Biology Quiz 8

After telophase I of meiosis, the chromosomal makeup of each daughter cell is

haploid, and the chromosomes are each composed of two chromatids.

The following question refers to the essential steps in meiosis described below. Formation of four new nuclei, each with half the chromosomes present in the parental nucleus Alignment of tetrads at the metaphase plate Separation of sister chromatids Separation of the homologs; no uncoupling of the centromere Synapsis, chromosomes moving to the middle of the cell in pairs Which of the steps takes place in both mitosis and meiosis?

3

A triploid cell contains three sets of chromosomes. If a cell of a usually diploid species with 42 chromosomes per cell is triploid, this cell would be expected to have which of the following?

63 chromosomes in 21 sets of 3

Which of these statements is false?

At sexual maturity, ovaries and testes produce diploid gametes by meiosis.

For the following questions, match the key event of meiosis with the stages listed below. Tetrads of chromosomes are aligned at the equator of the spindle; alignment determines independent assortment.

II

Which of the following happens at the conclusion of meiosis I?

Homologous chromosomes are separated.

Refer to the drawings in Figure 13.2 of a single pair of homologous chromosomes as they might appear during various stages of either mitosis or meiosis, and answer the following questions. Which diagram represents anaphase I of meiosis?

I

You have isolated DNA from three different cell types of an organism, determined the relative DNA content for each type, and plotted the results on the graph shown in Figure 13.3. Refer to the graph to answer the following questions. Which sample might represent a zygote?

I

You have isolated DNA from three different cell types of an organism, determined the relative DNA content for each type, and plotted the results on the graph shown in Figure 13.3. Refer to the graph to answer the following questions. Which sample of DNA might be from a nerve cell arrested in G0 of the cell cycle?

I

For the following questions, match the key event of meiosis with the stages listed below. Synaptonemal complexes form or are still present.

I only

Refer to the life cycles illustrated in Figure 13.1 to answer the following questions. Which of the life cycles is typical for animals?

I only

You have isolated DNA from three different cell types of an organism, determined the relative DNA content for each type, and plotted the results on the graph shown in Figure 13.3. Refer to the graph to answer the following questions. Which sample might represent an animal cell in the G2 phase of the cell cycle?

II

If a cell has completed the first meiotic division and is just beginning meiosis II, which of the following is an appropriate description of its contents?

It has half the amount of DNA as the cell that began meiosis.

A given organism has 46 chromosomes in its karyotype. We can therefore conclude which of the following?

Its gametes must have 23 chromosomes.

When homologous chromosomes crossover, what occurs?

Specific proteins break the two strands and re-join them with their homologs.

A cell divides to produce two daughter cells that are genetically different.

The statement is true for meiosis I only.

Independent assortment of chromosomes occurs.

The statement is true for meiosis I only.

Chromatids are separated from each other.

The statement is true for mitosis and meiosis II.

How do cells at the completion of meiosis compare with cells that have replicated their DNA and are just about to begin meiosis?

They have half the number of chromosomes and one-fourth the amount of DNA.

Which of the following best describes a karyotype?

a display of each of the chromosomes of a single cell

A human cell containing 22 autosomes and a Y chromosome is

a sperm.

If an organism is diploid and a certain gene found in the organism has 18 known alleles (variants), then any given organism of that species can/must have which of the following?

at most, 2 alleles for that gene

How does the sexual life cycle increase the genetic variation in a species?

by allowing crossing over

The human X and Y chromosomes

include genes that determine an individual's sex.

Homologous chromosomes move toward opposite poles of a dividing cell during

meiosis I.

At which stage of mitosis are chromosomes usually photographed in the preparation of a karyotype?

metaphase

Which life cycle stage is found in plants but not animals?

multicellular haploid

Refer to the following information and Figure 13.4 to answer the following questions. A certain (hypothetical) organism is diploid, has either blue or orange wings as the consequence of one of its genes on chromosome 12, and has either long or short antennae as the result of a second gene on chromosome 19, as shown in Figure 13.4. A certain female's number 12 chromosomes both have the blue gene and number 19 chromosomes both have the long gene. As cells in her ovaries undergo meiosis, her resulting eggs (ova) may have which of the following?

one chromosome 12 with one blue gene and one chromosome 19 with one long gene

Refer to the following information and Figure 13.4 to answer the following questions. A certain (hypothetical) organism is diploid, has either blue or orange wings as the consequence of one of its genes on chromosome 12, and has either long or short antennae as the result of a second gene on chromosome 19, as shown in Figure 13.4. f a female of this species has one chromosome 12 with a blue gene and another chromosome 12 with an orange gene, and has both number 19 chromosomes with short genes, she will produce which of the following egg types?

one-half blue short and one-half orange short gene eggs

When we see chiasmata under a microscope, that lets us know which of the following has occurred?

prophase I

Meiosis II is similar to mitosis in that

sister chromatids separate during anaphase.

Which of the following occurs in meiosis but not in mitosis?

synapsis of chromosomes

To visualize and identify meiotic cells at metaphase with a microscope, what would you look for?

tetrads all aligned at the cell's center

Which of the following defines a genome?

the complete set of an organism's genes

Independent assortment of chromosomes is a result of

the random and independent way in which each pair of homologous chromosomes lines up at the metaphase plate during meiosis I.