BIOL 1020 Lecture Notes - Lecture 22: Mitosis, Prophase, Metaphase

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blushseal731

2 Nov 2017

School

University of Manitoba

Department

Biological Sciences

Course

BIOL 1020

Professor

Michael P.Shaw

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BIOL 1020 Full Course Notes

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Division in meiosis 1 occur in four phases (takes us from 2n double stranded to 1n double stranded) Prophase 1 is typically occupying more than 90% of the time required for meiosis. In synapsis, homologous chromosomes loosely pair up, aligned gene by gene. In crossing over, non-sister chromatids exchange dna segments. Each pair of chromosomes forms a tetrad, a group of four chromatids. Each tetrad usually has one or more chiasmata. When homologous pairs line up together we call it a tetrad. In metaphase 1, tetrads line up at the metaphase plate, with one chromosome facing each pole. Microtubules form one pole are attached to the kinetochore of one chromosome of each tetrad. Microtubules form the other pole are attached to the kinetochore of the other chromosome. In anaphase 1, pairs of homologous chromosomes separate. One chromosome moves towards each pole, guided by the spindle apparatus.

Related Questions

31.????? interphase A. cytoplasm divided between the two daughter cells

32.????? chromosomenumber B. final phase of mitosis; daughter nuclei form

33.????? chromatid C. sum total of chromosomes in all cells of a given

type

34.????? cytokinesis D. chromosomes condense and mitotic spindle

begins to form

35.????? metaphase E. chromosomes line up at spindle equator

36.????? alleles F. sister chromatids separate, move to opposite

spindle poles now

37.????? prophase G. none between meiosis I and II

38.????? telophase H. half of a chromosome in prophase

39. ????? anaphase I. different molecular forms of the same gene

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ultramarineporpoise990

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.

yellowpig507

Question 1 (2 points)

In which phase of cell division is marked by the dissolution of the nuclear membrane, the condensation of chromosomes, and the formation of the mitotic spindle?

Question 1 options:

	prophase
	metaphase
	telophase
	anaphase

Question 2 (2 points)

The physical separation of cells during cell division is called:

Question 2 options:

	Cytokinesis
	Telophase
	Interphase
	Chromosome
	Cell plate

Question 3 (2 points)

Meiosis is necessary for sexual reproduction; the gametes formed during this process before fertilization are _______________.

Question 3 options:

	Haploid
	Diploid
	Zygote
	Homologous
	Tetrads

Question 4 (2 points)

Mitosis is the process by which a ___________ cell separates the chromosomes in its nucleus into two identical sets of nuclei.

Question 4 options:

	eukaryotic
	prokaryotic
	bacterial
	all of these are correct

Question 5 (2 points)

Which of the following statements about crossing over is INCORRECT?

Question 5 options:

	It occurs between homologous chromosomes
	It allows for two parents to produce many different types of offspring
	It contributes to genetic diversity in a population
	It occurs during prophase I of mitosis

BIOL 1020 Lecture Notes - Lecture 22: Mitosis, Prophase, Metaphase

BIOL 1020 Full Course Notes

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