Section 3: a) (Plant) Reproduction

Question 1

What is the male part of a flower called and what parts does it consist of?

Answer 1

The male part of the flower is called the stamen and it consists of the anther and filament.

Question 2

What is the female part of the flower called and what parts does it consist of?

Answer 2

The female part of the flower is called the carpel and it consists of the stigma, style and ovary.

Question 3

Where is the male gamete made and where is it found?

Answer 3

The male gamete is made in the anther and is found inside the pollen grain.

Question 4

Where is the female gamete found and what is called?

Answer 4

The female gamete is found in the ovary and is called an ovule.

Question 5

What is the function of the petals?

Answer 5

Petals attract insects to the flower. Some even have guide marks that act as landing strips for the insects, guiding them in towards the nectary.

Question 6

What is the function of the anther?

Answer 6

It produces the pollen, which contains the male sex cell or gamete.

Question 7

What is the function of the filament?

Answer 7

It holds the anther up so that pollen can be rubbed onto visiting insects.

Question 8

What is the function of the stigma?

Answer 8

This is part of the female reproductive organs and is where pollen lands.

Question 9

What is the function of the style?

Answer 9

It holds up the stigma and is the path down which the pollen grows a tube to carry the male gamete to the ovule.

Question 10

What is the function of the ovary?

Answer 10

It contains the ovules.

Question 11

What is the function of the ovules?

Answer 11

These are the eggs, also known as the female gametes.

Question 12

What is the function of the nectary?

Answer 12

It produces a sugary solution called nectar, that attracts insects.

Question 13

What is the function of the sepals?

Answer 13

They are usually green and are used to protect the flower when in bed.

Question 14

What is the function of the stamen?

Answer 14

It is the male part of the flower made from the anther and the filament.

Question 15

What is the function of the carpel?

Answer 15

It is the female part of the flower, made from the stigma, style and ovary.

Question 16

What is pollination?

Answer 16

Pollination is the act of transferring pollen grains from the male anther to the female stigma of a flower. There are two mechanisms for pollination: insect and wind pollination.

Question 17

Name three flowers that are insect-pollinated.

Answer 17

Magnolias, aster, lithops

Question 18

Give an example of a type of plant that is wind-pollinated.

Answer 18

Dandelions

Question 19

How are the petals adapted for fertilisation in insect-pollinated plants?

Answer 19

They are large and brightly-coloured to attract insects.

Question 20

How are the petals adapted for fertilisation in wind-pollinated plants?

Answer 20

They are small and often dull green or brown as there is no need to attract insects.

Question 21

How is the nectary adapted for fertilisation in insect-pollinated plants?

Answer 21

It has nectar to attract insects.

Question 22

How is the nectary adapted for fertilisation in wind-pollinated plants?

Answer 22

It has no nectar as there is no need to attract insects.

Question 23

How is the scent of the flower adapted for fertilisation in insect-pollinated plants?

Answer 23

Insect-pollinated plants are usually scented to attract insects.

Question 24

How is the scent of the flower adapted for fertilisation in wind-pollinated plants?

Answer 24

Wind-pollinated plants have no scent as there is no need to attract insects.

Question 25

How is the stigma adapted for fertilisation in insect-pollinated plants?

Answer 25

The stigma is inside the flower and is sticky so that pollen grains stick to it when an insect brushes past.

Question 26

How is the stigma adapted for fertilisation in wind-pollinated plants?

Answer 26

The stigma is outside the flower and is feathery in order to form a network to catch drifting pollen grains.

Question 27

How is the stamen adapted for fertilisation in insect-pollinated plants?

Answer 27

The stamen is inside the flower (within the petals) to maximise exposure of pollen from the anther to animals.

Question 28

How is the stamen adapted for fertilisation in wind-pollinated plants?

Answer 28

The stamen is outside the flower (it has a longer filament with reduced petals), exposing anthers to wind and maximising the pollen moved.

Question 29

Explain the difference between self-pollination and cross-pollination.

Answer 29

Self-pollination is the process of transferring the pollen grains from the anther to the stigma in the same flower.
Whereas, cross-pollination is the transfer of pollen grains from the anther of a flower to the stigma of another flower in a different plant of same or different species.

Question 30

Why is it preferable for a plant to encourage cross-pollination rather than self-pollination?

Answer 30

Cross-pollination is better than self-pollination as it creates genetic variation in the offspring, increasing the chance of survival in a changing environment or in adverse conditions.

Question 31

What stimulates the pollen tube to grow?

Answer 31

A pollen grain landing on the stigma of a flower of the correct species.

Question 32

Why do pollen grains only produce tubes in flowers of their own species?

Answer 32

They can have chemical signals specific for cells in the same species. Also, pollen grains can be too large to fit down the stigma and go down the style.

Question 33

How does the pollen tube grow down through the style?

Answer 33

It releases enzymes that digest a pathway through the style.

Question 34

How does the male gamete in flowers differ to the animal male gamete?

Answer 34

Sperm cells can swim whereas pollen grains can’t move.

Question 35

When does fertilisation occur?

Answer 35

When the male gamete fuses with the female gamete in the ovary.

Question 36

Describe what happens after the pollen tube has entered the ovule and how seeds and fruits form.

Answer 36

After the pollen tube has entered the ovule, it fuses with the female gamete (ovule) and fertilises it. The ovule then develops into a seed. Water leaves the seed, it dehydrates and becomes dormant because metabolic reactions stop. The ovary develops into fruit.

Question 37

Why do seeds need to be dispersed away from the parent plant?

Answer 37

In order to reduce competition for space, light, nutrients and water.

Question 38

What are the four mechanisms for seed dispersal?

Answer 38

Wind, water, mechanical and animals

Question 39

What seed dispersal mechanism does a lupin use and how is it adapted to suit the mechanism?

Answer 39

Mechanical-It dries unevenly and splits open with force shooting the seeds outwards.

Question 40

What seed dispersal mechanism does a blackberry use and how is it adapted to suit the mechanism?

Answer 40

Animals (inside)-Animals and birds eats its tasty and brightly-coloured flesh and excrete stones & pips to form new plants.

Question 41

What seed dispersal mechanism does a burdock use and how is it adapted to suit the mechanism?

Answer 41

Animals (outside)-It has hooks to which the seeds are attached. These hooks easily get caught in the fur of passing animals and they fall off.

Question 42

What seed dispersal mechanism does a sycamore use and how is it adapted to suit the mechanism?

Answer 42

Wind-Its seeds have lightweight parts/wings/parachutes that enable them to get transported easily over long distances by the wind.

Question 43

What seed dispersal mechanism does a coconut use and how is it adapted to suit the mechanism?

Answer 43

Water-The seed (coconut) floats due to an internal air cavity and its waterproof case protects the internal seed. It is drifted on ocean currents.

Question 44

What is germination and what conditions are needed for germination?

Answer 44

Germination is the process where a seed begins to grow (into a plant). The three conditions needed for germination are oxygen (air), warmth and moisture.

Question 45

Name the parts of a seed and state what each part is.

Answer 45

Cotyledons-Food stores/reserves, Plumule-Embryo shoot, Radicle-Embryo root, Testa-Tough seed coat, Micropyle-Hole made by pollen tube

Question 46

Why is the radicle the first part to grow out of the seed?

Answer 46

It needs to absorb more water.

Question 47

Why is it important for water to enter the seed?

Answer 47

It activates enzymes and also softens the testa to allow it to split.

Question 48

What do the enzymes do once they are activated?

Answer 48

The enzymes break down starch into maltose and then glucose. The glucose is then used in respiration to provide energy for growth.

Question 49

What is meant by the term dry mass?

Answer 49

Dry mass is the mass of solid matter with all water removed.

Question 50

How do germinating seeds use food stores before they can photosynthesise and how does this affect the dry mass?

Answer 50

As the seedling cannot photosynthesise yet, it uses up starch stores in the cotyledons, causing it to lose weight; the dry mass decreases. When the seedling can photosynthesise, it increases in weight and the plant grows; the dry mass increases.

Question 51

How can plants reproduce asexually using natural methods?

Answer 51

Using runners (fast-growing stems that grow out sideways, just above the ground).

Question 52

How can plants reproduce asexually using artificial methods?

Answer 52

Using cuttings

Question 53

In an experiment to investigate the conditions needed for germination, what could be done to make your results more reliable?

Answer 53

Carry out several sets of the experiment and calculate the average of all the results.