Chapter 2: Chromosomes and Cellular Reproduction

CH2 Test Questions and Answers

Eukaryotes and archaea

Histone proteins may be found associated with DNA in___.

True

Errors in chromosome separation can result in a miscarriage.

False

Errors in chromosome separation are rarely a problem for an organism.

True

Errors in chromosome separation can result in a child with severe handicaps.

True

Errors in chromosome separation can result in cancer.

True

Errors in chromosome separation can cause numerous problems for an organism.

Mitotic spindles form

What occurs during prophase of mitosis?

Centromere

The attachment point on the chromosome for spindle microtubules is the:

Origin of replication

In prokaryotes, replication usually begins at a specific place on the chromosome called the:

Chromosomes become highly condensed

What is NOT a common feature of cell reproduction in all organisms?

are circular

Prokaryotic chromosomes do NOT have telomeres because they___.

M (metaphase)

A dividing eukaryotic cell is treated with a drug that inhibits the molecular motors associated with kinetochores. At which cell cycle stage would it stop?

sporophyte; gametophyte

The ___ is a diploid cell that produces haploid spores through meiosis, and the ___ produces haploid gametes through mitosis.

Crossing over AND random assortment of maternal and paternal chromosomes

Which of the events of meiosis creates genetic variation among the gametes?

Chiasmata

During prophase I of meiosis, crossing over is indicated by what microscopically visible structure?

Cohesin

__ keeps sister chromatids together after DNA replication during S phase through metaphase of mitosis. The breakdown of _ allows the sister chromatids to separate from each other during anaphase. What is the term that can fill both blanks?

Meiosis II occurs in haploid cells (not diploid cells). Mitosis can occur in both haploid and diploid cells.

What is a key difference between meiosis II and mitosis?

shugoshin; sister chromatids

During meiosis I, () protects centromeric cohesin from being cleaved by separase, ensuring that () remain together until meiosis II.

7

The cells of a mature pea plant have 14 chromosomes. In a pea plant ovary, how many chromosomes would the nucleus of a megaspore contain?

metaphase II; 2n= 40

You take a cell from a newly identified animal species and look at it under a microscope. The cell is isolated from a testis of the animal. The cell has 20 condensed, replicated chromosomes attached to the spindle. These chromosomes look different from one another, have different lengths, and line up in the middle of the cell. The cell has no nuclear envelope, no bivalents, or any signs of cytokinesis. The cell is in (), and this species (not the cell) is ()

Telephase

Nuclear membrane disintegrates

Metaphase

Chromosomes line up in the middle of the cell

Prophase

Condensin proteins bind to DNA, causing chromosomes to condense

Telephase

Chromosomes relax (or decondense)

True

Archaea are more closely related to eukaryotes than to eubacteria.

Origins of replication; telomeres; a centromere

In order to be functional, what does a eukaryotic chromosome require?

protection of the chromosome ends

A eukaryotic chromosome that lacked telomeres would also lack:

telocentric

A chromosome with a centromere at the very end is called:

kinetochore

Which structural component of a eukaryotic chromosome is the attachment point for spindle microtubules during the M phase?

spindle-assembly checkpoint

A cell just finished its mitosis and gave rise to two daughter cells that contain losses of some chromosomes and extra copies of other chromosomes. Defects in what is most likely responsible for the aberrant outcomes?

occurs in a diploid sporophyte cell to generate haploid cells that will become gametophytes

Meiosis in plants:

Leptotene, zygotene, pachytene, diplotene, and diakinesis

Prophase I substages (in order):

prophase of meiosis I

Crossing over usually occurs during:

triploid

Following pollination, the endosperm is:

Haploid

Microspore

Diploid

Microsporocyte

Haploid

Megaspore

Triploid

Endosperm

No alleles of the A gene are on one of the homologous chromosomes; Two alleles of the same gene (D and d) are on the same chromosome; Sister chromatids do not have identical alleles for the B gene; It appears that homologous chromosomes rather than the sister chromatids are separating

Errors in the drawing of mitotic anaphase: