4.1 Sexual Reproduction In Plants

Question 1

Name 8 structures of a flower

Answer 1

1. Sepal
2. Receptacle
3. Petal
4. Anther
5. Filament
6. Stigma
7. Style
8. Ovary

Question 2

Name the parts of the flower thats in the Stamen

Answer 2

Fillament and anther

Male part

Question 3

Name the parts of the flower thats in the Carpel

Answer 3

Stigma
Style
Ovary

Female part

Question 4

Name the 4 modified set of leaves within a flower

Answer 4

Calyx
Corolla
Stamens
Carpel

Question 5

Function of:

Petals

Answer 5

Colourfull to attract insects

Question 6

Function of:

Stamen

Answer 6

The male part of the flower -made of the filament and anther

Question 7

Function of:

Filament

Answer 7

Supports the anther

Question 8

Function of:

Anther

Answer 8

Produces pollen grains

Question 9

Function of:

Carpel

Answer 9

Female part of the flower - stigma, style and ovary

Question 10

Function of:

Stigma

Answer 10

Collects pollen

Sticky

Question 11

Function of:

Style

Answer 11

Connects stigma to ovary

Question 12

Function of:

Ovule

Answer 12

The egg cell

Question 13

Function of:

Sepals

Answer 13

Protect flower in bud

Question 14

Function of:

Ovary

Answer 14

Produces egg

Question 15

Function of:

Pollen grain

Answer 15

Contains the male reproductive gammete

Question 16

What’s pollination?

Answer 16

the transfer of pollen from the anther of one flower to the mature stigma of another flower of the same species

Question 17

Explain the development of the male gammete

Answer 17

• A diploid mother cell undergoes MEISOIS
• To form a tetrad of four haploid pollen cells
• Then cells seporate to produce 4 imature pollen grains
• Young pollen grain undergoes MITOSIS to form a Generative neucleus and a Pollen tube nucleus
• Generative nucleus undergoes MEISOIS to form 2 male nuclei

Question 18

What’s dehiscence?

Answer 18

the opening of the anther, releasing pollen grains

Question 19

Explain the development of the female gamete

Answer 19

• Diploid megaspore mother cell undergoes MEIOSIS to produce 4 haploid megaspores
• 3 disintigrates
• Other undergoes 3 rounds of MITOSIS to form 8 haploid nuclei
• 2 polar nuclei fuse to from a diploid polar nucleus

Question 20

What’s the female gamet called?

Answer 20

oosphere

Question 21

Whats self polination?

Answer 21

Occurs when pollen falls from the anther onto the stigma of the same flower on the same plant

Question 22

How do flowers provent pollination?

Answer 22

• have stigmas above stamen
  OR
• Dichogamy: Stamen and stigma mature at different times
  Protandry = stigma ripens first
  Protogyny = stigma ripens first

Question 23

Explain double fertilisation

Answer 23

• When a compatible pollen grain lands on the stigma it germinates in the sucrose solution secreted by the stigma and produce a pollen tube
• Pollen tuble grows out of gap in cell wall of pollen grain
• PG travells down the style up a concentration gradient of chemattractants from ovule (digesting its way down style)
• Pollen tube nucleus is at tip of the with the 2 male nuclei behind
• Pollen tube grows through gap in interguments into embryo sac
• PTN disintigrates after completing it’s function - the growth of PT
• Tip of PT opens 2 male gametes released into embryo sac
• M + F gametes fuse to form a diploid zygote
• Other male gamete fuses with the diploid polar nucleus to form triploid nucleus

Question 24

Definition of fruit

Answer 24

Develops from the fertilised ovary
-Contains one or more seeds

Question 25

Definition of seed

Answer 25

Develops from the fertilised ovule
-contains embryonic plant and a food store

Question 26

Explain what’s a broad bean

Answer 26

• Dicotyledon (2 leaves)
• Non-endospermic seed - endosperm is absorbed into the cotyledons

Question 27

Explain whats maize

Answer 27

• Monocotyledon
• Endospermic seed - endosperm remains as the food store

Question 28

What’s a radicle?

Answer 28

Developing root

Question 29

What’s the plumule

Answer 29

Developing shoot

Question 30

What’s a testa

Answer 30

Out side coat of seed

Question 31

Germination defination

Answer 31

the biochemical and physiological processes through which a seed becomes a photosynthesising plant

Question 32

What are the 3 main requirements for germination?

Answer 32

1. Temperature
2. Water
3. Oxygen

Question 33

When do seeds germinate?

Answer 33

When conditions are optimum - they remain dormant (inactive) till this

Question 34

What does water do during germination?

Answer 34

• Seed absorbs water through micropyle
• This mobilises enzymes
• Increases cell size through formation of vaculoes causing testa to split
• Transports materials into seed

Question 35

What does temperature do during germination?

Answer 35

Optimum temp for enzyme activity

Question 36

What does oxygen do during germination?

Answer 36

for aerobic respiration - releases energy, fueling metabolism and growth

Question 37

Name a group of plant hormones responsible for growth and development

Answer 37

Gibberellin

Question 38

Explain the steps of germination of endospermic seeds

Answer 38

1. Water is absorbed through the micropyle
2. Gibberellins in the cotyledons are mobilised and carried into the outer layer of endosperm (aleurone)
3. This causes DNA to be transcripted into mRNA which is then translated into hydrolytic enzymes (e.g protease and amylase)
4. Protease hydrolyse protein in the aleurone layer to amino acids to make amylase and maltase
5. Amylase diffuses out of a;eurone layer and hydrolyses the starch stroed in the endosperm to maltoes and then gluscose
6. Glucose diffuses to embryo where radicle and plumule use it for respiration + growth