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bot grade 12 > Sexual rep in flowering plant > Flashcards

Sexual rep in flowering plant Flashcards

1
Q

Are we not lucky that plants reproduce sexually? The —- that we enjoy gazing at, the —- that we swoon over, the — that attract us, are all there as an aid to sexual reproduction.

A

myriads of flowers
scents and the perfumes
rich colours

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2
Q

Flowers do not exist only for us to be used for —.

A

our own selfishness

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3
Q

All flowering plants (—-) show sexual reproduction. T/F

A

Angiosperms
True

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4
Q

A look at the diversity of structures of the — , —- and — shows an amazing range of —- to ensure formation of the end products of
sexual reproduction, the — and —-.

A

inflorescences, flowers , floral parts,
adaptations
fruits and seeds

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5
Q

Human beings have had an intimate relationship with —- since time immemorial.

A

flowers

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6
Q

Flowers are objects of —- (5) value
– they have always been used as —-for conveying important human feelings such as love, affection,
happiness, grief, mourning, etc.

A

aesthetic, ornamental, social, religious and cultural
symbols

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7
Q

To a biologist, flowers are — and —marvels and the —-.

A

morphological and embryological
sites of sexual reproduction

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8
Q

Much before the actual flower is seen on a plant, the — has taken place.

A

decision that the plant is going to flower

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9
Q

Several — and —- changes are initiated which lead to the differentiation and further development of the —-.

A

hormonal and structural
floral primordium

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10
Q

Inflorescences are formed which bear the —- and then the —-.

A

floral buds
flowers

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11
Q

In the flower the male and female reproductive structures, the — and — differentiate and develop.

A

androecium and the gynoecium

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12
Q

Androecium consists of a whorl of —- representing the male reproductive organ and the — represents the female reproductive organ.

A

stamens
gynoecium

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13
Q

Two parts of a typical stamen – the —- called the filament, and the —
called the anther.

A

long and slender stalk
terminal generally bilobed structure

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14
Q

The proximal end of the filament
is attached to the —- of the flower.

A

thalamus or the petal

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15
Q

The — and —- of stamens are variable in flowers of different species.

A

number and length

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16
Q

A typical angiosperm anther is — with each lobe having —-, i.e. they are —–

A

bilobed
two theca, i.e., they are dithecous

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17
Q

Often a —– runs —- separating the theca.

A

longitudinal groove
lengthwise

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18
Q

The —- of an anther is very distinct in the transverse section of the anther.

A

bilobed nature

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19
Q

The anther is a —-sided (—) structure consisting of — located at the corners, two in each lobe.

A

four
tetragonal
four microsporangia

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20
Q

The microsporangia develop further and become —-

A

pollen sacs.

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21
Q

Pollen sac extend — all through the —- and are packed with —-

A

longitudinally
length of an anther
pollen grains.

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22
Q

Structure of microsporangium:
In a transverse section, a typical microsporangium appears — in outline.

A

near circular

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23
Q

Microsporangium generally surrounded by — wall layers – the —, —, — and —–.

A

four
epidermis, endothecium, middle layers and the tapetum

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24
Q

The — three wall layers perform the function of —- and help in
—- .

A

outer
protection
dehiscence of anther to release the pollen

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25
Q

The innermost wall layer is
the —. It nourishes the —-.

A

tapetum
developing pollen grains

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26
Q

Cells of the tapetum possess —-cytoplasm and generally have—-
nucleus.
Can you think of how tapetal cells could become BI-NUCLEATE?

A

dense
more than one

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27
Q

When the anther is —, a group of —, —– cells called the —- tissue occupies the centre of each
microsporangium.

A

young
compactly arranged homogenous cells
sporogenous

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28
Q

Microsporogenesis :
As the anther develops, the cells of the —– undergo meiotic divisions to form —-.
What would be the ploidy of the cells of the tetrad?

A

sporogenous tissue
MICROSPORE TETRADS

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29
Q

As each cell of the sporogenous tissue is capable of giving rise to a
—-. Each one is a —-.

A

microspore tetrad
potential pollen or microspore mother cell

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30
Q

The process of formation of —- from a —- through meiosis is called microsporogenesis.

A

microspores
pollen mother cell (PMC)

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31
Q

The microspores, as they
are formed, are arranged in a —-–the —-

A

cluster of four cells
microspore tetrad

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32
Q

As the anthers — and —-, the microspores dissociate from each other and develop into —

A

mature and dehydrate
pollen grains

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33
Q

Inside each microsporangium —- of microspores or pollen grains are formed that are released with the —-

A

several thousands
dehiscence of anther

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34
Q

The —– represent the male gametophytes.

A

pollen grains

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35
Q

If you touch the —- of Hibiscus or any other flower you would find
deposition of —– on your fingers.

A

opened anthers
yellowish powdery pollen grains

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36
Q

Sprinkle pollen grains on a drop of — taken on a —- and observe under a microscope. You will really be amazed at the variety of —-– sizes, shapes, colours, designs – seen on the pollen grains from different species

A

water, glass slide
architecture

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37
Q

Pollen grains are generally —measuring about —- in —-.

A

spherical
25-50 micrometers
diameters

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38
Q

Pollen has a prominent —-
wall.

A

two-layered

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39
Q

The —- outer layer called the —- is made up of —-

A

hard, exine
sporopollenin

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40
Q

Sporopollenin is one of the —-
known.

A

most resistant organic material

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41
Q

Sporopollenin can withstand —- and —-.
—- that degrades sporopollenin is so far known.

A

high temperatures
strong acids and alkali
No enzyme

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42
Q

Pollen grain exine has — called —- where sporopollenin is absent.

A

prominent apertures
germ pores

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43
Q

Pollen grains are well preserved as — because of the presence of —.

A

fossils
sporopollenin

44
Q

The exine exhibits a —–
Why do you think the exine should be hard? What is the function of germ pore?

A

fascinating array of patterns and designs.

45
Q

The inner wall of the pollen grain is
called the — .

A

intine

46
Q

Intine is a— and —- layer made up of —-.

A

thin and continuous
cellulose and pectin

47
Q

The cytoplasm of pollen grain is
surrounded by a —-.

A

plasma membrane

48
Q

When the pollen grain is
mature it contains — cells, the —-

A

two
vegetative cell and generative
cell

49
Q

The vegetative cell is —, has —- and a —- nucleus.

A

bigger
abundant food reserve
large irregularly shaped

50
Q

The generative cell is — and floats in the —–.

A

small
cytoplasm of the vegetative cell

51
Q

Generative cell is — shaped with — and a nucleus.

A

spindle
dense cytoplasm

52
Q

In —- of angiosperms, pollen grains
are shed at this 2-celled stage.
In the remaining species, the — cell divides —- to give rise to the —- before pollen grains are shed (3-celled stage).

A

over 60 per cent
generative, mitotically
two male gametes

53
Q

Pollen grains of many species cause —- and —- in some people often leading to — respiratory disorders–—, —–, etc.

A

severe allergies, bronchial afflictions
chronic
asthma, bronchitis

54
Q

It may be mentioned that —- that came into India as a — with—-,
has become — in occurrence and causes pollen allergy

A

Parthenium or carrot grass
contaminant
imported wheat
ubiquitous

54
Q

Pollen grains are rich in —. It has become a fashion in recent
years to use pollen tablets as food supplements. In western countries, a
large number of pollen products in the form of tablets and syrups are
available in the market. Pollen consumption has been claimed to increase
the performance of athletes and race horses (Figure 2.6).

A

nutrients

55
Q

It has become a —- in recent
years to use —- as — supplements.

A

fashion
pollen tablets
food

55
Q

In — countries, a large number of pollen products in the form of —- and —- are available in the market.

A

western (england in pic)
tablets and syrups

56
Q

Pollen consumption has been claimed to increase the performance of — and —-

A

athletes and race horses

57
Q

When once they are shed, pollen grains have to land on the stigma
before —- if they have to bring about fertilisation.

A

they lose viability

58
Q

How long do you think the pollen grains retain viability?
The period for which pollen
grains remain viable is —- and to some extent depends on the
—-, —-

A

highly variable
prevailing temperature and humidity

59
Q

In some —- such as rice and
wheat, pollen grains lose viability within —-

A

cereals, 30 minutes of their release,

60
Q

In some members of —, —, —- they
maintain viability for months.

A

Rosaceae, Leguminoseae and Solanaceae,

61
Q

You may have heard of storing —- of many animals including humans for —- .

A

semen/ sperms
artificial insemination

62
Q

It is possible to store pollen grains of a —- for —- in —- . Such stored pollen can be used as pollen banks,
similar to seed banks, in —-

A

large number of species
years
liquid nitrogen (-196C)
crop breeding programmes

63
Q

The — represents the female reproductive part of the flower.

A

gynoecium

64
Q

The gynoecium may consist of a single pistil (—-) or may have
more than one pistil (—-).

A

monocarpellary
multicarpellary

65
Q

When there are more than one,
the pistils may be fused together (–) or may be free (—)

A

syncarpous
apocarpous

66
Q

Each pistil has three parts
the —, —, —- .

A

stigma, style and ovary

67
Q

The stigma serves as a— for pollen grains.

A

landing platform

68
Q

The style is the —- part beneath the
stigma.

A

elongated slender

69
Q

The —- part of the pistil is the ovary.

A

basal bulged

70
Q

Inside the ovary is the ovarian cavity (—). The —- is located inside the ovarian cavity. .

A

locule
placenta

71
Q

Arising from the placenta are the —, commonly called —.

A

megasporangia
ovules

72
Q

The number of ovules in an ovary may be one (—-) to many (—).

A

wheat, paddy, mango
papaya, water melon, orchids

73
Q

The Megasporangium (—-) :
structure of a typical angiosperm ovule

A

Ovule

74
Q

The ovule is a — attached to the placenta by means of a — called —.

A

small structure
stalk == funicle

75
Q

The body of the ovule fuses with funicle in the region called —.

A

hilum

76
Q

Thus, hilum represents the junction between —, —- .

A

ovule and funicle

77
Q

Each ovule has one or two protective envelopes called —.

A

integuments

78
Q

Integuments encircle the —- except at the tip where a small opening called the — is organised.

A

nucellus
micropyle

79
Q

Opposite the micropylar end, is the —-, representing the — of the ovule.

A

chalaza
basal part

80
Q

Enclosed within the integuments is a mass of cells called the —.

A

nucellus

81
Q

Cells of the nucellus have —-.

A

abundant reserve food materials

82
Q

Located in the nucellus is the — or —.

A

embryo sac
female gametophyte

83
Q

An ovule generally has a — embryo sac formed from a megaspore

A

single

84
Q

Megasporogenesis :
The process of formation of — from the —-.

A

megaspores
megaspore mother cell

85
Q

Ovules generally differentiate — megaspore mother cell (MMC) in the — region of the nucellus.

A

a single
micropylar

86
Q

MMC is a — cell containing — and a
— nucleus.

A

large
dense cytoplasm, prominent

87
Q

The MMC undergoes — What is the
importance of the MMC undergoing meiosis? Meiosis results in the
production of —–megaspores

A

meiotic division.
four

88
Q

Female gametophyte :
In a majority of flowering plants, one of the megaspores is —- while the other three —-.

A

functional
degenerate

89
Q

Only the functional megaspore develops into the —-

A

female gametophyte (embryo
sac).

90
Q

This method of embryo sac formation from a single megaspore is termed —-

What will be the ploidy of the cells of the nucellus, MMC, the functional megaspore and female gametophyte?

A

monosporic development.

91
Q

The — of the functional megaspore divides — to form two —- which move to the —-, forming the 2-nucleate embryo sac.

A

nucleus
mitotically, nuclei
opposite poles

92
Q

Two more sequential mitotic nuclear divisions result in the formation of the — and —- stages
of the embryo sac.

A

4-nucleate and later the 8-nucleate

93
Q

It is of interest to note that these mitotic divisions are —, that is, nuclear divisions are not followed IMMEDIATELY by —

A

strictly free nuclear
cell wall formation.

94
Q

After the 8-nucleate stage, — are laid down leading to the — of the typical female gametophyte or embryo sac.

A

cell walls
organisation

95
Q

— of the 8 nuclei are surrounded by Cell walls and organised into — while the remaining — called —- are situated —- in the LARGE central cell

A

6
Cells
2 nuclei- polar nuclei
BELOW the egg apparatus

95
Q

There is —- of the cells in an embryo sac

A

Characteristic distribution

95
Q

— cells are grouped together at micropylar end and constitute —-

A

3, egg apparatus

96
Q

Egg apparatus consists of 2 — and 1 —

A

Synergids
Egg cell

97
Q

The synergids have —- at the —- tip called —-

A

Special cellular thickenings, micropylar tip –> filliform apparatus

98
Q

—– play an imp role in guiding the pollen tubes into the —-

A

Filliform apparatus
Synergids

99
Q

Three cells at chalazal end are called —

A

Antipodal

100
Q

Large central cell has — nuclei

A

2 Polar nuclei

101
Q

Thus a typical angiosperm embryo sac at maturity has —

A

7 cells tho it is 8 nucleate

102
Q
A

bot grade 12 (5 decks)

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