Chapter 14

Question 1

genetics

Answer 1

study of heredity

Question 2

genes are considered

Answer 2

heritable factors

Question 3

what is heredity

Answer 3

transmission of traits from parents to their
offspring

Question 4

trait

Answer 4

any characteristic of an individua

Question 5

what two hypotheses did Mendel prove wrong

Answer 5

• blending inheritance
• inheritance of acquired characteristics

Question 6

blending inheritance

Answer 6

Parental traits blend so that
their offspring have intermediate traits
- example: blond hair x black hair–> brown hair

Question 7

inheritance of acquired characteristics

Answer 7

Parental
traits are modified through use and then passed on
- example: parent uses right hand so offspring will use right hand

Question 8

polymorphic traits

Answer 8

Trait that appears commonly in two or more
different forms

Question 9

true breeding

Answer 9

plants that produce offspring of the same
variety when they self-pollinate
- same variety of parents

Question 10

how did Mendel control mating

Answer 10

remove male organs from flower to prevent self pollination

Question 11

cross pollination

Answer 11

used pollen from one flower to fertilize another flower

Question 12

which generation are true breeding parents

Answer 12

p generation- grandparents

Question 13

which generation are the hybrid offspring of P generation

Answer 13

F1 generation-parents

Question 14

what occurs when F1
individuals self-pollinate

Answer 14

F2 generation is produced
- children of F1
- grandchildren of P generation

Question 15

particulate inheritance

Answer 15

• Mendel proposed
• parents pass down alleles and genes to offspring in specific way
• traits don’t interact with each other

Question 16

what did Mendel propose about genes

Answer 16

• individual has two versions of each gene
• Different alleles are responsible for variation

Question 17

what are version of genes called

Answer 17

alleles

Question 18

what do alternative versions of genes account for (first concept)

Answer 18

variations in inherited characteristics
- alleles

Question 19

for each character, how are alleles inherited (third concept)

Answer 19

inherits two alleles, one from each parent
- alleles may be identical (homozygous), or
they may differ (heterozygous)
- dominant vs recessive

Question 20

dominant allele

Answer 20

determines the organism’s appearance

Question 21

recessive allele

Answer 21

no noticeable effect on the organism’s appearance

Question 22

principle of segregation

Answer 22

• two members of each gene pair must segregate
• separate into different gamete cells
• during formation of egg and sperm in parents

Question 23

law of segregation (fourth concept)

Answer 23

• accounts for the 3:1 ratio he
  observed in the F2
  generation
• possible combinations of sperm and egg
• each gamete receives just one gene copy randomly

Question 24

Monohybrid Cross

Answer 24

inheritance pattern of a
single trait

Question 25

dihybrid crosses

Answer 25

inheritance patterns of two traits that are linked - Mendel used this cross

Question 26

what does the dihybrid cross test

Answer 26

Independent assortment Dependent assortment

Question 27

Independent assortment

Answer 27

Alleles of different genes are transmitted independently of each other - traits don't interact

Question 28

dependent assortment

Answer 28

transmission of one allele depends on the transmission of another - one trait depends on the trait

Question 29

principle of independent assortment

Answer 29

- receive traits from parents individually - Mendel's results supported this hypothesis - use dihybrid cross

Question 30

testcross

Answer 30

homozygous recessive parent mated with a parent that has the dominant phenotype but an unknown genotype

Question 31

what can be found using a test cross

Answer 31

genotype of the second parent can be inferred from the results - further confirm principal of independent assortment

Question 32

Sex Linkage

Answer 32

- X and Y chromosomes - specific traits found on X and Y chromosomes

Question 33

Linkage

Answer 33

tendency of genes to be inherited together because they are on the same chromosome - gene stays with specific chromosome

Question 34

what do linked genes violate

Answer 34

- principle of independent assortment - linked genes are predicted to always be transmitted together during gamete formation

Question 35

what can be used to create a genetic map

Answer 35

frequency of crossing over

Question 36

when are genes more likely to cross over

Answer 36

far apart from each other

Question 37

can heritable characteristics determined by only one gene with two alleles

Answer 37

many cannot be

Question 38

what is multiple allelism

Answer 38

When there are more than two alleles of a gene in a population

Question 39

what is an example of multiple allelism

Answer 39

Humans have three common alleles for ABO blood types - Each codes for a version of an enzyme that adds polysaccharides to the membrane of red blood cells

Question 40

Complete dominance

Answer 40

phenotypes of the heterozygote and dominant homozygote are identical - example: one red flower and one white flower produce red offspring. Red would be dominant over white

Question 41

incomplete dominance

Answer 41

phenotype of F1 hybrids is somewhere between the phenotypes of the two parental varieties - phenotype between 2 parents is blended in offspring - example: one red flower and one white flower produce offspring that is pink in color

Question 42

codominance

Answer 42

two dominant alleles affect the phenotype in separate, distinguishable ways - example: one red flower and one white flower produce offspring which are partially red and partially white

Question 43

what is the relationship between dominance and phenotype

Answer 43

- dominant allele does not subdue a recessive allele; dominance is just what is expressed - Alleles are simply variations in a gene’s nucleotide sequence

Question 44

pleiotropy

Answer 44

multiple phenotypic effects - example: have a gene for a specific disease, but show different symptoms

Question 45

Polygenic inheritance

Answer 45

additive effects of two or more genes on a single phenotypic character - 1 gene acts together but has multiple different outcomes - example: human skin color

Question 46

what happens in epistasis

Answer 46

gene at one locus alters the phenotypic expression of a gene at a second locus

Question 47

what is an example of epistasis

Answer 47

coat color in mammals depends on two genes - One gene determines the pigment color - other determines whether the pigment will be deposited in the hair