genetics - exam 2

Question 1

blending inheritance

Answer 1

black x white = gray
gray x white = light gray
light gray x white = lighter gray

if true – eventually everything would be the same

Question 2

particulate inheritance

Answer 2

inheritance of “particles” (genes)

blue x yellow = blue + yellow + green

Question 3

why are peas a good model organism

Answer 3

easy to see traits

controlled matings

many offspring

short generation time

Question 4

monohybrid cross

Answer 4

P (parental) generation = true breeding plants
1 purple & 1 white

F1 = 1 trait seen (dominant) & 1 trait hidden (recessive)
purple

F2 = F1 purple + F1 purple = 3 purple & 1 white

Question 5

alleles

Answer 5

variants of a certain gene

Question 6

genetype

Answer 6

combination of alleles in an individual

genes

Question 7

phenotype

Answer 7

expression of a trait

physical traits

Question 8

segregation

Answer 8

genes come in pairs that separate from one another in the formation of gametes

reflects separation of homologous chromosomes during anaphase I of meiosis

Question 9

independent assortment

Answer 9

each pair of alleles segregates independently of any other pair of alleles - during gamete formation

causes lots of variation

Question 10

autosomal dominant

Answer 10

only one mutated allele needed

seen in every generation

if a person has condition, at least 1 parent has it

Question 11

autosomal recessive

Answer 11

needs 2 mutated alleles

not seen in parents but seen in offspring

Question 12

incomplete dominance

Answer 12

red + white = pink

heterozygote phenotype: intermediate

genotypic ratio = phenotypic ratio

F2 generation = 1 red: 2 pink: 1 white

Question 13

codominance

Answer 13

pink + white = spotted pink & white

heterozygote phenotype: exhibits both distinct traits

Question 14

polygenetic traits

Answer 14

more than one gene influences phenotype

Question 15

pleiotropy

Answer 15

one gene influences many traits

Question 16

sex linked traits male vs female

Answer 16

for males only need 1 mutation on x chromosome

for females need 2 mutations 1 on each x chromosome

Question 17

importance of Y chromosome

Answer 17

holds SRY gene which encodes testes-determining factor