Exam 4 part 6

Question 1

What does F1 stand for

Answer 1

First filial generation, first generation after parental generation

Question 2

Describe the meaning of dominant and recessive traits

Answer 2

For a recessiveallele to produce arecessivephenotype, the individual must have two copies, one from each parent. An individual with onedominantand onerecessive allele for agenewill have thedominantphenotype

Question 3

Describe what a reciprocal cross is

Answer 3

A pair of crosses between a male of one strain and a female of another, and vice versa

Question 4

What do we now identify as the “particles” in Mendel’s hypothesis of particulate inheritance

Answer 4

genes

Question 5

What are alleles

Answer 5

different versions of each gene

Question 6

Do individuals with the same genotype always have the same phenotype? Why or why not

Answer 6

Environmental conditions will cause them to appear different

Question 7

A gene that has two copies of the same allele is referred to as

Answer 7

homozygous

Question 8

A gene that has two different alleles is referred to as

Answer 8

heterozygous

Question 9

dominant alleles always mask recessive alleles when they are paired together.

Answer 9

true

Question 10

What is the difference between a monohybrid cross and a dihydrid cross

Answer 10

Monohybrid: crossing a single trait (ex: round vs wrinkled)
Dihybrid: crossing two traits (ex: round vs wrinkled AND yellow vs green)

Question 11

Did Mendel’s experiments support the hypothesis of independent assortment or dependent assortment

Answer 11

Independent assortment

Means that different traits don’t depend on each other

Question 12

What is a testcross

Answer 12

a parent that is homozygous recessive for a particular trait is mated with a parent that has the dominant phenotype but unknown genotype

Question 13

While doing a testcross, what are the possible genotypes of the unknown parents

Answer 13

Either heterozygous or homozygous dominant

Question 14

What is a wild type

Answer 14

The most common phenotype for each trait

Question 15

Mendel crossed a wrinkled pea pure line to an individual with round peas but an unknown genotype. All of the progeny had round peas. What was the unknown individuals genotype

Answer 15

RR

Question 16

What is the difference between a mutation and mutant

Answer 16

Mutation: phenotypes that differed from the wild type, results from the change in a gene
Mutants: individuals with traits attributable to mutation

Question 17

Genes on autosomes are said to show

Answer 17

autosomal inheritance

Question 18

What is sex-linked inheritance

Answer 18

The pattern of inheritance that may result from a gene located on either the X or Y chromosome

Question 19

What is the different between sex-linked and linked genes

Answer 19

Sex-linked means that it is on a sex chromosome

Linked genes are often transmitted together during gamete formation

Question 20

Multiple allelism is when genes have more than two alleles. When more than two two distinct phenotypes are present in a population due to multiple allelism, the trait is called what

Answer 20

polymorphic

Question 21

What is the difference between incomplete dominance and codominance

Answer 21

Incomplete: The heterozygotes have an intermediate phenotype
Codominance: a heterozygous organism that displays the phenotype of both alleles of a gene

Question 22

Genes that influence many traits are

Answer 22

pleiotropic

Question 23

What is the difference between a discrete and quantitative trait

Answer 23

Discrete traits are characteristics that are qualitatively different (ex: green vs yellow, nothing in between)
Quantitative traits are traits that are not discrete but fall into a continuum (ex: height, weight)

Question 24

What is a pedigree

Answer 24

Family tree used to analyze existing human crosses
Record gender and genetic relationships among individuals in a family
Help reveal patterns of inheritance

Question 25

Do males or females determine the gender of the zygote

Answer 25

males