Sexual Reproduction in Flowering Plants Flashcards
(148 cards)
1
Q
Reproduction has 2 basic functions, give them.
A
- replaces those organisms that die, maintaining the continuity of life.
- allows for an increase in numbers when conditions are suitable.
2
Q
Name the 2 types of reproduction.
A
asexual, sexual
3
Q
Whats asexual reproduction?
A
involves only one parent
4
Q
What does mitosis not require and not involve?
A
doesnt require meiosis and does not involve sex cells (gametes)
5
Q
What are sex cells called?
A
gametes
6
Q
In asexual reproduction, comment on the appearance of offspring. Why is this?
A
offspring are genetically identical to the parent because all the cell divisions are by mitosis
7
Q
Whats sexual reproduction?
A
involves the fusion of two sex cells or gametes (two parents)
8
Q
What are gametes?
A
haploid cells capable of fusion
9
Q
Whats essential for sexual reproduction? Why?
A
meiosis - to halve the chromosome number in the formation of gametes
10
Q
In sexual reproduction, comment on the appearance of offspring. Why is this?
A
offspring show variation due to the mixing of genes from two parents
11
Q
What happens gametes in sexual reproduction?
A
2 gametes fuse to form a diploid cell called a zygote
12
Q
What is the receptacle and what does it do?
A
part of flower from which the flowering parts arise.
it supports these parts.
13
Q
What colour are sepals usually?
What colour do they turn once the flower opens out?
A
green
brown
14
Q
What are sepals and what do they do?
A
leaf-like structures that protect the flower then it is a bud
15
Q
What are petals in animal-pollinanted plants and what do they do?
A
they are large and brightly coloured to attract animals
16
Q
What are petals in wind-pollinanted plants like?
A
petals are small (or absent) and green
17
Q
Are stamens male or female?
A
they are the male parts of the flower
18
Q
Are carpels male or female?
A
they are the female parts of the flower
19
Q
Stamens consist of?
A
filament and anther
20
Q
Whats a filament? Contains? What does it do?
A
thin stalk,
contains vascular bundles,
bring food and water up to the anther and supports anther.
21
Q
What 2 things does the anther do?
A
produces pollen grains,
releases pollen
22
Q
Where does the anther produce pollen grains and as a result of what?
A
produces pollen grains on its inside as a result of meiosis
23
Q
Each carpel has how many parts?
A
3
24
Q
Name the carpel parts.
A
stigma, style, ovary
25
What does stigma do? Why is it suited to this job?
traps the pollen,
stigma is sticky to catch the pollen
26
Whats the style?
where the pollen tube grows
27
The style 'tube' goes from where to where?
stigma to ovary
28
Ovary contains what?
one or more ovules (and eggs)
29
Where are eggs found in the plant?
ovary
30
Whats the difference between a carpEl and a carpAl?
carpel = the female part of a flower
carpal = a bone in the wrist
31
What are the two male parts called?
anther, filament
32
What are the three female parts called?
stigma, style, ovary
33
Meiosis occurs in ovule to produce a structure called?
Embryo sac
34
After fertilisation the...
ovule becomes?
ovary becomes?
ovule = the seed
ovary = the fruit
35
Whats an adaptation of petals for wind pollination?
- small (or absent)
- green (or no colour)
- no scent
36
Whats an adaptation of petals for animal pollination?
- large
- brightly coloured
- scented
37
Whats an adaptation of pollen for wind pollination?
- large amounts
- light
- small
- dry
38
Whats an adaptation of pollen for animal pollination?
- small amounts
- heavy
- large
- sticky
39
Whats an adaptation of anthers for wind pollination?
- large
- feathery outside petals
- loosely attached to filament
40
Whats an adaptation of anthers for animal pollination?
- small
- inside petals
- firmly attached to filament
41
Whats an adaptation of stigmas for wind pollination?
- large
- feathery outside petals
42
Whats an adaptation of stigmas for animal pollination?
- small
- sticky inside petals
43
In relation to male gamete formation, cells lining the inside of the anther are?
diploid (2n)
44
In relation to male gamete formation, the anther consists of 4 chambers called?
pollen sacs
45
In relation to male gamete formation, each pollen sac is enclosed by?
an epidermis for protection and a fibrous layer
46
In relation to male gamete formation, the tapetum is what? What does it do?
an added layer of cells inside the fibrous layer which acts as a food store and supplies energy for cell divisions in the pollen sac
47
In relation to male gamete formation, inside each pollen sac are what called what?
diploid cells called microspore mother cells
48
In relation to male gamete formation, the microspore mother cells divide by what and form things called?
divide by meiosis, forming 4 haploid cells called a tetrad
49
Whats a tetrad?
4 haploid cells
50
In relation to male gamete formation, each tetrad breaks apart forming? What are they called?
4 separate haploid pollen grains called microspores
51
Whats the difference between exine and intine?
exine is thick outer wall
intine is thin inner coat
52
Each pollen grain/microspore has a thick outer wall ___ and thin inner coat ___.
exine
intine
53
In relation to male gamete formation, each pollen grain may go on and divide by? What does this form?
mitosis.
forming 2 haploid nuclei, the tube nucleus and generative nuclei
54
In relation to male gamete formation, after pollination the tube nucleus forms the?
pollen tube and degenerates
55
In relation to male gamete formation, after pollination the generative nucleus will undergo? Forming what?
mitosis, forming 2 male gametes
56
What happens the anther when the pollen grains have matured?
anther splits and peels back
57
Give account of the formation of embryo sac.
1) megaspore mother cell
2) is diploid
3) divides by meiosis
4) forms 4 haploid cells
5) 3 of these degenerate
6) divides by mitosis 3 times
7) embryo sac contains 8 nuclei
8) one becomes the egg
9) two form the polar nuclei
58
Definition of pollination?
is the transfer of pollen from the anther to the stigma
59
Definition of self-pollination?
involves the transfer of pollen from the anther to the stigma within the same plant
60
Definition of cross-pollination?
involves the transfer of pollen from the anther to the stigma between different plants
61
Discuss variation in self-pollination and cross-pollination.
self-pollination, no variation in offspring.
cross-pollination, show more variation (seeds)
62
Whats an example of a self-pollinated plant?
cereal
63
Name 3 methods of pollination.
wind
animals
water
64
Give a point on wind for pollination.
is very wasteful of pollen
65
Give examplse of wind-pollinated plants.
coniferous plants
grasses
oak
hazel
66
Give a point on animals for pollination.
more precise in carrying pollen directly to the stigma, less pollen wasted
67
The most common animal pollinators are?
insects
68
As well as insects, what else can carry pollen?
bats, birds
69
Give examples of insect-pollinated plants.
dandelions
daisies
buttercups
70
What stage comes after pollination?
fertilisation
71
Definition of fertilisation?
is the fusion of the male and female gametes to form a diploid zygote
72
Give 9 points on fertilisation.
(including double fertilisation)
1) pollen grain germinates
2) produces pollen tube
3) tube nucleus digests through the style
4) reaches the ovary
5) generative nucleus divides by mitosis
6) form 2 male nuclei
7) enter embryo sac
8) one male nucleus fuses with the egg nucleus to form a diploid zygote
9) the second male nucleus fuses with the two polar nuclei to form a triploid endosperm
73
Give 2 points on double fertilisation.
1) one male nucleus fuses with the egg nucleus to form a diploid zygote
2) the second male nucleus fuses with the two polar nuclei to form a triploid endosperm
74
The ovary develops what?
embryo sac
75
What are 2 advantages of cross-pollination?
prevents interbreeding
greater variation in the species
76
The fertilised ovule becomes?
the seed
77
A seed comes from?
the fertilised ovule
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What does the radicle develop into?
a root
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What does the plumule develop into?
the shoot
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What's a cotyledon?
a seed leaf
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Whats a non-endospermic seed?
has no endosperm when fully formed
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Whats an endospermic seed?
contains some endosperm when fully formed
83
The main foods stored by seeds are? What are these called
fats (or oils), proteins, starch = biomolecules
84
The walls of the ovule dry up and form?
the wall of the seed (testa)
85
Whats the walls of the ovule called?
integuments
86
During seed formation, the diploid zygote grows repeatedly by ___ and forms a group of cells that form the ___.
mitosis
embryo
87
(In seed formation) the embryo consists of?
the future root - radicle
the future shoot - plumule
88
In seed formation, some embryo cells grow to form?
cotyledons
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During seed formation, the endosperm nucleus? What happens then?
divides repeatedly by mitosis producing many endosperm cells
these expand and absorb the nucleus and the endosperm acts as a food store
90
The endosperm acts as?
a food store
91
What foods are stored in seeds?
lipids and starch
92
2 examples of a non-endospermic seed?
broad bean, peanut
93
2 examples of endospermic seeds?
maize, corn
94
Whats the difference between monocot and dicot in terms of storing food?
monocot: rarely store food in cotyledons, instead the growing embryo absorbs food stored in the endosperm
dicot: food stored in the cotyledons
95
Instead of storing food what happens with monocots?
the growing embryo absorbs food stored in the endosperm
96
Give examples of monocotyledons.
grasses, daffodils
97
Give examples of dicotyledons.
broad beans, peanuts
98
Definition of a fruit?
a developed ovary
99
What becomes the fruit?
ovary
100
Two functions of fruit?
to aid seed dispersal
protect seeds
101
Name for the wall of the fruit?
pericarp
102
Why are grains also called fruits?
have an internal seed
103
Whats a false fruit? Give eg.
develop from other parts of a flower besides the ovary, eg. apple
104
The development of a fruit without a seed is called?
parthenocarpy
105
What are two ways seedless fruits can be formed? Give eg's.
1) form genetically or by special breeding, eg: bananas, pineapples
2) spray plants with growth regulators, eg: auxins to form seedless grapes
106
Discuss ethene.
a plant growth regulator used to ripen fruit and is pumped into large storage containers, like for bananas
107
Definition of dispersal?
the transfer of a seed or fruit away from the parent plant
108
Dispersal is necessary to what? (4)
- avoid large numbers of seeds competing with each other
- increase the chance of survival for the plant
- find new areas for growth
- increase numbers of the species
109
Name the main methods of seed dispersal.
wind, water, animal, self
110
Give an example of wind dispersal and explain.
dandelions and thistles produce parachute devices that help disperse seeds widely.
sycamore produce fruit with wings which spiral down to the ground and increase the distance over which the seeds may be dispersed.
111
Give an example of water dispersal and explain.
coconut trees and water lillies have light air-filled fruits that float allowing them to be dispersed by rivers
112
Explain animal dispersal.
animals carry seeds or fruits long distances
113
Give an example of self dispersal and explain.
some fruits have mechanisms that catapult seeds away, pea pods that dry out and split open
114
Fruits dispersed by animals have either of two major adaptations, name them.
sticky fruits,
edible fleshy or succulent fruits
115
Describe sticky fruits. Give eg's.
fruits with hooks may cling to an animal's hair/fur and be carried away.
these seeds are dispersed by attaching to the external surface of the animal.
Eg's: burdock, goose grass.
116
Describe edible, fleshy or succulent fruits. Give eg's.
fruits attract animals by being brightly coloured with strong scents and lots of food.
the animal eats and digests the fruit but the seeds pass through the intestine unharmed.
these seeds are released with the faeces, which even acts as a fertiliser for them.
Eg: strawberries, blackberries, acorns, tomatoes.
117
Definition of dormancy?
period of low metabolic activity
/
period of no growth
118
Dormancy is brought about by what 4 ways?
- growth inhibitors which delay growth
- the testa may be impermeable to water or oxygen
- the testa may be too tough to allow the embryo to emerge
- may be a lack of suitable growth regulator needed
119
How is the knowledge of seed dormancy useful to humans?
- correct environment for storage
- optimum showing time
- maximise growing season
120
What are advantages of dormancy?
- survive adverse conditions
- gives time for dispersal (of the seed)
121
Definition of germination?
growth of a seed into a new plant
122
Name the three conditions needed for germination.
water, oxygen, temperature
123
How is water needed for germination?
needed to allow enzyme reactions to occur, the seed absorbs water from the soil causing the seed to swell and let enzymes function
124
How is oxygen needed for germination?
needed for aerobic respiration, its absorbed from the soil
125
How is temperature needed for germination?
must be suitable to allow enzyme reactions take place
126
What are the roles of water in germination?
- soften the testa
- activate enzymes
- increase metabolism
- transport nutrients
- dissolve nutrients
127
The role of digestion in germination?
provide soluble nutrients
128
The role of respiration in germination?
provides (or releases) energy for growth
129
State advantages of dispersal to the plant.
less competition with the parent plant,
colonise new habitats
130
Outline the events in germination.
1: seed absorbs water through a tiny hole called the micropyle and through the testa, water allowing enzymes be activated.
2: oils are digested to fatty acids and glycerol, starch is digested to glucose and proteins are digested to amino acids.
3: the products of digestion are moved to the growing embryo.
4: glucose & amino acids are used to make new structures like cell walls/enzymes.
5: the fats & some of the glucose are used in respiration to produce energy.
6: the dry mass of the seed falls due to the foods used in respiration.
7: as the mass of the food stores falls, the mass of the embryo increases as the food has been passed from seed to embryo.
8: the radicle bursts through the testa.
9: the plumule emerges above ground and leaves are produced.
10: once the first leaves start to photosynthesise, the dry weight of the seedling increases again.
131
Proteins being digested to amino acids refers to what human system?
digestive
132
The mass of the seed falls between days 0 and 9 due to?
respiration
133
From day 9 on, the mass of the seed increases due to?
photosynthesis
134
CHANGES IN DRY MASS DURING GERMINATION:
- why does the graph decrease?
- why does the graph increase?
decreases due to respiration and food being used up.
increases due to photosynthesis and food being made.
135
Name an example of germination in which the cotyledons remain below the soil.
broad bean
136
What does hypogeal mean?
cotyledons remain below the soil
137
What does epigeal mean?
cotyledons move above the soil
138
Discuss cotyledons remaining below soil.
- seed absorbs water, enzymes become active and radicle starts growing.
- radicle bursts out through testa and grows down due to geotropism.
- plumule emerges and region between cotlyedon and plumule called the epicotyl grows.
- cotyledons shrivel as food is transferred from them.
- radicle develops into the primary root.
- once above ground, plumule straightens and produces the first true leaves which become and green and start photosynthesising.
139
Discuss cotyledons moving above the soil.
- region between emerging radicle and cotyledons called the hypocotyl grows, causing the cotyledons to be carried above the soil.
- once above the soil, the fruit wall falls to the ground, the cotyledons open out becoming green and photosynthetic.
- plumule emerges from between the cotyledons and forms the first foliage leaves.
140
Name an example of germination in which the cotyledons move above the soil.
sunflower seeds
141
What is the pericarp?
fruit wall
142
What is the testa?
seed wall
143
The fruit wall is called what?
pericarp
144
The seed wall is called what?
testa
145
Benefits of dormancy for farmers?
optimum storage,
optimum ploughing/sewing time,
how to store seeds
when to sow seeds
146
As well as movement what does pseudopod do?
engulf prey
147
Function of anther, sepal and petal?
- produces pollen
- protects (developing flower
- attract pollinators
148
Two fertilisations occur after pollination, name the products of both fertilisations.
zygote - diploid
endosperm - triploid
