Chapter 10 (test 3) Flashcards
1
Q
nuclear division, reducing the chromosome number from the diploid (2n) to the haploid (n) number.
A
Meiosis
2
Q
the total number of chromosomes, which exists in two sets.
A
diploid (2n) number
3
Q
half of the diploid number of chromosomes.
A
haploid (n) number
4
Q
What happens in sexual reproduction?
A
gamete formation and then fusion of gametes to form a zygote.
5
Q
reproductive cell
A
gamete
6
Q
fusion of gametes form a
A
zygote
7
Q
A zygote always has the (blank) number of chromosomes.
A
full, or diploid (2n)
8
Q
If gametes contained the same number of chromosomes as body cells, (blank) would soon fill cells.
A
doubling
9
Q
In diploid body cells, chromosomes occur as (blank).
A
pairs
10
Q
Each set of chromosomes is a (blank); each member is a (blank) or (blank)
(blank) look alike, have the same length and centromere position, and have a similar banding
pattern when stained.
A
homologous pair; homologous chromosome or
homologue.
Homologue
11
Q
A (blank) on one homologue contains a gene for the same trait that occurs at this (blank) on the other
homologue, although the genes may code for different variations of that trait; alternate forms of a
gene are called (blank).
A
location; locus; alleles.
12
Q
Chromosomes (blank) immediately prior to nuclear division.
A
duplicate
13
Q
Duplication produces two identical parts called (blank); they are held together at the (blank)
A
sister chromatids; centromere
14
Q
One member of each homologous pair is inherited from the (blank) parent, the other member from the
(blank) parent.
A
male, female
15
Q
One member of each homologous pair will be placed in each (blank) or (blank)
A
sperm or egg
16
Q
Meiosis involves (blank) nuclear divisions and produces (blank) haploid daughter cells.
A
two; four
17
Q
Each daughter cell has (blank) the number of chromosomes found in the diploid parent nucleus.
A
half
18
Q
Meiosis I is the (blank) nuclear division.
A
first
19
Q
Prior to meiosis I, (blank) occurs, each chromosome thus has (blank) sister chromatids.
A
DNA replication; two
20
Q
During meiosis I, homologous chromosomes pair forming a (blank); this process is called (blank).
A
synaptonemal complex; synapsis
21
Q
During synapsis, the two sets of paired chromosomes lay alongside each other as a (blank) (sometimes called a tetrad).
A
bivalent
22
Q
In meiosis II, the (blank) divide and (blank) (derived as sister chromatids) separate.
A
centromeres; daughter chromosomes
23
Q
No replication of DNA is needed between meiosis I and II because chromosomes are already (blank)
A
doubled
24
Q
In Meiosis II, Chromosomes in the four daughter cells have (blank) chromatid(s)
A
one
25
In Meiosis II, Counting the number of centromeres verifies that parent cells were (blank); each daughter cell is (blank)
diploid; haploid.
26
In the animal life cycle, daughter cells become (blank) that fuse during (blank).
gametes; fertilization
27
Fertilization restores the (blank) number in cells.
diploid
28
In the plant life cycle, daughter cells become haploid (blank) that (blank) to become a haploid
generation.
spores; germinate
29
Due to (blank), offspring have a different combination of genes than their parents.
genetic recombination
30
Without recombination, asexual organisms must rely on (blank) to generate variation among offspring;
this is sufficient because they have great numbers of offspring.
mutations
31
Meiosis brings about genetic recombination in two ways:
crossing-over and independent assortment
32
an exchange of genetic material between non-sister chromatids of a bivalent; this introduces variation.
crossing-over
33
{Genetic Recombination} At synapsis, homologous chromosomes are held in position by a (blank) (the synaptonemal complex).
nucleoprotein lattice
34
{Genetic Recombination} The lattice holds the (blank) together so that the (blank) of the duplicated chromosomes of each homologue pair is aligned, then (blank) may occur.
bivalent; DNA; crossing-over
35
{Genetic Recombination} As the lattice of the synaptonemal complex breaks down, homologues are temporarily held together by (blank), regions where the non-sister chromatids are attached due to DNA strand exchange and crossing-over.
chiasmata
36
{Genetic Recombination} The homologues (blank) and are distributed to (blank) Due to this (blank) daughter chromosomes derived from sister chromatids are no longer identical.
separate; daughter cells; genetic recombination
37
During (blank), the homologous chromosomes separate independently or in a random
manner.
independent assortment
38
Independent assortment in a cell with only three pairs of chromosomes is 2^3 or eight combinations of
(blank and blank) chromosomes.
maternal and paternal
39
In humans who have (blank) pairs of chromosomes, the combinations possible from independent assortment
alone are 2 23 or 8,388,608.
23
40
When gametes fuse at fertilization, chromosomes donated by parents (blank)
combine
41
The chromosomally different zygotes from same parents have (blank) or 70,368,744,000,000 combinations possible without crossing-over. If crossing-over occurs once, then (blank) or 4,951,760,200,000,000,000,000,000,000 genetically different zygotes are possible for one couple.
(2^23 )^2; (4^23 )^2
42
A successful parent in a particular environment can reproduce (blank) and produce (blank) adapted to
that environment.
asexually; offspring
43
If the environment changes, differences among (blank) provide the (blank) of sexually reproducing
parents with much improved chances of survival.
offspring, offspring
44
Both meiosis I and meiosis II have four phases:
prophase, metaphase, anaphase, and telophase.
45
In Prophase I, (blank) is about to occur: (blank) disappears; (blank) fragments; (blank) migrate away from each other; and (blank) assemble.
nuclear division; nucleolus; nuclear envelope; centrosomes; spindle fibers
46
In Prophase I, Homologous chromosomes undergo (blank) to form (blank); (blank) may occur at this time in which case sister chromatids are no longer identical.
synapsis; bivalents; crossing-over
47
In Prophase !, (blank) condenses and (blank) become microscopically visible.
Chromatin; chromosomes
48
In Metaphase I, (blank) held together by (blank) have moved toward the (blank) plate at the equator of the
(blank).
Bivalents; chiasmata; metaphase; spindle
49
In metaphase I, there is a fully formed (blank) and alignment of the (blank) at the (blank) plate.
spindle; bivalents; metaphase
50
In metaphase I, (blank), protein complexes just outside the centromeres attach to spindle fibers called kinetochore spindle fibers.
Kinetochores; kinetochore spindle fibers.
51
In metaphase I, (blank) independently align themselves at the metaphase plate of the (blank).
Bivalents; spindle
52
In metaphase I, (blank) and (blank) homologues of each (blank) may be oriented toward either (blank).
Maternal and paternal; bivalents; pole
53
In Anaphase I, The (blank) of each bivalent separate and move toward opposite (poles).
homologues; separate; poles
54
In Anaphase I, Each chromosome still has two (blank)
chromatids
55
In Telophase I, In (blank), this stage occurs at the end of meiosis I.
animals
56
In Telophase, When it occurs, the (blank) reforms and (blank) reappear.
nuclear envelope; nucleoli
57
In Telophase I, This phase may or may not be accompanied by (blank)
cytokinesis
58
(blank) between meiosis I and II is similar to the (blank) between mitotic divisions; however, no
(blank) occurs (the chromosomes are already duplicated).
Interkinesis; interphase; DNA replication
59
During metaphase II, the (blank) number of chromosomes align at the (blank) plate.
haploid; metaphase
60
During anaphase II, the (blank) separate at the (blank); the two (blank) move toward the poles.
sister chromatids; centromeres; daughter chromosomes
61
In meiosis II, Due to (blank), each (blank) can contain chromosomes with different types of (blank)
crossing-over; gamete; genes
62
At the end of telophase II and cytokinesis, there are (blank) haploid cells.
four
63
In meiosis II, In animals, the (blank) mature and develop into (blank)
haploid cells; gametes
64
In meiosis II, In plants, the (blank) become (blank) and divide to produce a haploid generation; these haploid
cells fuse to become a (blank) that develops into a diploid generation.
daughter cells ;spores; zygote
65
The type of life cycle of alternating haploid and diploid generations is called
alternation of generations.
66
Meiosis requires two (blank); mitosis requires only one (blank).
nuclear divisions; nuclear division
67
The daughter cells produced by meiosis are (blank); the daughter cells produced by mitosis are (blank)
haploid; diploid
68
The daughter cells produced by meiosis are not (blank); the daughter cells produced by mitosis are (blank) to each other and to the (blank).
genetically identical; genetically identical; parent cell
69
In humans, meiosis occurs only in (blank) to produce (blank).
reproductive organ; gametes
70
Mitosis occurs in all (blank) for growth and repair.
tissues
71
During prophase I of meiosis, (blank) pair and undergo crossing-over; this does not occur during (blank).
homologous chromosomes; mitosis
72
During metaphase I of meiosis, (blank) align at the metaphase plate; in mitosis (blank, blank) align.
bivalents; individual chromosomes
73
During anaphase I in meiosis, (blank, blank) (with centromeres intact) separate and move to opposite poles; in mitosis at this stage, (blank, blank) separate and move to opposite poles.
homologous chromosomes; sister chromatids
74
Events of meiosis II are similar to those of mitosis. However, in meiosis II, the nuclei contain the (blank) number of chromosomes.
haploid
75
refers to all reproductive events between one generation and the next.
life cycle
76
In animals, the adult is always (blank) [Instructors note: some (blank), etc., have haploid male adults].
diploid; bees
77
In plants, there are two adult stages: one is diploid (blank) and one is haploid (blank)
called the sporophyte; called the gametophyte
78
in plants, the sporophyte is (blank)
diploid
79
in plants, the gametophyte is (blank)
haploid
80
Mosses are (blank) most of their cycle; the majority of higher plants are (blank) most of their cycle.
haploid; diploid
81
In fungi and some algae, only the zygote is (blank), and it undergoes (blank)
diploid; meiosis
82
Animals are (blank), and meiosis occurs during the production of (blank)
diploid; gametes
83
the production of gametes
gametogenesis
84
In males, meiosis is part of (blank), and occurs in the (blank).
spermatogenesis; testes
85
production of sperm
spermatogenesis
86
In females, meiosis is part of (blank), and this occurs in the (blank)
oogenesis; ovaries
87
the production of eggs
oogenesis
88
After birth, mitotic cell division is involved in growth and tissue regeneration of (blank, blank)
somatic tissue
89
In the testes of males, primary (blank) with (blank) chromosomes undergo meiosis I to form two
secondary (blank), each with (blank) duplicated chromosomes.
spermatocytes; 46; spermatocytes; 23
90
Secondary spermatocytes divide (meiosis II) to produce (how many blank), also with (blank) daughter chromosomes. Spermatids then differentiate into (blank, blank)
four spermatids; 23; sperm (spermatozoa).
91
Meiotic cell division in males always results in (blank) cells that become (blank).
four; sperm
92
In the ovaries of human females, primary (blank) with (blank) chromosomes undergo meiosis I to form two cells, each with (blank) duplicated chromosomes.
oocytes; 46; 23
93
In oogenesis, one of the cells, a secondary (blank), receives almost all the (blank); the other cell, (blank, blank), disintegrates or divides again.
oocyte; cytoplasm; a polar body
94
The secondary oocyte begins (blank) and then stops at (blank)
meiosis II; metaphase II.
95
At ovulation, the secondary oocyte leaves the ovary and enters an (blank) where it may meet a sperm.
oviduct; sperm
96
If a (blank) enters the secondary oocyte, the oocyte is activated to continue (blank) to completion; the result is a mature (blank) and another (blank, blank), each with (blank) daughter chromosomes.
sperm; meiosis II; egg; polar body; 23
97
Meiosis produces (blank) egg and (blank) polar bodies;(blank) serve to discard unnecessary chromosomes and retain most of the cytoplasm in the egg. The (blank) serves as a source of nutrients for the developing (blank)
one; three; polar bodies; cytoplasm; embryo.
98
failure of chromosomes to separate
nondisjunction
99
changes in chromosome number or structure
chromosomal mutations
100
name what increases the amount of variation among offspring (4)
1. Mutations
2. Crossing-over
3. Recombination of chromosomes during meiosis
4. Gamete fusion during fertilization,
101
The correct number of chromosomes in a species is called
euploidy
102
changes in chromosome number resulting from nondisjunction during meiosis is called
aneuploidy.
103
(2n – 1) occurs when an individual has only one of a particular type of chromosome.
Monosomy
104
(2n + 1) occurs when an individual has three of a particular type of chromosome.
Trisomy
105
In nondisjunction both members of the homologous pair go into the same (blank)
gamete
106
occurs during meiosis I when both members of a homologous pair go into the same daughter cell
Primary nondisjunction
107
occurs during meiosis II when the sister chromatids fail to separate and both daughter chromosomes go into the same gamete.
Secondary nondisjunction
108
Monosomy and trisomy occur in plants and animals; in (blank) of animals, it is generally lethal.
autosomes
109
the most common autosomal trisomy in humans.
Trisomy 21
110
(blank) also called (blank) occurs when three copies of chromosome 21 are present.
Trisomy 21 (also called Down syndrome)
111
Usually (blank) copies of chromosome 21 are contributed by the egg; in 23% of the cases, the (blank) had the extra chromosome 21.
two; sperm
112
Chances of a woman having a Down syndrome child increase with (blank)
age
113
A Down syndrome child has many characteristic signs and symptoms, including a tendency for (blank), (blank), (blank), (blank), and an increased chance of developing (BLANK) disease later in life.
leukemia, cataracts, faster aging, mental retardation; Alzheimer
114
A (blank), a visual display of the chromosomes arranged by (blank), (blank), and (blank) may be performed to identify babies with Down syndrome and other aneuploid conditions.
karyotype; shape, size, and banding pattern
115
Nondisjunction during oogenesis can result in too few or too many (blank) chromosomes; nondisjunction during
spermatogenesis can result in missing or too many (blank) chromosomes.
X; Y
116
Any additional X chromosomes become an inactive mass called a (blank)
Barr body
117
(blank) syndrome females have only one sex chromosome, an X; thus, they are XO, with O signifying
the absence of a second sex chromosome.
Turner
118
(blank) females are short, have a broad chest and widely spaced nipples, along with a low
posterior hairline and neck webbing.
Turner
119
(blank) of Turner females never become functional; therefore, females do not undergo puberty.
Ovaries
120
(blank) syndrome males have one Y chromosome and two or more X chromosomes (e.g., XXY).
Klinefelter syndrome
121
Characteristics of (blank) Affected individuals are sterile males; the testes and prostate are underdeveloped. Individuals have large hands and feet, long arms and legs, and lack facial hair.
Klinefelter syndrome
122
In Klinefelter syndrome, Presence of the (blank) chromosome drives male formation but more than two (blank) chromosomes may result in mental retardation. (blank) usually only seen in the nuclei of a female’s cells, is seen in this syndrome due to the two X chromosomes.
Y; X; A Barr body
123
(blank) females (or superfemale) have three or more X chromosomes and therefore extra (blank) in the nucleus.
Poly-X; Barr bodies
124
There is no increased femininity; most lack any physical abnormalities. (blank) individuals are not mentally retarded but may have delayed motor and language development; (blank) females are usually tall and severely mentally retarded. Some experience menstrual irregularities but many menstruate regularly and are fertile; Characteristics of (blank)
XXX; XXXX; Poly-X
125
(blank) syndrome (XYY) are males with two Y chromosomes instead of one. This results from (blank) during spermatogenesis.
Jacobs; nondisjunction
126
Males with (blank) syndrome are usually taller than average, suffer from persistent acne, and tend to have speech and reading problems.
Jacobs
127
Environmental factors including (blank), (blank), and (blank) can cause chromosomes to break; if the broken ends do not rejoin in the same pattern, this causes a change in chromosomal structure.
radiation, chemicals, and viruses
128
A (blank) occurs when an end of a chromosome breaks off or when two simultaneous breaks lead to the
loss of an internal segment.
deletion
129
A (blank) is the presence of a chromosomal segment more than once in the same chromosome.
duplication
130
A broken segment from one chromosome can simply attach to its (blank) or unequal (blank) may occur.
homologue; crossing-over
131
A duplication may also involve an (blank) where a segment that has become separated from the chromosome is reinserted at the same place but in reverse; the position and sequence of genes are altered.
inversion
132
A (blank) is the movement of a chromosomal segment from one chromosome and inserted into another non homologous chromosome
translocation
133
in Down syndrome, 5% of cases are due to a (blank) between chromosome 21 and 14, a situation that runs in the family of the father or mother.
translocation
134
(blank) occurs when chromosome 7 loses an end piece: children look like pixies, have poor academic skills but good verbal and musical skills; lack of elastin causes cardiovascular problems and skin aging.
Williams syndrome
135
(blank) (“cry of the cat”) is a deletion in which an individual has a small head, is mentally retarded, has facial abnormalities, and an abnormal glottis and larynx resulting in a cry resembling that of a cat.
Cri du chat syndrome
136
If a (blank) results in the normal amount of genetic material, the person will remain healthy; if a person inherits (blank) of the translocated chromosomes, that person may have only one or three (blank) rather than the normal two.
translocation; one; alleles
137
In (blank), chromosomes 2 and 20 exchange segments, causing a small deletion on chromosome 20 that may produce some abnormalities.
Alagille syndrome
