Mer Scott
Quiz by , created more than 1 year ago

• Explain what the sexual cycle is. • Identify the structures of meiosis. • Summarise the order of events in meiosis. • Compare and contrast the events that occur in meiosis and mitosis. • Illustrate how meiosis leads to gametic and zygotic diversity

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Mer Scott
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L20 The sexual cycle, meiosis and the value of sex

Question 1 of 14

1

Choose the incorrect statement about the sexual cycle.

Select one of the following:

  • Adult eukaryotic cells are diploid.

  • Cells in the ovaries and testes are the only cells which undergo meiosis.

  • Gametic cells are diploid.

  • The ovum or sperm is haploid.

  • When an adult gametic cell undergoes mitosis, it is still diploid.

Explanation

Question 2 of 14

1

Choose the correct statements.

Select one or more of the following:

  • Two gametes which are haploid fuse to make a diploid zygote.

  • Meiosis halves the number of of chromosomes going into gametes.

  • Mitosis creates two haploid daughter cells.

  • Meiosis creates four diploid daughter cells.

Explanation

Question 3 of 14

1

Meiosis I separates sister chromatids.

Select one of the following:

  • True
  • False

Explanation

Question 4 of 14

1

Choose the incorrect statement about Meiosis I.

Select one of the following:

  • Crossing over occurs between homologous pairs during metaphase.

  • Four sister chromatids form a tetrad in prophase.

  • Crossing over occurs at a chiasmata, the joining of a locus on each chromatid.

  • In anaphase I, sister chromatids remain attached when the spindles shorten.

Explanation

Question 5 of 14

1

Meiosis I produces two diploid cells.

Select one of the following:

  • True
  • False

Explanation

Question 6 of 14

1

Choose the statements about Meiosis II that are false.

Select one or more of the following:

  • Two haploid cells with doubled chromosomes enter prophase II.

  • Crossing over occurs between sister chromosomes during prophase II.

  • In anaphase II, sister chromatids are pulled apart.

  • At the end of telophase II, two haploid cells are present.

Explanation

Question 7 of 14

1

There are no chiasmata formed in mitosis.

Select one of the following:

  • True
  • False

Explanation

Question 8 of 14

1

If the sperm of a mouse has 3 picograms of DNA,
the amount of DNA in the nucleus of a somatic cell
about to divide by mitosis would be:

Select one of the following:

  • 3pg

  • 6pg

  • 12pg

  • 24pg

Explanation

Question 9 of 14

1

The structures that move to the spindle poles at
anaphase of meiosis I usually differ from those that
move to the poles at anaphase II with respect to:

Select one of the following:

  • chromatid number

  • gene copy number

  • the ratio of maternal to paternal genes

  • all of the above

Explanation

Question 10 of 14

1

In males, diploid spermatocytes undergo meiosis to produce two secondary spermatocytes. These undergo meiosis to form haploid spermatids, or, sperm. Tens of of these can be produced per day.
In females, 500,000 oocytes are present in a six month old fetus. These begin meiosis I but are suspended in until ovulation. After ovulation, meiosis I and produces two haploid cells, one becomes a oocyte and the other becomes the first polar body. The first polar body is suspended in until fertilisation, upon which it completes meiosis II and makes two . The secondary oocyte undergoes meiosis II to produce the fourth polar body, and the , which are both haploid. than 500 ovum will be produced in the female lifespan.

Drag and drop to complete the text.

    primary
    I
    haploid
    II
    millions
    thousands
    diploid primary
    prophase I
    finishes
    secondary
    metaphase II
    haploid polar bodies
    ovum
    Less

Explanation

Question 11 of 14

1

How can you calculate the possible number of gamete combinations using the haploid number n?

Select one of the following:

  • 2n

  • 2n^2

  • n^2

  • 2^n

Explanation

Question 12 of 14

1

Because of sexual reproduction, and because human's haploid number is 23 chromosomes, there are approximately 8 million gametic combinations.

Select one of the following:

  • True
  • False

Explanation

Question 13 of 14

1

Drosophila males do not undergo crossing over at meiosis. If Drosophila has a diploid number of 8, how many genetically distinct types of gametes can be produced by a male Drosophila?

Select one of the following:

  • 4

  • 8

  • 16

  • 32

Explanation

Question 14 of 14

1

Presence of the sexual cycle in a species has the potential to:

Select one of the following:

  • decrease competition among offspring

  • allow the species to respond better
    to parasites

  • increase evolutionary flexibility

  • all of the above

Explanation

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