Mendelian Genetics (Lec 3 & 4)

Question 1

What were Mendel’s conclusions from monohybrid crosses?

Answer 1

each plant must possess two alleles; two alleles in each plant separate when gametes are formed; traits that appear unchanged in F1 heterozygotes are dominant; traits that disappeared in F1 heterozygotes are recessive

Question 2

Explain Mendel’s first law (principle of segregation)

Answer 2

each individual diploid organism processes two alleles for any particular characteristic. These two alleles segregate when gametes are formed, and one allele goes into each gamete

Question 3

What is the concept of dominance?

Answer 3

when two different alleles are present in a genotype, only the trait encoded by one of them - the dominant allele - is observed in the phenotype

Question 4

A 1:2:1 ratio for a monohybrid cross indicates what?

Answer 4

incomplete dominance

Question 5

What is a test cross?

Answer 5

a cross between an individual of unknown genotype and a homozygous recessive individual

Question 6

What is a back cross?

Answer 6

F1 and one of the parental genotypes

Question 7

Dihybrid crosses relate the principle of independent assortment to ____

Answer 7

meiosis

Question 8

Dihybrid crosses demonstrate that gametes located on different chromosomes will __ ____

Answer 8

sort independently