Meiosis

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Terms in this set (...)

homologous chromosomes
Two copies of the same kind of chromosome, judged by length and location of the centromere. Also, they contain genes fore the same traits in the same order.
synapsis
When homologous chromosomes pair
homologous chromosomes
Separate so each daughter cell receives one from each pair
independent assortment
Creates an increased number of possible combinations of chromosomes in each gamete.
crossing over
Shuffles the alleles between homologous chromosomes to create even more variation.
genetic variability
This phenomenon ensures that at least some individuals will have traits that will allow a species to survive adverse conditions
crossing over
Two daughter cells that share the same parent cell from Meiosis 1 are identical unless __________ has occurred.
interkinesis
The intervening cell cycle between meiotic divisions.
interkinesis
Differs from interphases in that the stages of cell cycle do not occur. The chromosomes are already duplicated.
metaphase 1
In _________ __ of meiosis, homologous chromosomes are not paired, and sister chromatids are attached to spindle fibers from opposite spindle poles.
meiosis 2
Resembles mitosis because sister chromatids are separated during both processes.
meiosis 2
Differs from mitosis because the cells are haploid and not diploid
testes
Where are the primary spermatocytes located in males?
ovaries
Where are the primary oocytes located in females?
aneuploidy
An extra or missing chromosome; can be caused by non-disjunction in Meiosis
sex
_____ chromosome aneuploidy is more common because only one of the X chromosomes is active.
barr bodies
Any extra X chromosomes become _____ _____.
inversion
Involves the reversal of a piece of chromosome from within, and normally does not cause symptoms.
translocation
Swapping of two chromosome fragments form one to the other, and while not usually troublesome, may cause severe problems in offspring if the two chromosomes go into separate cells.
spermatogenesis
Production of sperm in males by the process of meiosis and maturation
bivalent
Describes a pair of homologous chromosomes at the metaphase plate during Meiosis 1
polar body
A nonfunctional product of oogenesis
secondary oocyte
The functional product of Meiosis 1 in Oogenisis, which becomes the egg
homologue
Member of a pair of chromosomes in which both members carry genes for the same traits
anaphase
Phase of Meiosis where the homologous chromosomes separate
bivalent
A way to describe the paired homologous chromosomes
23
If a parent cell has 46 chromosomes, then each of the daughter cells following meiosis will have ___ chromosomes.
bivalents
At the metaphase plate during metaphase 1 of meiosis, there are ____, or homologous pairs of chromosomes.
unpaired
At the metaphase plate during metaphase II of meiosis, there are _____ duplicated chromosomes
separate
Gametes contain one of each kind of chromosome because the homologous chromosomes _____ during Meiosis.
nonsister
Crossing-over occurs between _____ chromatids of a bivalent
anaphase 2
During which phase of Meiosis do homologous chromosomes separate?
prophase 1
During which phase of Meiosis does crossing-over occur?
four, one
Spermatogenesis produces _____ viable gametes, while oogenesis only produces _____.
spermatogenesis, oogenesis
________ goes to completion, while _____ does not always go to completion.
one
Nondisjunction during Meiosis 1 of oogenesis will result in eggs that have _____ too many chromosomes and _____ less than the normal number of chromosomes.
synapsis
Deletion and duplication are two chromosomal mutations most likely to occur when an inverted chromosome is undergoing _____.
Klinefelter
A male with underdeveloped testes and some breast development most likely has _____ syndrome.
24, 12
If a parent cell has 24 chromosomes, the daughter cells following mitosis will have ____ chromosomes and following meiosis will have ____ chromosomes.
spermatogenesis, oogenesis
Meiosis in males is a part of _____, and meiosis in females is a part of _____.
fertilization
Oogenesis will not go to completion unless _____ occurs.
gametes, spores
In humans, meiosis produces _____, and in plants, meiosis produces _____.
diploid, haploid
During oogenesis, the primary oocyte has the _____ and the secondary oocyte has the _____ number of chromosomes.
Meiosis 1
A parent cell with ten duplicated chromosomes will produce daughter cells with five duplicated chromosomes each in this phase
Meiosis 1
This phase involves pairing of duplicated homologous chromosomes
Meiosis 2
A parent with five duplicated chromosomes will produce daughter cells with five chromosomes consisting of one chromatid each in this phase
Mitosis
A parent cell with ten duplicated chromosomes will produce daughter cells with ten chromosomes consisting of one chromatid each in this phase
Mitosis
Involved in growth and repair of tissues
mitosis, meiosis
_____ keeps the chromosome number constant during growth and repair of tissues, and _____ reduces the chromosome number during the production of gametes.
meiosis
The nuclear division that halves the chromosome number in preparation for sexual reproduction.
fuse
When gametes _____, the full number of chromosomes is restored.
twice, four
The phases of meiosis occur _____ and result in _____ daughter cells.
haploid
Following Meiosis 1, the daughter cells are _____.
nondisjunction
When _____ occurs, gametes carry the incorrect number of chromosomes.
1
In Meiosis __, the homologous pairs synapse and then separate
2
In Meiosis __, the sister chromatids separate, becoming daughter chromosomes = four haploid daughter cells
constant
Meiosis ensures that the chromosome number in offspring stays _____ generation after generation.
2
Following Meiosis __, the chromosomes are no longer duplicated.
Meiosis
Replication of DNA takes place before _____ begins.
metaphase
During Meiosis 1, the homologues undergo _____ (resulting in a bivalent) and align independently at the _____ plate.
1
During Meiosis __, the daughter cells receive one member of each pair of homologous chromosomes.
2
During Meiosis __, the sister chromatids separate, becoming daughter chromosomes that move to opposite poles as they do in mitosis.
separate, poles
During Meiosis 2, the sister chromatids _____, becoming daughter chromosomes that move to opposite _____ as they do mitosis.
2
During Meiosis __, the four daughter cells contain the haploid number of chromosomes and only one of each kind.
haploid, one
During Meiosis 2, the four daughter cells contain the _____ number of chromosomes and only _____ of each kind.
synapsis, genetic
Crossing over; when homologous chromosomes lie side by side during _____, nonsister chromatids may exchange _____ material.
prophase 1
In this phase of Meiosis 1, the bivalents form, and crossing-over occurs as chromosomes condense; the nuclear envelope fragments
metaphase 1
In this phase of Meiosis 1, the bivalents independently align at the metaphase plate
anaphase 1
In this phase of Meiosis 1, homologous chromosomes separate, and duplicated chromosomes move to poles
telophase 1
In this phase of Meiosis 1, the nuclei become haploid, having received one duplicated chromosome from each homologous pair
prophase 2
In this phase of Meiosis 2, the chromosomes condense, and the nuclear envelope fragments
metaphase 2
In this phase of Meiosis 2, the haploid number of still duplicated chromosomes align at the metaphase plate
anaphase 2
In this phase of Meiosis 2, the sister chromatids separate, becoming daughter chromosomes that move to the poles
telophase 2
In this phase of Meiosis 2, four haploid daughter cells are genetically different from the parent cell
prophase
In this phase of Meiosis 1, the homologous chromosomes are PAIRED, while in Mitosis, there is NO PAIRING of chromosomes.
metaphase
In this phase of Meiosis 1, the BIVALENTS align at the metaphase plate, while in Mitosis, the DUPLICATED CHROMOSOMES align at the metaphase plate
anaphase
In this phase of Meiosis 1, the HOMOLOGOUS chromosomes separate and move to the poles, while in Mitosis, the sister chromatids separate, becoming DAUGHTER chromosomes that move to the poles
telophase
In this phase of Meiosis 1, the Daughter nuclei have the HAPLOID number of chromosomes, while in Mitosis, the daughter nuclei have the PARENT cell chromosome number
haploid
Meiosis 2 is like Mitosis except the nuclei are _____.
gametes
In the animal life cycle, only _____ are haploid
spores
In plants, meiosis produces _____ that develop into multicellular haploid adult that produces the gametes
zygote, spores
In unicellular protists/fungi, the _____ undergoes meiosis, and _____ become a haploid adult that gives rise to gametes.
polar
Oogenesis produces one egg and two/three nonfunctional _____ bodies.
monosomy
_____ occurs when an individual has only one particular type of chromosome.
trisomy
_____ occurs when an individual has three of a particular type of chromosome
autosomes
Aneuploidy of the sex chromosomes is tolerated more easily than aneuploidy of the _____.
aneuploidy
Extra/missing copies of the chromosomes caused by nondisjunction
sex
Turner syndrome, Klinefelter syndrome, Poly-X females, and Jacobs syndrome are examples of _____ chromosome aneuploidy.
crossing-over
Abnormalities in _______ may result in deletions, duplications, inversions, and translocations within chromosomes.
chromosome.
Many human syndromes, including Williams syndrome, Cri Du Chat syndrome, and Alagille syndrome, result form changes in _____ structure.