1
Q
Most cells in an organism are in this phase
A
G0 phase (quiescent)
2
Q
Cells that are not going through the cell cycle
A
Quiescent cells
3
Q
Phases of cell division (short) (4)
A
- G1 phase
- S phase (synthesis)
- G2 phase
- M phase (mitosis)
4
Q
Series of events in which an organism’s cells grow and divide to form two genetically identical diploid daughter cells
A
The cell cycle
5
Q
Three major phases of the cell cycle and what happens
A
- Interphase: make everything and prep to divide
- M phase (mitosis): organization and separation of material
- Cytokinesis: actual division
6
Q
G0 (non-dividing cells) can enter and leave the cell cycle based on ___ and ___
A
Environmental signals, cues
7
Q
How often cells divide is usually a function of how often they are ___ or exposed to ___ conditions
A
Used, damaging
8
Q
Do all cells go through the cell cycle?
A
No
9
Q
How long do the cell cycle, interphase, and mitosis phase take
A
Total: ~24hrs
Interphase: 23/24hrs
Mitosis phase: 1/24hrs
10
Q
Developing organisms require production of new cells that each possess a complete ___ in order to grow
A
Genome
11
Q
Organismal Growth occurs when cell production is ___ than cell death
A
Greater
12
Q
Adult, multicellular organisms utilize the cell cycle in order to replace ___ or ___ somatic cells
A
Damaged, dying
13
Q
Somatic cells
A
Body cells
14
Q
Steps of interphase (3)
A
- G1 (growth 1)
- Synthesis (DNA)
- G2 (growth 2)
15
Q
G1 cycle steps (2)
A
- Cell grows
- More VIP molecules (nucleotides, enzymes, etc) and structures are produced
16
Q
S (synthesis) cycle steps
A
DNA is replicated
17
Q
G2 cycle steps (2)
A
- Cell finishes growing
- More VIP molecules and structures are produced in preparation for division
18
Q
Steps of mitosis (4)
A
- Prophase
- Metaphase
- Anaphase
- Telophase
19
Q
Prophase steps (3)
A
- Nucleus dissolves
- DNA condenses, chromosomes are visible
- Spindle fibers form
20
Q
Metaphase steps (2)
A
- Spindle fibers attach to chromosomes
- Chromosomes line up on the equatorial plate
21
Q
Equatorial plate
A
Middle of the cell
22
Q
Anaphase steps
A
Spindle fibers contract to move one set of chromosomes to opposite poles of the cell
23
Q
Telophase steps (3)
A
- Nucleus reforms
- DNA decondenses
- Cell membrane starts pinching in
24
Q
Cytokinesis steps (2)
A
- Cytoplasm divides
- Cell membrane pinches in to form 2 genetically identical daughter cells
25
Differential coexpression of these proteins control cell progression through the cell cycle
Cyclins and Cyclin Dependent Kinases (CDKs)
26
1. ___ signals the cell to produce checkpoint-specific ___ proteins
Growth factor, cyclin
27
2. Cyclin proteins produced via protein synthesis build up in the ___
Cell
28
3. At high enough concentrations, cyclin binds to its specific ___
CDK
29
4. CDK initiates a ___ cascade that allows the cell to pass the ___ and continue the cell cycle
Phosphorylation, checkpoint
30
5. Phase specific cyclin is broken down to prevent ___
Improper signalling
31
Cycle of cyclins (5)
1. Growth factor signals the cell to produce checkpoint-specific cyclin proteins
2. Cyclin proteins produced via protein synthesis build up in the cell.
3. At high enough concentrations, cyclin binds to its specific Cyclin Dependent Kinase (CDK)
4. CDK initiates a phosphorylation cascade that allows the cell to pass the checkpoint and continue the cell cycle
5. Phase specific cyclin is broken down to prevent improper signaling
32
How many checkpoints must cells pass through to progress with the cell cycle
3
33
Cell cycle checkpoints (3)
1. G1 checkpoint
2. G2 checkpoint
3. M checkpoint
34
What cells check for at each checkpoint (3)
1. Damage
2. Mutations
3. Proper internal conditions
35
What happens to damaged/mutated cells
They enter cell cycle arrest
36
The cell produces inhibitors of cyclin proteins to prevent progression through the cell cycle
Cell cycle arrest
37
What normally happens to repairable damaged/mutated cells
The damaged DNA is repaired and continues through the cell cycle
38
What normally happens to unrepairable damaged/mutated cells
The cell goes through programmed cell death and is eliminated
39
Uncontrolled cell growth leading to tumors
Cancer
40
Cancer cells have an accumulation of ___ in genes that prevent damaged cells from continuing through the cell cycle.
These mutations prevent programmed ___ and allow the cancer cell to grow and divide unlimitedly
Mutations, cell death
41
Programmed cell death
Apoptosis
42
WHere does the M-spindle checkpoint occur in mitosis
Metaphase
43
A protein complex assembled on the centromeric region of DNA that provides the major attachment point for the spindle microtubules during division to pull the chromosomes apart. These are required to be connected in order for the cell to pass the M-spindle checkpoint
Kinetochore
44
Possible problems that can cause uncontrolled cell growth (2)
1. Molecules that promote cell division (promoters) are expressed more than usual
2. Molecules that hinder cell division are repressed or tagged for destruction
45
Potential sources of faulty cyclin checkpoints (3)
1. Viral infections
2. UV damage/radiation
3. Genetic defects
46
Aggressive virus known to cause checkpoint errors and thus cancer
HPV
47
An abnormal number of chromosomes
Aneuploidy
48
Centromere locations (3)
1. Metacentric
2. Submetacentric
3. Acrocentric
49
Centromere in the center of the chromosome
Metacentric
50
Centromere at the end of the chromosome
Acrocentric
51
Centromere in between the center and end of the chromosome
Submetacentric
52
Errors that occur when part of a chromosome is missing or in the wrong location
Structural errors
53
Structural errors (4)
1. Inversions
2. Deletions
3. translocations
4. Duplications
54
When a section of a chromosome breaks off and reattaches upside down
Inversion
55
When a section of a chromosome is completely absent
Deletion
56
When a section of the chromosome is repeated
Duplication
57
When a section of a chromosome breaks off and attaches to another chromosome
Translocation
58
3 main phases of the cell cycle
1. Interphase
2. Mitosis
3. Cytokinesis
59
Mitosis is the division of the ___ and ___ into two daughter cells
Nucleus, DNA
60
Cytokinesis is the division of the ___ and ___ into two daughter cells
Cytoplasm, organelles
61
Can mitosis and cytokinesis happen simultaneously?
Yes
62
Cytokinesis in plant cells (3)
1. The Golgi buds off vesicles that move toward the cell equator
2. The vesicles fuse together to create the cell plate, which extends until it reaches and fuses with the sides of the parent cell, thereby completely separating the two new daughter cells
3. Both daughter cells then release cellulose by exocytosis into the space between the two membranes. The cellulose builds the cell wall of each daughter cell
63
What fuses together to form the cell plate
Vesicles
64
In plant cytokinesis, what do daughter cells release into the space between the two membranes to build the cell wall, and what process do they use to do this
Released: cellulose. How: exocytosis
65
Cytokinesis in animal cells (2)
1. Contractile proteins called actin and myosin form rings at the equator of the cell. These proteins contract pulled the cell membrane inwards to form a cleavage furrow
2. The cell membrane cleavage furrow pinches in until the cells splits into two daughter cells
66
Contractile proteins that form the contractile ring (2)
1. Actin
2. Myosin
67
Dips in the cell membrane that deepen to separate the cell into two daughter cells
Cleavage furrow
68
When a eukaryotic cell divides, each daughter cell must receive all of the essential cell components, including the ___
Organelles
69
Organelles that are disassembled by the dividing cell and then distributed and reformed during cytokinesis (3)
1. Nucleus
2. Endoplasmic reticulum
3. Golgi apparatus
70
Organelles that undergo their own division to repopulate the new daughter cells (2)
1. Mitochondria
2. Chloroplasts
71
An asymmetric division mechanism used by most yeasts to reproduce asexually. The nucleus divides by mitosis, then during cytokinesis the daughter cell receives only a small portion of the cytoplasm. The daughter cell initially remains attached to the parent cell before the cells are separated and the daughter cell matures into a new cell. Used by most yeasts
Budding
72
The production of an egg (ovum) cell. The cytoplasm is divided unevenly during cytokinesis to produce one large egg cell and three small polar bodies. The single egg contains the cytoplasm of all four daughter cells. The large volume of cytoplasm in the egg cell is used to provide all the organelles and stored energy to sustain the developing embryo
Oogenesis
73
After replication, the two genetically identical strands of DNA are each called a ___
Sister chromatid
74
Ways that sister chromatids are held together (2)
1. Centromere
2. Cohesin
75
Function of the centromere (2)
1. Adheres sister chromatids to each other
2. Site of kinetochore and microtubule attachment for chromosome movement
76
A protein complex that holds sister chromatids together so they remain connected until anaphase
Cohesin
77
When is cohesin established
Interphase
78
When is cohesin removed
Start of anaphase
79
Eukaryote cell DNA wraps around ___ proteins to form a ___
Histone, nucleosome
80
Nucleosomes coil and stack together to form fibers called ___
Chromatin
81
Chromatin condenses during mitosis and meiosis to form ___
Chromosomes
82
Because it needs to be accessible to enzymes, most of the DNA is in ___ form during interphase
Chromatin
83
Chromatin DNA is accessible by ___
RNA Polymerases
84
The DNA condenses by ___ so that it can more easily be moved to the poles of the cell without getting ___ and/or ___
Supercoiling, tangled, broken
85
Microtubules, long polymers of a protein called ___, are components of the cell's ___
Tubulin, cytoskeleton
86
What links the chromatids to the microtubules
Kinetochores
87
Chromosome analogy, rope, harness, person, waist
Rope: microtubules
Harness: kinetochore
Person: Chromosome
Waist: centromere
88
These proteins of kinetochores drive their movement along the microtubules to the poles of the cell
Motor proteins
89
Type of motor protein
Kinesin
90
Replicated chromatin vs. replicated chromosome
Replicated chromatin: two loosely coiled sister chromatids w/ a centromere.
Replicated chromosome: two supercoiled sister chromatids w/ a centromere
91
Form & phase: DNA double helix is wrapped around histones to form a chain of nucleosomes
Unreplicated chromatin, interphase G1
92
Form & phase: DNA has been replicated in S phase and has two sister chromatids in chromatin form
Replicated chromatin, interphase G2
93
Form & phase: DNA has condensed by supercoiling in prophase and has two sister chromatids in chromosome form
Replicated chromosome, metaphase
94
Form & phase: sister chromatids have separated and now each is a single supercoiled chromosome
Unreplicated chromosome, anaphase
95
Why do organisms reproduce
To pass their genes to the next generation
96
2 major reproductive strategies
1. Asexual reproduction
2. Sexual reproduction
97
Reproduction that does not require the production and fusion of gametes. Organisms go through a mitosis-like process to form two genetically identical offspring
Asexual preproduction
98
Pros (3) and cons (2) of asexual reproduction
Pros:
1. Offspring auto adapted to their environment
2. No mate required
3. Very fast way to reproduce
Cons:
1. Fast reproduction can lead to overpopulation and limited resources
2. No genetic diversity
99
Reproduction that requires meiosis and mitosis.
Parent organisms copulate, gametes undergo fertilization and form a single celled zygote which goes through growth and differentiation
Sexual reproduction
100
Pros (2) and cons (3) of sexual reproduction
Pros:
1. Allows for genetic diversity
2. Babies are “cute”
Cons:
1. Requires energy and time
2. Offspring are not auto adapted to their environment
3. Finding a mate can be difficult
101
Process by which sexually reproducing organisms produce genetically diverse haploid gametes
Meiosis
102
Haploid Sex Cell (Ex: Sperm and Egg)
Gamete
103
Cell with half the normal number of chromosomes. 23 in humans
Haploid
104
Fancy term for a diploid body cell (Ex: Heart cell, skin cell, lung cell, etc.)
Somatic cell
105
Cell with a full set of chromosomes. 46 in humans
Diploid
106
Cromosomes that possess the same structure and genes
Homologous chromosome
107
Process in which homologous chromosomes flop over each other and exchange genes
Crossing over
108
Steps of meiosis 1 (6)
1. Interphase
2. Prophase 1
3. Metaphase 1
4. Anaphase 1
5. Telophase 1
6. Cytokinesis 1
109
Steps of meiosis 2 (6)
1. Interkinesis
2. Prophase 2
3. Metaphase 2
4. Anaphase 2
5. Telophase 2
6. Cytokinesis 2
110
Chromosomes in meiosis 2 are referred to as ___
Sister chromatids
111
End result of meiosis 2
4 genetically diverse haploid daughter cells
112
Is meiosis a cycle
No
113
Mitosis vs. meiosis: mitosis (6)
1. One round of cell division
2. Occurs in somatic cells
3. Part of a cycle (cells can re-enter)
4. Start and end with same # of chromosomes in each daughter cell
5. End Result: Two genetically identical diploid somatic (body) cells
6. Mutations in somatic cells are not passed on to the offspring
114
Mitosis vs. meiosis: meiosis (7)
1. Two rounds of cell division
2. Occur in gametes (sperm and egg)
3. Not part of a cycle (cells cannot re-enter)
4. Start and end with different #’s of chromosomes in each gamete
5. End Result: Four genetically distinct haploid gamete (sex) cells
7. Mutations that occur in gamete cells are passed onto the offspring
115
Overall process of chromosomal segregation is ___ in mitosis vs. meiosis
The same
116
How meiosis contributes to genetic diversity (2)
1. Crossing over during prophase 1 allows for new combinations of alleles on chromosomes
2. Chromosomes are randomly sorted into the gamete cells during anaphase, allowing for unique combinations of alleles for different traits in the gamete (law of independent assortment)
117
Random ___ of gametes generates an offspring with unique ___ combinations because half of the DNA comes from each parent
Fertilization, Allele
118
Where to genetic mutations occur
Gametes
119
Types of chromosomal mutations (5)
1. Deletion
2. Insertion
3. Translocation
4. Inversion
5. Duplication
120
When are chromosomal mistakes made
When crossing over occurs
121
An entire section of a chromosome is missing
Deletion
122
One section of the chromosome is doubled
Duplication
123
A section of a chromosome has its gene sequences reversed
Inversion
124
Part of one chromosome is inserted into a different chromosome
Insertion
125
Two non-homologous chromosomes go through crossing over and exchange alleles
Translocation
126
A type of mutation that occurs when homologous chromosomes do not separate properly during meiosis. Results in gametes with incorrect numbers of chromosomes
Nondisjunction
127
Why is Down syndrome more likely the older the mother becomes?
Older women have lower amounts of cohesin in their eggs, which leads to instability in the homologous chromosome pairs and a higher likelihood nondisjunction will occur at anaphase 1
128
Variation within a species
intraspecies variation
129
What genetic variation in a species can result from (4)
1. Mutation
2. Gene flow
3. Meiosis
4. Sexual reproduction
130
the movement of genes between different groups of organisms
Gene flow
131
Crossing over between non-sister ___ of homologous chromosomes during ___ of meiosis creates new combinations of alleles that are on ___ chromosome(s)
Chromatids, prophase 1, the same
132
Random orientation and independent assortment of ___ during ___ of meiosis creates gametes with new combinations of alleles that are on ___ chromosome(s)
Bivalents, metaphase 1, different
133
The location at which the fragments for chromosomes switch during crossing over (there can be multiple on one chromosome)
Chiasma (plural: chiasmata)
134
Chromosomes with new combinations of alleles not present in either parent
Recombinant chromosomes
135
Two homologous chromosomes (one from each parent) that pair up during meiosis
Bivalent chromosomes
136
the orientation of one bivalent does not affect the other bivalents
Independent assortment
137
There are __ possible ways chromosomes can independently assort into gametes
2^n ("n” is the number of chromosomes in a haploid cell of an organism)
138
there are ___ possible combinations of maternal and paternal chromosomes when assorting into gametes during meiosis
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