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.

Question 12

What does “Homo”- mean?

Answer 12

“Same”

As in “same chromosomes” when referring to homologous chromosomes or even “same versions of genes” when referring to homozygous recessive or homozygous dominant.

Question 13

What does -“ploid” mean?

Answer 13

number of copies of DNA

Example, humans are Diploid (two copies)
sperm and egg cells are haploid (one copy)
some strawberries are octploid (eight copies)

Question 14

What does “tetra”- mean?

What is a “tetrad”?

Answer 14

A group of four (also why tetris shapes are built from four blocks in the game)

A tetrad is a group of 4 homologous chromosomes.

Question 15

What are alleles?

Answer 15

different versions of the same gene.

Example, gene for blood type has 3 different alleles: A B and O.