BIOL 112 Lecture Notes - Lecture 9: Meiosis, Ploidy, Metaphase

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18 Nov 2016

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BIOL 112 Full Course Notes

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1 nuclear division = form identical diploid 2n cells: prophase = no synapsis/no crossing over, metaphase = individual chromosomes align, anaphase = chromatids separate. 2 nuclear divisions = form different haploid n cells: prophase 1 = synapsis & crossing over - tetrads, metaphase 1 = tetrads/pairs align - independent. Assortment: anaphase 1 = tetrads/pairs separate, metaphase 2 = individual chromosomes align, anaphase 3= chromatids separate. * fusion of 2 haploid gametes = fertilization/syngamy diploid zygote. 1- meiosis in sporangia produces spores = n haploid. 2- spores do mitosis & become multicellular = n haploid gametophyte since spores already n haploid. 3- gametes fuse & produce 2n diploid zygote & grows by mitosis to become sporophyte. 4- 2n diploid cells in sporophyte -sporangia- undergo meiosis to produce n haploid spores which. Alternation of generations- alternation of 2n diploid & n haploid stages.

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Determine whether the following applies to mitosis, meiosis, orboth; also identify the specific stage of cell division thatapplies (e.g. mitosis prophase, meiosis anaphase II, etc)

1) chromosomes pairs line up across the center of the cell

2) sister chromatids seperate

3) spindle fibers separate homologous chromosomes

4) 4 haploid daughter cells are produced

5) a cell 1st undergoes DNA replication

6) chromosomes line up single file across the middle of thecell

7) sister chromatids separate from each other

8) 2 haploid daughter cells form

9) the nuclear membrane re forms

10) spindle fibers attach to pairs of homologous chromosomes

11) the nuclear membrane begins to dissolve

12) centrosomes duplicate

13) synapsis and crossing over occurs

14) 2 diploid daughter cells form

turquoiseporpoise808

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

What is the purpose of meiosis?

To enable an organism to produce gametes

To allow for growth

To allow an organism to replace damaged cells

Question 2

Select one answer.

10 points

Mitosis results in ________ and meiosis results in ________.

gametes, somatic cells

gametes, gametes

somatic cells, somatic cells

somatic cells, gametes

Question 3

Select one answer.

10 points

Which of the following tasks is accomplished through the processof meiosis?

Cell growth

Production of sperm or eggs

Replacement of dysfunctional cells

Question 4

Select one answer.

10 points

What advantage does sexual reproduction have over asexualreproduction?

All other selections are true.

Sexual reproduction provides more genetic variability

Sexual reproduction doubles the number of chromosomes in aspecies

Sexual reproduction is more efficient

Question 5

Select one answer.

10 points

Crossing over occurs between homologous chromosomes during whatstage of cell division? (Read each option carefully.)

Prophase I of meiosis

Prophase of mitosis

Prophase II of meiosis

Interphase

Question 6

Select one answer.

10 points

Corn has 20 chromosomes. When corn undergoes meiosis how manychromosomes are found in the gametes?

Question 7

Select one answer.

10 points

Homologous chromosomes separate and are pulled to opposite sidesof the cell during what stage of cell division? (Read each optioncarefully.)

Metaphase I of meiosis

Anaphase II of meiosis

Anaphase I of meiosis

Anaphase of mitosis

Question 8

Select one answer.

10 points

Mitosis results in ______ cells and meiosis results in _______cells.

diploid, haploid

haploid, diploid

diploid, diploid

haploid, haploid

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BIOL 112 Lecture Notes - Lecture 9: Meiosis, Ploidy, Metaphase

BIOL 112 Full Course Notes

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