Meiosis Flashcards
1
Q
heredity
A
continuity of biological traits from one generation to the next
2
Q
heredity results from
A
transmission of herediart units from parent to offspring
3
Q
variation is due to
A
- crossing over
- mutations
4
Q
variation
A
inherited differences among individuals of the same species
5
Q
genetics
A
study of heredity and heredity variation
6
Q
DNA
A
type of nucleic acid that is a polymer of 4 different kinds of nucleotides
7
Q
consist of a single long and highly folded DNA molecules that are coiled along proteins
A
chromosomes
8
Q
locus
A
specific location on a chromosome that contains a gene
9
Q
contain genetic information arranged in a linear sequence and coded by genes
A
chromosome
10
Q
sexual reproduction occurs ONLY in
A
eukaryotes
11
Q
during the formation of gamates, chromosome number is
A
reduced in half
12
Q
gametes are
A
haploid
13
Q
somatic cells are
A
diploid
14
Q
gametes return to being diploid when
A
two gametes fuse in fertilization
15
Q
ploidy
A
number of sets of chromosomes
16
Q
haploid organisms have
A
one set of chromosomes
17
Q
diploid organisms have
A
two sets of chromosomes
18
Q
meiosis
A
segregates one copy of each homologous chromosome into each new gamete
19
Q
meiosis is a specialized type of
A
nuclear division
20
Q
somatic cells in the human body are produced by
A
mitosis
21
Q
germ line cells are produced by
A
meiosis
22
Q
meiosis is restricted to the
A
gonads
23
Q
the vast majority of cell division in human body are
A
mitotic
24
Q
human somatic cells have ____ pairs of chromosomes
A
23
25
karyotype
ordered display of chromosomes pairs from a cell
26
the two chromosomes in each pair are
homologous chromosomes (homologs)
27
chromosomes in a homologous pair are the
same length, shape and carry the same genes
28
sex chromosomes
determine the sex of an individual
29
X and Y chromosomes are
sex chromosomes
30
human female phenotype
homologous pair of X chromosomes (XX)
31
human male phenotype
have one X and Y chromosome
32
autosomes
remaining 22 pairs of chromosomes
33
homologous chromosome pairs include
one chromosome inherited by each parnet
34
46 chromosomes in somatic cells are two sets of
23; one from each parent
35
diploid number for humans
46
36
sister chromatids
a pair of the SAME parent
37
non-sister chromatids
a pair from DIFFERENT parents (one from each parent)
38
karyotypes can be used to screen for
defective or abnormal chromosome numbers
39
how are karyotypes prepared
isolated somatic cells
40
genetic link to our parents
genes
41
what is the genetic program language made from
DNA
42
vehicle that transmit genes from one generation to the next
gametes
43
where is DNA mostly packed
nucleus
44
where else can DNA be packed
mitochondria or chloroplast
45
diploid is represented by
2n
46
haploid is represented by
n
47
is the cell still diploid after undergoing DNA synthesis
YES
48
when does the human life cycle begin
haploid sperm from father fuses with haploid egg from mother
49
fertilization
union of gamates
50
results in a fertilized egg known as a zygote
fertilization
51
the zygote is
diploid
52
what generates all the somatic cells in the body
mitosis of the zygote
53
only cells not produced by mitosis
gametes
54
how to gametes develop
from germ cells in the gonads
55
gonads in males
testes
56
gonads in females
ovaries
57
meiosis does what to the number of chromosomes
reduces from two to one in the gametes
58
_______ and _______ maintain a constant number of chromosomes in each species from different generations
fertilization and meiosis
59
what is common to ALL organisms that reproduce sexually
alternation of meiosis and fertilization
60
Is this sexual or asexual reproduction
single individual is the sole parent
asexual
61
Is this sexual or asexual reproduction
two parents give rise to offspring
sexual
62
Is this sexual or asexual reproduction
single parent passes on ALL its genes to the offspring
asexual
63
Is this sexual or asexual reproduction
each parent passes on HALF its genes to offspring
sexual
64
Is this sexual or asexual reproduction
offspring are genetically identical to the parent
asexual
65
Is this sexual or asexual reproduction
offspring are unique from both parents and each other
sexual
66
Is this sexual or asexual reproduction
results in a clone
aseuxal
67
Is this sexual or asexual reproduction
results in genetic variation in offspring
sexual
68
clone
genetically identical individual with rare genetic differences from mutations
69
____ can divide by mitosis depending on the type of life cycle
haploid OR diploid
70
______ can undergo meiosis
diploid cells ONLY
71
In meiosis, the single duplication stage is followed by
TWO consecutive cell divisions
72
what does meiosis result in
4 daughter cells with ONE set of chromosomes each
73
the only animal haploid ccell
gametes
74
what process produces gametes
meiosis
75
do gametes undergo more cell division before fertilization
NO
76
what is formed when gametes fuse
diploid zygote
77
what results in a multicellular organism
dividing gametes by mitosis
78
what show alternation of generations
plants and some algae
79
alternation of generations includes
both a diploid and haploid multicellular stage
80
what is the diploid organism called in alternation of generations
sporophyte
81
what part of alternation of generations makes the haploid spores
the sporophyte by meiosis
82
how do the spores grow into the haploid organism in alternation of generations
by mitosis
83
what is the haploid organisms known as in alternation of generations
gametophyte
84
how do gametophytes make haploid gametes
by mitosis
85
what does fertilization of gametes result in for the alternation of generations
a diploid sporophyte
86
what is the only diploid stage in most fungi and some protists
single-celled zygote
87
is there a multicellular stage in most fungi and some protists
NO
88
what does the zygote produce in fungi
haploid cells by meiosis
89
how do each haploid cell grow into the organism in fungi
by mitosis
90
how do the haploid adults produce gametes in fungi
mitosis
91
is the multicellular organism in fungi diploid or haploid
haploid
92
meiosis I is also known as
reductional division
93
meiosis 2 is also known as
equational division
94
what happens to chromosomes in meiosis I
homologous chromosomes seperate
95
what separates in meiosis II
sister chromatids
96
allele
different versions of genes at corresponding loci
97
what meiosis phase does this represent?
centrosomes begin to seperate
prophase 1
98
what meiosis phase does this represent?
spindle begins to form
prophase 1
99
what meiosis phase does this represent?
nuclear envelope begins to break down
prophase 1
100
what meiosis phase does this represent?
each centrosome pairs with its homologue
early prophase 1
101
how are homologous pairs aligned during prophase 1
allele by allele
102
what meiosis phase does this represent?
crossing over occurs
early prophase 1
103
crossing over
DNA molecules of NON-SISTER chromatids are broken and rejoined to each other
104
x shaped region where crossing over has occurred
chiasmata
105
what meiosis phase does this represent?
microtubules from one pole will attach to the two kinetochores
late prophase 1
106
where do the microtubules attach in late prophase 1
one at the centromere of each homologue
107
what meiosis phase does this represent?
pairs of chromosomes are at the metaphase plate
metaphase 1
108
how are the chromosomes arranged in metaphase 1
one chromosome of each pair facing each pole
109
what meiosis phase does this represent?
both chromatids of one homologue are attached to kinetochore microtubules
metaphase 1
110
what meiosis phase does this represent?
sister chromatid cohesion along the chromatid arm breaks apart= homologues seperate
anaphase 1
111
what meiosis phase does this represent?
sister chromatid cohesion continues at the centromere
anaphase 1
112
what meiosis phase does this represent?
each half of the cell has a complete haploid set of duplicated chromosomes
telophase 1
113
what occurs at the same time as telophase 1
cytokinesis
114
what forms during cytokinesis in animals
cleavage furrow
115
what forms during cytokinesis in plant cells
cell plat forms
116
what does NOT occur between meiosis 1 and 2
chromosome duplication
117
chromosomes do what throughout prophase 1
condense progressively
118
what meiosis phase does this represent?
spindle apparatus forms
prophase 2
119
what meiosis phase does this represent?
chromosomes move toward metaphase 2 plate
late prophase 2
120
what are the chromosomes made up of during late prophase 2
two chromatids associated at the centromeres
121
what meiosis phase does this represent?
chromosomes are positioned at the metaphase plate
metaphase 2
122
what meiosis phase does this represent?
kinetochores of sister chromatids are attached to microtubules from opposite poles
metaphase 2
123
what meiosis phase does this represent?
breakdown of proteins holding sister chromatids together
anaphase 2
124
what meiosis phase does this represent?
chromatids separate
anaphase 2
125
what meiosis phase does this represent?
move to opposite poles as individual chromosomes
anaphase 2
126
what is the result of crossing over in meiosis 1
sister chromatids are NOT genetically identical
127
what meiosis phase does this represent?
nuclei forms
telophase 2
128
what meiosis phase does this represent?
the chromosomes begin decondensing
telophase 2
129
what is the final product of meiotic division
four daughter cells
130
what does each daughter cell have
haploid set of chromosomes
131
what has been done to chromosomes after interphase
they have been duplicated
132
how are sister chromatids held together after interphase
proteins called choesins
133
synaptonemal complex
zipper-like structure that holds one homologue tightly to the other
134
what must occur for homologous pairs to remain together as they move to the metaphase 1 plate
at least ONE crossing over
135
is this meiosis or mitosis?
reduces the number of chromosomes from diploid to haploid
meiosis
136
is this meiosis or mitosis?
produces cells that are genetically different
meiosis
137
is this meiosis or mitosis?
conserves the number of chromosomes
mitosis
138
is this meiosis or mitosis?
produces cells that are genetically identical
mitosis
139
is this meiosis or mitosis?
occurs in both haploid and diploid cells
mitosis
140
is this meiosis or mitosis?
one division
mitosis
141
is this meiosis or mitosis?
synopsis of homologous chromosomes doesn't occur
mitosis
142
is this meiosis or mitosis?
two daughter cells
mitosis
143
is this meiosis or mitosis?
enables multicellular plant or animal to arise from a single cell
mitosis
144
is this meiosis or mitosis?
produces cells for growth, repair, asexual reproduction
mitosis
145
is this meiosis or mitosis?
produces gametes in the gametophyte plant
mitosis
146
is this meiosis or mitosis?
occurs ONLY in diploid cells
meiosis
147
is this meiosis or mitosis?
two divisions
meiosis
148
is this meiosis or mitosis?
synapsis of homologous chromosomes occurs
meiosis
149
is this meiosis or mitosis?
four daughter cells
meiosis
150
is this meiosis or mitosis?
produces gametes in animals
meiosis
151
is this meiosis or mitosis?
produces spores in sporophyte plant
meiosis
152
is this meiosis or mitosis?
introduces genetic variability in gametes and spores
meiosis
153
what does DNA replication take place in BOTH meiosis and mitosis
interphase
154
3 events unique to meiosis (occur in meiosis 1)
1. synapsis and crossing over
2. alignment of homologous pairs at metaphase plate
3. separation of homologues
155
synapsis and crossing over occur in
prophase 1
156
synapsis and crossing over
duplicated homologues pair up and crossing over occurs
157
does synapsis and crossing over happen in mitosis
NO
158
alignment of homologous pairs at the metaphase plate occurs
metaphase 1
159
how is the position of chromosomes at the metaphase plate different in meiosis than in mitosis
in meiosis = pairs of homologues
in mitosis = individual chromosomes
160
separation of homologues occurs
anaphase 1
161
separation of homologues
Duplicated chromosomes of each homologous pair move toward opposite poles
162
what happens to sister chromatids during separation of homologues
remain attached
163
what happens to sister chromatids in mitosis
seperate
164
what is the original source of genetic diveristy
mutations
165
mutations
changes in organism's DNA that create different versions of alleles
166
most of the variation between each generation during SEXUAL reproduction
behaviour of chromosomes during meiosis and fertilization
167
Three mechanisms that contribute to the genetic variation from sexual reproduction
Independent assortment of chromosomes
Crossing over
Random fertilization
168
Independent assortment of chromosomes
random orientation of pairs of homologous chromosomes at metaphase of meiosis 1
169
the orientation of maternal and paternal chromosomes is
random
170
the first meiotic division results in
each pair of chromosomes sortings its maternal and paternal chromosomes independently of each other
171
The number of possible combinations when chromosomes sort independently is represented by
2n
172
crossing over produces
recombinant chromosomes
173
recombinant chromosomes
Individual chromosomes that carry genes (DNA) from two different parents
174
the chromosomes after crossing over have
new combinations of maternal and paternal alleles
175
The different possible arrangements of non-identical sister chromatids during meiosis II increases with the
number of genetic types of daughter cells
176
The individuals best suited to the environment leave the
most offspring and transmit their genes
177
original source of different alleles
mutations
178
When does sexual reproduction seem to be less advantageous than asexual reproduction
stabe environment
179
Why is sexual reproduction universal in animals
Ability to produce genetic diversity is the common explanation for evolutionary processes
180
Gregor Mendel
a theory of inheritance that helps explain genetic variation
181
Darwin could not explain why
offspring resemble their parents but are NOT identical
182
gametogenesis
process of forming gametes from diploid cells of the germ line
183
types of gametogenesis
1. spermatogenesis
2. oogenesis
184
spermatogenesis
process of forming sperm cells by meiosis
185
spermatogenesis in plants
by mitosis
186
where does spermatogenesis happen
in specialized organs known as gonads
187
what happens after division in spermatogenesis
cells undergo differentiation to become sperm cells
188
Oogenesis
process of forming an ovum by meiosis
189
where does Oogenesis happen
in specialized gonads known as ovaries
190
in Oogenesis where does most of the cytoplasm go
into one large egg
191
polar bodies
the three other cells in Oogenesis that do not develop
192
what happens to the meiotic products in spermatogenesis
all 4 are developed into gamates
193
who brings the genetic material AND the needed support for the cell
ovum
