exam 4 Flashcards
1
Q
Many ___ organisms can reproduce genetically identical clones of themselves
A
unicellular
2
Q
Most ___ organisms including humans use another method of reproduction
A
multicellular
3
Q
___ ___ requires parent organisms to produce two specialized cells which then fuse during ___ to form a single, unique cell.
A
sexual reproduction, fertilization
4
Q
the genetically unique cell then divides ___ tens of thousands of time into an adult organism
A
mitotically
5
Q
___ is the union of two cells from two different organisms
A
fertilization
6
Q
if those two cells each contain one set of chromosomes they are ___, and the cell resulting from fertilization will be __ or have two sets of chromosomes
A
haploid, diploid
7
Q
if the chromosomes were not reduced the number would ___ ___ ____
A
double each generation
8
Q
therefore sexual reproduction includes fertilization and a type of nuclear division that reduces the number of chromosome sets in ___
A
half
9
Q
the haploid cells that are required for sexual reproduction are produced by a type of cell division called
A
meiosis
10
Q
meiosis and fertilization introduce __ into offspring that may account for the evolutionary success of sexual reproduction
A
variation
11
Q
the majority of cells in many multicellular organisms are diploid. These are called __ __
A
somatic cells (germ cells)
12
Q
multicellular organisms are haploid. an example of this would be ___
A
gametes
13
Q
there are two rounds of division during meiosis these stages are called
A
meiosis I and meiosis II
14
Q
When is the genetic material replicated?
A
s phase
15
Q
as the nuclear envelope begins to break down the ___ ___ pair with each other
A
homologous chromosomes
16
Q
a lattice of proteins forms between the homologous chromosomes down the entire length. This is called ___ ____
A
synaptonemal complex
17
Q
the tight pairing of homologous chromosomes is called ___
A
synapsis
18
Q
in synapsis the chromatids of the homologous chromosomes are aligned so there is a ___ overlap in genes
A
precise
19
Q
synapsis supports the exchange of chromosomal segments between ___ ___ of homologous pairs. This is called ___ ___.
A
non sister chromatids, crossing over
20
Q
__ __ is the first source of genetic variation in the nuclei produced by meiosis
A
crossing over
21
Q
unique combinations of genes that result from crossing over
A
alleles
22
Q
as prophase I progresses the synaptonemal complex begins to break down and the chromosomes __
A
condense
23
Q
during prophase I the structures become visible and this is called
A
tetrads
24
Q
prometaphase I is characterized by the attachment of the spindle fiber microtubules to __ proteins at the centromeres of the two fused homologous chromosomes.
A
kinetochore
25
at the end of prometaphase I, each tetrad is attached to microtubules from __ at opposite poles
centrosomes
26
by the end of ___ the nuclear membrane has entirely broken down
prometaphase I
27
during metaphase I the ___ line up at the metaphase plate. the alignment of these is __
tetrads, random
28
during metaphase I centrosomes reach the poles and __ __ fully forms
meiotic spindle
29
during anaphase I ___ pull tetrads apart
microtubules
30
during anaphase I __ __ separate to opposite ends and __ __ remain tightly bound to centromeres
homologous pairs, sister chromatids
31
What is the role of centrosomes and the meiotic spindle in meiosis?
pulls the whole chromosome apart
32
What is a synapse and what is its purpose?
the pairing of homologous chromosomes, the crossing over
33
where does crossing over occur
between the chromosomes (nucleus)
34
In telophase, the separated
chromosomes arrive at ___
poles.
opposite
35
In anaphase I of meiosis, what do the microtubules separate?
the tetrad of entire chromosome
36
Cytokinesis after meiosis I results in cells of what ploidy level?
haploid
37
Meiosis I ends with the formation of two essentially __ daughter cells.
haploid
38
In some species, the cells may enter a brief interphase, or ___ before entering meiosis II.
interkinesis
39
it is important to note that if present, interkinesis lacks the __ phase. chromosomes __ ___ ___ preceding meiosis II.
S, do not replicate
40
the two cells from meiosis begin prophase II in __
synchrony
41
during prometaphase II each ___ __ forms and individual ___ that attaches to microtubules from opposing poles
sister chromatids, kinetochores
42
during metaphase II the __ __ is completely reformed
mitotic spindle
43
during metaphase II ___ __ are maximally condensed and align at the __ __
sister chromatids, metaphase plate
44
during anaphase II the __ __ are pulled apart by the kinetochore microtubules and move toward opposing pulls
sister chromatids
45
during telophase II and cytokinesis the chromosomes arrive at opposite pulls and begins to __
decondense
46
during telophase II cytokinesis ___ __ form around the chromosomes
nuclear envelopes
47
during telophase II and cytokinesis the two cells are separated into __ __ __ __
four unique haploid cells
48
meiosis and mitosis are both forms of __ __
cell division
49
mitosis is the ___ __ __ resulting in genetically __ daughter cells
single nuclear division, identical
50
meiosis consists of __ __ __ resulting in four genetically ___ daughter cells with the ploidy level reduced
two nuclear divisions, unique
51
sexual reproduction was an early evolutionary process in ____ __
eukaryotic cells
52
most eukaryotes are able to reproduce sexually and in most animals it is the only form of ___
reproduction
53
What is the main evolutionary advantage of meiosis and
fertilization events?
diversity
54
What is the ultimate source of variation between both sexual and asexual organisms?
mutation
55
___ is the ultimate source of variation in sexual and asexual organisms.
mutation
56
the variation in offspring created by sexual reproduction is very important to the survival and reproduction of the population. This is the ___ __ ___
red queen hypothesis
57
sexually reproducing organisms alternate cycles of __ and ___
fertilization, meiosis
58
what is the diploid dominant life cycle have?
most animals and humans
59
what does the haploid dominant life cycle have
fungi and most algae
60
what does the alternation of generations have ?
all plants and some algae
61
in diploid dominant organisms the multicellular diploid stage is the most ___ __
obvious stage
62
in diploid dominant the cells the gametes from two individuals undergo fertilization to produce a diploid __
zygote
63
the diploid zygote divides mitotically to produce a multicellular __ organism
diploid
64
in ___ ___ ___ the multicellular body of the organism is haploid
haploid dominant organisms
65
in haploid dominant cells meiosis occurs __ fertilization
after
66
organisms displaying an ___ __ __ life cycle has both haploid dominant and diploid dominant multi cellular organisms
alternation of generations
67
haploid multicellular organisms are called ___
gametophytes
68
diploid multicellular organisms are called
sporophytes
69
in haploid dominant cells the haploid spores divide mitotically to form the ___ ___ life stage
multicellular haploid
70
in haploid dominant cells the zygote undergoes meiosis to form ___ haploid cells called ___
four, spores
71
in haploid dominant cells the gametes from two individuals undergo fertilization to produce a ___ zygote
diploid
72
in haploid dominant The multicellular haploid organism produces specialized
haploid cells called
gametes
73
in diploid dominant The multicellular diploid organism produces specialized
haploid cells called
gametes
74
what form is a spore
haploid
75
what is a gamephyte
haploid
76
what is a sporophyte
diploid
77
Name and describe the events in the three types of multicellular
reproductive cycles. How are they similar? How do they differ?
haploid dominant, diploid dominant, alternation of cycles.
78
What is the most obvious multicellular life stage in each of the
reproductive cycles?
diploid dominant- diploid
haploid dominant- haploid
alternation of generations- both
79
in alternation of generations the multicellular haploid gametophytes produce haploid gametes from
specialized cells
80
in alternation of generations gametes from two individuals undergo fertilization to produce a diploid ___.
zygote
81
in alternation of generations the zygote divides mitotically to produce ___ ___
multicellular sporophytes
82
in alternations of generations sporophytes contain specialized cells that will undergo meiosis to produce haploid __
spores
83
in alternation of generations ___ divide mitotically to produce the multicellular haploid ___
zygote, gametophytes
84
A __ is the physical appearance of a heritable characteristic
trait
85
who's work forms the basis for modern day genetics
johannn gregor mendel
86
Mendle performed ___ or crosses of different individual pea plants
hybridizations
87
plants used in the initial crosses were called __ (parental generation)
P0
88
the first generation of plants resulting from the initial cross were called the ___ (first filial generation)
F1
89
Mendel then allowed the F1 generation to self-pollinate naturally, and he collected and grew the seeds to produce the __ (second filial generation)
F2
90
for the parential generation mendal made sure he had plants that were bred true for one trait. what does this mean
self pollinated for several generations until each plant could only produce one color of flower
91
When he allowed the F1generation to self-pollinate, the seeds produced F2generation plants with violet flowers and white flowers in a ratio of 3:1. Mendel obtained these same results when he used pollen from the plant with the contrasting trait as well. This is called a
reciprocal cross
92
In Mendel’s crosses between true breeds that differed in one trait, what
were the phenotypic characteristics of the F1 generation?
phenotypic-only purple
93
When Mendel then allowed the F1 generation to self-pollinate, what were the genotypic and phenotypic characteristics of the F2 generation?
3:1 ratio
94
What was the purpose of performing the reciprocal crosses for each of
the seven traits?
they have the same results, the dominant always remains dominant
95
what are the three laws associated with the laws of inheritance
law of dominance
law of segregation
law of independent assortment
96
the traits associated with the law of dominance are __ and __
dominant, recessive,
97
in the law of dominance in organisms possessing two different copies of a single trait, one copy may ___ the presence of the other copy of the trait for the same characteristics
conceal
98
in the law of segregation, for any single characteristic, each parent will contribute only __ of the two copies of the trait to the gamete, and the allocation of the copies is __
one, random
99
in the law of individual assortment different characteristics are passed on to offspring __ of other characteristics
independently
100
we understand that the physical expression of traits has to do with the expression of __ carried on __
genes, chromosomes
101
we know that many organisms have two copies of their genome, and they are called _
diploid
102
gene variants are called
alleles
103
which phases of meiosis contribute to mendel's law of segregation
anaphase I
104
what phases of meiosis contribute to the law of independent assortment
Metaphase I
105
the observable physical trait expressed by the organism is called the __
phenoytype
106
the underlying genetic alleles is called
genotype
107
the true breeding parent plants that mendel used in the parental cross were __ for the trait in question
homozygous
108
when the alleles for one specific gene location on homologous chromosomes are different, the organism is said to ___ for that trait
heterozygous
109
if a diploid organisms is ___ for a trait it can only be one genotype
heterozygous
110
How did Mendel come to understand that his plants possessed two copies of each of the seven traits, and that one parent transmitted one of its copies to the next generation?
he had f1 cross pollinated and f2 was self pollinated. one of the two traits would disappear in the f1 generation and reappear in the f2 generation in a ratio of 3:1
111
The fact that each of his plants possessed two copies of each trait
meant that plants showing the recessive trait had what genotype?
homozygous
112
What does it mean if an organism is homozygous or heterozygous?
How does this relate to Mendel’s P0, F1, and F2 generations?
p0 homozygous
f1 heterozygous
f2 both
113
Name and describe the two genotypic conditions under which an
organism could display the dominant characteristic.
homozygous dominant
heterozygous
114
in ___ __ the heterozygous genotype results in a phenotype that is intermediate
incomplete dominance
115
in situations of ___ a heterozygous genotype results in a phenotype in which both alleles are fully expressed
codominance
116
in population __ __ may exist for a given gene
multiple alleles
117
when many alleles exist for the same gene, it is conventional to denote the most common combination in the population as the ___ __
wild type (+)
118
all other genotypes and phenotypes are considered __. The __ alleles may be dominant or recessive to wild type alleles
variants, variant
119
in humans and many animals and plants the sex of the individual organisms is determined by __ __
sex chromosomes
120
humans have 22 pairs of __ and one pair of sex chromosomes
autosomes
121
when a gene in question is present on the X chromosome, but not on the shorter Y chromosome, it is said to be ___
X linked
122
males have only one allele for any X linked gene. this is called ___.
hemizygosity
123
in males whatever allele is present on the single X chromosome is ___ expressed
phenotypically
124
females heterozygous for the trait are known as ___
carriers
125
Occasionally, in a population of organisms, a mutation will result in a ___ allele for an __ gene
non-functional, essential
126
The __ __ may be transmitted through the population in one of two ways
lethal allele
127
genes located on the same chromosome are likely to be inherited together. The close they are, the more likely the two genes will be inherited together. This is called ___ ___
genetic linkage
128
__ ___ __ was an American biologist/ geneticist/ embryologist.
Thomas Hunt Morgan
129
Thomas Hunt Morgan is credited with providing a large part of the evidence in support of __ __ of __
Mendel's Theory of Inheritance
130
Thomas Hunt Morgan provided a large part of the evidence through his work with the __ __
fruit fly
131
In 1933 __ won the Nobel prize in physiology/medicine for his discoveries demonstrating the role chromosome play in heredity
Morgan
132
Inherited disorder can arise when chromosomes behave abnormally during __
meiosis
133
Chromosomal inherited disorders can happen in one of two ways:
abnormalities in __ __
chromosomal ___ ___
chromosome number, structure arrangements
134
Because even small segments of chromosomes can span __ __, chromosomal disorder are usually dramatic and often fatal
many genes
135
A __ is made by isolating and microscopically photographing each individual chromosome, and then arranging the pictures onto a chart, or ___
karyotype, karyogram
136
disorders include __ or __ __ __ __, as well as changes in the number of complete sets of chromosomes (ploidy)
These are all caused by __
duplication, loss of entire chromosome, nondisjunction
137
nondisjunction occurs when pairs of homologous chromosomes or sister chromatids __ to separate during __
fail, meiosis
138
Causes of nondisjunction include:
misaligned or incomplete ___
dysfunction of the __ __
synapsis, spindle apparatus
139
If homologous chromosomes fail to separate during meiosis I:
two gametes will lack that __ __
two gametes will have two copies of that ___
particular chromosome
chromosome
140
if sister chromatids fail to separate during meiosis II:
one gamete lacks that ___
two normal __
one gamete with two copies of the __
chromosome, gametes, chromosome
141
What are the two broad ways that
chromosomal abnormalities can happen?
change in number, change in sequence
142
Why are chromosomal abnormalities usually of such high consequence?
the span of chromosome covers a wide variety of genes
143
What is the primary cause of all disorders in
chromosome number?
nondisjunction
144
Name two examples of how nondisjunction could happen.
the synapse, spindle fibers
145
What are the end results of non-disjunction if it occurs in meiosis I vs. meiosis II?
Meiosis I: one is monosomies and one is trisomies
Meiosis: 2 normal, 1 mono, and 1 tri
146
An individual with the normal number of
chromosomes for their species is called __
euploid
147
An individual with an error in chromosome
number is described as
aneuploid
148
Aneuploid individuals can have __
(loss of one chromosome) or __ (gain of
an extra chromosome)
monosomy, trisomy
149
The problem in trisomic individuals is an excess in something called __ __
gene dose
150
chromosome 21 is the __ of the 22 chromosomes
shortest
151
trisomy of the 21 is __ __ . and is also the most common
down syndrome
152
an individual with more than the normal number of chromosome sets is called __
polyploid
153
triploid:
when the developing zygote has 69 chromosomes instead of 46. results in __ or death shortly after birth
miscariage
154
mosaicism is the result of mutation or nondisjunction during __ __ __
mitosis following fertilization
155
in the plant kingdom, polyploid organisms are actually known for being phenotypically __ and more __ than euploids of the same species
larger, robust
156
when nondisjunction occurs in sex chromosomes the effects are __
mild
157
The mild effects of nondisjunction in sex chromosomes are due to something called __ __
X-inactivation
158
When does meiosis not occur successfully in
polyploid organisms?
when there is an odd number of chromosomes
159
early in development, females inactivate one X chromosome by tightly condensing into a dormant structure called a __ __
Barr body
160
Whether the inactivated X chromosome is maternally or paternally derived is __ in every single cell
random
161
Once inactivation has occurred every daughter cell from the mitotic division of that cell will have the __ __ __
same X inactivation
162
abnormal numbers of X chromosomes will be inactivated as well, but a few inactivated genes are __ __
always expressed
163
errors in sex chromosome number include the XXX genotype or ___ __ ___
triple x syndrome
164
errors in sex chromosome number include the XYY genotype or __ __
jacob's syndrome
165
Why does Jacob’s Syndrome usually result
in very few symptoms?
the y chromosome has less genes
166
XXY corresponds to one type of __ __ a phenotypically male individual with small testes, enlarged breasts, and reduced body hair
Klinefelter's syndrome
167
Klinefelter’s can be more complex, with up to 5 X chromosomes (XXXXXY). Every X
chromosome but one undergoes ___
inactivation
168
__ __ is the results of an x0 genotype. phenotypically female individuals results.
turner syndrome
169
In this disorder there is a deletion of most of the small arm of (p) of chromosome 5. infants with __ __ __ genotype have a high pitched cry. long term include effects include nervous system abnormalities and noticeable physical features
Cri-du-chat
170
There are several different structural arrangements on chromosomes that have been documented. What are the most common?
inversion and translocation
171
__ the detachment and 180 degree rotation and reinsertion of part of a chromosome. usually they only change the orientation and have __ __
inversion, mild effects
172
chromosome ___ occurs when a segment of a chromosome dissociates and reattaches to a different, non-homologous chromosome. the consequences can be benign or disease causing
translocation,
173
specific translocations are associated with __ and __
cancer, schizophrenia
174
How are abnormalities in structural arrangement different
from other forms of chromosomal abnormalities?
genes are displaced into a new position
