Exam 2

Question 1

Mendel studied:

Answer 1

autosomal inheritance

Question 2

Gene

Answer 2

holds two alleles, influences a particular trait

Question 3

allele

Answer 3

a particular form of gene

Question 4

Genotype

Answer 4

a listing of the alleles of particular genes in an individual

Question 5

phenotype

Answer 5

an individual’s observable traits

Question 6

homozygous

Answer 6

having two of the same allele

Question 7

heterozygous

Answer 7

having two different alleles

Question 8

autosomal

Answer 8

a chromosome that isn’t sex

Question 9

a gamete carries _____

Answer 9

1 allele for each trait

Question 10

Principle of separation

Answer 10

allele pairs split from each other during the production of gametes

Question 11

monohybrid cross

Answer 11

cross between two heterozygotes

Question 12

Monohybrid cross (Rr) genotype values

Answer 12

1/4 RR
2/4 Rr
1/4 rr

Question 13

monohybrid cross (Rr) phenotype values

Answer 13

3:1

Question 14

what principle does monohybrid cross show?

Answer 14

principle of segregation

Question 15

Independent assortment

Answer 15

alleles of different genes (seed shape and color) are transmitted independently of each other

Question 16

dependent assortment

Answer 16

alleles of different genes (seed shape and color) are transmitted together

Question 17

both

Answer 17

rule of multiplication

Question 18

either, or

Answer 18

rule of addition

Question 19

dihybrid cross

Answer 19

two traits

Question 20

Offspring genotypes values (RrYy x RrYy)

Answer 20

9/16 R-Y-
3/16 R-yy
3/16 rrY-
1/16 rryy

Question 21

Offspring phenotype values (RrYy x RrYy)

Answer 21

9/16 R-Y-
3/16 R-yy
3/16 rrY-
1/16 rryy

Question 22

what principle does dihybrid cross show?

Answer 22

principle of independent assortment

Question 23

how does meiosis explain principle of segregation

Answer 23

separation of homologous chromosomes in anaphase 1

Question 24

how does meiosis explain principle of independent assortment

Answer 24

Genes on different chromosomes assort independently in Meiosis 1
(4 types of gametes are produced)

Question 25

chromosome theory of inheritance

Answer 25

-genes are located on chromosomes
- independent alignment and separation of homologous chromosomes in Meiosis 1

Question 26

homogametic vs. heterogametic

Answer 26

XX vs. XY
EXCEPTIONS: fish, birds, butterflies, moths (ZZ, ZW)

Question 27

what supports chromosome theory of inheritance

Answer 27

X-linked inheritance

Question 28

what violates the principle of independent assortment and why?

Answer 28

Linkage
-alleles are inherited together
-DIFFERENT than sex-linked genes
-two, rather than four, types of gametes

Question 29

crossing over

Answer 29

alleles on the same chromosomes don’t always stick together (four types of gametes)

Question 30

crossing over and meiosis 1 relationship

Answer 30

-only in females

Question 31

polymorphic traits: Codominance

Answer 31

expression of both alleles in a heterozygote

Question 32

Polymorphic traits: Incomplete dominance

Answer 32

heterozygote is mixture of parents

Question 33

Incomplete dominance flower color ex

Answer 33

red (RR) white (rr)
pink (Rr)
1/4 (RR) 1/4 (Rr) 1/4(Rr) 1/4 (rr)

Question 34

Pleiotropy

Answer 34

one gene affects many traits (ex: diseases)

Question 35

Influences on phenotypes: Gene-Gene

Answer 35

different genes work together to affect the phenotype

Question 36

influences on phenotypes: Environment

Answer 36

combined affects of genes and environment
Rose comb (RRpp) x Pea comb (rrPP) = all walnut combs

Question 37

epistasis

Answer 37

expression of phenotype of one gene is masked by phenotype of another

Question 38

discrete vs. quantitiative (continuous) traits

Answer 38

(ex: kernel color)
Aa Bb Cc thing

Question 39

Extensions of Mendel’s work:

Answer 39

1. Inheritance of genes on same chromosome
2. More than two alleles
3. Other allele phenotypes
4. Gene influences on traits
5. other influences on phenotypes
6. Quantitative traits