Ch 2 - Chromosomes & Cellular Reproduction Flashcards
1
Q
____ cells are compartmentalized by intracellular membranes.
A
Eukaryotic
2
Q
_______ are unicellular; _____ are unicellular or multicellular.
A
Prokaryotes; eukaryotes
3
Q
_____ are true bacteria; _____ are ancient bacteria.
A
Eubacteria; archaea
4
Q
T or F: archaea are more closely related to eubacteria than to eukaryotic organisms.
A
False; they aren’t more closely related to either.
5
Q
Eukaryotes are distinguished from prokaryotes in that _______ (RNA synthesis) is physically separated from ______ (protein synthesis).
A
Transcription; translation
6
Q
In ______ organisms, transcription and translation occur in the same compartment.
A
prokaryotes
7
Q
The difference in transcription and translation for prokaryotes and eukaryotes affects how genes are regulated, meaning that _________ dictates ________.
A
Structure dictates function.
8
Q
50% of the protein in DNA is a special class of proteins called _________ which facilitate packing huge amounts of DNA into small spaces.
A
Histones
9
Q
______ is made of DNA and proteins (about 50/50).
A
Chromatin
10
Q
During ________, DNA is wrapped around a core of 8 _____ proteins to form a nucleosome.
A
Interphase; histone
11
Q
A _____ is a basic repeating unit of chromatin consisting of a core of 8 histone proteins and ~146 bp of DNA that wraps around the core just under 2x.
A
nucleosome
12
Q
Bacteria usually have _______ chromosome(s) that is ______ in shape/form.
A
one; circular
13
Q
Eukaryotes have multiple _______ that each have a single DNA molecule that is _______ in shape/form.
A
chromosomes; linear
14
Q
T or F: viruses are a living cell.
A
False; they are a cellular parasite.
15
Q
Viral genes are most closely related to their cellular ______.
A
cellular hosts
16
Q
Viruses have either _____ or _____, but not both; and their genetic material is either ______-stranded or _______- stranded.
A
DNA or RNA; single- or double-stranded.
17
Q
Typical error rate of DNA replication is?
A
~10^-9, or about 1 error per billion nucleotides
18
Q
The 3 critical steps to cell replication are _____ replication of DNA; completed copies of the genome must be ________ to different regions of the cell; and the cell must divide.
A
faithful (accurate); separated
19
Q
Human cells contain ~_____B nucleotides
A
4B
20
Q
DNA synthesis in prokaryotes is ~____ to ____ bp/min in prokaryotes usually results in < 1 error per ______ Mbp.
A
600 - 700 bp (nucleotides); per 3M base pairs
21
Q
DNA replication in prokaryotes is __-_______ with specific _____ of replication.
A
bi-directional; origins of replication
22
Q
_____ are circular, self- replicating DNA molecules (much smaller than the genome) found in prokaryotes that are completely autonomous and can be lost without consequence to the organism.
A
Plasmids
23
Q
Many plasmids carry genes for _______ ______ which is especially consequential in human medicine.
A
antibiotic resistance.
24
Q
Plasmids can be _____ between different species of prokaryotes.
A
transferred
25
F-factor in E. coli is a plasmid that is required for _______ (genetic exchange) between organisms.
conjugation
26
DNA is distributed along multiple _____ in eukaryotic organisms.
chromosomes
27
Chromosomes are separated from the cytoplasm by a _____ _____.
Nuclear envelope
28
The nucleus has an extensive protein network crisscrossing all around called the nuclear _______.
Matrix.
29
T or F: the complexity of an organism can be predicted by the number of chromosomes.
False
30
Cells with two sets of chromosomes are ______, aka _____ cells.
diploid; somatic
31
_____ cells are cells that are designed to be gametes and have ____ member of each homologous pair.
germline; one
32
A karyotype is typically made from a cell in ______; this is when the chromosomes are most ________.
Metaphase; condensed
33
In humans, 3 pairs of chromosome 21 yields?
Down syndrome
34
Nearly ______ chromosomes form a _________ pair.
identical; homologous
35
Variants of the same genetic locus due to different DNA sequences are said to be _____.
Alleles
36
During most of the cell cycle, the chromosomes are diffuse state known as ________.
chromatin
37
Name the 3 essential elements of chromosomal anatomy.
Centromere, telomere, and origin of replication
38
The _____ is the DNA sequence that specifies where the kinetochore forms, and there is exactly _____ per chromosome.
centromere; one
39
The ______ serves as the attachment site for spindle microtubules (forms over the centromere).
kinetochore
40
The ____ _______ are responsible for pulling chromosomes to the edges of the cell during division.
spindle microtubules
41
What happens when a chromosome lacks a centromere?
The chromosome cannot take part in cell division and is lost.
42
Homologous chromosomes joined at the centromere are called _____ _____.
Sister chromatids.
43
Centromere positions: ____ is centrally located; _____ is slightly skewed from center; _____ is close to the end; and _____ is terminally located.
metacentric; submetacentric; acrocentric; and telocentric
44
T or F: centromere position is absolute.
False - it is relative and different people may disagree whether it is acrocentric or submetacentric
45
______ are special structures on the ends of chromosomes required for chromosomal stability.
Telomeres
46
_____ shorten over time and may play a role in controlling cell division, and / or possibly aging, and cancer.
Telomeres
47
As cells age, telomeres begin to shorten due to reduced ______.
Telomerase
48
Once telomerase is all gone and telomeres have shrunk to nothing, the cells initiate _______, or programmed death.
apoptosis
49
It's common in cancer to find that ____ have been reactivated due to increased ____ activity.
telomeres; telomerase
50
Following DNA replication, each sister chromatid contains a single ______ molecule.
DNA
51
The process that passes an exact copy of the genetic information from a parent to two daughter cells is _____.
mitosis
52
The two major phases of mitosis are _____ and ______.
interphase and mitotic (M) phase
53
Interphase begins with _____ where cell growth and synthesis of proteins needed for cellular devision are made.
G1
54
T or F: interphase lasts for several minutes
False: several hours
55
______ are regulated key transition points during mitosis that allow or prohibit cellular division to proceed to the next stage.
Checkpoints.
56
Interphase is divided into what 3 stages?
G1 (gap 1); S (DNA synthesis); and G2 (gap 2)
57
T or F: after passing G1/S checkpoint, cells may go on to S phase or G0.
False: once the G1/S checkpoint has passed, the cell is committed.
58
T or F: Cells in G0 are unstable
False
59
T or F: cells in G0 are recycled and resubmitted to G1
False; they can remain in G0 indefinitely, cycle round and round through G1/G0, or just chill in G0.
60
In S phase, _____ synthesis must take place before the cell can proceed.
DNA
61
After S phase, each chromosome is composed of ____ _____ ______.
2 sister chromatids
62
In S phase, un-replicated or damaged DNA can inhibit the activation of certain _______ that are necessary for mitosis to take place.
proteins
63
After the ____/_____ checkpoint has passed, the cell is ready to divide and enters ____ phase.
G2/M checkpoint; M phase
64
Cells undergoing mitosis spend ___ hours in G1, ___ hours in S, and ____ in G2.
10; 9; 4
65
T or F: throughout interphase, chromosomes are in a relaxed and uncoiled state.
False: they are relaxed, but they are not uncoiled.
66
Sister chromatids separate and the cell divides under _____ phase.
M (mitotic)
67
M phase is divided into 6 stages (from the end of interphase): Peter Pan Masturbates And Tinkerbell Cums.
Prophase, prometaphase, metaphase, anaphase, telophase, cytokinesis
68
A cell in G2 has twice the _____ molecules, but the same number of _______ as the parent cell.
DNA; chromosomes
69
In prophase, a group of proteins called ______ bind to DNA and bring about condensation of chromatin.
Condensins
70
In prophase, the ____ ____ (an organized array of microtubules) forms.
mitotic spindle
71
In animal cells, the mitotic spindle grows from a pair of _________ (during prophase) that migrate to opposite sides of the cell. Within each centrosome is an organelle called a _______ which is also composed of microtubules.
centrosomes; centriole
72
Some plant cells don't have ______ or ______, but they do have mitotic spindles.
centrosomes or centrioles.
73
During ______ of M phase, chromosome structure becomes visible using light microscopy.
prophase.
74
Using FISH visualization techniques, ____ filaments appear orange while _____ appears blue.
actin; DNA
75
In a diploid cell that has undergone S phase, what is the ratio of chromosomes to chromatids?
There are twice as many chromatids as there are chromosomes (bound at the centromere.
76
______ ______ is the process by which prokaryotic cells divide.
binary fission
77
During _______ in mitosis, the nuclear envelope/membrane ______, and spindle microtubules enter the _______.
prometaphase; disintegrates; nuclear region
78
Disintegration of the nuclear envelope/membrane marks the beginning of _________.
prometaphase.
79
By the end of _______ in mitosis, the microtubules anchor each sister chromatid one of two centrosomes. The cell will then go on to ________.
prometaphase; metaphase
80
During _______, chromosomes align in a single line called the ________ plate.
metaphase; metaphase
81
During metaphase, the _____-______ checkpoint confirms that each chromosome is attached to a spindle fiber, and that the spindle fibers of each sister chromatid are attached to opposite poles of the cell.
spindle-assembly
82
During metaphase, chromosomes align such that the metaphase plate runs through the _______ of each chromosome which is aligned vertically/horizontally along each plate?
middle; vertically.
83
During ________, tension at the ________ is required before the big "pull" in order to pass the spindle-assembly checkpoint.
metaphase; kinetochore
84
What would happen if sister chromatids are not properly attached to microtubules at the spindle-assembly checkpoint?
A cell could end up with an abnormal number of chromosomes.
85
After the spindle-assembly checkpoint has passed, the connection between sister chromatids (known as the _______) begins to break down - this marks the end of _______ and the separation of sister chromatids marks the beginning of ________.
centromere; metaphase; anaphase
86
During ________, chromosomes begin to move towards opposite spindle poles. The movement is due to the disassembly of _____ molecules at both the + end ( the ______ end) and the -- end (the ______ _____ end) via special proteins called molecular ______.
anaphase; tubulin; kinetochore; spindle pole; motors.
87
During metaphase, there are ____ chromosomes, during anaphase, there are _____ chromosomes.
4; 8
88
Arrival of chromosomes at the spindle poles marks the beginning of ________.
telophase
89
During _______, the nuclear envelop re-forms around both sets of chromosomes, and the chromosomes relax.
telophase.
90
During telophase, chromosomes are no longer _______ under a light microscope. Why?
visible; because they're no longer condensed (relaxed, diffuse state).
91
The end of ______ is marked by the division of cytoplasm, and the process is known as _____ - the final stage in mitosis. However, in some cells, ______ is simultaneous with ________.
telophase; cytokinesis. cytokinesis; telophase.
92
The professor states that a diploid cell undergoing mitosis becomes _______ during S phase, but returns to diploid after _______.
tetraploid (4n); cytokinesis
93
T or F: mitosis yields 2 genetically identical cells, including mitochondrial DNA (and chloroplasts for plants).
False: DNA is the same, but mitochondrial/chloroplastic DNA is different.
94
The cellular process of _______ reshuffles parental genes amongst progeny.
meiosis
95
Mitosis has ____ nuclear division, meiosis has ____.
One; two.
96
As in mitosis, DNA replication occurs in ______ in meiosis.
S phase
97
Meiosis 1 begins with ________, including all of the same stages as mitosis: ___, _____, and _____.
interphase; G1, S, G2
98
____ _____ is often called reduction division because the number of chromosomes is reduced by half; _____ _____ is called equational division because the number of chromosomes have already been halved.
Meiosis I; meiosis II
99
In the beginning of prophase I during meiosis 1, the chromosomes ______ and become visible.
condense
100
In mid-prophase I of meiosis 1, homologous chromosomes form a close pairing association known as ______; and the two pairs of sister chromatids (four chromatids altogether) are called a ______ or a ______.
synapsis; bivalent or tetrad (bi refers to two pairs; tetra refers 4 individuals)
101
Meiosis II is functionally equivalent to _____.
mitosis.
102
During late __ 1 of Meiosis 1, homologous chromosomes align nucleotide by nucleotide.
prophase
103
Crossing over (aka ________ ________) takes place in ______ ____ during late ______ ____; and the location where chromosomes cross is called ______. Independent assortment (aka random distribution) takes place in ____ ___ during ______ after their random alignment in metaphase 1.
genetic recombination; meiosis 1; prophase 1; chiasma (pl. chiasmata). meiosis 1; anaphase 1.
104
Metaphase 1 (meiosis) vs. metaphase (mitosis): in meiosis, homologs line up ____-____-____ along the metaphase _______, and the centromere is/is not split; whereas with mitosis, homologs line up ____ each other with the centromere of sister chromatids _______ by the metaphase plate.
side-by-side; plate; is not split; below; split
105
Anaphase 1 (meiosis) vs anaphase (mitosis): in anaphase 1 of meiosis, the _______ _______ separate and move towards opposite poles; in anaphase of mitosis, the _______ ________ separate and move towards opposite poles.
homologous chromosomes; sister chromatids
106
T or F: the centromere splits in anaphase 1.
False: anaphase 1 takes place in meiosis 1, and the homologous pairs (maternal and paternal) separate after crossing over, not the sister chromatids.
107
_______ 1 follows anaphase 1, and in this phase, _____ chromosomes arrive at the ______ poles and cytoplasm divides.
telophase 1; homologous; spindle
108
Meiosis 2 is functionally ______ to mitosis in that ______ _______ divide at the _______.
equivalent; sister chromatids; centromere
109
Recombinant vs non-recombinant?
Recombinant = crossing over (in prophase 1); non-recombinant = no crossing over / clone of parental.
110
Are any of the daughter cells genetically identical if there is no crossing over?
Yes - 50/50 identical to each other.
111
What caused genetic variation in Mendel's experiments? At what point does this phenomenon occur?
Random assortment of chromosomes. At the end of meiosis 1, specifically at anaphase 1 (after the chromosomes randomly aligned in metaphase 1). NOTE: the sister chromatids are still attached, but the homologous pairs are randomly distributed.
112
At the end of meiosis 1, there are ____ daughter cells; at the end of meiosis 2, there are ______ daughter cells.
2; 4
113
The consequence of meiosis vs. mitosis is that at the end of meiosis there are genetically ______ haploid daughter cells; and at the end of mitosis there are genetically ______ haploid daughter cells.
distinct; identical
114
Genetic diversity in meiosis comes from what two mechanisms?
Crossing over (aka genetic recombination) and independent assortment (random distribution) of chromosomes.
115
The number of possible chromosomal combinations in gametes is equal to (without genetic redistribution)? What would it be in humans? (give the answer in exponent form).
2^n where n = the number of homologous pairs. In humans, 2^23
116
List the major/upper level stages of meiosis 1 and 2 (Px3, M, A T C)(PMATC)
Middle through late prophase (3 stages), metaphase 1, anaphase 1, telophase 1, cytokinesis 1. Prophase 2, metaphase 2, anaphase 2, cytokinesis 2.
117
During prophase 1, chromosomes ______, homologs synapse, ______ over takes place, the ___ membrane breaks down, and the mitotic _____ forms.
condense; crossing over; nuclear; spindle
118
During metaphase 1, homologues line along the ______ _____ in a ______ order.
metaphase plate; random
119
During anaphase 1, homologous pairs ______ in a random fashion (but ___ ____ remain attached) and move toward opposite poles.
separate; sister chromatids
120
During prophase 2, chromosomes _____, the mitotic ____ forms, and the _____ _____ disintegrates.
condense; spindle; nuclear membrane
121
during metaphase 2, individual ______ line up along the _____ _____ with the ________ down the middle.
chromosomes; metaphase plate; centromeres
122
During anaphase 2, _____ _____ separate.
sister chromatids
123
During telophase 2, chromatids arrive at the ______ ______, the ___ breaks down, and the ____ ____ reforms.
spindle poles; spindle; nuclear membrane.
124
Explain what is meant by reduction division (in meiosis 1). Include why this can be confusing.
The parent cell starts as a diploid cell, but the first pair of daughter cells become haploid after anaphase. This is confusing because after DNA synthesis in S phase, there's more DNA molecules/chromatids, but they are still sister chromatids and not separate - it's the separation of the homologs that counts as the 'reduction'.
125
_____ is a protein that holds sister chromatids together (not to be confused with the DNA sequence where the kinetochore forms).
Cohesin
126
A homologous pair of chromosomes means that one chromosome is ______, the other is _______.
Maternal, paternal.
127
Bottom line, meiosis gives rise to ______ cells that are _______ variable and that fuse during ______ to produce diploid progeny.
haploid; genetically; fertilization
128
T or F: Plasmids replicate independent of the genome.
True
129
A diploid cell with 3 pairs of homologous chromosomes will have ____ discrete chromosomes in a germline cell (e.g. egg or sperm) after completing meiosis.
3
