9084324
Descripción
Pregunta 1
Pregunta
Choose the incorrect statement about the sexual cycle.
Respuesta
-
Adult eukaryotic cells are diploid.
-
Cells in the ovaries and testes are the only cells which undergo meiosis.
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Gametic cells are diploid.
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The ovum or sperm is haploid.
-
When an adult gametic cell undergoes mitosis, it is still diploid.
Pregunta 2
Pregunta
Choose the correct statements.
Respuesta
-
Two gametes which are haploid fuse to make a diploid zygote.
-
Meiosis halves the number of of chromosomes going into gametes.
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Mitosis creates two haploid daughter cells.
-
Meiosis creates four diploid daughter cells.
Pregunta 3
Pregunta
Meiosis I separates sister chromatids.
Respuesta
- True
- False
Pregunta 4
Pregunta
Choose the incorrect statement about Meiosis I.
Respuesta
-
Crossing over occurs between homologous pairs during metaphase.
-
Four sister chromatids form a tetrad in prophase.
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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.
Pregunta 5
Pregunta
Meiosis I produces two diploid cells.
Respuesta
- True
- False
Pregunta 6
Pregunta
Choose the statements about Meiosis II that are false.
Respuesta
-
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.
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At the end of telophase II, two haploid cells are present.
Pregunta 7
Pregunta
There are no chiasmata formed in mitosis.
Respuesta
- True
- False
Pregunta 8
Pregunta
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:
Respuesta
-
3pg
-
6pg
-
12pg
-
24pg
Pregunta 9
Pregunta
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:
Respuesta
-
chromatid number
-
gene copy number
-
the ratio of maternal to paternal genes
-
all of the above
Pregunta 10
Pregunta
In males, diploid [blank_start]primary[blank_end] spermatocytes undergo meiosis [blank_start]I[blank_end] to produce two [blank_start]haploid[blank_end] secondary spermatocytes. These undergo meiosis [blank_start]II[blank_end] to form haploid spermatids, or, sperm. Tens of [blank_start]millions[blank_end] of these can be produced per day.
In females, 500,000 [blank_start]diploid primary[blank_end] oocytes are present in a six month old fetus. These begin meiosis I but are suspended in [blank_start]prophase I[blank_end] until ovulation. After ovulation, meiosis I [blank_start]finished[blank_end] and produces two haploid cells, one becomes a [blank_start]secondary[blank_end] oocyte and the other becomes the first polar body. The first polar body is suspended in [blank_start]metaphase II[blank_end] until fertilisation, upon which it completes meiosis II and makes two [blank_start]haploid polar bodies[blank_end]. The secondary oocyte undergoes meiosis II to produce the fourth polar body, and the [blank_start]ovum[blank_end], which are both haploid. [blank_start]Less[blank_end] than 500 ovum will be produced in the female lifespan.
Respuesta
-
primary
-
I
-
haploid
-
II
-
millions
-
thousands
-
diploid primary
-
prophase I
-
finishes
-
secondary
-
metaphase II
-
haploid polar bodies
-
ovum
-
Less
Pregunta 11
Pregunta
How can you calculate the possible number of gamete combinations using the haploid number n?
Respuesta
-
2n
-
2n^2
-
n^2
-
2^n
Pregunta 12
Pregunta
Because of sexual reproduction, and because human's haploid number is 23 chromosomes, there are approximately 8 million gametic combinations.
Respuesta
- True
- False
Pregunta 13
Pregunta
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?
Respuesta
-
4
-
8
-
16
-
32
Pregunta 14
Pregunta
Presence of the sexual cycle in a species has the potential to:
Respuesta
-
decrease competition among offspring
-
allow the species to respond better to parasites
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increase evolutionary flexibility
-
all of the above
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