Plant Reproduction

Question 1

Name the male parts of a flower

Answer 1

The anther and filament, together called the stamen

Question 2

Name the female parts of a flower

Answer 2

Stigma, style, ovary, ovule. Together called the carpel

Question 3

What is the function of the filament in a flower?

Answer 3

Contains the xylem and phloem that supply the anther

Question 4

What is the function of the anther?

Answer 4

To produce pollen

Question 5

Describe/draw a cross section of an anther

Answer 5

The anther should contain four pollen sacs. Each pollen sac is surrounded by tapetum. This is a food store and will provide energy for future cell divisions. Around this is a fibrous layer
, then a protective epidermis

Question 6

What is the term for an anther splitting to release the pollen?

Answer 6

Dehiscence

Question 7

Give the steps of pollen formation

Answer 7

Diploid pollen mother cells divides by meiosis-> a tetrad of haploid microspores. Microspore nucleus divides by mitosis forming a tube nucleus and a generative nucleus. Intine and exine layers develop around the cell. This is now a pollen grain.

Question 8

Name the eight nuclei in the pollen sac and give their position

Answer 8

Three at the top are antipodal, two in the middle are polar, two synergids and an egg cell at the bottom

Question 9

Give the steps in embryo sac formation

Answer 9

A mother megaspore cell divides by meiosis to form 4 haploid megaspore cells. Three degenerate, one survives and goes through three rounds of mitosis

Question 10

Name the walls around the ovule

Answer 10

Inner and outer integument

Question 11

Name the stalk that connects the ovule to the ovary

Answer 11

The funicle

Question 12

Name the hole at the bottom of the ovule that the pollen tube enters through

Answer 12

Micropyle

Question 13

How are flowers adapted for insect pollination?

Answer 13

Pollen is barbed to hook onto insect fur. Nectar, a scent, and brightly coloured petals. Sticky stigma

Question 14

How are flowers adapted for wind pollination?

Answer 14

Pollen is small, smooth and light, produced in large numbers. No scent, no nectary, small green petals. Feathery stigma and exposed anthers

Question 15

What are cross and self pollination?

Answer 15

Cross pollination is when pollen travels from the anther of one plant and lands on the stigma of another. Self pollination the pollen lands on the stigma of the same plant

Question 16

What are the advantages and disadvantages of cross pollination?

Answer 16

Advantage is that it increases genetic variation, which helps species adapt to changing environments. However self pollination is more suited to a stable environment.

Question 17

How do plants prevent self pollination?

Answer 17

Having the stigma above the stamen, having them mature at different times, genetic incompatibility, or separate male/female flowers or plants

Question 18

What is pollination?

Answer 18

When pollen lands on the stigma

Question 19

What happens after pollination?

Answer 19

The pollen germinates to produce a pollen tube, which digests a path down the style to the ovary. The generative nucleus divides by mitosis to produce two male gametes

Question 20

What is the function of the tube nucleus in pollen?

Answer 20

To control the growth of the pollen tube and code for production of hydrolytic enzymes

Question 21

What is double fertilisation?

Answer 21

When the tip of the pollen tube bursts, one male nucleus fertilises the egg, forming the diploid zygote. The other fertilises the two polar nuclei, forming the triploid endosperm

Question 22

What is the function of the endosperm?

Answer 22

It is a storage tissue that normally provides nutrients to the developing embryo

Question 23

After fertilisation, what do the ovule, ovary, funicle and integuments become?

Answer 23

The ovule becomes the seed, ovary the fruit, funicle leaves a scar called the hilum, integuments become the testa

Question 24

Which part of the embryo forms the root, and which part the shoot?

Answer 24

Radicle becomes the root, plumule the shoot

Question 25

What are the two possible food stores of a seed?

Answer 25

The endosperm or the cotyledons

Question 26

What are the two groups flowering plants are divided into based on their seeds?

Answer 26

Monocotyledons and dicotyledons

Question 27

List four ways seeds can be dispersed

Answer 27

Wind, water, mechanical, animals

Question 28

Give the three conditions seeds need for germination

Answer 28

Water, oxygen, suitable temperature

Question 29

Why do seeds need to inbibe water to break down food reserves?

Answer 29

Water activates the gene coding for gibberellin. Gibberellin diffuses to the aleurone layer and causes production of amylase, which breaks down the starch in the food store to maltose

Question 30

Why do seeds need to inbibe water to respire aerobically?

Answer 30

When water is imbibed through the micropyle the cotyledons swell and the testa split to allow entry of more oxygen for aerobic respiration

Question 31

What happens to a seed planted too deep in the soil?

Answer 31

It will use its full food store before the leaves reach the surface to photosynthesise