Cell Cycle And Cell Division Flashcards

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1
Q

During the division of cell , ______ and ______ also takes place .

A

DNA replication

Cell growth

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2
Q

Although ______ is a continuous process , _____ occurs only during one specific stage in the cell cycle .

A

Cell growth

DNA synthesis

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3
Q

Cell growth in terms of _______is a continuous process .

A

Cytoplasmic increase

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4
Q

A typical eukaryotic human cell has a cell cycle of _____hours .

A

24

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5
Q

Cell cycle of yeast lasts for about -

A

90 minutes

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6
Q

The 2 basic phases of cell cycle -

A

Interphase

M Phase /Mitosis

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7
Q

In the average life cycle of 24 hours , cell division proper lasts for only about -

A

1 hour

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8
Q

The ______ lasts for more than 95% of the duration of the cell cycle .

A

Interphase

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9
Q

M phase of cell cycle starts with the _______division called ____ .

A

Nuclear

Karyokinesis

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10
Q

Division of cytoplasm called ______ occurs after karyokinesis .

A

Cytokinesis

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11
Q

During interphase , the cell is undergoing both ______ and _____ in an orderly manner .

A

Cell growth

DNA replication

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12
Q

Interphase is divided into -

A

3 sub phases -
G1
S
G2

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13
Q

______ phase corresponds to the interval between mitosis and DNA replication .

A

G1

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14
Q

During G1 phase , the cell is ________and _______ but DOES NOT REPLICATE ITS DNA .

A

METABOLICALLY ACTIVE

CONTINUOUSLY GROWS

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15
Q

S phase marks the period during which _______ takes place .

A

DNA synthesis or replication

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16
Q

During S phase , the amount of ______ per cell doubles .

A

DNA

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17
Q

During S phase , there is no increase in _______ .

A

Chromosome number .

At G1 , if the cell had 2n chromosomes , then after S phase , the number will still be 2n .

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18
Q

In animal cells , during the S phase , DNA replication begins in the _______ and the _______ duplicates in the cytoplasm .

A

Nucleus

Centriole

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19
Q

During G2 phase , _____ are synthesised in preparation for mitosis while ________ continues .

A

Proteins

Cell growth

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20
Q

Some cells in animals do not appear to exhibit division . Example-

A

Heart cells

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21
Q

The cells that do not divide further ______ G1 phase to enter an INACTIVE stage called QUIESCENT STAGE (G0).

A

Exit

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22
Q

G0 stage is achieved when cells exit ______.

A

G1

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23
Q

Cells in this stage remain metabolically active but no longer proliferate unless called on to do so .

A

Quiescent stage

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24
Q

In ______ , mitotic division is only seen in diploid somatic cells . Against this , ________ can show mitosis in both HAPLOID and DIPLOID cells .

A

Animals

Plants

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25
Q

Exception of a animal where mitosis is seen in haploid cells .

A

Male honey bees

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26
Q

This is the most dramatic period of the cell cycle , involving a major reorganisation of virtually all components of the cell .

A

M phase - mitosis

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27
Q

Since the number of ________ in the parent and the progeny is same , mitosis is also called _________.

A

equational division

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28
Q

Mitosis has beeen divided into 4 stages of ______ division .

A

Nuclear -karyokinesis

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29
Q

Prophase of mitosis follows ___ phases of interphase .

A

S and G2

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30
Q

In ______phases the new DNA molecules formed are not distinct but intertwined .

A

S and G2

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31
Q

Prophase is marked by the initiation of _______ .

A

Condensation of chromosomal materials

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32
Q

The centrosome which had undergone duplication in the ______ phase , begins to move towards opposite poles in prophase .

A

S phase

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33
Q

Completion of prophase is marked by -

Late prophase

A

Chromosomal material condenses to form chromosomes
Chromosomes are composed of 2 chromatids joined at the centromere .
Centrosomes move to opposite poles .
2 asters along with spindle fibres form mitotic apparatus .

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34
Q

During late prophase , each _______ radiates out MICROTUBULES called ASTERS .

A

Centrosome

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35
Q

Mitotic apparatus consists of -

A

2 asters together with spindle fibres

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36
Q

Disappearance of organelles occurs during late/early prophase .

A

Late

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37
Q

Difference between early and late prophase .state different events .

A

Early - initiation of chromosome condensation ; centrosome moves to opposite poles
Late- compact chromosomes formed wth sister chromatids joined at centromere ; centrosome radiates out asters ; organelles disappear ( including nucleolus and nuclear envelope )

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38
Q

Nucleolus and nuclear envelope disappears during -

A

Late prophase ( end )

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39
Q

______ marks the start of 2nd phase of mitosis - metaphase .

A

Complete disintegration of nuclear envelope

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40
Q

In _____ phase , chromosomes are spread throughout the cytoplasm of the cell .

A

Metaphase

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41
Q

By this stage , condensation of chromosomes is completed and they can be observed clearly under the microscope .

A

Metaphase

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42
Q

Metaphase is the best stage to study the _______ of chromosomes .

A

Morphology

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43
Q

_______ chromosome is made up of 2 sister chromatids joined at the centromere .

A

Metaphase

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44
Q

Small disc shaped structures on the surface of centromeres are called _____ ans they can be seen in ________ phase .

A

KINETOCHORES

Metaphase - for attachment of spindle

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45
Q

KINETOCHORES are formed by __________ during ________ phase

A

Spindle fibres

Metaphase

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46
Q

______ serve as sites of attachment of spindle fibres .

A

KINETOCHORES

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47
Q

_______ phase is characterised by on chromatids of each chromosome connected by its kinetochore to spindle fibres from one pole and its sister chromatid connected by its kinetochore to spindle fibres from opposite pole .

A

Metaphase

Arranged at equator

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48
Q

The plane of allignment of the chromosomes at metaphase is referred to as ______ .

A

Metaphase plate

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49
Q

Features of metaphase -

A

Spindle fibres attach to KINETOCHORES of chromosomes .

Chromosomes aligned at the equator

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50
Q

During anaphase , daughter chromatids are referred to as __________.

A

Daughter chromosomes of the future nuclei

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51
Q

What happens in early anaphase ?

A

Each chromosome is split simultaneously and the 2 daughter chromatids migrate towards opposite poles .

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52
Q

As each chromosome moves away from the equatorial plate , the _______ of each chromosome remains directed towards the POLE and hence at the LEADING EDGE , with the _______ of the chromosome trailing behind .

A

Centromere

Arms

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53
Q

Chromatids move to opposite poles during late/early anaphase .

A

Late

Early - chromatids separate

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54
Q

At the beginning of telophase , _______ that have reached opposite poles DECONDENSE and ___________ .

A

Chromosomes

Lose their individuality

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55
Q

Decondensation of chromosomes occurs in early /late telophase .

A

Early

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56
Q

In early telophase , individual chromosomes can no longer be seen and a set of ________ tends to collect at each pole

A

Chromatin material

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57
Q

Nucleolus , Golgi complex and ER reform in -

A

Late telophase

58
Q

Segregation of duplicated chromosomes into daughter nuclei is called -

A

Karyokinesis

59
Q

In an animal cell ,cytokinesis is achieved by the appearance of a ________ in the ________ .

A

Furrow

Plasma membrane

60
Q

Formation of a furrow in animal cell is from ______ to _______ .
Inside/outside

A

Outside to inside

Centripetal

61
Q

In plant cells , wall formation starts in the _______ of the cell and grows ______ to meet the existing lateral walls .

A

Centre
Outward
( centrifugal )

62
Q

Formation of a new ________ begins with the formation of a simple precursor called the CELL PLATE in plant cells .

A

Cell wall

63
Q

The cell plate ( precursor of cell wall ) in plat cells represents ______ between the walls of the two adjacent cells .

A

Middle lamella

64
Q

At the time of CYTOPLASMIC DIVISION , organelles like ______ and ______ get distributed between the 2 daughter cells .

A

Mitochondria

Plastid

65
Q

In some organelles ______ is not followed by _______ , as a result of MULTINUCLEATE condition arises .

A

Karyokinesis

Cytokinesis

66
Q

The multinucleate condition leads to the formation of ________.

A

Syncytium

Liquid endosperm in coconut

67
Q

Mitosis is usually restricted to the ______ cells only .

A

Diploid

68
Q

In some ____ and some social ______ haploid cells also divide by mitosis .

A

Lower plants

Social insects

69
Q

The growth of ________ organisms is due to mitosis .

A

Multicellular

70
Q

Cell growth results in disturbing the ratio between _____ and ______.

A

Nucleus

Cytoplasm

71
Q

It becomes essential for the cell to divide and restore the ______ ratio , when it is disturbed due to cell GROWTH .

A

Nucleo-cytoplasmic ratio

72
Q

Meiosis insures the production of _____ phase in the life cycle of sexually reproducing organisms .

A

Haploid

73
Q

________ restores DIPLOID phase in the life cycle of sexually reproducing organisms .

A

Fertilisation

74
Q

We come across meiosis during _______ in plants and animals .

A

Gametogenesis

75
Q

Meiosis involves 2 sequential cycles of ____ and _______ but only a single cycle of _________.

A

Nuclear division
Cell division
DNA replication

76
Q

DNA replication occurs how many times in meiosis ?

A

1

77
Q

Meiosis 1 is initiated after the parental chromosomes have replicated to produce identical sister chromatids at the _______ phase .

A

S

78
Q

Meiosis involves pairing of ______ chromosomes .

A

Homologous

79
Q

Meiosis involves RECOMBINATION between _______.

A

Non-sister chromatids of homologous chromosomes

80
Q

4 haploid cells are formed at the end of ______.

A

Meiosis 2

81
Q

Meiosis I is initiated at the ______ phase .

A

S

When sister chromatids are formed from chromosomes

82
Q

Prophase of ______ is typically LONGER and MORE COMPLEX as compared to prophase of ______ .

A

Meiosis 1

Mitosis

83
Q

Prophase 1 of meiosis 1 is subdivided into 5 phases based on -

A

Chromosomal behaviour

84
Q

5 subdivisions of prophase 1 :

A
Leptotene
Zygotene
Pachytene
Diplotene
Diakinesis
85
Q

Prophase of the first meiotic division is typically _______ and ________ when compared to prophase of MITOSIS .

A

Longer

More complex

86
Q

During ___ stage , chromosomes become gradually visible under a light microscope .

A

Leptotene

87
Q

The compaction of chromosomes continues through _______.

stage of prophase 1

A

Leptotene

88
Q

What happens during the first phase of prophase 1 ?

A

Leptotene - compaction of chromosomes continues

89
Q

Leptotene is followed by -

A

Zygotene

90
Q

During ______ , chromosomes starts pairing together . ( stage of prophase 1 )

A

Zygotene

91
Q

Pairing of chromosomes is called ______ and occurs during _____ .

A

Synapsis

Zygotene

92
Q

Such paired chromosomes as seen during ZYGOTENE after synapsis are called ________ .

A

Homologous chromosomes

93
Q

ELECTRON MICROGRAPHS of this stage indicate that synapsis is accompanied by the formation of complex structure called SYNAPTONEMAL COMPLEX .

A

Zygotene

94
Q

The complex formed by a pair of SYNAPSED HOMOLOGOUS CHROMOSOMES is called a _______ or _____ .

A

Bivalent

Tetrad

95
Q

Bivalent or tetrad formed in zygotene are clearly visible during which stage ?

A

Pachytene - visible

Zygotene - formed

96
Q

The ______ stages of prophase 1 are relatively shorter as compared to PACHYTENE .

A

1st two - leptotene and zygotene

97
Q

Homologous chromosomes are formed during _______ (stage of prophase 1)

A

Zygotene

Synapsis -> homologous chromosomes ->synaptonemal complex -> bivalent /tetrad

98
Q

During this stage pf prophase 1 , 4 CHROMATIDS of each bivalent chromosomes become distinct and clearly appear as TETRAD ( bivalent )

A

Pachytene

99
Q

Pachytene phase is characterised by the appearance of __________ .

A

Recombination nodules

100
Q

What are recombination nodules and and when do they appear ?

A

Sites at which crossing over occurs between non-sister chromatids of homologous chromosomes .
They appear during pachytene

101
Q

– – – – –Is the exchange of genetic material between two homologous chromosomes .

A

Crossing over

102
Q

Crossing over is also an – – – – – mediated process and The enzyme involved is called – – – – – .

A

Enzyme -mediated

Recombinase

103
Q

________ leads to recombination of genetic material on the 2 chromosomes .

A

Crossing over .

104
Q

_______ is an enzyme-mediated process .

A

Crossing over - recombination

105
Q

________ is completed at the end of PACHYTENE .

A

Recombination between HOMOLOGOUS chromosomes

106
Q

Recombination occurs during _______ , leaving the chromosomes linked at the sites of CROSSING OVER .

A

Pachytene

107
Q

The beginning of ________ is recognised by the DISSSOLUTION of SYNAPTONEMAL complex .( stage of prophase 1)

A

Diplotene

108
Q

_______ is recognised by the tendency of the RECOMBINED homologous chromosomes of the BIVALENTS to separate from each other except at the sites of cross overs .

A

Diplotene

109
Q

X -shaped structures called CHIASMATA are formed during -

A

Diplotene

110
Q

Longest stage of prophase 1 -

A

Diplotene - can last for months or years in oocytes of some vertebrates

111
Q

Which stage of prophase 1 can last for months or years in the OOCYTES OF SOME VERTEBRATES ?

A

Diplotene

112
Q

The final stage of meiotic prophase 1 is -

A

Diakinesis

113
Q

________is marked by terminalisation of chiasmata

A

Diakinesis

114
Q

Diplotene is characterised by ______ and diakinesis is recognise by ______.

A

Dissolution of synaptonemal complex

Terminalisationof chiasmata

115
Q

During this phase of prophase 1 , chromosomes are fully condensed and the meiotic spindle is assembled to prepare the homologous chromosomes for separation .

A

Diakinesis

116
Q

During diakinesis , _______ is assembled to. Prepare the homologous chromosomes for separation .

A

MEIOTIC spindle

117
Q

What happens at the end of diakinesis ?

A

Nucleolus disappears and nuclear envelope also breaks down

118
Q

_______ stage of prophase 1 represents transition to metaphase 1.

A

Diakinesis

119
Q

During which phase of meiotic prophase 1 , homologous chromosomes are prepared for separation ?

A

Diakinesis

120
Q

The ______ chromosomes align on the equatorial plate during metaphase 1 of meiosis 1 .

A

Bivalent

121
Q

During metaphase 1 MICROTUBULES from the opposite poles of the spindle attach to the KINETOCHORE of ________.

A

Homologous chromosomes

122
Q

During metaphase 2 of meiosis 2 , MICROTUBULES from the opposite poles of the spindle get attached to the KINETOCHORE of _________.

A

Sister chromatids

123
Q

During _______ of meiosis , HOMOLOGOUS CHROMOSOMES separate , while sister chromatids remain associated at their centromeres .

A

Anaphase 1

124
Q

Dyad of cells appears in ______ stage .

A

Telophase 1 of meiosis 1

125
Q

Tetrad of cells appear in _______.

A

Telophase 2 of meiosis 2

126
Q

During telophase 1 , _________ and ________reappear and ________ follows .

A

Nuclear membrane
Nuceolus
Cytokinesis

127
Q

During telophase 1 , nucleolus and nuclear membrane reappears , cytokinesis follows and this is called as ________ .

A

Dyad of cells

128
Q

The stage between 2 meiotic divisions is called _______.

A

Interkinesis

129
Q

Interkinesis is generally _____ lived .

A

Short

Interphase - long

130
Q

There is replication of DNA during interkinesis . T/F

A

F . No replication of DNA during interkinesis as against that of interphase

131
Q

Interkinesis is followed by -

A

Prophase 2

132
Q

Which is simpler - prophase 1 or 2 of meiosis .?

A

2

133
Q

Meiosis 2 is initiated immediately after -

A

Cytokinesis , usually before chromosomes have fully elongated .

134
Q

meiosis 1/ 2 resembles a normal mitosis .

A

2

135
Q

What happens by the end of prophase 2 ?

A

Nuclear membrane disappears

Chromosomes again become compact

136
Q

Pairing = - ———- And it occurs in which phase ?

A

Synapsis

Zygotene

137
Q

Definition of synapsis and crossing over ?

A

Synapsis - formation of homologous chromosomes . Zygotene

Crossing over - exchange of genetic material between 2 homologous chromosomes. Pachytene

138
Q

Crossing over = - ——- and it occurs in ?

A

Recombination

Pachytene

139
Q

Non -sister chromatids are involved in -

Homologous chromosomes are involved in -

A

Recombination -crossing over

Synapsis - pairing

140
Q

Bouquet stage occurs in which stage of prophase 1 ?

A

Leptotene

141
Q

Part of plant suitable for the study of meiosis -

A

Anther

142
Q

In meiosis , how many cycles of chromosomal division occurs ?

A

1