3.1.2 Sexual Reproduction in Flowering Plants

Question 1

Flowers are the reproductive organs of:

Answer 1

Flowers are the reproductive organs of plants

Question 2

Flowers contain both male and female:

Answer 2

reproductive parts

Question 3

Plants produce pollen, which contains a nucleus inside that is the:

Answer 3

male gamete

Question 4

Unlike the male gamete in humans (sperm), pollen is not capable of:

Answer 4

Locomotion (moving from one place to another)

Question 5

Because plants are not capable of Locomotion, This means plants have to have mechanisms in place to transfer:

Answer 5

pollen from the anther (male part of the flower) to the stigma

Question 6

Name 2 main mechanisms by which pollination occurs:

Answer 6

1. Pollination where the pollen is transferred by insects (or sometimes other animals like birds or bats)

Question 7

What is the role of the Sepal in a flower

Answer 7

It protects the unopened flower

Question 8

What is the role of the Petal in a flower

Answer 8

To attract insects

Question 9

What is the role of the Anther in a flower

Answer 9

Produces and releases the male sex cell (pollen grain)

Question 10

What is the role of the Stigma in a flower

Answer 10

It is the top of the female flower which collects pollen grain

Question 11

What is the role of the Ovum in a flower

Answer 11

Produces the female sex cell (Ovum)

Question 12

What is the role of the Ovule in a flower

Answer 12

Contains the female sex cell

Question 13

For the flowers of many plant species, the pollinating agents are:

Answer 13

Insects (Bees)

Question 14

Insects often visit these flowers to collect:

Answer 14

nectar (a sugary substance produced by insect-pollinated flowers and the base of their petals, which provides the insects with energy)

Question 15

As an insect enters the flowers in search of nectar, it often brushes against the anthers, which deposit ? ? onto the insect’s body

Answer 15

As an insect enters the flowers in search of nectar, it often brushes against the anthers, which deposit sticky pollen onto the insect’s body

Question 16

When the insect visits another flower, it may brush against the stigma of this second flower and in the process, may deposit some of the pollen from the first flower, resulting in:

Answer 16

pollination

Question 17

For wind-pollinated flowers, the process of pollination is more ? than it is for insect-pollinated flowers

Answer 17

For wind-pollinated flowers, the process of pollination is more random than it is for insect-pollinated flowers

Question 18

When ripe, what do the anthers do

Answer 18

When ripe, the anthers open and shed their pollen into the open air, the pollen is then either blown by the wind or carried by air currents until it (by chance) lands on the stigma of a plant of the same species, resulting in pollination

Question 19

In insect or wind-pollinated plants, pollination can either occur via:

Answer 19

cross-pollination or self-pollination

Question 20

Cross-pollination occurs when the pollen from one plant is transferred to the stigma of:

Answer 20

another plant of the same species, this is the way most plants carry out pollination as it increases the genetic variation in the offspring

Question 21

Occasionally, the pollen from a flower can land on its own stigma or on the stigma of another flower on the same plant, what is this known as:

Answer 21

Self pollination

Question 22

Why does self-pollination reduce genetic variation?

Answer 22

all the gametes come from the same parent (and are therefore genetically identical)

Question 23

Is Lack of variation in the offspring an advantage or disadvantage

Answer 23

A disadvantage, if environmental conditions change, as it is less likely that any offspring will have adaptations that suit the new conditions well

Question 24

In plants, the ovary contains one or more:

Answer 24

ovules, The ovules are the structures that eventually develop into seeds

Question 25

Each ovule contains an:

Answer 25

ovum, An ovum is an egg cell that contains the female nucleus that a male pollen nucleus can fuse with

Question 26

In plants, fertilization occurs when the pollen grain nucleus fuses with the:

Answer 26

ovum nucleus

Question 27

Unlike the male gametes in animals (sperm), the pollen grain has no ‘tail’ to swim to the:

Answer 27

ovary of the flower

Question 28

in order to reach the ovum nucleus, the pollen grain grows a:

Answer 28

pollen tube, This only happens if the pollen grain has landed on the right kind of stigma (i.e. of the same species as the flower the pollen came from)

Question 29

Once the nucleus of the pollen grain and the nucleus of the ovum have fused (joined together), that particular ovule has been fertilized, due to this what is formed

Answer 29

a zygote has been formed, The zygote will then start to divide (it is the structure that eventually develops into an embryo plant)

Question 30

After fertilization, the ovule (that contains the zygote) develops into the:

Answer 30

seed

Question 31

The wall of the ovule develops into the seed coat, known as the:

Answer 31

testa

Question 32

The parts of the flower surrounding the ovule (mainly the ovary walls) develop into the

Answer 32

fruit, which contains the seeds. The fruit provides a mechanism for seed dispersal (getting the seeds away from the parent plant). Some fruits are eaten by animals, which then disperse the seeds in their droppings (the tough outer coat of seeds stops them from being digested) Some other fruits have sticky hooks that get caught in the fur of passing animals.

Question 33

As different plants have different numbers of ovules, this explains why different fruits have different numbers of:

Answer 33

Seeds (which develop from the ovules)

Question 34

Germination is the start of growth in:

Answer 34

the seed

Question 35

The seed contains the zygote (the fertilized egg cell), which divides into cells that then develop into the:

Answer 35

embryo plant

Question 36

When the seed germinates, this embryo begins to grow into the:

Answer 36

young seedling

Question 37

What type of structure surrounds the embryo

Answer 37

cotyledons, some plants have one cotyledon, whereas others have two. The cotyledons contain food reserves that supply the young seedling with food (and, therefore, energy for growth) when the seed starts to germinate

Question 38

After taking in water, the seed coat (testa) does what:

Answer 38

It splits, This leads to the production of the plumule (the first emerging shoot) and radicle (the first emerging root)