Chapter 11 Vocab

Question 1

Heredity

Answer 1

Transmission of genetic info from parent to offspring
Follows predictable patters

Question 2

Genetics

Answer 2

The science of heredity.
Studies genetic similarities and variation differenced between parents and offspring or among individuals of a population.

Question 3

Character

Answer 3

Observable physical feature.
Ex: seed shape, flower color

Question 4

Trait

Answer 4

(Specific) Form of a character.
Ex: Round or wrinkled seeds, purple or white flowers.

Question 5

Phenotype

Answer 5

The physical appearance of an organism.

Question 6

Genotype

Answer 6

The genetic makeup.

Question 7

What are the P, F1, and F2 gens?

Answer 7

P- Parental generation (two separate plants)
F1- First filial generation (seeds and offspring)
F2- Second filial generation (F1 plants that were allowed to self- pollinate.

Question 8

Locus

Answer 8

The site a gene occupies in the chromosome

Question 9

Alleles

Answer 9

Different forms of a particular gene which occupy corresponding loci on homologous chromosomes

Question 10

Homozygous

Answer 10

Two identical alleles

Question 11

Heterozygous

Answer 11

Two different alleles for a particular gene

Question 12

During what process do alleles for each locus segregate?

Answer 12

Meiosis

Question 13

Monohybrid cross

Answer 13

A cross between homozygous parents with different alleles for a particular character.

Question 14

Dihybrid cross

Answer 14

Parents differ at two loci.
Two pairs of alleles carried on non-homologous chromosomes are inherited independently.
Ex: BBSS x bbss

Question 15

Punnett square
What generation are the results?

Answer 15

A grid arrangement that shows the possible combinations of alleles.
Shows F2 combinations.

Question 16

Test cross

Answer 16

Cross an individual of unknown genotype with a recessive individual to determine the unknown genotype.

Question 17

Dosage compensation

Answer 17

A mechanism that allows males and females to produce the same amounts of proteins coded by X-linked genes.

Question 18

Polymorphic

Answer 18

A genetic locus is polymorphic if there are two or more distinct phenotypes produced in a population (not just one wild type).

Question 18

Barr body

Answer 18

A dense, metabolically inactive X chromosome.

Question 19

Incomplete dominance

Answer 19

The heterozygote is intermediate in phenotype.
The heterozygote is neither parental color.
Ex: Red + White = Pink

Question 20

Codominance

Answer 20

Two alleles produce phenotypes that are both present in the heterozygote.
Ex: Red + White = Candy cane stripes

Question 21

Pleiotropy

Answer 21

The ability of one gene to have several effects on different characters
Most cases traced to a single cause, such as a defective enzyme that affects many cells.

Ex: an allele codes for hair color and length instead of just one trait

Question 22

Phenylketonuria

Answer 22

Results from a mutation in the gene for a liver enzyme that converts the amino acid Phenylalanine to tyrosine.
Effect: Mutated allele is pleiotropic- results in mental retardation and reduced pigmentation

Question 23

Epistasis

Answer 23

Phenotypic expression of one gene is influenced by another gene.
Ex: coat color in Labrador retrievers
For alleles B (black) and b (brown) to be expressed, allele E (pigment deposition) must be expressed.
An ee dog is yellow regardless of which B alleles are present. E is epistatic to B.

Question 24

Polygenic Inheritance

Answer 24

Multiple independent pairs of genes may have similar and additive effects on the phenotype.
Ex: As many as 60 loci may contribute to inheritance of skin pigmentation in humans.