Bio-110 Chapter 8B

An individual with a malignant tumor is said to have____________.

Cancer

Which of the following statements is correct?

Meiosis results in gametes that are used in reproduction.

______________ is the spread of cancer cells from their site of origin to other sites in the body.

Metastasis

A ___________ is a lump of abnormal cells that, although growing out of control, remains at its original site.

benign tumor

Meiosis starts with _____ cells and produces _____ gametes.

diploid ... haploid

A single cell passing through meiosis and cytokinesis results in the formation of __________.

four haploid cells In mitosis a cell that has doubled its genetic material divides into two diploid daughter cells. In meiosis a cell that has doubled its genetic material undergoes two rounds of division, resulting in four haploid cells.

Meiosis starts with a single diploid cell and produces

four haploid cells.

Meiosis II typically produces _____ cells, each of which is _____.

four...haploid

The _____ separate in meiosis I; the _____ separate in meiosis II.

homologous chromosomes ... sister chromatids

During prophase I of meiosis,

homologous chromosomes stick together in pairs.

Which term is used to describe the way homologous pairs of chromosomes line up in random orientations relative to each other during metaphase I?

independent assortment As homologous chromosomes line up during metaphase I, every pair has one chromosome from the father and one from the mother. Independent assortment means that each daughter cell randomly inherits either the maternal or paternal chromosome from each pair.

A cell preparing to undergo meiosis duplicates its chromosomes during

interphase.

A ________________ is an abnormally growing mass of cells that is actively spreading through the body.

malignant tumor

Looking through a light microscope at a cell undergoing meiosis, you see that the chromosomes have joined into XX-shaped tetrads. These tetrads are lined up along a plane that runs through the center of the cell. This cell is in _____.

meiosis I

Accidents can occur in meiosis wherein members of a chromosome pair fail to separate at anaphase. This is called __________.

nondisjunction When chromosomes don't separate, it is called nondisjunction. The resulting gametes can have either too many or too few chromosomes.

The correct order of events during meiosis is

prophase I, metaphase I, anaphase I, telophase I, cytokinesis, meiosis II.

During meiosis, segments of nonsister chromatids can trade places. This recombination of maternal and paternal genetic material is a key feature of meiosis. During what phase of meiosis does recombination occur?

prophase I. Segments of nonsister chromatids trade places during prophase I, resulting in recombination.

The function(s) of meiosis is/are _____.

reproduction (production of gametes)

Crossing over is __________.

the exchange of corresponding portions of homologous chromosomes Parts of homologous chromosomes are shuffled before they separate. The result is new combinations of genetic material (genetic recombination).

Meiosis is typically accomplished in _____.

three steps. All of the chromosomes are duplicated in a diploid cell, and then there are two cell divisions to produce a total of four haploid gametes.