plant reproduction

Question 1

draw and label a diagram of a typical flower

Answer 1

stigma, style, ovary, anther, filament, sepal, receptacle

Question 2

what’s the function of the receptacle

Answer 2

part of the flower from which the flower part arises

Question 3

what’s the function of the sepals

Answer 3

leaf like structures that protect the flower when it is a bud

Question 4

what’s the function of the petal

Answer 4

to attract animals for pollination

Question 5

define stamen

Answer 5

the male parts of the flower

Question 6

define carpel

Answer 6

female parts of the flower

Question 7

what’s the function of the filament

Answer 7

has vascular bundles to bring food wand water to the filament

Question 8

what’s the function of the anther

Answer 8

produce pollen grains as a result of meiosis

Question 9

what’s the function of the stigma

Answer 9

where the pollen lands

Question 10

what’s the function of the style

Answer 10

through which the pollen tube grows

Question 11

where is the embryo sack produced

Answer 11

ovule as a result of meiosis

Question 12

describe the formation of a mature pollen grain

Answer 12

anther has 4 chambers called pollen sacs. in each pollen sac are diploid microspore pollen cells. these cells divide by meiosis to produce a cluster of 4 haploid cells called a tetrad. each tetrad breaks up to form 4 seperate haploid pollen grains. these pollen grains can divide by mitosis to produce two haploid nuclei (tube and generative)

Question 13

describe the formation of the embryo sac

Answer 13

each ovary contains one or more ovules. one cell low down in the ovule is called hte megaspore mother cell, it is diploid and divides by meiosis to form 4 haploid cells. three of these cells degenerate. the remaining one is called the embryo sac. the haploid nucleus in this embryo sac divides by mitosis 3 times to form 8 haploid nuclei. 5 degenerate and the three remaining form the female gametes. two form the polar nuclei in the embryo sac, the other forms a cell wall and becomes the egg cell.

Question 14

explain double fertilisation

Answer 14

one sperm nucleus joins with the egg nucleus to form a diploid zygote which will develop into an embryo. the second sperm nucleus joins with the two polar nuclei to form a triploid endosperm nucleus

Question 15

define fertilisation

Answer 15

the union of male and female gametes to form a diploid zygote

Question 16

explian the process of fertilisation

Answer 16

pollen grain lands on stigma and is stimulated to grow by hormones produced. the tube nucleus in the pollen grain forms a pollen tube down through the style to the ovule. tube nucleus degenerates once it reaches the micropyle. the haploid generative nucleus divides by mitosis to produce two sperm nuclei (male gametes) and then double fertilisation occurs

Question 17

explain seed formation

Answer 17

fertilised ovule becomes the seed. integuments dry up and become the testa (wall of seed). the zygote divides by mitosis rapidly to give rise to the embryo which contains a radicle and plumule. some embryro cells form seed leaves. the endosperm nucleus also divides by mitosis to form many endosperm cells which absorb the nucellus and act as a food store

Question 18

outline the main events in germination

Answer 18

seed absorbs water through micropyle and testa, activating enzymes. oils are digested to fatty acids/glycerol and starch is digested to glucose and proteins digested to amino acids. products of digestion moved to embryo. glucose and amino acids are used to create cell walls, enzymes and other structures. fats and some glucose are used in respiration. weight of seed decreases as weight of embryo increases. radicle bursts through testa, plumule emerges from the ground and leaves form.