Pages 263-266, 223-226, 237-246

Question 1

Dihybrid cross

Answer 1

mating between two individuals both heterozygous for two traits.

Question 2

Independent assortment

Answer 2

two alleles are sorted into gametes independently of each other.

Question 3

Dependent Assortment

Answer 3

transmission of one allele to a gamete depends on the transmission of another.

Question 4

Principle of independent assortment

Answer 4

alleles of different genes are transmitted independently of one another.

Question 5

Testcross

Answer 5

uses a parent that contributes only recessive alleles to its offspring and helps to determine the unknown genotype of the second parent.

Question 6

Transmission of genetics framework based on:

Answer 6

(1) The segregation of discrete, paired genes into separate gametes.
(2) The independent assortment of genes that affect different traits.

Question 7

Mitosis

Answer 7

during cell replication, this divides the replicated chromosomes to form two daughter nuclei with identical chromosomes and genes. Usually accomplished by cytokinesis.

Question 8

Cytokinesis

Answer 8

cytoplasmic division that results in two daughter cells.

Question 9

Chromatin

Answer 9

eukaryotic chromosomes consist of DNA warped around the globular histone proteins.

Question 10

Centromere

Answer 10

structure that joins sister chromatids.

Question 11

Kinetochores

Answer 11

structures on sister chromatids where microtubules attach.

Question 12

Weismann

Answer 12

proposed a hypothesis that there must be a distinctive type of cell division that leads to a reduction in chromosome number during reproduction.

Question 13

meiosis

Answer 13

nuclear division that leads to a halving of chromosome number and ultimately to the production of sperm and egg.

Question 14

Homologous chromosomes (homologs)

Answer 14

chromosomes that are the same size and shape. A pair is a homologous pair. Carry the same genes.

Question 15

Diploid

Answer 15

organisms that have two versions of each type of chromosome. Have two alleles of each gene. One allele is carried on each of the homologous pairs of chromosomes.

Question 16

Haploid

Answer 16

organisms who cells contain just one type of each chromosome. Only have one copy of each chromosome and just one allele of each gene.

Question 17

Haploid number

Answer 17

n; stands for the number of distinct type of chromosomes in a given cell. If sex chromosomes are present, they are counted as a single type in the haploid number. To indicate the number of complete chromosome sets observed, a number is placed before the n.

Question 18

Ploidy

Answer 18

combination of the number of sets and n. Indicates the number of each type of chromosome present. Stating a cell’s ploidy is the same as stating the number of haploid chromosome sets present.

Question 19

Polyloid

Answer 19

have three or more of each type of chromosome in each cell.

Question 20

Sister chromatids

Answer 20

contain identical copies of the DNA double helix present in the un-replicated chromosome and the same genetic info.

Question 21

Non-sister chromatids

Answer 21

chromatids belonging to homologous chromosomes.

Question 22

bivalent (tetrad)

Answer 22

homologous replicated chromosomes that are joined together during prophase I and metaphase I of meiosis.

Question 23

diploid number

Answer 23

number of chromosomes present in a diploid cell; symbolized 2n.