BIO152H5 Lecture Notes - Lecture 5: Metaphase, Sister Chromatids, Homologous Chromosome

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taupegoldfish605

7 Dec 2016

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Document Summary

Chromosomes: 23 types of chromosomes and 2 types of each chromosome, homologous chromosome: one from each parent, x and y are sex chromosomes, humans: 2n=46. Each chromosome replicates prior to undergoing meiosis. During meiosis, chromosome number in each cell is reduced. A full complement of chromosomes is restored during fertilization: only in gametes to produce haploid gametes, phases of meiosis 1. One chromosome of each homologous pair is distributed to a different daughter cell: phases of meiosis 2. 4 daughter cells, each haploid: meiotic errors. Nondisjunction: failure of homologous chromosomes to separate. Getting less or more homologous chromosomal pairs in a daughter cell. Embryos with other aneuploidies are spontaneously aborted before birth so we do not see them. The sex chromosome and chromosome 21 may be more prone to aneuploidy than others. Why does meiosis exist: meiosis leads to genetic variation. Pairing of homologous pairs creates different patterns. Dna exchange between maternal and paternal chromatids.

Related Questions

Consider each of the following statements.

In meiosis, the chromosomal material doubles during the lastpremeiotic interphase.

The greater the number of chromosome pairs, the greater is theeffect of meiosis in producing genetically distinct gametes.

The diploid number of chromosomes is half the haploidnumber.

A cell that will not divide again remains in the GÂ2 stage ofinterphase.

The correct sequence of events during meiosis is: synapsis ?dyad formation ? chiasma formation

In an organism with n = 3, there is a 1 in 8 probability of agamete with all maternally derived chromosomes contributing to theproduction of a zygote.

An organism with n = 3 can produce 8 different kinds of gametesin relation to combinations of maternal and paternalchromosomes.

Separation of sister chromatids occurs during anaphase I ofmeiosis and is the physical basis for the law of independentassortment.

A single diploid cell that undergoes meiosis in the male testiswill produce 4 genetically different gametes if crossing-over isignored.

The independent alignment of different tetrads at metaphase I ofmeiosis is the physical basis of the law of independentassortment.

If a diploid cell has 20 pairs of chromosomes, there will be 10tetrads during prophase I of meiosis.

If a diploid cell has 20 pairs of chromosomes, there will be 20bivalents during prophase I of meiosis.

If a diploid cell has 20 pairs of chromosomes, there will be 80chromatids present during metaphase of mitosis.

If a diploid cell has 20 pairs of chromosmes, the organism canmake 20² types of gametes if crossing-over isignored.

Segregation of sister chromatids occurs during anaphase I ofmeiosis and is the physical basis of the law of segregation.

For an individual with a diploid number of 30 chromosomes, therewill be 60 chromatids at metaphase I of meiosis.

For an individual with a diploid number of 30 chromosomes, therewill be 15 tetrads at metaphase II of meiosis.

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PLEASE HELP

Which of the following statements are true?

a. In meiosis, the chromosomal material doubles during the lastpremeiotic interphase.

b. The greater the number of chromosome pairs, the greater isthe effect of meiosis in producing genetically distinctgametes.

c. The diploid number of chromosomes is half the haploidnumber.

d. A cell that will not divide again remains in theGÂ₂ stage of interphase.

e. The correct sequence of events during meiosis is: synapsis âdyad formation â chiasma formation

f. In an organism with n = 3, there is a 1 in 8 probability of agamete with all maternally derived chromosomes contributing to theproduction of a zygote.

g. An organism with n = 3 can produce 8 different kinds ofgametes in relation to combinations of maternal and paternalchromosomes.

h. Separation of sister chromatids occurs during anaphase I ofmeiosis and is the physical basis for the law of independentassortment.

i. A single diploid cell that undergoes meiosis in the maletestis will produce 4 genetically different gametes ifcrossing-over is ignored.

j. The independent alignment of different tetrads at metaphase Iof meiosis is the physical basis of the law of independentassortment.

k. If a diploid cell has 20 pairs of chromosomes, there will be10 tetrads during prophase I of meiosis.

l. If a diploid cell has 20 pairs of chromosomes, there will be20 bivalents during prophase I of meiosis.

m. If a diploid cell has 20 pairs of chromosomes, there will be80 chromatids present during metaphase of mitosis.

n. If a diploid cell has 20 pairs of chromosmes, the organismcan make 20² types of gametes if crossing-over isignored.

o. Segregation of sister chromatids occurs during anaphase I ofmeiosis and is the physical basis of the law of segregation.

p. For an individual with a diploid number of 30 chromosomes,there will be 60 chromatids at metaphase I of meiosis.

q. For an individual with a diploid number of 30 chromosomes,there will be 15 tetrads at metaphase II of meiosis.

taupecicada359

Which of the following statements are true. CHALLENGEQUESTION:

a. In meiosis, the chromosomal material doubles during the lastpremeiotic interphase.

b. The greater the number of chromosome pairs, the greater isthe effect of meiosis in producing genetically distinctgametes.

c. The diploid number of chromosomes is half the haploidnumber.

d. A cell that will not divide again remains in the GÂ2 stage ofinterphase.