2.4.10 Seeds

Question 0

What must happen for a seed to develop?

Answer 0

The ovule must be fertilised by the nucleus from a pollen grain

Question 1

What are seeds adapted to ensure?b

Answer 1

They are adapted to ensure they:

• protect the embryo
• aid dispersal
• provide nutrition for the new plant

Question 2

What happens to the outer layers of a seed?

Answer 2

They become lignified, forming a tough seed coat

Question 3

What is the plumule?

Answer 3

It is the young shoot

Question 4

What is the role of the testa?

Answer 4

To protect the seed

Question 5

What is the role of the storage cotyledons?

Answer 5

To store nutrients for the plant

Question 6

What is the raducule?

Answer 6

It is the young root, which absorbs water

Question 7

What is the role of the microphyle?

Answer 7

To absorb water in germination

Question 8

What are the 4 dispersal methods of seeds?

Answer 8

• wind
• animal
• water
• self dispersal

Question 9

How is starch used to ‘thicken’ products such as custard and wallpaper paste?

Answer 9

• ‘gelatinisation’ occurs when starch granules are heated in water
• the granules swell, absorbing water
• this makes the solution thicker

Question 10

How is starch used to stiffen fabrics?

Answer 10

• known as ‘sizing’
• a starch mixture is applied to fabrics and gelatinised
• it is cooled, allowing bonds to form between starch molecules
• adding water reverses the process

Question 11

How is starch used as a super absorbent?

Answer 11

• starch is chemically cross linked, gelatinised, and then dried
• the particles can take up large amounts of water

Question 12

How is starch foam made?

Answer 12

• if the pressure is increased during gelatinisation, the starch forms a plastic mass
• when the pressure is suddenly released, steam forms and the starch puffs

Question 13

Why is biodiesel better for the environment than regular diesel?

Answer 13

Biodiesel produces less sulphur dioxide