Cell cycle and cell division Flashcards
1
Q
The two major characteristics of living cells are
A
Growth and reproduction
2
Q
The three important events of a cell cycle are
A
Cell division, DNA replication and cell growth
3
Q
The sequence of events by which a cell duplicates a genome, synthesises the other constituents of cell and eventually divides into two daughter cells is termed as
A
Cell cycle
4
Q
A cell cycle of a typical eukaryotic cell which is illustrated by human cells in culture is completed in
A
24 hours
5
Q
A yeast cell can complete one cell cycle is about
A
90 minutes
6
Q
A cell cycle is divided into two basic phases, namely
A
Interphase and M phase(Mitosis phase)
7
Q
The phase of cell cycle when actual cell division occurs is?
A
M phase (Mitosis phase)
8
Q
The phase between two successive M phases is represented by
A
Interphase
9
Q
The % duration of interphase during the cell cycle is
A
more than 95%
10
Q
The % duration of M phase during the cell cycle is
A
Less than 5%
11
Q
M phase starts with the process of
A
nuclear division
12
Q
M phase ends with the process of
A
cytokinesis
13
Q
The process of separation of daughter chromosomes is called
A
Karyokinesis
14
Q
The process of division of cytoplasm is termed as
A
Cytokinesis
15
Q
Interphase is also known as
A
resting phase
16
Q
During interphase, cell prepares itself for division by undergoing both processes, namely ____ and ____
A
cell growth and DNA replicaton
17
Q
The phase during which cell prepares for division is
A
interphase
18
Q
Interphase is divided into 3 phases, namely
A
G1 phase, S phase and G2 phase
19
Q
The phase which acts as an interval between mitosis and initiation of DNA replication is
A
G1 phase
20
Q
The phase in which cell is metabolically active and continuously grows but does not replicate its DNA is
A
G1 phase
21
Q
The phase of cell cycle during which DNA replication takes place
A
Synthesis phase
22
Q
During S phase, the amount of DNA per cell
A
doubles
23
Q
If the chromosome number is 2n, then by the end of S phase, it will be
A
2n
24
Q
If the initial amount of DNA is 2C, then by the end of S phase, it will be
A
4C
25
In animal cells, during S phase, DNA replication begins in ___
nucleus
26
Duplication of centriole during S phase occurs in ___
Cytoplasm
27
Proteins for preparation of M phase are synthesised during ____
G2 phase
28
The cells of adult animals which do not undergo division are
heart cells
29
The cells which do not divide further exit G1 phase to enter into an inactive stage are called
Quiescent stage (G0)
30
The phase of cell cycle in which cells remain metabolically active but donot poliferate unless called upon is
Quiescent stage (G0)
31
The metabolic stage of cells during G0 phase is
Active
32
In animals, mitotic cell division is only seen in
diploid somatic cells
33
In which organisms, haploid cells divide by mitosis?
male honey bees
34
Reorganisation of virtually all components of the cell occurs during which phase?
M phase
35
The phase of cell cycle which is called as an equational division is
M phase
36
The four stages of karyokinesis are namely
Prophase, metaphase, anaphase and telophase
37
The first stage of karyokinesis occuring after G2 phase is
Prophase
38
The stage of mitosis marked by the initiation of condensation of chromosomal materials is
Prophase
39
During prophase, the structure which begins to move towards opposite poles of the cell is
Centrosome
40
Centrosome duplicates during ____ of interphase
S phase
41
During prophase, chromosomal material condenses to form compact mitotic ____
chromosomes
42
Chromosomes are composed of two chromatids attached together at
Centromere
43
Asters radiating out of centrosome are structurally
microtubules
44
Each centrosome radiates out microtubules called
asters
45
Mitotic apparatus is formed by spindle fibres and
2 asters
46
The component which along with asters form mitotic apparatus is
spindle fibres
47
The complete disintegration of nuclear envelope marks the start of which phase of mitosis?
metaphase
48
_____ of chromosomes is completed by the beginning of metaphase
Condensation
49
Metaphase is the stage to study ____ completely
Morphology of chromosomes
50
Chromosomes are clearly visible under microscope by which stage of mitosis?
metaphase
51
Metaphase of chromosomes is composed of
two sister chromatids
52
Two sister chromatids are held together by
Centromere
53
Small disc shaped structures at the surface of centromere are called
Kinetochores
54
The structures that serve as the site for attachment of spindle fibres are
kinetochores
55
During metaphase, chromosomes are seen to lie at
equator
56
Chromatids are connected via kinetochores to their respective _____
spindle fibres
57
The plane of alignment of chromosomes at metaphase is referred as
metaphase plate
58
Spindle fibres getting attached to kinetochores of chromosomes is the characteristic feature of which phase?
metaphase
59
The phase of mitosis characterised by splitting of daughter chromatids in order to migrate towards two opposite poles is
anaphase
60
In anaphase, what migrate towards two opposite poles from equatorial plate?
Daughter chromatids
61
During which phase centromeres split and chromatids separate?
anaphase
62
The final stage of karyokinesis is
telophase
63
The chromosomes that have reached their respective poles decondense during which phase of mitosis?
telophase
64
Identity of chromosomes is lost as a discrete elements during which mitotic phase?
telophase
65
______, _______ and _____ are reformed during telophase
Nucleolus, golgi complex and ER
66
During telophase, _____ develops around chromosome clusters at each pole forming two daughter nuclei
Nuclear envelope
67
After karyokinesis, cell division gets completed by the process of
cytokinesis
68
Cytokinesis is achieved by the appearance of a furrow in the plasma membrane of _____ cells
animals
69
Wall formation starts in the centre of the cell and grows outward to meet the existing lateral walls in ___ cells
plant
70
The precursor for formation of new cell wall in plant cells is
Cell-plate
71
The middle lamella between the walls of adjacent plant cells is represented by
cell - plate
72
The cell organelles which get distributed between two daughter cells during cytokinesis are
mitochondria and plastids
73
Karyokinesis, when not followed by cytokinesis leads to the formation of
syncytium
74
Liquid endosperm in coconut is an example of
syncytium
75
The type of cell division which generally results in the production of diploid cells is
mitosis
76
Mitosis usually results in production of _____ with identical genetic compliment
diploid daughter cells
77
The growth of multicellular organisms is due to
mitosis
78
Cell division is necessary to restore the ____ ratio
nuclear-cytoplasmic
79
Cells are repaired by which cell division?
mitosis
80
Continuous growth of plants is due to meristematic tissues by the process _____
mitoss
81
The cell division that reduces the chromosome number by half in production of haploid in production of haploid daughter cells is
meiosis
82
The type of cell division which endures the production of haploid phase in life cycle of sexually reproducing organisms is
meiosis
83
The formation of haploid gametes in both plants and animals occur by
meiosis
84
Meiosis involves ____ cycles of nuclear and cell division
two sequential
85
Meiosis involves pairing of which chromosomes?
homologous chromosomes
86
Two type of cell cycle which involves recombination between non sister chromatids of homologous chromosomes is
meiosis
87
At the end of meiosis II ____ cells are formed
four haploid
88
The 5 sub phases of prophase I are
leptotene, zygotene, pachytene, diplotene and diakinesis
89
The stage of meiosis during which compaction of chromosomes occur is
leptotene
90
The process of pairing of chromosomes is called
synapsis
91
Synapsis occurs during which phase of meiosis I?
zygotene
92
The paired chromosomes are called
homologous chromosomes
93
Chromosome synapsis is accompained by the formation of complex structure called
synaptonemal complex
94
The complex formed by a pair of synapsed homologous chromosomes is called
bivalent or tetrad
95
The two short lived stages of prophase Iare ____ and ____
leptotene and zygotene
96
The phase of prophase I during which four chromatids of each bivalent chromosome become distinct and clearly appear as tetrads is _____
pachytene
97
The stage characterised by the appearance of recombination nodules is
pachytene
98
The sites at which crossing over occurs between non sister chromatids of the homologous chromosomes are called
recombination nodules
99
The process of the exchange of genetic material between two homologous chromosomes is called
crossing over
100
The process of crossing over occurs during stage of meiosis?
pachytene
101
The beginning of which stage is characterised by the dissolution of the synaptonemal complex?
Diplotene
102
The homologous chromosomes of bivalent tend to separate from each other except at the site of _____
crossovers
103
The X-shaped structure formed after crossing over is called
chiasmata
104
Diplotene can last for months or years in _____ of some vertebrates
Oocytes
105
The final stage of prophase I is
Diakinesis
106
The stage of prophase marked by terminalisation of chiasmata is
Diakinesis
107
By the end of diakinesis, nucleolus and nuclear envelope ____
disappears
108
During which phase, the chromosomes are fully condensed and the meiotic spindle is assembled to prepare the homologous chromosomes for separation?
diakinesis
109
The bivalent chromosomes align on equatorial plate during which phase of meiosis I?
Metaphase I
110
The structure which attaches spindle fibres from opposite poles of kinetochore of homologous chromosomes
microtubules
111
Homologous chromosomes separate while ____ remain associated during anaphase I
Sister chromatids
112
Dyad of cells is formed by the end of which stage of meiosis I?
telophase I
113
The stage between two meiotic divisions is called
Interkinesis
114
The stage of meiosis which is short lived and where no replication of DNA occurs is
Interkinesis
115
By the end of prophase II, ____membrane diappears
Nuclear
116
Meiosis II resembles ____
normal mitosis
117
During metaphase II, chromosomes align at the equator and the microtubules from opposite poles of the spindle get attached to the kinetochores of ___
Sister chromatids
118
The structure that holds sister chromatids together is
Centromere
119
The process of meiosis ends with which phase?
telophase II
120
After telophase II, cytokinesis results in the formation of
four daughter haploid cells/ tetrad
121
The significance of meiosis is that it conserves ____ of species
chromosome number
122
The process of meiosis results in reduction of chromosome number by
half
123
The process of cell division which increases the genetic variability in the population of organisms from one generation to next is
meiosis
