ASEXUAL AND SEXUAL REPRODUCTION (PLANTS)

Pollen grains are transferred from the anthers to the stigma. The pollen grains adhere to the

sticky stigma. The statements describe what happens next.

1 The pollen grain grows a pollen tube.

2 The pollen tube enters the ovule.

3 The pollen tube grows down the style.

4 The male nucleus fuses with an egg cell nucleus.

In which order do these stages occur?

• 1 → 2 → 4 → 3

• 1 → 3 → 2 → 4

• 2 → 3 → 1 → 4

• 3 → 1 → 4 → 2

Specific grape varieties are maintained using stem cuttings from mature plants that are then

planted and cultivated to produce grapes. This is an example of artificial asexual reproduction.

What is a disadvantage of using asexual reproduction to produce fruit?

• An outbreak of disease will affect the whole crop in the same way.

• Genetically identical fruit is produced relatively quickly

• No pollination or pollinators are required

• The characteristics of the grapes will vary between plants.

Which two statements are correct for the process of cross-pollination in plants?

1 increases potential for variation in offspring

2 pollen is transferred to a different flower on the same plant

3 reduces potential to respond to environmental change

4 pollen is transferred to a flower on a different plant of the same species

• 1 and 2

• 1 and 4

• 2 and 3

• 3 and 4

What is an advantage, for an organism, of using asexual reproduction?

• Disease spreads rapidly.

• It does not cause variation

• It easily adapts to environmental change

• Population increases rapidly

The diploid number in Ovis aries (sheep) is 54.

How many chromosomes will there be in a zygote of this species?

• 0

• 27

• 54

• 108

Crop plants produced by asexual reproduction are identical. This can be a disadvantage.

Which statements describe disadvantages?

1 Crop plants are produced rapidly.

2 A disease could kill all of the plants.

3 Only one parent is needed.

4 The plants cannot adapt to environmental changes.

• 1 and 2

• 1 and 3

• 2 and 4

• 3 and 4

A wind-pollinated plant has which features?

• large anthers, coloured petals and produces nectar

• large petals, small anthers and a sticky stigma

• small petals, large anthers and a feathery stigma

• small petals, produces nectar and has a strong scent

Which environmental factor is not always a requirement for seed germination?

• light

• oxygen

• suitable temperature

• water

After fertilisation, how many chromosomes are in the zygote?

• half as many as in an ovum

• the same as in an ovum

• the same as in a sperm

• twice as many as in a sperm

The diagram shows half a flower.

After pollination, where would pollen grains be found?

• P and Q

• Q and R

• R and S

• S and P