Chapter 10 connect
When a chromosome is broken in two places and reconnected so that a region is flipped from the normal order, this is called
A. inversion.
Which of the following is a correct sequence of cells in spermatogenesis?
A. spermatogonium -> primary spermatocyte -> secondary spermatocyte
Daughter cells produced in meiosis have
B. half the number of chromosomes as daughter cells produced in mitosis.
Synapsis is the side-by-side alignment of
B. homologous chromosomes.
Random orientation of homologous chromosomes occurs in ________ of meiosis.
B. metaphase I
During spermatogenesis, which of the following cells is the first to become haploid?
B. secondary spermatocyte
chromosomal alignment during meiosis I
Bivalents independently align at metaphase plate Each chromosome pair contains four chromatids Picture: two chromatids over 2 chromatids ( blue red red blue)
Consider a cell that has four pairs of chromosomes. What is the number of possible chromosome orientations in that cell?
C. 16
Watch the video, then arrange the following events in the proper order in which they occur during meiosis I. 1 = Separation of homologous chromosomes 2 = Crossing-over 3 = Independent assortment
C. 2,3,1
Which of the following is unique to meiosis?
C. crossing-over
Euploidy
Contains the correct number of chromosomes Very High viability
The orientation of each tetrad at the spindle equator is
D. Random
Separation of ________ occurs in anaphase II of meiosis.
D. Separation of ________ occurs in anaphase II of meiosis.
At the end of meiosis II, there are
D. four haploid cells, with each chromosome consisting of a single chromatid.
At the end of meiosis I, each daughter cell is
D. haploid, and each chromosome consists of two chromatids.
A cross-over in meiosis is an exchange of genetic material between
D. nonsister chromatids of homologous chromosomes.
The spindle apparatus is fully formed by the end of
D. prometaphase II.
Which of the following occurs when a piece of one chromosome breaks off and is attached to another nonhomologous chromosome?
D. simple translocation
The number of cells produced in meiosis is
D. twice the number of cells produced in mitosis.
These chromosomes contain genes in the same location that code for the same type of traits, but individual traits could be ______ for each.
Different
Which of the following describes meiosis II in humans
E. 1N --> 1N
Which of the following statements about crossing-over is TRUE?
E. None of these answer choices are true.
T/F: Crossing-over occurs in metaphase I.
False
T/F: Crossing-over has no effect on the genetic makeup of the resulting gametes.
False
T/F: Daughter cells produced in meiosis are identical.
False
T/F: Each orientation of chromosomes produces gametes with the same genetic information from each parent.
False
T/F: Meiosis II of spermatogenesis results in the formation of secondary spermatocytes.
False
T/F: Replication of chromosomes occurs between meiosis I and meiosis II.
False
T/F: The number of possible chromosomal orientations during metaphase I is equal to the number of chromosome pairs raised to the 2nd power.
False
T/F:Independent assortment occurs during prophase I. True
False
_______ with only one X chromosome have the genotype _____ and are said to have_________ syndrome. They tend to have physical differences and _________ reproductive organs, but tend to lead normal lives with __________treatment.
Females, XO, Turner, underdeveloped, hormone
_________with an extra X chromosome have the genotype ____ are are said to have _________ syndrome. They tend to be very tall and lean and can have learning difficulties and reproductive problems, but are often typically developed otherwise.
Females, XXX, Poly X
Turner syndrome
Genetically and physically female example of monosomy causes underdevelopment of reproduction organs and can cause physical differences
Klinefelter syndrome
Genetically and physically male example of trisomy causes underdevelopment of reproductive organs learning difficulties and long limbs
During independent assortment, _______chromosomes separate.
Homologous
Prophase I or Meiosis I
Homologous chromosomes pair up crossing over may occur
_______with an extra Y chromosome have the genotype _____ and are said to have______ syndrome. They tend to be tall, have persistant acne, and have speech and reading problems.
Males, XYY, Jacobs
Duplications
May or may not cause physical abnormalities Occurs when the same piece is repeated within a chromosome
Label the componetnts of the human life cycle in the correct order (starting from the human feet)
Meiosis, n, n, fertilization, zygote 2n,2n,Mitosis, 2n, mitosis
During _________, _________align independently along the equator. (2nd)
Metaphase I, homologues
Monosomy
Missing one chromosome from a pair very limited viability results from nondisjunction A type of aneuploidy or incorrect number of chromosomes
Inversions
Occurs when a piece of a chromosome breaks and reattaches upside down May or may not cause physical abnormalities
Meiosis I
Results in 2 genetically diverse haploid nuclei crossing-over occurs during synapsis Homologous chromosomes pair up during prophase Homologous chromosomes align at the spindle equator during metaphase
Mitosis
Results in 2 genetically identical diploid nuclei A diploid number of chromosomes align at the spindle equator during metaphase.
Meiosis II
Results in 4 gentically diverse haploid nuclei A haploid number of chromosomes align at the spindle equator during metaphase
T/F: A chromosomal mutation is a substantial change in the structure of a chromosome or chromosomes.
True
T/F: During spermatogenesis, spermatids differentiate into spermatozoa.
True
T/F: In animal cells, cell division is accomplished by the formation of a cleavage furrow.
True
T/F: At the end of meiosis I, there are two haploid cells, each with two sister chromatids per chromosome.
True
T/F: Both inversions and translocations can lead to overall deficiencies and duplications of genetic material. True
True
T/F: Chromosome duplication occurs prior to both mitosis and meiosis.
True
T/F: Crossing-over occurs during prophase I of meiosis.
True
T/F: Telophase II of meiosis is basically prophase I in reverse.
True
T/F: The period between meiosis I and II is termed interkinesis.
True
Life cycle of plants
Vegetative state can be 2n or n Alternation of generations is seen where the haploid phase alternates with the diploid phase The haploid phase of the life cycle produces gamete nuclei without the need for meiosis
The sex chromosomes in males are X and ____; the sex chromosomes in females are the X and ____.
Y,X
During________, homologues separate.(3rd)
anaphase I
During________, the sister chromatids separate and move towards the poles.(7th)
anaphase II
Homologues separate and move to opposite ends of the cell where they are split into genetically ______ daughter cells. (5th)
different
If an egg that contains 22 chromosomes instead of 23 chromosomes is fertilized by a normal sperm, _______is said to have occurred.
monosomy
These chromosomes stay close together, and_________ chromatids exchange genetic material, an event also known as _______ (3rd)
nonsister, crossing-over
The___________ breaks down and homologues are temporarily held together by ________, or regions where the nonsister chromatids are attached.( 4th)
nucleoprotein lattice, chiasmata
A ___________ forms to hold the bivalents together so that the DNA of the duplicated chromosomes of each homologue pair is aligned. This forms a________, or four chromatids grouped together. (2nd)
nucleoprotein lattice, tetrad
During meiosis I, if both members of a homologous pair go into the same daughter cell,___________ is said to occur and no normal gametes are produced.
primary nondisjunction
During_______, the nuclear envelope fragments, spindle fibers begin to form, and condensed homologues undergo______ (1st)
prophase I, synapsis
During _______, each duplicated chromosome attaches to the spindle. (5th)
prophase II
This separation is_______; it is due to their alignment down the metaphase plate.
random
During meiosis II, if the sister chromatids fail to separate and both daughter chromosomes go into the same gamete, ________ is said to occur. Half the gametes are aneuploid while the other half are euploid.
secondary nondisjunction
After_________, the resulting 2 daughter nuclei are_____meaning they each contain one chromosome from each homologue. (4th)
telophase I, haploid
During _______, the spindle disappears and upon completion of cytokinesis, 4 _____ daughter cells result. (8th)
telophase II, haploid
Life cycle of animals
vegetative stat is 2n Gametes are the only haploid phase of life cycle Meiosis results in gametophytes
Humans have ___ pairs of chromosomes; members of each pair are called __________ chromosomes, as seen in A above.
23, homologous
Meiosis I or II image selection (bottom row left to right)
2n=4, 2n=4, m=2, n=2
The exchange of genetic material between nonsister chromatids is called crossing-over and occurs during which phase of meiosis?
A. Prophase I
What is the overall purpose of meiosis?
A. To produce four genetically different haploid cells
2n
Also called diploid seen in somatic cells
1n
Also called haploid Seen in animal gametes
Centromeres divide during
B. Mitosis and Meiosis II
Which cells in the body originated through the process of meiosis?
B. Sperm and egg cells
Which of the following causes an extra copy of a chromosomal region to occur?
B. duplication
Spermatogenesis occurs in the
B. seminiferous tubules.
Select all of the following ways in which meiosis II is different than meiosis I.
D. All of the answer choices are correct.
Which of the following events occur during prophase I?
E. breakdown of the nuclear envelope, condensation of chromosomes, and movement of centrosomes
A tetrad is made up of
E. two homologous chromosomes, each consisting of two chromatids.
Oogenesis: Meiosis II
Egg
Translocation
Examples include Alagille syndrome, chronic myelogenous leukemia, and Burkitt leukemia Occurs when pieces of a chromosome are exchanged between nonhomologous pairs
________ with an extra X chromosome have the genotype ________ and are said to have _______r syndrome. They tend to have long limbs, __________reproductive organs, and can have learning difficulties
Males, XXY, Klinefelter, underdeveloped
Meiosis I or II image selection (top row left to right)
Meiosis I, Meiosis II
asexual reproduction
Relies of mutations to generate variation. offspring are genetically identical to parents. Necessary when cells need to be genetically identical, such as with skin cells or blood cells
sexual reproduction
Reproduction itself generates genetic variation. Offspring are genetic combinations of both parents and are thus genetically different from individual parents. Variation occurs because of crossing over during synopsis and independent assortment. Necessary when genetic variation is beneficial, such as a sudden shift in the environmental conditions.
Trisomy
Results from nondisjunction A type of aneuploidy or incorrect number of chromosomes limited viability has an extra chromosome within a pair
Oopenersis: Meiosis I
Secondary Oocyte
Spermatogensis: Meiosis I
Secondary spematocytes
When chromosomes replicate, as shown in B, each of the replicates are called ___________ __________.
Sister chromatids
These ______ are exact copies of each other and contain the same genes in the same locations with the ____ traits.
Sister chromatids, same
Spermatogenesis: Maturation
Sperm
Spermatogensis: Meiosis II
Spermatids
This results from ________ copy of chromosome 21, usually donated from the ________
an extra, egg
There are 22 pairs of chromosomes called _______ and one pair of chromosomes called ____________.
autosomes, sex chromosomes
During meiosis I, _____________ separate and move towards opposite ends of the poles.
homologous chromosomes
During ______, homologous chromosomes line up side by side, an event also known as _____. (1st)
meiosis 1, synapsis
Individuals with Down syndrome tend to have similar characteristics, including short stature, an extra eyelid fold, stubby fingers, a fissured tongue, and sometimes ____________
mental disabilities.
The maternal or paternal homologue may be oriented toward either ______
pole
This variation helps in the long-term _______ of the species
survival
If an egg that contains 24 chromosomes instead of 23 chromosomes is fertilized by a normal sperm, _________ is said to have occurred.
trisomy
An example of nondisjunction in autosomes is_______ also called Down syndrome.
trisomy 21,
This randomized separation aids in genetic ________ of offspring.
variation
Mitosis
Primary spermatocytes Primary oocytes
Which of the following events occur during anaphase I?
A. separation of homologous chromosomes
How many tetrads (bivalents) are formed in a cell with 20 chromosomes at the beginning of meiosis I?
C. 10
During anaphase I of meiosis, ________ move towards opposite cell poles, whereas during anaphase II of meiosis, ________ are separated.
C. homologous chromosomes; sister chromatids
Deletions
Examples include Willams syndrome and cri du chat syndrome Occurs when pieces of a chromosome are lost
chromosomal alignment during Mitosis
Individual chromosomes align at the metaphase plate Each chromosome contains two chromatids Picture: all chromosomes lined up in a straight line down the center
Prophase of Mitosis
No pairing of chromosomes crossing-over does not occur
The chance of having a child with Down syndrome__________with maternal age due to the greater chance of ___________ occurring among developing egg cells.
increases,nondisjunction
During _______, duplicated chromosomes line up at the equator.(6th)
metaphase II
During meiosis II, __________ separate and move towards opposite ends of the poles.
sister chromatids
T/F:Germ-line cells are haploid but gametes are diploid. True
False