Chapter 8

Question 1

Differentiate between the 2 hypotheses of inheritance that were prevalent at the time of Mendel’s experiments

Answer 1

• The blending hypothesis: traits blend, they mix like paint, original traits never reappear in future generations.
• The particulate hypothesis: genetic traits from parents occurs in distant units, traits can reappear, traits can skip a generation, units remain separate/maintain individual identity

Question 2

Provide basic details of Mendel’s model system (garden pea plants) and his experimental set-up/method

Answer 2

Mendel used manual pollination, he removed all the stamens from the flower, using brushes he was able to control which plants were fertilized with each type of pollen.

Question 3

Define P generation

Answer 3

Parental (first generation)

Question 4

Definition F1 generation

Answer 4

First FILIAL generation (offspring of the P generation)

Question 5

Define F2 generation

Answer 5

Second filial generation, offspring after the F¬1 generation

Question 6

Define Gene

Answer 6

Specific DNA sequence containing instructions for a certain characteristic

Question 7

Define Allele

Answer 7

A version of a gene

Question 8

Define Dominant

Answer 8

Allele that dominates when present with another allele

Question 9

Define Recessive

Answer 9

Allele that does not dominate when present with another allele

Question 10

Define Homozygous

Answer 10

Both alleles are the same (both dominant or both recessive)

Question 11

Define Heterozygous

Answer 11

Two different alleles (one dominant and the other recessive

Question 12

Define Genotype

Answer 12

The two alleles for a gene present in a genome

Question 13

Define Phenotype

Answer 13

A physical trait based on a particular genotype

Question 14

Define Mutation

Answer 14

change in a DNA sequence, Creates new alleles of a gene

Question 15

Define Incomplete Dominance

Answer 15

Neither allele is dominant resulting in intermediate phenotype

Question 16

Define Codominance

Answer 16

Both alleles are dominant, both phenotypes appear

Question 17

Define Epistasis

Answer 17

one gene/protein functions UPSTREAM from another protein, thus another gene cannot contribute its phenotype in the absence if another gene. Think assembly line or lab puppies (if a gene says no color then it doesn’t matter what follows, there will be no color)

Question 18

When 2 genes are “linked,” it means they are:

Answer 18

Genes that are located near each other on a chromosome are called linked genes. They are linked because they travel together during meiosis. This means they get packaged into the same gamete more often than not.

Question 19

How do recombinant phenotypes arise when 2 genes are linked?

Answer 19

Recombination

Question 20

Your mitochondrial DNA comes from your ___________. Why?

Answer 20

The egg cell contains mitochondria while the sperm does not contribute mitochondria to the zygote, thus the mitochondrial DNA comes from the mother in humans.