Sexual Reproduction In Flowering Plants

Question 1

asexual reproduction

Answer 1

a type of reproduction where there is no fusion of gametes as only one parent is involved, and offspring produced are identical to the parent

Question 2

sexual reproduction

Answer 2

a type of reproduction which gives rise to variation as it involves the fusion of male and female gametes, one from each parent

Question 3

pollination

Answer 3

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

Question 4

self-pollination

Answer 4

transfer of pollen from the anther to the stigma of a flower on the same plant

Question 5

cross-pollination

Answer 5

transfer of pollen from the anther to the stigma of a flower on a different plant of the same species

Question 6

fertilisation

Answer 6

the fusion of the male (n) and female (n) gametes to produce a zygote (2n)

Question 7

radicle

Answer 7

grows into the root

Question 8

plumule

Answer 8

grows into the shoot

Question 9

cotyledon

Answer 9

embryonic seed leaf

Question 10

monocotyledon

Answer 10

contains one embryonic seed leaf

Question 11

dicotyledon

Answer 11

contains two embryonic seed leaves

Question 12

fruit

Answer 12

a developed seed leaf

Question 13

dispersal

Answer 13

transfer (spreading out) of seeds away from parent plant

Question 14

dormancy

Answer 14

a resting period when seeds undergo no growth and have reduced cell activity or metabolism

Question 15

germination

Answer 15

the re-growth of the embryo after a period of dormancy, if the environmental conditions are suitable

Question 16

location of male gamete formation

Answer 16

pollen grain

Question 17

pollen grain development (Male)

Answer 17

microspore mother cell (2n) divides by meiosis in the pollen sac in the anther
tetrad of pollen is produced
pollen grains separate and the nucleus in each divides by mitosis
generative nucleus and tube nucleus formed, both haploid

Question 18

tube nucleus

Answer 18

forms pollen tube

Question 19

generative nucleus

Answer 19

divides by mitosis to produce two male gametes

Question 20

location of female gamete formation

Answer 20

embryo sac

Question 21

embryo sac formation (female)

Answer 21

megaspore mother cell (2n) divides by meiosis in the ovule
four haploid cells produced
three die off and one becomes the embryo sac
embryo sac divides by mitosis 3 times to produce eight haploid nuclei: two are polar nuclei one is egg cell

Question 22

pollination methods

Answer 22

wind or animals/insects

Question 23

wind pollination

Answer 23

eg sycamore tree, oak tree
adaptations: 
no nector
stigmas large, feathery
anthers large, outside petal

Question 24

animal/insect pollination

Answer 24

eg bees, dandelions, buttercups
adaptations:
petals brightly coloured, scented with nectaries
small amounts of sticky pollen
pollen larger

Question 25

events leading to fertilisation

Answer 25

chemotropism; release of chemicals from the ovary which stimulates the pollen tube to develop from the tube nucleus in the pollen grain pollen tube develops down the style to the ovule through the micropyle generative nucleus moves down the pollen tube behind the tube nucleus generative nucleus divides by mitosis twice; forms the male gametes two male gametes enter the embryo sac through the micropyle

Question 26

location of fertilisation

Answer 26

embryo sac

Question 27

Double fertilisation

Answer 27

one male gamete fuses with the two polar nuclei to form the triploid endosperm nucleus one male gamete fuses with the egg nucleus to form the diploid zygote

Question 28

seed formation

Answer 28

integuments(ovule walls) - seed coat (testa) ovule- seed ovary-fruit zygote 2n- embryo 2n (after dividing by mitosis) containing plumule, radicle, cotyledon Endosperm nucleus 3n- endosperm( food store;fats,oils proteins) cotyledon absorbs endosperm

Question 29

classification of seeds

Answer 29

``` non endospermic (monocot) endospermic (dicot) ```

Question 30

non endospermic seed

Answer 30

all of endosperm is absorbed cotyledon is food store eg peanut, broad bean

Question 31

endospermic seed

Answer 31

retains some endosperm endosperm is food store eg maize,corn

Question 32

walls of fruit

Answer 32

pericarp

Question 33

seedless fruit

Answer 33

egg hasnt been fertilised

Question 34

fruit formation

Answer 34

stimulated by auxins produced by the seeds 1. Genetically - either naturally or by special breeding porgrammes eg bananas, pineapples 2. Growth regulators- eg gibberllins produce seedless grapes

Question 35

commercial regulator

Answer 35

ethene (inhibitor) breaks down chlorophyll

Question 36

advantages of seed and fruit dispersal

Answer 36

minimises competition avoids overcrowding increases chance of survival

Question 37

methods of fruit and seed dispersal

Answer 37

animal, wind, water, self

Question 38

animal dispersal

Answer 38

hooked, sticky (to attach to coat), juicy, tasty (to allow digestion) eg raspberries, stick-weed

Question 39

water

Answer 39

air spaces, light, buoyant | eg coconut

Question 40

wind

Answer 40

light, winged | eg sycamore

Question 41

self

Answer 41

in a pod that bursts to release seeds | eg peas

Question 42

advantages of dormancy

Answer 42

plant avoids harsh winter conditions gives the embryo time to develop provides time for dispersal

Question 43

how dormancy is brought about

Answer 43

growth inhibitors on outer part of seed testa is impermeable to oxygen,water testa is too tough for embryo to emerge

Question 44

application of dormancy in agriculture

Answer 44

optimum storage conditions can be provided, allows maximum growth grower can choose when to sow seeds

Question 45

artificial/commercial procedures used to break dormancy

Answer 45

physical damage - slightly damaging seed coat with a knife (scarifying) pre-chilling- storing seeds in cold temp light availability- exposing seeds to light/dark

Question 46

factors necessary for germination

Answer 46

water- medium for metabolic reactions eg digestion, transport oxygen- aerobic respiration warmth- allows maximum enzyme activity, optimum for metabolic reactions

Question 47

main events in germination

Answer 47

digestion of stored food in endosperm/cotyledon to provide soluble nutrients respiration to produce ATP to carry out cell division

Question 48

germination of a typical seed eg broad bean

Answer 48

water absorbed through micropyle - activates enzymes food store broken down- brought to growing embryo respiration occurs in embryo- ATP produced radicle bursts and grows downward, plumule later develops in shoot above ground and photosynthesis in leaves begins cotyledons below ground, remain as food store

Question 49

cotyledons above ground

Answer 49

sunflower

Question 50

cotyledons below ground`

Answer 50

broad bean

Question 51

changes in dry mass in seeds during germination

Answer 51

endosperm or cotyledon mass decreases as embryo uses glucose stored here for respiration embryo mass increases as glucose produced in photosynthesis dry mass of total seed decreases due to respiration; loss of carbon dioxide causes loss in mass

Question 52

dry mass

Answer 52

the mass of a tissue with its water content removed

Question 53

why is dry mass recorded

Answer 53

water content varies from seed to seed