Sexual Reproduction in the Flowering Plant Flashcards
(164 cards)
1
Q
which part of the plant is specialised for sexual reproduction
A
the flower
2
Q
gamete
A
haploid cell, capable of fusion
3
Q
when do gamete nuclei fuse and what is made
A
they fuse at fertilisation to form a diploid zygote
4
Q
zygote becomes a
A
seed
5
Q
seed becomes a
A
new plant
6
Q
plants produced by sexual reproduction will show
A
genetic variation
7
Q
gametes to zygote and endosperm
A
polination and fertilisation
8
Q
zygote and endosperm to seed
A
mitosis
9
Q
seed to plant 3
A
germination
dispersal
dormancy
10
Q
bit that the flower sits on
A
sepal
11
Q
what are all the parts of the flower attached to
A
the receptacle at the top of the flower shoot
12
Q
sepals
A
green leaf-life structures which protect the flower while it is a bud
13
Q
petals
A
brightly coloured with nectaries
14
Q
function of petals
A
attract insects for pollination
15
Q
male part
A
stamen
16
Q
stamen
A
consists of filament (stalk) and anther
17
Q
function of anther
A
produces pollen
18
Q
female part
A
carpel
19
Q
carpel
A
consists of the stigma, style and ovary with ovule
20
Q
function of the stigma
A
receives pollen
21
Q
function of the ovule
A
produces the egg
22
Q
end result of sexual reproduction of a flower plant
A
a seed or seeds inside of a fruit
23
Q
after fertilisation the ovule becomes
A
a seed
24
Q
after fertilisation the ovary becomes
A
the fruit
25
what does an anther have?
4 pollen sacs
26
what occurs in the pollen sacs (first)
diploid microspore mother cells divide by meiosis to produce four halpoid microspores each
27
what happens to each microspore
each microspore divides by mitosis to form a pollen grain with 2 haploid nuclei
28
the 2 haploid nuclei in the pollen grain are called
the generative nucleus and tube nucleus
29
the mature pollen grain forms
a wall
30
what does each carpel have at its base
an ovary with 2 or more ovules
31
first thing that occurs in the ovule
the diploid megaspore mother cell divides by mitosis to form 4 haploid cells
32
what happens to the 4 haploid cells in the ovule
3 break down
33
4th haploid cell in the ovule that does not break down
enlarges to form the embryo sac
34
what happens to the embryo sac
it divides 3 times to form 8 nuclei
35
what happens to 3 of the 8 nuclei from the embryo sac
one nucleus becomes the egg cell (n) and 2 become the polar nuclei (n) these are the female gamete
36
describe the walls of a mature ovule
it has 2 walls called the integuments that enclose the embryo sac and there is a tiny opening in the integuments for the micropyle (for entry of pollen tube)
37
as the pollen grains mature, what happens to the anther
the wall of the anther shrinks and dies out
38
how are the pollen grains released when anther dies
a line of dehiscence (split) appears down each side of the anther, the walls split open and the pollen grains are released
39
what must happen so that fertilisation and seed production to occur
pollen grains must be transferred from the anther to the stigma
40
pollination
the transfer of pollen from anther to stigma
41
2 types of pollination
self pollination
| cross pollination
42
self pollination
pollen grains are transferred onto the stigma of the same flower (or onto another flower of the same plant)
43
cross pollination
pollen grains are transferred onto the stigma of a flower on another plant of the same species
44
what does cross pollination do
increases genetic variation
45
which type of pollination is more common
cross pollination
46
how is cross pollination carried out
by insects or the wind
47
3 parts of insect pollinated flowers that show characteristics
flowers, pollen grains and stigmas
48
flowers of insect pollinated flowers
brightly coloured petals, sweet smelling and have nectaries to attract insects 1
49
pollen grains of insect pollinated flowers
spiked and sticky and they will stick well to the insects body
50
stigmas of insect pollinated flowers
flat and stick and inside the flower to ensue that the insect brushes against them
51
3 insect pollinated flowers
buttercup
daisy
wallflower
52
flowers of wind pollinated flowers
flowers are small, seals and petals are green or often absent to allow free circulation of air, no perfume or nectar
53
pollen of wind pollinated flowers
large quantity of pollen produced to increase chances of pollination
54
pollen grains of wind pollinated flowers
small, smooth and light to make them easily airborne
55
stigmas of wind pollinated flowers
feathery stigmas hang outside the flower to catch pollen in the air
56
filaments of wind pollinated flowers
long filaments to allow anthers to hang outside of the flower - easy removal of pollen
57
3 examples of wind pollinated flowers
grasses oak birch
58
fertilisation
the fusion of males and female gametes to form a zygote
59
first step of fertilisation
pollen grains land on the stigma and absorb a sugary material
60
what happens to each pollen during fertilisation
each pollen germinates to form a pollen tube that grows down to the style
61
what controls the growth of the pollen tube
the tube nucleus at the tip
62
what directs growth of pollen tubd towards the ovule
chemicals produced in the ovule (chemotropism)
63
how does the pollen tube enter the ovule and what happens when it does
via the micropyle and the nucleus breaks down
64
while the pollen tube enters the ovule, what happens to the generative nucleus
the generative nucleus divides by mitosis to form 2 male gamete nuclei
65
what happens to the male nuclei during fertilisation
the male nuclei move down the pollen tube and into the embryo sac
66
final step of fertilisation
double fertilisation occurs
67
first thing in double fertilisation occurs
one male nucleus (n) fuses with egg cell (n) forming a diploid zygote
68
other occurrence
one male nucleus (n) fuses with 2 polar nuclei (2n) to produce endosperm (3n)
69
after fertilisation occurs what happens to the zygote
it divides by mitosis to form the embryo
70
what happens to the embryo during seed formation
it is differentiated into the plumule (future shoot) and radicle (future root) and 1 or 2 cotyledons (seed leaves)
71
what happens to the 3n endosperm during seed formation
divides by mitosis to form the endosperm
72
function of the endosperm
this is a food storage tissue that surrounds the developing embryo and supplies it with food
73
what happens to the integuments during seed formation
the integuments fry out to become the seed coat or testa
74
what happens to the ovule during seed formation
the ovule enlarges and develops into the seed
75
what happens to the ovary during seed formation
the ovary develops into the fruit
76
what happens to the seed when it is fully formed and why
when the seed is fully formed it loses most of its water, this reduces the metabolism in the embryo and the seed becomes dormant
77
endospermic seeds
the endosperm is the main food storage tissue in the mature seed eg. maize, wheat
78
non-endospermic seeds
the cotyledons (seed-leaves) are the food storage tissue in the mature seeds eg. peas, beans
79
what happens to endosperm food in non-endospermic seeds
the food is used up by the developing cotyledons
80
3 parts of a seed
testa
embryo
emdosperm
81
testa
seed coat
82
function of testa
encloses and protects the embryo and food store
83
embryo
an elongated structure
84
5b parts of embryo
```
plumule
epicotyl
hypocotyl
radicle
cotyledons
```
85
plumule
upper tip of embryo that forms shoot
86
epicotyl
part of the embryo between the plumule and the cotyledons
87
hypocotyl
part of the embryo between the radicle and the cotyledons
88
radicle
lower tip of embryo that forms root
89
cotyledons
seed leaves that store food
90
function of endosperm
stores food
91
is an endosperm present in all seeds
no
92
a typical seed stores what
carbohydrates, proteins and lipids, either in cotyledons or endosperm
93
scar at the bottom of a seed
hilium
94
example of non-endospermic, dicot seed
broad bean seed
95
example of endospermic monocot seed
maize grain
96
maize grain is really
a fruit
97
outer wall of maize grain consists of
pericarp (fruit wall) and testa (seed coat)
98
what happens after pollination and fertilisation
the ovule becomes a seed and the ovary becomes a fruit
99
developing seeds produce what and why?
growth regulators (auxins and gibberellins) that stimulate the ovary to become a fruit
100
fruit formation of seedless fruit
development of a fruit without a seed inside (egg is not fertilised)
101
2 ways in which seedless fruit may be produced
selective breeding eg. bananas, seedless oranges
using growth regulators eg. auxins or gibberellins sprayed on flowers to form fruit without fertilisation and seed development eg.grapes
102
2 functions of fruit
protect the seed
| disperse the seeds (carry away from parent plant)
103
3 functions of seed dispersal
```
allow plant to colonise new areas
reduce competition (space, water, minerals)
increase chance of survival of species
```
104
4 types of seed dispersal
mechanical or self-dispersal
wind dispersal
animal dispersal
water dispersal
105
mechanical or self-dispersal
dry, dehiscent fruits open and scatter seeds some distance away from parent plant eg. pea/bean
106
wind dispersal 2
winged fruits eg. ash/sycamore
| plumed fruits eg. hairy tuft of dandeline
107
animal dispersal 2
fleshy or succulent fruits often eaten by animals, seeds pass through digestive system and deposited far awasy eg. raspberry/tomato
hooked fruits or seeds become attached to coat of on animal eg. goosegrass
108
water dispersal
plants growing in or near water produce seeds with spongy covering that gives buoyancy eg. water lily
109
2 changes that take place as ovary ripens into a fruit
cell walls break down and chlorophyll content decreases
110
what causes the changes that take place as ovary ripens into a fruit
the gas ethene, a growth regulator produced by ripening fruit
111
hay fever
an allergic reaction to pollen or other allergens present on fungal spores, animal skin, house dust mites etc
112
symptoms of hay fever
itching and tears in the eyes, sneezing and a runny inflamed nose
113
treatment of hay fever
treated with antihistamines to reduce inflammation or with decongestants to clear the nose
114
dormancy 2
a period of low metabolism
| a period of no growth
115
3 advantages of seed dormancy
germination is delayed until conditions are suitable for growth
ensures survival of plant during unfavourable conditions
allows time for greater dispersal of seeds by water, wind and animals
116
special conditions to break seed dormancy in horticultural practices
seeds soaked in H2O
seeds scrapes to break testa (more permeable)
seeds are treated to a cold period
117
suggest 3 ways in which a knowledge of dormancy is useful to farmers and gardeners
it gives information about;
- seed treatment before sowing seeds
- optimum time for sowing seeds
- optimum conditions for storing seeds
118
germination of seeds
when the embryo begins to grow again
119
4 factors that germination requires
water
oxygen
suitable temperature (5-30ºC)
light (some do eg.lettuce)
120
H2O in germination 4
hydrates cytoplasm (enzyme reactions)
swells seed and testa bursts
for movement of materials
for formation of new tissues
121
O2 in germination
needed for aerobic respiration (for energy)
122
suitable temperature in germination
needed to provide optimum temperature for enzyme reactions
123
light in germination
some seeds need light
124
what does the seed absorb during germination and how
seed absorbs H2O and O2 through the testa
125
cytoplasm during germination
becomes hydrated
126
enzymes during germination
enzymes begin to digest food un cotyledons or endosperm into a soluble form
127
soluble food molecules during germination
move to the developing embryo (mass of cotyledon or endosperm decreases and mass of embryo increases)
128
nutrients during germination 2
some nutrients used as structural materials by the embryo
| some used in respiration to provide energy for growth
129
first stage of germination in the broad bean
the seed absorbs water and swells, radicle bursts through testa
130
once radicle bursts through testa in germination in the broad bean
the hooked plumule emerges, radicle elongates and becomes foot
131
once plumule emerges in germination in the broad bean
the epicotyl elongates and pushes the plumule upwards
132
after the plumule has been pushed upwards in germination in the broad bean
the plumule straightens above ground and forms the first green leaves (photosynthesis begins)
133
cotyledons in germination in the broad bean
shrink and remain underground
134
end of germination young plant is called
seedling
135
how does a seedling grow into a mature plant
by cell division in the meristems in shoot and root tips
136
cell division in the meristems in shoot and root tips is followed by
cell elongation and cell differentiation (where tissues develop)
137
what is energy needed for in germination
digestion and growth
138
where does energy come from for germination
from respiration
139
dry weight initially during germination
small decrease
140
why does dry weight initially decrease during germination
due to respiration
141
dry weight after drop during germination
increases
142
why does dry weight after drop increase during germination
due to photosynthesis occurring when green leaves are formed
143
why is dry weight taken
amount of water varies between seeds
144
to obtain dry weight
heat material in oven at 100ºC until the weight remains constant
145
to investigate the effect of water, oxygen and temperature on seed germination
which seeds
pea seeds
146
to investigate the effect of water, oxygen and temperature on seed germination
how many seeds in each test tube
10
147
to investigate the effect of water, oxygen and temperature on seed germination
how long do you leave them
6 days but check them daily
148
to investigate the effect of water, oxygen and temperature on seed germination
how to remove water
at dry cotton wool and no water
149
to investigate the effect of water, oxygen and temperature on seed germination
how to remove heat
put it in the fridge at about 4ºC
150
to investigate the effect of water, oxygen and temperature on seed germination
how to remove oxygen
place in anaerobic jar
151
to investigate the effect of water, oxygen and temperature on seed germination
how to add water
wet cotton wool
152
to show digestive activity of seeds during germination using starch agar plates
what beans
been seeds
153
to show digestive activity of seeds during germination using starch agar plates
digestive activity
bean seeds release amylase onto starch agar and it breaks down some of the starch
154
to show digestive activity of seeds during germination using starch agar plates
how to test for digestive activity
iodine shows the presence or absence of starch
155
to show digestive activity of seeds during germination using starch agar plates
control
dead seeds (boiled)
156
to show digestive activity of seeds during germination using starch agar plates
how to kill control seeds
place them in boiling water for 10 minutes
157
to show digestive activity of seeds during germination using starch agar plates
how to expose embryo
split each in half and separate the cotyledons and expose the embryo
158
to show digestive activity of seeds during germination using starch agar plates
what is it important to do to all seeds before experiment
sterilise them in disinfectant solution
159
to show digestive activity of seeds during germination using starch agar plates
how to sterilise forceps
flame it
160
to show digestive activity of seeds during germination using starch agar plates
how do you place seeds
use sterile forceps to place seed halves open-side down
161
to show digestive activity of seeds during germination using starch agar plates
why are they placed open side down
so that the enzymes are in contact with the substrate
162
to show digestive activity of seeds during germination using starch agar plates
how long do you incubate for?
2 days
163
result for control
blue all over
| no clear spots
164
result for live seeds
clear areas under seeds
