9B — Plant Growth

Question 1

1) What is photosynthesis?

2) What is the word equation for photosynthesis?

Answer 1

1) A process that plants use to make their own food. It needs light to work.
2) Carbon dioxide + water —> glucose + oxygen

Question 2

How are roots adapted to their function?

Answer 2

Roots are adapted to their function by being branched and spread out to help them to absorb water from a large volume of soil. Also, root hair cells have a large surface area to help them absorb water quickly.

Question 3

1) Where does photosynthesis happen?

2) What are chloroplasts?

Answer 3

1) Photosynthesis happens in the leaves of the plant.
2) Chloroplasts contain chlorophyll, a green chemical that absorbs energy transferred by light and uses it to power photosynthesis.

Question 4

1) What is the word equation for aerobic respiration?

2) When can photosynthesis only happen?

Answer 4

1) Glucose + oxygen —> carbon dioxide + water

2) Photosynthesis can only happen when there is light.

Question 5

1) What is glucose?
2) What is glucose used for?
3) How are new substances carried around the plant?

Answer 5

1) Glucose is a type of sugar.
2) It is used for three things:
● respiration to release energy
● making other substances that act as stores of energy (e.g. starch), which can be turned back into glucose for respiration when needed
● making new materials for growth, e.g. cellulose (for cell walls), lipids (e.g. for cell membranes) and proteins (e.g. for enzymes).To make proteins, mineral salts called nitrates are needed
3) New substances made by a plant are carried around the plant in phloem vessels.

Question 6

What modern farming methods can cause environmental problems?

Answer 6

— Land is cleared of hedges and trees, but it destroys habitats and lack of roots can cause soil erosion.
— Pesticides (e.g. herbicides, insecticides) are used, but they can kill useful organisms as well as pests.
— Fertilisers are used, but they cause water pollution and kill organisms that live in the water
— Varieties of plants are chosen that produce the highest yield, but it reduces biodiversity

Question 7

1) What is selective breeding?

2) What is cross breeding?

Answer 7

1) When humans choose an organism that has a certain characteristic and breed more of these organisms, often making that chosen characteristic more and more obvious.
2) Cross breeding is when two different varieties are bred together to try to produce offspring with characteristics from both varieties.

Question 8

How do plants get carbon dioxide?

Answer 8

Air, containing carbon dioxide, diffuses into leaves through small holes called stomata.