Module #8: Mendelian Genetics

Question 1

True Breeding

Answer 1

If an organism has a certain characteristic that is always passed on to it’s offspring we say that this organism bred true with respect to that characteristic

Question 2

Allele

Answer 2

One of a pair of genes that occupies the same position on homologous chromosomes

Question 3

Genotype

Answer 3

Two letter set that represents the alleles an organism possesses for a certain trait

Question 4

Phenotype

Answer 4

The observable expression of an organism’s genes

Question 5

Homozygous genotype

Answer 5

A genotype in which both alleles are identical

Question 6

Heterozygous genotype

Answer 6

A genotype with two different alleles

Question 7

Dominant allele

Answer 7

An allele that will determine the phenotype if just one is present in the genotype

Question 8

Recessive allele

Answer 8

An allele that will not determine the phenotype unless the genotype is homozygous in that allele

Question 9

Pedigree

Answer 9

A diagram that follows a particular phenotype through several generations

Question 10

Monohybrid cross

Answer 10

A cross between two individuals concentrating on only one definable trait

Question 11

Dihybrid cross

Answer 11

A cross between two individuals, concentrating on two definable traits

Question 12

Autosomes

Answer 12

Chromosomes that do not determine the sex of an individual

Question 13

Sex chromosomes

Answer 13

Chromosomes that determine the sex of an individual

Question 14

Antigen

Answer 14

A protein that, when introduced in the blood, triggers the production of an antibody

Question 15

Autosomal inheritance

Answer 15

Inheritance of a genetic trait not on a sex chromosome

Question 16

Genetic disease carrier

Answer 16

A person who is heterozygous in a recessive genetic disorder

Question 17

Sex linked inheritance

Answer 17

Inheritance of a genetic trait located on the sex chromosome

Question 18

Change in chromosome structure

Answer 18

A situation in which a chromosome loses or gains genes during meiosis

Question 19

Mutation

Answer 19

A radical chemical change in one or more alleles

Question 20

Change in chromosome number

Answer 20

A situation in which abnormal cellular events in meiosis lead to either none of a particular chromosome in the gamete or more than one chromosome in the gamete

Question 21

Mendel’s principals of genetics

Answer 21

1. The traits of an organism are determined by its genes
2. Each organism has two alleles that make up the genotype for a given trait
3. In sexual reproduction, each parent contributes ONLY ONE of it’s alleles to it’s offspring
4. In each genotype there is a dominant allele. If it exists in an organism, the phenotype is determined by that allele