Answer 10

Put iodine solution on to the object you are testing.
If starch is present the brown iodine will turn blue black.

Question 11

Describe how you could carry out an experiment to show that light is needed for starch production.

Answer 11

1. Put a plant in darkness for 24 hours to get rid of the starch in the leaves
2. Put a strip of black tape across one of the leaves
3. Leave the plant in the light for 24 hours
4. Take the leaf of the plant and remove the tape.
5. Boil the leaf in water for a few minutes to soften it.
6. Put the leaf into a test tube of ethanol and put the tube into the boiling water, the ethanol will boil and remove the chlorophyll from the leaf
7. Wash the colourless leaf to get rid of the ethanol.
8. Put iodine on the leaf to see if there is any starch.
9. The leaf will be blue black where the light could get to it and brown where the tape was showing that light is needed to produce starch.

Question 12

Describe an experiment to show that oxygen is produced during photosynthesis

Answer 12

1. Out a water plant such as Elodea into a beaker of sodium hydrogen carbonate solution (this gives the plant the CO2 it needs).
2. Cover the plant with a funnel and put a measuring cylinder of water over the top.
3. Watch for bubbles of gas given off by the plant.
4. Measure the amount of gas given off in a given time by using the measuring cylinder.
5. You can test the gas with a glowing splint- if it relights it is oxygen.