Biology Chapter 8

How many pairs of autosomes do humans have?

22

A human somatic cell contains _____ chromosomes.

46

Oncologists (medical doctors who treat cancer patients) routinely take biopsies (samples) of tissue from patients to determine whether the tissue is cancerous or not. What would be the best experiment to do to determine whether cells from the tissue sample are cancerous?

Add cells from the tissue sample to a cell culture dish and compare their growth against a sample of noncancerous cells from the patient.

Which of the following statements is false?

An X chromosome is an autosome.

During meiosis I, homologous chromosomes form a tetrad and crossing over occurs. What is the outcome of crossing over?

Crossing over creates new combinations of genes present on a single chromosome.

The first step of bacterial replication is _____.

DNA replication

Which of the following statements correctly describes the behavior of a tetrad during anaphase I of meiosis?

It splits into two pairs of sister chromatids, and one pair goes to each pole of the dividing cell.

Which of the following statements regarding the function of mitosis is false?

Mitosis allows organisms to generate genetic diversity.

What event will immediately follow the event shown in this image?

The cell will divide into two plant cells.

Within one chromosome, what is the relationship between the sequence of bases in DNA of one sister chromatid compared to the other?

The sequences are identical.

You are asked to culture an unidentified sample of animal tissue. You notice that the cells seem to fail to exhibit density-dependent inhibition. The source of this tissue sample is most likely

a cancerous tumor.

What is different concerning the DNA in bacterial cells as opposed to eukaryotic cells?

all of the above are differences between prokaryotic and eukaryotic DNA

The stage of mitosis during which the chromosomes move toward separate poles of the cell is _____.

anaphase

In many organisms, including humans, chromosomes are found in homologous pairs. Homologous chromosomes _____.

are identical in the arrangement of their genes, but some versions of the genes may differ between the chromosomes

Mature human nerve cells and muscle cells

are permanently in a state of nondivision.

Bacteria divide by:

binary fission

Which of the following occurs during interphase?

cell growth and duplication of the chromosomes

In the picture below, the chromosomal region where the nonsister chromatids are crossing over is called a(n) _____.

chiasma

Meiosis differs from mitosis in that _____ only occurs in meiosis.

crossing over

A cleavage furrow forms in an animal cell during _____.

cytokinesis

The process by which the cytoplasm of a eukaryotic cell divides to produce two cells is called

cytokinesis.

As a patch of scraped skin heals, the cells fill in the injured area but do not grow beyond that. This is an example of

density-dependent inhibition.

In bacterial cells, binary fission involves __________.

distribution of a copy of the single parental chromosome to each daughter cell

The function of meiosis is to make __________.

four cells with a haploid number of chromosomes

What is the typical result when a diploid cell undergoes meiosis?

four haploid cells

At the conclusion of meiosis I, the daughter cells are _____

haploid and the sister chromatids are joined

Eukaryotic cells spend most of their cell cycle in which phase?

interphase

When we say that an organism is haploid, we mean that _____.

its cells each have one set of chromosomes

During which phase of mitosis do the chromosomes line up on a plane equidistant from the two spindle poles?

metaphase

Down syndrome can be the result of _____.

nondisjunction of chromosome 21 during meiosis

Asexual reproduction _____.

produces offspring genetically identical to the parent

Crossing over occurs during _____.

prophase I

During which stage of meiosis do synapsis and crossing over occur?

prophase I

Which of the following shows mitosis in the correct chronological order?

prophase, prometaphase, metaphase, anaphase, telophase

Prior to mitosis, each chromosome of a eukaryotic cell consists of a pair of identical structures called

sister chromatids

The kinetochores are __________.

sites at which microtubules attach to chromosomes

During which phase of mitosis does the nuclear envelope re-form?

telophase

Mitosis and cytokinesis result in the formation of __________; meiosis and cytokinesis result in the formation of __________.

two diploid cells : four haploid cells

At the end of telophase I of meiosis, as cytokinesis occurs, there are __________.

two haploid cells