Sexual Reproduction In The Flowering Plant

Question 1

Sexual reproduction

Answer 1

Two parents involved…fusion of two sex cells

Question 2

Gamete

Answer 2

Haploid cell capable of fusion

Question 3

Advantages of sexual reproduction

Answer 3

Introduces variation in the in the offspring

Question 4

What is variation

Answer 4

Differences in members of the same species

Question 5

Name the features of the flowering plant and their purpose

Answer 5

Petal- brightly coloured to attract insects
Sepal- protects flower as a bud
Stalk
Receptacle
Carpel- female reproductive part
- stigma- entry point of pollen into carpel
-style- pollen grain enter to ovule through here
-ovary
stamen- male reproductive part
-Anter- pollen production
-filament-

Question 6

Pollination

Answer 6

The transfer of pollen from the anter to the stigma of a flower from the same species.

Question 7

Self pollination

Answer 7

Transfer of pollen from the anter to the stigma of the same plant

Question 8

Cross pollination

Answer 8

Transfer of pollen from anter to stigma of a different plant from the same species

Question 9

Give the features of a wind pollinated plant and give examples

Answer 9

Eg grasses
Small/absent petals
Pollen is small, light, dry and produced in large amounts
Angers are large and outside petals, long filaments
Stigmas are large and feathery increase surface area , outside petals

Question 10

Give the features of a insect pollinated plant and give examples

Answer 10

Eg buttercups
Petals are large and brightly coloured, nectary present
Pollen is large, sticky, heavy and produced in small amounts
Antlers are small, inside petals
Stigmas are small, sticky and inside petals

Question 11

2 ways a plant can be pollinated

Answer 11

Wind and insects

Question 12

Describe the formation of the male gametes/ mature pollen grain

Answer 12

The microspore mother cell ( diploid) divides my meiosis to create 4 haploid cells clumped together ( tetrad).
Cells separate, they divide by mitosis to form 2 haploid nuclei ( generative nuclei and the tube nuclei) the generative nucleus divides by mitosis to form 2 male gametes, the tribe nucleus will go on to form the pollen tube

Question 13

Describe the development of the embryo sec

Answer 13

Megastore mother cell ( diploid) divides by meiosis to form 4 haploid cells, 3 die /degenerate, the surviving cell divides by mitosis 3 times to form 8 haploid nuclei. 5 die and 3 haploid nuclei remain. 2 of these cells form 2 polar nuclei (n), the remaining cell forms the egg cell (2n)

Question 14

Describe the process before fertilisation

Answer 14

The pollen grain lands on the sigma, the generative nucleus divides by mitosis to form 2 male gametes by hormones and enzymes ,the tube nucleus forms the pollen tube. The male gametes travel towards the pollen tube through the micropile ( opening) to enter the embryo sac.

Question 15

What is double fertilisation and where does it occur

Answer 15

Occurs in the ovule - becoming enters sac
It is when one male gamete fuses (n)with the egg cell(n) to form the zygote(2n)

The other male gamete fuses with the 2 polar nuclei (n+n) to form the endosperm nucleus (3n)

Question 16

What does the zygote go on to form

Answer 16

Zygote divides my mitosis to form the embryo which will develop the radical and the plumule

Question 17

What is the purpose of the endosperm

Answer 17

Divides by mitosis to become a source of food for the developing embryo

Question 18

Name the sources of food storage in a seed

Answer 18

Cotyledon, endosperm

Question 19

What is the seed formed from?

Answer 19

Ovule

Question 20

What is the testa formed from

Answer 20

Ovule wall/ integument

Question 21

What is the fruit formed from

Answer 21

The ovary

Question 22

What does the ovary wall form

Answer 22

Pericup

Question 23

Name the two types of seed and give an example

Answer 23

Endospermic seed eg corn
Non endospermis seed eg broad bean

Question 24

What is an endospermic seed

Answer 24

The endosperm remains as a food store
Usually monocot

Question 25

What is a non endospermic sead

Answer 25

The endosperm is absorbed by the cotyledon Usually dicot

Question 26

What is a monocot seed

Answer 26

1 seed leaf

Question 27

What is a dicot seed

Answer 27

Contains two seed leafs

Question 28

List the features of a endospermic seed

Answer 28

Tests- seed coat Endosperm, Plumel , radical Cotelydon

Question 29

What will the radical go on to form

Answer 29

The future root

Question 30

What will the plumel go to form

Answer 30

Future shoot

Question 31

Name the types of fruit

Answer 31

Fleshy fruits Dry fruit false fruits- don’t develop form ovary Seedless fruits

Question 32

How are seedless fruits formed

Answer 32

Spray plants with growth regulators Selective breeding

Question 33

What is seed dispersal

Answer 33

Dispersal is when seeds are scattered away from the parent plant

Question 34

Advantages of seed dispersal

Answer 34

Reduce competition , less overcrowding Colonise new habitats

Question 35

Methods of seed dispersal

Answer 35

Water eg coconut Wind - dandelion ( wings, hairs) Animal- tomato ( edible fruits w/seeds) Self- eg poppy

Question 36

What is Dormancy

Answer 36

A period of low metabolic activity when seeds do not germinate

Question 37

Advantages or dormancy for the seed

Answer 37

Allows seeds to survive unfavourable conditions Give time for embryo to develop Allows time for seed dispersal

Question 38

Reasons of dormancy

Answer 38

Testa is too tough for emerging embryo Tests importable to water oxygen Presence of growth inhibitors

Question 39

Advantages for farmers of dormancy

Answer 39

Provides knowledge on how to store seed without germination occurring Provides knowledge on to treat seeds before planting

Question 40

Why does the embryo mass increase

Answer 40

The use of dissolved foods, the food reserves are digested and dissolved and transported to the embryo

Question 41

Why does the endosperm mass fall

Answer 41

It’s being used up for food ( using up food store)

Question 42

What is germination

Answer 42

The re growth of the embryo after a period of dormancy if conditions are suitable

Question 43

What are the factors required for germination

Answer 43

Water- medium necessary for chemical reactions to occur/enzymes dissolve and transport digested biomolecules Suitable temperature-optimum enzyme activity @ 27C Oxygen -aerobic respiration

Question 44

What occurrs during germination?

Answer 44

The water is absorbed and enzymes activated Enzymes digests fats and starch and transported to the growing embryo This provides energy and other resources used in respiration The dry weight of the seed falls due to food being used in respiration, weight of embryo increases

Question 45

Why is dry weight used

Answer 45

Water content varied between seeds so dry weight is more reliable ( bake in over)

Question 46

Explain the process for the experiment of factors necessary for germination

Answer 46

Radish seeds in test tubes Keep one dry Keep one anaerobic( boiled water with a layer of oil on top Keep one refrigerated Keep one perfect( this one germinates as it has all the conditions for germination)

Question 47

What is nutrient agar

Answer 47

A medium that contains all the food in a microorganism needs to grow

Question 48

Describe method of showing starch is digested during germination

Answer 48

Soak broad beans overnight- softens tests and commences the germination process Boil half of the seeds as control- denatures Soak seeds and wash disinfectant to kill mo Sterilise forceps under flame Split each bean in half to separate cotyledons( ls) with a backed blade, place face down Minimal opening( minimise contamination) Incubate plated @ 27Cc for 72 hrs allow germination Flood plated with iodine

Question 49

Describe the results for showing starch is digested during germination.

Answer 49

Unboiled Iodine remains brown under areas of bean( starch has been digested during germination) Boiled( entire plate is blue black starch has not been digested by living seed during germination )