STUDY GUIDE Flashcards
1
Q
what does the cell cycle consist of?
A
Interphase
Mitotic (M) phase (Mitosis and Cytokinesis)
2
Q
In the cell cycle what is the function of Interphase?
A
Cell growth and copying of chromosomes in preparation for cell division
3
Q
What are the subphases of Interphase?
A
G1 Phase ("first gap")
S Phase ("synthesis")
G2 Phase ("second gap")
4
Q
In what phase are the chromosomes duplicated?
A
S phase
5
Q
In what phase does the cell divide?
A
Mitotic phase
6
Q
The cell (blank) during all three phases
A
grows
7
Q
A particular human cell might undergo one division in (blank)
A
24 hours
8
Q
What are the five phases of Mitosis?
A
Prophase Prometaphase Metaphase Anaphase Telophase
9
Q
(blank) overlaps the latter stages of mitosis
A
Cytokinesis
10
Q
List what happens during G2 of Interphase
A
- Nuclear envelope encloses nucleus
- 2 centrosomes have formed (duplication)
- Chromosomes cannot be seen individually
- Nucleous contains 1+ nucleoli
11
Q
Regions in animal cells that organize the microtubules of the mitotic spindle
A
Centrosomes
12
Q
Microtubule organizing center
A
mitotic spindle
13
Q
each centrosome contains (blank) centrioles
A
two
14
Q
a structure in centrosome composed of a cylinder of microtubule triplets
A
centriole
15
Q
List what happens during Prophase
A
- Chromatin fibers coiled
- Chromosomes condense and observable with light microscope
- Nucleoli disappear
- Each duplicated chromosome appears as 2 identical sister chromatids
- Mitotic spindle forms
- Centrosomes move away from each other by microtubules
16
Q
Chromatin
A
the entire complex of DNA and protein
building material of chromsomes
17
Q
Sister chromatids
A
Joined copies (at centromere by cohesin) of original chromosome
18
Q
Composed of centrosomes and microtubules that extend from them
A
Mitotic spindle
19
Q
Radial arrays of shorter microtubules that extend from the centrosomes
A
asters (“stars”)
20
Q
List what happens during prometaphase
A
- nuclear envelope fragments
- microtubules can invade
- chromsomes more condensed
- each of two chromatids of each chromosome has kinetochore
- some microtubules attach to kinetochores
- nonkinetochore microtubules interact with others from opposite pole
21
Q
specialized protein structure at the centromere
A
kinetochore
22
Q
what do kinetochore microtubules do?
A
jerk chromosomes back and forth
23
Q
List what happens during metaphase
A
- centrosomes at opposite poles
- chromosomes align at metaphase plate
- kinetochores of sister chromatids are attached to kinetochore microtubules from opposite poles
24
Q
an imaginary plane that is equidistant between the spindle’s two poles
A
metaphase plate
25
List what happens during Anaphase
- short
- chohesin proteins cleaved (2 sister chromatids of each pair separate to become chromosomes)
- daughter chromosomes move to opposite ends of cell as kinetochore microtubules shorten
- cell elongates
26
In anaphase, where do the chromosomes move to first?
centromere
27
What has happened by the end of anaphase?
two ends of cell have equivalent and complete collections of chromosomes
28
How many different kinds of gametes can individuals with each of the following genotypes produce? AA
1 kind of gamete (A)
29
How many different kinds of gametes can individuals with each of the following genotypes produce? aa
1 kind of gamete (a)
30
How many different kinds of gametes can individuals with each of the following genotypes produce? Aa
2 kinds of gametes (A or a)
31
How many different kinds of gametes can individuals with each of the following genotypes produce? AaBB
2 kinds of gametes (either AB o aB)
32
How many different kinds of gametes can individuals with each of the following genotypes produce? AaBb
4 kinds of gametes (AB, Ab, aB, and ab)
33
How many different kinds of gametes can individuals with each of the following genotypes produce?AaBbCcDdEeFf
64
34
General rule for determining the number of different gametes organisms can produce
Number of different kinds of gametes = 2n, where n= number of heterzygous alleles
35
List what happens during Telophase
- 2 daughter nuclei form in cell
- Nuclear envelope reforms
- Nuceloli reappear
- Chromosomes less condensed
36
The eukarotic cell is regulated by a (blank)
molecular control system
37
The cell cycle is driven by (blank) in the (blank)
specific chemical signals present in the cytoplasm
38
The sequential events of the cell cycle are directed by a distinct (blank)
cell cycle control system
39
the cell cycle is regulated at certain (blank)
checkpoints
40
Animal cells generally have built-in stop signals that halt the cell cycle at checkpoints (blank) by go-ahead signals
until overridden
41
What checkpoint seems to be the most important for most cells?
G1
42
What happens if a cell receives a go-ahead signal at the G1 checkpoint?
It will usually complete the S, G2, and M phases and divide
43
What happens if a cell does not receive a go-ahead signal at the G1 checkpoint?
It will exit the cell cycle and go to he non-dividing state of G0
44
What are the 3 major checkpoints?
G1, G2, and M
45
"restriction point" in mammalian cells
G1 checkpoint
46
G1 checkpoint examples include:
- Adequate cell size
- Sufficient nutrients
- Undamaged DNA
47
M checkpoint examples include:
- chromosomes attached to spindle
- chromosomes segregate
- MPF absent
48
G2 checkpoint examples include:
- chromosomes replicated
- undamaged DNA
- MPF activated and present
49
2 types of regulatory proteins involved in cell cycle control
cyclins
| cyclin-dependent kinases (CDKs)
50
Cdks activity (blank) during the cell cycle
fluctuates
51
cyclin-CDK complex that triggers a cell's passage past the G2 checkpoint into the M phase
MPF
52
What does MPF stand for?
Maturation-Promoting Factor
53
To be active, kinases must (blank)
be attached to cyclin
54
The peak of MPF activity corresponds with the (blank) of cyclin concentration
peak
55
Why are cancer cells abnormal? Simple answer
They divide excessively and invade other tissue
56
Important properties of cancer cells
- do not stop dividing when growth factors depleted: often due to mutation in signaling pathway that conveys the growth factor's signal
- abnormal cell cycle system causes growth
- stop dividing at random points not checkpoints
- immortal
57
Single cell in a issue undergoes (blank) which converts normal cell to cancer cell
transformation
58
If a transformed is not recognized what may happen?
proliferate and from tumor
59
mass of abnormal tissue within normal tissue
tumor
60
What are the two types of tumors?
Benign and malignant
61
Abnormal cells that remain at original site lead to what
Benign (not cancer)
62
Cells that are able to relocate and survive, impairing multiple organs
Metastatic cancer
63
(Blank) are the original source of genetic diversity
Mutations
64
changes in an organism's DNA
Mutations
65
Mutations create different versions of genes called (blank)
alleles
66
Three mechanisms that contribute to genetic variation
- Independent assortment
- Crossing over
- Random fertilization
67
Homologous pairs of chromosomes orient randomly at metaphase I of meiosis
Independent assortment
68
The first meiotic division results in each pair sorting its (blank) into daughter cells independently of every other pair
maternal and paternal homologs
69
Each pair of chromosomes sorts maternal and paternal homologs into daughter cells independently of the other pairs
independent assortment
70
Independent assortment
Each pair of chromosomes sorts maternal and paternal homologs into daughter cells independently of the other pairs
71
In independent assortment, (blank) represents one outcome of all possible combinations of maternal and paternal chromosomes
daughter cell
72
The number of combinations possible when chromosomes assort independently into gametes is (blank)
2n, n = haploid #
73
In humans, there are (blank) possible combinations of chromosomes
2 to the 23
74
Crossing over produces (blank), which combine DNA inserted from each parent.
recombinant chromosomes
75
When does crossing over begin? How?
Prophase I
| Homologous chromosomes pair up loosely along their lengths gene by gene
76
In a single cross over event, homologous portions of (blank) trade places.
two non-sister chromatids
77
Crossing over contributes to genetic variation by combining (blank) from two parents into (blank)
DNA
| Single chromosome
78
any sperm can fuse with any ovum
random fertilization
79
the fusion of two gametes produces (blank)
zygote
80
the fusion is when two (blank) become (blank)
haploids, diploid
81
an idea that genetic material from the two parents blends together which will lead to a uniform population
blending hypothesis
82
The blending hypothesis also fails to explain other phenomena of inheritance such as (blank)
traits reappearing after skipping a generation
83
Parents pass on discrete heritable units (genes) that retain their separate identities in offspring
particulate hypothesis
84
Mendel documented a (blank) through his experiments with (blank)
particulate mechanism, peas
85
heritable feature that varies among individuals
character
86
Mendel chose (blank) as traits
easily recognizable phenotypes
87
variant for a character
trait
88
Flower color is a (blank), while the specific color is a (blank)
character, trait
89
In a typical experiment, Mendel mated 2 contrasting, true-breeding varieties, a process called (blank)
hybridization
90
true-breeding parents are called the (blank)
P generation
91
hybrid offspring of the P generation are called the (blank)
F1 generation
92
when F1 individuals self pollinate or cross-pollinate with other F1 hybrids, the (blank) is produced
F2 generation
93
2 fundamental principles of heredity
law of segregation and law of independent assortment
94
Mendel reasoned that the heritable factor for white-flowers did no disappear in the F1 plants, but was somehow (blank) when the purple-flower factor was present
hidden, or masked
95
Purple flower = (blank) trait
dominant
96
White flower = (blank) trait
recessive
97
What Mendel called a "heritable" factor, is what we now call a (blank)
gene
98
Mendel's four concepts
1) Alternative versions of genes (alleles) account for variations in inherited characters
2) For each character, an organism inherits 2 alleles (1 from each parent)
3) If the two alleles at a locus differ, then one (dominant) determines the organism's appearance, and the other (recessive) has no noticeable effect on appearance
4) Law of segregation- two alleles for a heritable character separate during gamete formation and end up in different gametes
99
allele pairs separate during gamete production and sex cells carry one allele for each inherited character
law of segregation
100
Each gene resides at a specific (blank) on a specific (blank)
locus, chromosome
101
two identical alleles
homozygous
102
two different alleles
heterozygous
103
heterzygotes are not
true-breeding
104
phenotype
physical appearance
105
genotype
genetic makeup
106
How can we tell the genotype of an individual with the dominant phenotype?
testcross
107
Breeding the mystery individual with a homozygous recessive individual. If any offspring display the recessive phenotype, the mystery parent must be heterozygous
Testcross
108
individuals that are heterozygous for one character
monohybrids
109
A cross between individuals that are heterozygous for one character
monohybrid cross
110
Crossing two true-breeding parents differing in two characters produces dihybrids in the F1 generation, heterozygous for both characters
Dihybrid cross
111
Can determine whether two characters are transmitted to offspring as a package or independently
Dihybrid cross
112
Using a dihybrid cross, Mendel developed the (blank)
law of independent assortment
113
Each pair of alleles segregates independently o each other pair of alleles during gamete formation
Law of independent assortment
114
Genes are packaged into gametes in all possible alllic combinations, as long as each gamete has one allele for each gene
Independent assortment
115
dyhybrid cross results in a phenotypic ratio of
9:3:3:1
116
the probability that two or more independent events will occur together is the product of their individual probabilities
multiplication rule
117
states that the probability that any one of two or more exclusive events will occur is calculated by adding together their individual probabilities
addition rule
118
Can be used to figure out the probability that an F2 plant from a monohybrid cross will be heterozygous rather than homozygous
addition rule
119
Can be used to predict probability in a F1 monohybrid cross
multiplication rule
120
Neither allele is completely dominant and the F1 hybrids have a phenotype somewhere between those of the two parental varieties
incomplete dominance
121
What is an example of incomplete dominance?
Red snapdragons crossed with white snapdragons and F1 generation = pink
122
Two dominant alleles affect the phenotype in separate, distinguishable ways.
Codominance
123
Example of codominance
cows or human blood
124
Gene has multiple phenotypic effects
Pleiotropy
125
Single gene can affect a number of characteristics in an organism
Pleiotropy
126
many genes contributing to a single effect
Polygenic trait
127
a gene at one locus alters the phenotypic expression of a gene at a second locus
epistasis
128
What is an example of epistasis?
Labrador retrievers coat color
129
Family tree that describes the interrelationships of parents and children across generations.
pedigree
130
Inheritance patterns of particular traits can be traced and described using (blank)
pedigrees
131
Show up only in individuals homozygous for the allele.
Recessively inherited disorders
132
Heterozygous individuals who carry the recessive allele but are phenotypically normal
carriers
133
Most individuals with recessive disorders are born to (blank)
carrier parents
134
Dominant alleles that cause a lethal disease are (blank)
rare and arise by mutation
135
a gene that is located on either sex chromosome is called a (blank)
sex-linked gene
136
Who discovered evidence associating a specific gene with a specific chromosome?
Thomas Morgan
137
Morgans experiments with (blank) provided convincing evidence that chromosomes are the location of Mendel's heritable factors.
Fruit flies
138
normal phenotypes common in fly populations
wild type
139
non-normal traits opposite of wild type
mutant
140
What did Mendel find from the fruit fly experiment?
Red eyes with female
White eyes with male
White-eyed mutant allele located on the X chromosome
141
For a male fruit fly, a single copy of the mutant allele would confer white eyes, since a male only has one (blank)- no (blank) allele present
X chromosome
| Wild type
142
Morgan's finding supported the (blank)
chromosome theory of inheritance
143
A chromosome in a diploid organism is (blank) when only one copy is present.
Hemizygous
144
Hemizygosity is also observed when one copy of a gene is (blank), or in the heterogamic sex when (blank) is located on a sex chromosome
deleted
| gene
145
If a phenotype is due to an autosomal recessive allele, then
- individuals must be homozygous
- if parents of affected individual don't have trait, then parents are likely heterozygous (carriers)
- skipped generation
146
If a phenotype is due to an autosomal dominant allele then,
- unaffected offspring are homozygous recessive
| - affected offspring have at least one affected parent (homo or hetero)
147
General X-linked inheritance patterns
- phenotype more often in males (need 1 copy not 2)
- male with mutation only passes allele to daughters
- daughters who receive mutation are carriers and phenotypically normal
- mutation can skill generation (male-daughter-son)
148
X linked recessive traits
- male affected more frequently
- never passed father to son
- all daughters of affected male carriers
- skip generation
149
X linked dominant traits
- males and females likely affected equally
- likely that all daughters affected, no sons
- does not skip generation
150
List what is happening in Early Prophase I
- chromosomes condense
- homologs loosely pair and are aligned gene by gene
- synapsis
- crossing over
151
List what is happening in middle Prophase I
- synapsis ends with disassemply of complex and chromosomes in pairs moved apart slightly
- each homologous pair has chiasmata
- chiasma exists where cross over occured
- sister chromatid cohesin holds together
- centrosome movement, spindle formation, and nuclear envelope
152
List what is happening in late Prophase I
- microtubules attach to 2 kinetochores
| - homologous pairs move toward metaphase plate
153
List what is happening in Metaphase I
- pairs of homologous chromosomes aligned at metaphase plate
- chromatids of one homolog attached to kinetochore microtubules
- those of other homolog attached to other pole km
154
List what is happening in Anaphase I
- breakdown of proteins responsible for sister chromatid cohesion
- homologs separate
- homologs move toward opposite poles
- sister chromatid cohesin persists at centromere so chromatids move as unit
155
List what is happening during Telophase I
- each half of cell has a complete haploid set of duplicated chromosomes
- each chromosome composed of 2 sister chromatids
- no chromosome duplication occurs
156
List what is happening during Cytokinesis
- division of cytoplasm
- forms 2 haploid daughter cells
- cleavage furrow forms in animal
157
List what is happening during Prophase II
- spindle apparatus forms
| - chromsomes (composed of 2 chromatids) move towards metaphase II plate
158
List what is happening during Metaphase II
- chromosomes aligned at metaphase plate
- sister chromatids not genetically identical
- kinetochores of sister chromatids attached to microtubules extending from opposite poles
159
List what is happening during Anaphase II
- breakdown of proteins allows chromatids to separate
| - chromatids move toward opposite poles as individual chromosomes
160
List what is happening during Telophase II and Cytokinesis
- nuclei form, chromosomes less condensed
- four daughter cells each with haploid set of chromosomes produced
- four daughter cells genetically distinct
161
The three events that are unique to meiosis all occur in (blank)
meiosis I
162
What are the 3 events that occur that are unique to meiosis?
1) Synapsis and crossing over in prophase I
2) Paired homologous chromosomes (tetrads) at metaphase plate instead of individual replicated chromosomes
3) Homologous chromsomes not sister chromatids that separate
163
Synapsis and crossing over in prophase I
Homologous chromosomes physically connect and exchange genetic information
