DAT bio chapter 5 Cell Division Flashcards
1
Q
Genome
A
- all the DNA in a cell.
2
Q
Chromosome
A
composed of a single DNA molecule. Multiple chromosomes up the entire genome.
3
Q
Homologous chromosome pairs
A
Two different copies of the same chromosome. one copy is give by the mother and the other copy given by the father
4
Q
Sister chromatids
A
identical copies of a replicated chromosome. joined together at the centromere to form a dyad
5
Q
Dyads -
A
replicated chromosomes containing
two sister chromatids that look like an “X”.
6
Q
Centromeres -
A
- regions of DNA that connect
sister chromatids in a dyad.
7
Q
Kinetochores -
A
proteins on the sides of
centromeres that help microtubules pull sister
chromatids apart during cell division.
8
Q
Karyokinesis
A
division of the nucleus.
9
Q
Cytokinesis
A
physical division of the
cytoplasm and cell membrane.
10
Q
Parent cell
A
one parent cell produces two
daughter cells after division.
11
Q
Ploidy
A
describes the number of chromosome
sets found in the body. Humans are diploid
because they contain two sets of
chromosomes (46 chromosomes, 23 pairs),
one from each parent. However, they also
have haploid cells (gametes) that only contain
one chromosome set (23 chromosomes).
12
Q
Sex chromosomes
A
- one pair in the human
body; they determine sex.
13
Q
Autosomes -
A
- 22 pairs in the human body; they
are nonsex chromosomes.
14
Q
Gametes -
A
haploid cells (sperm and eggs).
15
Q
Germ cells
A
diploid cells that divide by meiosis
to produce gametes.
16
Q
Gametocyte
A
- eukaryotic germ cells that can
either divide to form more gametocytes or
produce gametes.
17
Q
Somatic cells
A
- all body cells excluding the
gametes. Diploid in humans.
18
Q
Cell cycle is divided into what two phases?
A
interphase (G1 , G0 , S,
and G2 ) and the M phase.
19
Q
what percent of the cell cycle happens in during interphase?
A
90%
20
Q
Where does karyokinesis and cytokinesis occur.
A
M phase
21
Q
DAT Mnemonic for the cell cycle:
A
Go = Gap Phase 1 (G1 ) of interphase Sam = Synthesis Phase (S) of interphase Go = Gap Phase 2 (G2 ) of interphase Make = Mitosis of the M phase Cake = Cytokinesis of the M phase
22
Q
Steps for interphase (Gap phase 1 (G1 )
A
cell grows in preparation
for cell division. Also checks for favorable
conditions. If favorable, cell will enter S phase.
If unfavorable, cell will enter G0 phase.
23
Q
What is G0 phase
A
- cells still carry out their
functions but halt in the cell cycle. Cells
that do not divide are stuck here.
24
Q
Steps for interphase (Synthesis phase (S))
A
Centrosome is duplicated
DNA is replicated. Each chromosome replicates to form two sister chromatids held at a centromere
25
Steps for interphase (Gap phase 2 (G2)
cell continues to grow and
prepare for cell division by checking DNA for
any errors after replication. Also checks for
mitosis promoting factor (MPF), which needs
to be present in adequate amounts for cell
cycle continuation. Organelles are replicated
here.
26
What is microtubule organizing centers? where are they present?
Present in eukaryotic cells. they organize extension
of microtubules, which are made of the protein
tubulin. MTOCs are responsible for forming the
spindle apparatus, which guides chromosomes
during karyokinesis.
27
Centrosomes
organelles found in animal cells
that contain a pair of centrioles. They act as
microtubule organizing centers (MTOCs).
28
3 microtubules in the spindle apparatus
Kinetochore microtubules
Astral microtubules
Polar microtubules
29
Kinetochore microtubules
extend from
centrosomes and attach to kinetochores on
chromosomes.
30
Astral microtubules
extend from
centrosomes to the cell membrane to orient
the spindle apparatus.
31
Polar microtubules
extend from the two
centrosomes and connect with each other.
They push centrosomes to opposite ends of
the cell.
32
Centrioles
hollow cylinders made of nine
| triplets of microtubules (9x3 array).
33
Centrosomes location
located near the nucleus and contain a pair of
centrioles oriented at 90 degree angles to one
another (attached to each other by
interconnecting fibers). They replicate during the
S phase of the cell cycle so that each daughter cell
after cell division has one centrosome.
34
what material surrounds the
centrioles and is responsible for microtubule
nucleation (anchoring tubulin to start microtubule
extension).
pericentriolar material
35
What is microtubule nucleation>
(anchoring tubulin to start microtubule
| extension).
36
Cilia and flagella
nine doublets of
microtubules with two singles in the center (9+2
array).
37
Where are cilia and flagella produced>
basal body, which
is initially formed by the mother centriole (older
centriole after S phase replication) attaching itself
to the cell membrane.
38
M phase
stage in the cell cycle where
| karyokinesis and cytokinesis occur.
39
Type of karyokinesis (nuclear division)
Mitosis
40
What happens in mitosis
that involves
a diploid parent cell dividing into two diploid
daughter cells.
41
phase 1 of mitosis
| prophase
chromatin condenses into
chromosomes (X-shaped dyads). The
nucleolus and nuclear envelope disappear.
Spindle apparatus forms.
42
phase 2 of mitosis
| metaphase
- the spindle apparatus guides
the chromosomes to the metaphase plate
(midpoint of cell) in a single file.
43
phase 3 of mitosis
| Anaphase
kinetochore microtubules
shorten to pull sister chromatids apart. Now,
the sister chromatids are considered separate
chromosomes. Chromosome number
doubles.
44
phase 4 of mitosis
| telophase
chromosomes have segregated
and nuclear membranes reform. In addition,
nucleoli reappear and chromosomes
decondense into chromatin.
45
What is the physical separation of the
cytoplasm and cell membrane into two daughter
cells.
Cytokinesis
46
In animal cells, cytokinesis begins in late______ with the formation of a _____
anaphase
| cleavage furrow.
47
What is cleavage furrow?
contractile ring of actin
microfilaments and myosin motors that pinches the
cell into two.
48
In plant cells, cytokinesis begins in_____ with the formation of a ______
telophase
| cell plate
49
What is the cell plate made out of?
created by vesicles from the Golgi apparatus and
ends up producing the middle lamella (cements
plant cells together).
50
How does cell cycle influence cell division
through
limitations to growth and regulation to prevent
cancerous growth.
51
2 types of functional limitations
Surface to volume ratio (S/V)
| Genome to volume ratio (G/V) -
52
Surface to volume ratio (S/V)
cell division
occurs when volume is too large because cells
rely on the surface area of their cell
membrane for transport of material. Decrease
in S/V ratio leads to cell division.
53
Genome to volume ratio (G/V)
cell division
occurs when the volume of the cell is too large
to be supported by the limited size of the
genome. Decrease in G/V ratio leads to cell
division.
54
Cell specific regulations:
Cell specific checkpoints -
- -Cyclin-dependent kinases (CDKs) -
- -Growth factors
- -Density dependent inhibition
- -Anchorage dependence
55
Cell specific checkpoints - G1 restriction
| point
(checks for favorable conditions to grow,
enters G0 phase if unfavorable), end of G2
(checks accuracy of DNA replication and MPF
levels), and M checkpoint (during metaphase,
checks for chromosomal attachment to spindle
fibers).
56
Cyclin-dependent kinases (CDKs) -
phosphorylate certain substrates to signal cell
cycle progression. Activated by cyclin, a
protein that cycles through stages of synthesis
and degradation.
57
Growth factors -
- bind to receptors in the
| plasma membrane to signal for cell division.
58
Density dependent inhibition
- halting of cell
| division when density of cells is high.
59
Anchorage dependence
- cells divide only
| when attached to an external surface.
60
Goal of mitosis
increase the number of cells in
| an organism,
61
Goal of binary fission and who uses it?
is used by
archaea, bacteria, and certain organelles to
reproduce.
62
What happens during binary fusion?
organisms will replicate
their genome while cell division is happening (no S
phase for DNA replication). Also, there is no spindle
apparatus.
63
Meiosis produces what?
produces four haploid daughter cells from
| one diploid parent cell.
64
How does meiosis produce four haploid daughter cells from
| one diploid parent cell.
It does this by repeating the
| steps of karyokinesis twice.
65
Meiosis can be divided into two parts
meiosis I (homologous chromosomes
separate)
meiosis II (sister chromatids
separate).
66
Meiosis 1 (reductional division)
produces two
haploid daughter cells through separation of
homologous chromosomes.
67
Meiosis 1
| prophase 1
```
chromatin condenses into
chromosomes (X-shaped dyads). The
nucleolus and nuclear envelope will
disappear. Homologous chromosomes pair
up and crossing over occurs.
```
68
Meiosis 1
(prophase 1)
Synapsis
the pairing up of homologous
chromosomes to form tetrads (aka
bivalents).
69
Meiosis 1
(prophase 1)
Synaptonemal complex
protein
structure that forms between
homologous chromosomes during
synapsis.
70
Meiosis 1
(prophase 1)
Tetrads (bivalents)
pair of two
homologous chromosomes each with
two sister chromatids.
71
Meiosis 1
(prophase 1)
Chiasmata
where two
chromosomes of a homologous pair
cross over during synapsis, causing
genetic recombination.
72
Meiosis 1
(prophase 1)
Genetic recombination
exchange
of DNA between chromosomes to
produce genetically diverse offspring.
73
Meiosis 1
| Metaphase I
tetrads randomly line up
double-file on the metaphase plate; this
contributes to genetic diversity.
74
Meiosis 1
| Anaphase I
```
kinetochore microtubules
shorten to separate homologous
chromosomes from each other. Will not
begin unless at least one chiasmata has
formed within each tetrad.
```
75
Meiosis 1
| Telophase and Cytokinesis I
```
- after
tetrads have been pulled to opposite
poles, nuclear membranes reform. In
addition, nucleoli reappear and
chromosomes decondense into
chromatin. A Cleavage furrow forms in
animal cells and a cell plate forms in
plant cells.
```
76
Meiosis II
very similar to mitosis because sister
chromatids are separated. Two haploid cells divide
into four haploid daughter cells.
77
Meiosis II
| Prophase II
chromatin condenses into
chromosomes (X-shaped dyads). The nucleolus
and nuclear envelope will disappear. Spindle
apparatus forms. No crossing over occurs.
78
Meiosis II
| Metaphase II
chromosomes line up
single-file at the metaphase plate just like in
mitosis.
79
Meiosis II
| Anaphase II
- kinetochore microtubules
shorten to pull sister chromatids apart. Sister
chromatids become separate chromosomes
and chromosome number doubles.
80
Meiosis II
| Telophase and Cytokinesis II
```
- nuclear
membranes reform, nucleoli reappear, and
chromosomes decondense into chromatin.
Four haploid daughter cells are produced in
total.
```
81
Mitosis
| number of chromosomes and chromatids
During the S phase of the cell cycle, a human’s 46
chromosomes are duplicated. Afterwards, there
are still 46 chromosomes but also 92 chromatids.
They line up in metaphase individually as shown
below:
82
During anaphase of mitosis, sister chromatids
| split. How many chromosomes and chromatids are produced?
of mitosis, sister chromatids
split. This produces 92 separate chromosomes,
which are also counted as 92 chromatids. Each
separated cell will have 46 chromosomes (46
chromatids). These cells are diploid.
83
For meiosis I, number of chromosomes and chromatids
a human goes through the same
DNA replication in S phase as mitosis that results
in 46 chromosomes and 92 chromatids.
However, during metaphase the chromosomes
double up as shown below:
84
During anaphase of meiosis I, homologous
chromosomes split up.
How many chromosomes and chromatids are produced?
This results in the same
total numbers - 46 chromosomes and 92
chromatids. Each cell will have 23 chromosomes
and 46 chromatids.
85
Meiosis II is very similar to mitosis, how?
involves
chromosomes lining up individually in metaphase.
During anaphase, sister chromatids are
separated, resulting in 23 chromosomes (23
chromatids) in each daughter cell. These cells are
haploid.
86
Where is the genome and DNA located in the cell?
nucleus
87
What is a genome in simple term
sum total of an organism DNA
88
How to get DNA from old cell to new cell?
Mitosis!
89
HOw many chromosomes are found in each nuclues of human cells?
46 chromosomes
90
Duplication of DNA happens before mitosis T/F
True. in interphase
