Biology 1201A Lecture Notes - Lecture 9: Kinetochore, Prometaphase, Microtubule

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emeraldwallaby169

27 Mar 2016

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We continue our exploration the origins of genetic diversity. Outcomes: meiosis 4 unique haploid and mitosis 2 identical diploid. Prophase of meiosis: pairing of homologous chromosomes (tetrads) Meiosis in germ cells (sex) and mitosis in somatic cells. Meiosis has two divisions and mitosis has one division. Meiosis i separates homologous chromosomes and mitosis separates chromatids of chromosomes. Physical exchange of sequences between chromatids of homologous chromosome. When they form a tetrad, they"re not side by side, but rather on top of each other. Swapping pieces of one homologous chromosome to another. Protein complex ( synaptonemal complex") forms between homologous chromosomes. Segments of non-sister chromatids cross-over (forming chiasmata") are swapped. Results in new combinations of alleles on chromosomes. The letter case difference is for the difference in alleles. Another way to get gene combination is when they switch pieces but in the wrong place. We end up with two copies on one chromatid.

Related Questions

Which of the following statements are false about the comparison between mitosis and meiosis? Select all. that apply.

1.Two cytokinesis events occur in mitosis but only one in meiosis

2.Meiosis results in half the number of homologous chromosome pairs as the original cell whereas mitosis has the same number as the original cell

3. Mitosis occurs in somatic cells while meiosis only occurs in germ cells

4.Both haploid and diploid cells undergo mitosis and meiosis

5.Both mitosis and meiosis have one round of DNA replication in the preceding Interphase period

6. Chromosomes undergo disjunction in mitosis but not in meiosis

7.Meiosis leads to a reductive division in the number of chromosomes whereas mitosis does not

Thank you!

Which of the following statements are false about the comparison between mitosis and meiosis? Select all. that apply. Multiple answers: You can select more than one option A Two cytokinesis events occur in mitosis but only one in meiosis B Meiosis results in half the number of homologous chromosome pairs as the original cell whereas mitosis has the same number as the original cell C Mitosis occurs in somatic cells while meiosis only occurs in germ cells D Both haploid and diploid cells undergo mitosis and meiosis E Both mitosis and meiosis have one round of DNA replication in the preceding Interphase period F Chromosomes undergo disjunction in mitosis but not in meiosis G Meiosis leads to a reductive division in the number of chromosomes whereas mitosis does not Unanswered

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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Biology 1201A Lecture Notes - Lecture 9: Kinetochore, Prometaphase, Microtubule

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