Chapter 12

Question 1

Who is Mendel? What did he contribute towards the study of inheritance?

Answer 1

used the scientific method to study inheritance.

Question 2

Know the difference between character, trait, phenotype, and genotype

Answer 2

character -> Observable physical features
trait -> form of a character
phenotype -> physical makeup
genotype -> genetic makeup

Question 3

What does P, F1 and F2 refer to?

Answer 3

P -> parent generation
F1 -> first filial generation
F2 -> second filial generation

Question 4

Know the terms dominant and recessive, haploid and diploid, homozygous and
heterozygous.

Answer 4

dominant -> expressed
recessive -> if alone won’t be expressed
haploid -> one set of chromosomes
diploid -> two sets of chromosomes
homozygous -> pair of same alleles
heterozygous -> two different alleles

Question 5

Know the difference between monohybrid and dihybrid crosses and how to predict
allele combinations using Punnett Squares.

Answer 5

monohybrid cross -> a cross of one single character; 3:1
dihybrid cross -> a cross of two characteristics; 9:3:3:1

Question 6

Mendel’s first law of segregation and second law of independent assortment

Answer 6

first -> Two copies of a gene separate during gamete formation; each gamete receives only one copy
second -> Copies of different genes assort independently (in the context of meiosis)

Question 7

Know the expected phenotypic ratios of monohybrid and dihybrid crosses for the F2
generation assuming F1 are monohybrids and self-pollinate

Answer 7

F2 monohybrid -> 3:1
F2 dihybrid -> 9:3:3:1

Question 8

What is a pedigree, and why is it useful?

Answer 8

pedigree -> family trees that show the occurrence of phenotypes in several generations
-Can be used to determine if an allele is dominant or recessive

Question 9

Know how to read a pedigree

Question 10

Be able to recognize a pedigree tracing a dominant trait v. a recessive trait.

Answer 10

Rare dominant alleles -> Affected person has an affected parent ; Half of the offspring of an affected parent are also affected
Rare recessive alleles -> Affected people can have two parents who are not affected; Small proportion of people are affected ; Associated w/ inbreeding

Question 11

Know the difference between incomplete dominance and codominance

Answer 11

incomplete dominance -> Heterozygotes have intermediate phenotypes (blend of traits)
codominance -> Alleles produce phenotypes that are both present in the heterozygote (shared dominance)

Question 12

Blood-typing—understand the different types and compatibility

Answer 12

-A group make A antigen and anti-B antibodies
-B group make B antigen and anti-A antibodies
-AB group make both A and B antigens and no antibodies
-O group have no antigen and anti-AB antibodies

Question 13

Pleiotropy and epistasis

Answer 13

Pleiotropic → one allele has multiple phenotypic effects
Epistasis → phenotypic expression of one gene is influenced by another gene

Question 14

What is inbreeding and why is it typically not a good thing

Answer 14

Interbreeding → mating among close relatives; can result in offspring with reduced fitness
Inbreeding can produce offspring of smaller size/ lower quality

Question 15

Qualitative v. quantitative traits

Answer 15

qualitative -> describes things
quantitative -> something you can be very specific about

Question 16

Discussing x-linked traits

Answer 16

X-linked → trait carried on X chromosome; generally see it affect only one sex
X-linked dominant → typically affect females
X-linked recessive → typically affect males