Cell Division (Handout) Flashcards
1
Q
process by which cells
reproduce themselves
A
cell division
2
Q
Cell division enables multicellular
organism
A
to grow and develop
to replace worn out or damaged tissues
3
Q
cell division consists of two activities:
A
karyokinesis
cytokinesis
4
Q
nuclear
division
A
karyokinesis
5
Q
cytoplasmic
division
A
cytokinesis
6
Q
- two kinds of nuclear cell division:
A
mitosis
meiosis
7
Q
a cycle that a cell
undergoes that the cell undergoes
that a time it is formed until it
prepares itself for cell division
A
cell cycle
8
Q
molecules synthesized in G1
A
RNA
proteins
9
Q
- 3 types of RNA molecules:
A
rRNA
tRNA
mRNA
10
Q
how many hydrogen bonds
between adenine and thymine
A
2 bonds
11
Q
how many hydrogen bonds
between cytosine and guanine
A
3 hydrogen bonds
12
Q
most critical stage of the
cell cycle
A
s stage
13
Q
arranged to be
spindle fibers
A
microtubules
14
Q
binding sites for
spindle fibers
A
kinetochore
15
Q
a protein structure that connects chromosomes to spindle microtubules during cell division.
A
kinetochore
16
Q
come
from centrioles attach to kinetochore
A
kinetochore microtubule
17
Q
grow
outward but do not attach to
kinetochore
A
non kinetochore microtubule
18
Q
radiate outward,
important in the stability of the
location of centrioles
A
aster microtubule
19
Q
– cells divide how many times
in mitosis
A
once
20
Q
cells divide how many times
in meiosis
A
twice
21
Q
meiosis I is also
called this
A
reduction division
22
Q
– meiosis II is
called this
A
equatorial division
23
Q
homologous
chromosomes (1-22nd pairs)
A
autosomes
24
Q
– determines the sex of the
child
A
father
25
can detect a person’s
genetic defect
karyotyping
26
also known as down
syndrome
trisomy 21
27
spermatogenesis/oogenesis
gatemogenesis
28
main organ of the male
reproductive system
testes
29
immature cells (2n)
in sperms
spermatogonia
30
spermatogonia undergo
what to become a primary
spermatocyte
mitosis
31
after undergoing
mitosis has the complete set of
chromosomes
spermatocyte
32
after undergoing
mitosis has the complete set of
chromosomes
secondary spermatocyte
33
the primary spermatocyte
undergoes this to become the
secondary spermatocyte
meiosis I
34
the secondary
spermatocyte undergoes this to
become the early spermatid
meiosis II
35
– number of chromosomes of
a early spermatid
haploid
36
early spermatid
undergoes this to become a late
spermatid
maturation
37
the late spermatid
undergoes maturation to become
this
spermatozoa
38
spermatogenesis ratio
1:2:4
* 1 primary spermatocyte > 2
secondary spermatocyte > 4
spermatozoa
39
primary reproductive
organ of females
ovaries
40
prior to birth, the
female gametes are these
oogonium (2n)
41
during
childhood, the ovary of a female child
has this
primary oocyte
42
– each month the primary
oocyte undergoes this to become a
secondary oocyte
meiosis I
43
this is the stage
where the egg is released
secondary oocyte
44
contains half the
number of chromosomes (n)
first polar body
45
when the egg meets
the sperm, the secondary oocyte
undergoes meiosis II when this
happen
fertilization
46
when the secondary oocyte is
fertilized by a sperm this forms
ootid
47
as a result of
meiosis II in oogenesis, this can form
second polar bodies
48
ratio in oogenesis
1:2:4
49
ratio of viability in oogenesis
1:1:1
50
production of sperm
occurs when
every day
51
production of egg cells
occurs when
monthly
52
study oogenesis labels
+1
53
a series of activities through which a cell passes from the time it is formed until it
reproduces
cell cycle
54
* last for about 90% of the cell cycle
cell cycle
55
§ referred to as the “resting stage” of the cell
interphase
56
it is during this stage that the replication of DNA, centrosomes, and
centrioles occurs and the RNA and protein needed to produce
structures required for doubling all cellular components are
manufactured
interphase
57
§ three distinct periods of interphase:
G1
G2
S
58
during which cells are
engaged in growth, metabolism, and the production of
substances required for DNA synthesis and cell division
G1 (growth period)
59
highly changeable ranging from non-existent in
rapidly dividing cells to days, weeks, or years;
however, it usually takes 8-10 hour
G1
60
cells that are intended to never divide again are
permanently arrested in this phase
g1 phase
61
most nerve cells are in this state because after about
6 months of development they become permanent
cells of the central nervous system
g1 phase
62
is the period of interphase during
which chromosomes are replicated (Figure 6.2)
s period
63
ü during DNA ___ , its double helical structure
partially unwinds and the two strands separate at the
points where hydrogen bonds join base pairs.
replication
64
ü during DNA replication, its double helical structure
partially unwinds and the two strands separate at the
points where ___ ____ join base pairs.
hydrogen bond
65
each exposed base then picks up a
complementary base
66
S phase takes about __ hours
6-8
67
once a cell goes through the S-phase, it is committed
to enter
cell division
68
– the mitochondria divide and the cell continues to
grow in preparation for cell division
what phase
g2 period
69
since the _-phases are stages when there are no
events related to chromosomal replication, they are
thought of as gaps or interruptions in DNA synthesis
G
70
karyokinesis (mitosis) is divided into
prophase
metaphase
anaphase
telophase
71
s finalizes cell division
cytokinesis
72
the time required for ___differs with the kind of cell, its location
and other factors such as temperature
mitosis
73
mitosis and takes cytokinesis about
1-2 hours
74
* somatic “body” cell division
mitosis
75
a parent cell divides once to produce two identical cells called
daughter
76
the process ensures that each daughter cell has the same number and kind of
chromosomes as the original parent cell (diploid)
mitosis
77
study mitosis phase page 4
+1
78
this kind of cell division allows growth of multicellular organisms, asexual
reproduction, and wound healing
mitosis
79
the chromatin condenses and shortens into chromosomes
prohpase
80
since DNA replication takes place during interphase, each prophase
chromosome contains a pair of identical double-stranded DNA
molecules called
chromatids
81
§ each chromatid pair is held together by a small spherical body called
a __that is required for the proper segregation of
chromosome
centromere
82
attached to the outside of each centromere is a protein complex
known as
kinetochore
83
the nucleoli disappear, and RNA synthesis also stops, and the nuclear
envelope breaks down and is absorbed in the cytosol
prophase
84
a centrosome and its centrioles each move to opposite poles of the
cell and as they do so the centrioles start to form th
mitotic spindle
85
as the mitotic spindle continues to develop, three types of
microtubules form:
non kinetochore microtubule
kinetochore microtubule
aster microtubule
86
grow from centrosomes,
extend inward, but do not bind to kinetochores
non kinetochore microtubule
87
grow from centrosomes, extend
inward, and attach to kinetochores
kinetochore microtubule
88
grow out of centrosomes but radiate
outward from the mitotic spindles
aster microtubule
89
is the attachment site for chromosomes and also distributes
chromosomes to opposite poles of the cell
spindl
90
by late prophase the chromosomes move towards th
equator of the cell
91
the period when maximum condensation of chromosomes is very
evident
metaphase
92
the centromeres of the chromatid pairs line up at the exact center of
the mitotic spindle; this midpoint region is called the
metaphase plate
equatorial plain region
93
§ characterized by the splitting and separation of centromeres and the
movement of the two sister chromatids of each pair towards the
opposite poles of the cell
anaphase
94
the sister chromatids are referred to as
daughter chromosomes
95
the movement of the chromosomes is due to the shortening of
___microtubules and elongation of the ___
microtubule
kinetochore
nonkinetochore
96
§ begins as soon as chromosomal movement stops
telophase
97
§ opposite of prophas
telophase
98
the identical sets of chromosomes at the opposite poles of the cell
uncoil and revert to their threadlike ___form.
chromatin
99
____ microtubules disappear, and ___
microtubules elongate even mor
kinetochore
nonkinetochore
100
§ a new nuclear envelope reforms around each chromatin mass
telophase
101
new nucleoli reappear in the daughter nuclei and mitotic spindle
breaks up
telophase
102
* division of the parent cell’s cytoplasm and organelles
cytokinesis
103
occurs during the telophase stage with formation of the ___ ___(a slight
indentation of the plasma membrane extends around the center of the cell)
cleavage furrow
104
the ___ gradually deepens until opposite surfaces of the cell make contact and the
cell is split in two
cleavage furrow
105
when cytokinesis is complete, ___ begins
interphase
106
* the result of cytokinesis is ___ separated daughter cells, each with separate portions
of cytoplasm and organelles and its own set of identical chromosomes
two
107
* reproductive “gamete” cell division
meiosis
108
* a parent cell divides twice producing four haploid nuclei
meiosis
109
can exchange genetic material before being
separated, therefore the daughter cells are genetically different from the parent cell
(and from each other)
homologous chromosomes
110
* the mechanism by which gametes (sex cells) are produced, this is the basis of sexual
reproduction
meiosis
111
without ___, the number of chromosomes of asexually reproducing species
would be doubled in each generation
meiosis
112
two successive divisions of meiosis
meiosis I and II
113
also called Reduction Division since the number of chromosomes in a cell is
halved (2n → n)
meiosis I
114
preceded by interphase apparently identical as that of mitosis, DNA and
organelles are duplicated and stored ATP is used
meiosis I
115
stage of meiosis I
prophase I
metaphase I
anaphase I
telophase I
116
prophase I is further divided into the following substages:
leptonema
zygonema
pachynema
diplonema
diakinesis
117
“thin threads”
leptonema/leptotene
118
ü chromosomes appear like “beads-on-a-string”
leptonema
119
initiation of homology search
leptonema
120
“yoked threads”
zygonema
121
condensation continues in meiosis I
zygonema
122
“rough pairing” – initial alignment of homologous
chromosome
what stage of meiosis I
zygonema
123
formation of bivalents (# of bivalents = n)
zygonema
124
= “thick threads”
pachynema
125
homologous chromosomes are already distinguished
under the microscope
pachynema
126
– intimate pairing of homologous
chromosomes
synapsis (pachynema)
127
ü four sister chromatids are evident and form a tetrad
pachynema
128
study meiosis I label (page 8)
+1
129
e = ‘double threads”
diplonema
130
one or more areas of
the non-sister chromatids remain in contact; sites of
crossing over (genetic exchange between maternal
and paternal chromosomes)
chiasmata
131
= “moving apart”
diakinesis
132
chromosome separation proceeds but as this
happens, the chiasmata move towards the end of
each tetrad
what phase
diakinesis
133
what process where chromosome separation proceeds but as this
happens, the chiasmata move towards the end of
each tetrad (
diakinesis
134
ü disintegration of nucleolus and nuclear membrane
what phase in meiosis I
diakinesis
135
ü centromeres of each tetrad attach to mitotic spindle
what phase in meiosis I
diakinesis
136
maximum condensation of chromosomes is attained
Ø terminal chiasmata of each tetrad are visible and appear to be
the only factor holding the non-sister chromatids together
metaphase I
137
Ø movement of homologous chromosomes to metaphase plate
metaphase I
138
Ø tetrads separate and dyads move towards opposite poles
anaphase I
139
Ø new nuclear membrane reforms
Ø nucleus enters into a short interphase
Ø some cells proceed directly to Meiosis II
telophase I
140
o also called Equatorial Division since the haploid cells produced by meiosis I
divide producing 4 haploid cells that are genetically different from one
another
equatorial division
141
very similar to mitosis in that it results in the separation of sister chromatids
meiosis II
142
each dyad is made up of two sister chromatids joined
together by a common centromere
prohpase II
143
Ø alignment of centromeres at metaphase plate in meiosis II
metaphase II
144
study mitosis and meiosis figure page 10
+1
145
Ø splitting of centromeres and movement of monads towards
opposite poles of the cell
anaphase II
146
monads reach opposite poles
telophase II
147
Ø nucleolus and nuclear membrane reform
Ø chromosomes uncoil and become inconspicuous; cytokinesis
occurs
telophase II
148
no. of daughter cells formed per cycle (mitosis vs meiosis)
two
four
