Lab 3 Inheritance

Question 1

Gregor Mendel

Answer 1

A European monk who conducted tests on pea plants and identified two important principles of classification.

Question 2

Law of segregation

Answer 2

Law stating that the units (or genes) for traits appear separately in the (sex cells of) parents and are then reunited in an offspring.

Question 3

Law of independent assortment

Answer 3

Law stating that the units (or genes) for different traits are sorted (and passed on) independently of one another.

Question 4

Dominant

Answer 4

A dominant allele masks the effects of other alleles for a trait; may also be used in reference to dominant traits or dominant phenotypes.

Question 5

Recessive

Answer 5

A recessive allele is masked by a dominant allele for a trait; may also be used in reference to recessive traits or recessive phenotypes.

Question 6

Genotype

Answer 6

The specific alleles an organism has for a trait.

Question 7

Homozygous dominant

Answer 7

An organism’s genotype for a trait when it has two dominant alleles for the trait (such as RR).

Question 8

Homozygous recessive

Answer 8

An organism’s genotype for a trait when it has two recessive alleles for the trait (such as rr).

Question 9

Heterozygous

Answer 9

An organism’s genotype for a trait when it has one dominant allele and one recessive allele for the trait (such as Rr).

Question 10

Phenotype

Answer 10

The physical expression of an organism’s genotype for a trait.

Question 11

Punnett square

Answer 11

The method of diagramming inheritance where parental genotypes are used to estimate the probability of various genotypes in a potential offspring.

Question 12

Pedigree diagram

Answer 12

The method of diagramming inheritance that shows the phenotypes of individuals from multiple generations in a family.

Question 13

Mendelian trait

Answer 13

A trait controlled by one gene (although there may be multiple alleles for that one gene).

Question 14

Genetic locus (loci, plural)

Answer 14

The location of a gene on a chromosome.

Question 15

Polygenic trait
Polygenic trait

Answer 15

A trait controlled by alleles at multiple genetic loci.

Question 16

Sex-linked trait
Sex-linked trait

Answer 16

A trait coded for by a gene on the X or Y chromosome (although typically used to refer to traits on the X chromosome).

Question 17

Antigen (in ABO blood group system)

Answer 17

The cell surface marker found on red blood cells that relates to an individual’s ABO blood type and triggers antibody reactions to a foreign blood antigen.

Question 17

Color blindness
Color blindness

Answer 17

Limited perception of certain colors, which may be the result of variation in the alleles for color vision.

Question 18

Codominant

Answer 18

Circumstance where multiple alleles are expressed in the phenotype, without one being clearly dominant over the other.

Question 19

Antibody

Answer 19

A protein that attacks antigens directly or marks them for attack by other parts of the immune system.