Text Chapter 7: Patterns / Chromosomal Basis of Inheritance

Question 1

Principle of Genetic Segregation

Answer 1

in the formation of gametes, the members of a pair of alleles separate (or segregate) cleanly from each other so that only one member is included in each gamete- each gamete has an equal probability of containing either member of the allele pair

Question 2

Principle of Independent Assortment

Answer 2

when gametes are formed, the alleles of one gene segregate independently of the alleles of another gene producing equal proportions of all possible gamete types

Question 3

Allele

Answer 3

alternate form of a gene

Question 4

Gene

Answer 4

sequence of DNA that codes for a protein, gives rise to a physical trait

Question 5

Dominant

Answer 5

masks recessive alleles, homozygous dominant, heterozygous

Question 6

Recessive

Answer 6

masked by dominant, homozygous recessive

Question 7

Genotype

Answer 7

alleles carried by an individual

Question 8

Phenotype

Answer 8

physical characteristic or appearance of an individual

Question 9

F1

Answer 9

first generation

Question 10

F2

Answer 10

second generation

Question 11

Heterozygous

Answer 11

cells contain two different alleles at a gene

Question 12

Homozygous

Answer 12

cells contain two of the same allele at a gene

Question 13

Autosome

Answer 13

any chromosome that is not a sex chromosome

Question 14

Sex Chromosome

Answer 14

homologous chromosomes that differ in genetic composition between males and females

Question 15

Incomplete Dominance

Answer 15

neither allele masks the other and both are observed as blending in the heterozygote

Question 16

Codominance

Answer 16

neither allele masks the other so that effects of both alleles are observed in heterozygotes without blending

Question 17

Complete Dominance

Answer 17

the dominant allele completely masks the recessive allele in a heterozygous condition

Question 18

Locus

Answer 18

area on the chromosome where gene is located

Question 19

Multiple Alleles

Answer 19

three or more alleles exist for one trait

Question 20

Peiotropic Effects

Answer 20

one gene effects many traits

Question 21

Polygenic Inheritance

Answer 21

many genes affect one trait

Question 22

How Gender is Determined

Answer 22

Gender is determined by the sperm- females donate one X chromosome and males donate either an X or a Y chromosome which determines the sex of the child

Question 23

Pattern of Inheritance for Sex-Linked Traits

Answer 23

Males carry only one copy of genes on the X chromosome but females carry two copies, therefore their sex-linked traits have a greater influence on male children

Question 24

How Human Chromosomal Abnormalities Arise

Answer 24

Nondisjunction

Question 25

Nondisjunction

Answer 25

the failure of homologues or chromatids to separate during meiosis