Chapter 11.4

Question 1

How many sets of genes are found in most adult organisms?

Answer 1

The diploid cells of most adult organisms contain two complete sets of inherited chromosomes and two complete sets of genes

Question 2

What events occur during each phase of meiosis?

Answer 2

Prophase l- each replicated chromosome pairs with its corresponding homologous chromosome
Metaphase l- paired homologous chromosomes line up across the center of the cell
Anaphase l- spindle fibers pull each homologous chromosome pair toward opposite ends of the cell
Telophase l- nuclear membrane forms around each cluster of chromosomes. Cytokinesis follows forming 2 new cells.
Prophase II- chromosomes (2 chromatids) become visible
Metaphase ll- chromomes line up across center of cell
Anaphase ll- spindle fibers pull chromosomes toward opposite ends of the cell
Telophase 11- nuclear membrane forms around each cluster of chromosomes. Cytokinesis follows forming a total of 4 new haploid cells

Question 3

How is meiosis different from mitosis?

Answer 3

Mitosis - two sets of genetic material separate, each daughter cell receives one complete set of chromosomes. Does not change the chromosome number (23 pairs) in daughter cells.
Meiosis - two sets of genetic material separate, each daughter cell receives on complete set of chromosomes, but then another round of division takes place to produce a total of 4 cells with a haploid number (half normal number of chromosomes in a body cell).

Question 4

How can two alleles from different genes be inherited together?

Answer 4

Alleles of different genes tend to be inherited together from one generation to the next when those genes are located on the same chromosome. (like hitch-hiking)

Question 5

Homologous

Answer 5

homo = same. Means that each of the four chromosomes from the male parent has a corresponding chromosome from the female parent.

Question 6

Diploid

Answer 6

A cell contains both sets of homologous chromosomes. “Di” = 2.

Question 7

Haploid

Answer 7

cells that only contain a single set of chromosomes. Example = gametes (sperm and eggs)

Question 8

Meiosis

Answer 8

process in which the number of chromosomes per cell is cut in half through the separation of homologous chromosomes in a diploid cell.

Question 9

Tetrad

Answer 9

Structure that contains 4 chromatids (homologous chromosomes form tetrads).

Question 10

Crossing-over

Answer 10

Homologous chromosomes share parts of their genes by switching areas on a chromatid.

Question 11

Zygote

Answer 11

a fertilized egg (meaning combined sperm and egg) which will eventually undergo cell division to form a new organism.