Sexual Reproduction In Plants

Question 1

Receptacle

Answer 1

Supports the floral part

Question 2

Sepal

Answer 2

Protects the flower bud

Question 3

Petal

Answer 3

Attracts insect pollinators - bees

Question 4

Stamen

Answer 4

Male sexual organ

Question 5

Filament

Answer 5

Positions the anther so the pollinators can pick up the pollen

Question 6

Anther

Answer 6

Produces pollen grains by Meiosis

Question 7

Carpel

Answer 7

Female sexual organ

Question 8

Stigma

Answer 8

Receives/ trap the pollen

Question 9

Style

Answer 9

Positions the stigma for effective pollen collection

Question 10

Ovary

Answer 10

Produces the ovule by meiosis

Question 11

Male gamete formation

Answer 11

•pollon grain
-diploid microsphere mother cells divide by meiosis
-produce four haploid cells
-each divides by mitosis to produce a pollen grain with two haploid nuclei- the generative nuclear and tube nucleas

Question 12

Female gamete formation

Answer 12

•ovum
-diploid megaspore mother cells divide divides by meiosis to produce four haploid cells
-three of these cells die
-one becomes the haploid embryo sac
-this undergoes mitosis three times to form eight haploid nuclei
-five of these nuclei die , two form polar nuclei and one forms the egg

Question 13

Pollination

Answer 13

Transfer of pollen from the anther to the stigma of a flower from the same species

Question 14

Types of pollination
1

Answer 14

Self pollination - transfer of pollen from an anther to a stigma on the same plant
Adv- can occur without a pollinator
Disadv- no variation

Question 15

Types of pollination
2

Answer 15

Cross pollination - transfer of pollen from an anther to a stigma on a different plant of the same species
Adv- more variations
Disadv- pollinator is needed

Question 16

Wind pollination adaptations

Answer 16

Petal - small, not bright ,no scent
Pollen - large amount,light ,small
Anthers - large size,outside of petals
Stigma - large size, outside of petals

Question 17

Animal pollination adaptations
Insect

Answer 17

Petal- large,brightly coloured, scented
Pollen- small amount , heavy,large
Anthers- small size , inside of petals
Stigma- small size , inside of petals

Question 18

Fertilisation

Answer 18

The fusion of a male gamete and female gamete to form a diploid zygote

Question 19

Fertilisation process

Answer 19

-pollen grain lands on stigma
-tube nucleas produces a pollen tube digests through the style and reaches the ovary
-generative nucleus by mitosis in the tube to form two male haploid nuclei
-these enter the embryo sac ( site of fertilisation)
-double fertilisation occurs
•sperm nucleas + egg nucleas = diploid zygote (2n)
•the second sperm nucleas and the two polar nuclei die= endosperm (3n)

Question 20

Seed formation

Answer 20

The ovule develops into a seed

Question 21

Seed parts
Testa

Answer 21

Protects the embryo

Question 22

Seed parts
Plumule

Answer 22

Develops into the shoot

Question 23

Seed parts
Radicle

Answer 23

Develops into the root

Question 24

Seed parts
Cotyledon

Answer 24

Function-Food storage
Seed leaf

Question 25

Embryo

Answer 25

Develops into a new plant

Question 26

Monocytledons (one seed leaf)

Answer 26

Food stored - endosperm An endospermic seed contains some endosperm when fully formed eg maize

Question 27

Dicotyledons (two seed leaves)

Answer 27

-food stored - cotyledon This is a typical of non endospermic eg broad bean seeds A non endospermic seed has no endosperm when fully formed eg

Question 28

Fruit formation

Answer 28

-seeds produce growth regulators to stimulates growth of the fruit tissues -developed from the ovary -protects seeds and aids in seed dispersal

Question 29

Fruit and seed dispersal

Answer 29

The transfer of a seed or fruit away from the parent plant

Question 30

Methods of seed dispersal

Answer 30

1 wind eg dandelion 2 animal eg burdock seed head stuck in dogs hair 3 self dispersal eg pea plant exploding open 4 water eg water lily

Question 31

Advantages of seed dispersal

Answer 31

Better chance of survival Reduces overcrowding and competition

Question 32

Dormancy

Answer 32

The resting period when seeds undergo no growth and have reduced metabolism

Question 33

Advantages of dormancy

Answer 33

-reduced competition -survival germination delayed until conditions are suitable for growth

Question 34

Knowledge of dormancy in agriculture and horticulture

Answer 34

-optimum storage conditions eg dry and cold -optimum sowing time -maximise the growing season

Question 35

Digestion + role in germination

Answer 35

Makes nutrients available -the food reserved in the endosperm and cotyledon is broken down by enzymes into simple soluble subunits that can be absorbed Starch= glucose Protein = amino acids

Question 36

Respiration + role in germination

Answer 36

Release energy from food -much of the reserve food is used in anaerobic respiration to supply energy for growth

Question 37

Germination

Answer 37

The regrowth of the embryo after a period of dormancy if environmental conditions are suitable * events of germination stop when the plant leaves have developed and the plant has started photosynthesis

Question 38

Conditions required for germination

Answer 38

Water - medium for reactions Suitable temp- for optimum enzyme activity Oxygen - needed for aerobic respiration/ energy

Question 39

Why is the dry mass investigated

Answer 39

Water content could vary between seeds

Question 40

Sexual reproductions

Answer 40

Adv - variation of offspring + less disease Disadv- variation in offspring + depends on outside agents eg for pollination and dispersal

Question 41

Asexual reproduction

Answer 41

Adv - no variation + fast process Disadv- no variation + more disease

Question 42

Asexual reproduction in plants called

Answer 42

Vegetative propagation No gametes flowers or seeds involved

Question 43

Natural vegetative propagation

Answer 43

Involves forming new plants from a stem root leaf or bud

Question 44

Stem - natural vegetative propagation

Answer 44

Strawberries by runners

Question 45

Root - natural vegetative propagation

Answer 45

Dahlia tubers

Question 46

Leaf - natural vegetative propagation

Answer 46

Mother of thousands

Question 47

Bud - natural vegetative propagation

Answer 47

Bulb of onion

Question 48

Artificial vegetative propagation Methods 1

Answer 48

Cuttings - is a portion of a plant that is removed from the parent plant and grown into a new independent plant

Question 49

Artificial vegetative propagation Methods 2

Answer 49

Layering - the growth of a new plant from a stem that is attached to the parent plant

Question 50

Artificial vegetative propagation Methods 3

Answer 50

Grafting- the joining and untieing of part of one plant with a second plant

Question 51

Artificial vegetative propagation Methods 4

Answer 51

Micro propagation - growth of plants from small pieces of tissue under sterile conditions on an artificial medium