chapter 14 a and 14b

Question 1

define hereditary

Answer 1

the transmission of traits from parents to their offspring

Question 2

define trait

Answer 2

any characteristics of an individual

Question 3

what is the blending hypothesis

Answer 3

the idea that parental traits blend so that their offspring have intermediate traits

Question 4

what is the particulate hypothesis

Answer 4

the idea that parents pass on discrete heritable units (genes)

(mendel and his pea plants helped him figure this one out)

Question 4

what is the inheritance of acquired characteristics hypothesis

Answer 4

parental traits are modified through use and then passed on

Question 5

what are polymorphic traits

Answer 5

trait that appears more commonly in two or more different forms (ex: purple vs white flowers)

Question 6

what are pure lines

Answer 6

organism that produces offspring identical to themselves when self fertilized

Question 7

p vs F1 and F2 generation

Answer 7

p = grandparents
F1 =parents
F2 = grand babies

Question 8

what is a monohybrid cross

what ratio are these offspring

Answer 8

mating between two parents that are both heterozygous for one gene

3:1 only one has recessive genes only

Question 9

define genotype

Answer 9

the combination of alleles found in an individual

Question 10

what is mendel’s principle of segregation

Answer 10

the two members of each gene pair must segregate. They separate into different gamete cells during formation of eggs and sperm in the parents

Question 11

what is a dihybrid cross

Answer 11

a dihybrid cross is a mating between parents that are both heterozygous for 2 traits

Question 12

independent assortment vs dependent assortment. which one supported mendels result

Answer 12

o Independent assortment: alleles of different genes are
transmitted independently of each other.

o Dependent assortment: the transmission of one allele
depends on the transmission of another.

accurate = principle of independent assortment

Question 13

in a dihybrid cross what is the phenotypic ratio of the F2 generation

Answer 13

9:3:3:1

Question 14

what is a testcross

Answer 14

a homozygous recessive parent is mated with a parent that has a dominant phenotype but unknow genotype

Question 15

what is the multiplication rule

Answer 15

states that the probability of two or more independent events will occur together is the product of their individual probabilities

Question 16

what is the rule of addition

Answer 16

states that the probability that any one of two or more exclusive events will occur is calculated by adding together their individual probabilities

Question 17

what part or cell division is responsible for Mendel’s principle of segregation

Answer 17

the physical separation of alleles during meiosis I

the genes for different traits assort independently of one another at meiosis I because they are located on different homologous chromosomes
- different nonhomologous chromosomes assort independently of one another

Question 18

wild type vs mutant

Answer 18

wild type is the most common phenotype for each trait

mutants are individuals with traits caused by mutations

Question 19

what does the SRY gene on the Y chromosome do

Answer 19

encodes a protein that is the trigger for male development

Question 20

are pure lines always homozygous

Answer 20

yes

Question 21

do all of the genes on the sex chromosomes relate to the sex of the individual?

Answer 21

No, they produce proteins that have other functions

Question 22

what is sex linkage

Answer 22

the general term for genes being on either sex chromosome

a gene located on the x chromosome is x - linkage

Question 23

when genes are close together on the same chromosome they are _____

what is linkage

Answer 23

linked

linkage is the tendency of genes to be inherited together because they are on the same chromosome

Question 24

why are we only analyzing the male offspring in the fruit fly experiment

Answer 24

only have one copy of that gene on x chromosomes. Females have 2 copies. one on each chromosome

Question 25

when does cross over occur in meiosis

Answer 25

prophase I

Question 26

what is the frequency of recombination?

Answer 26

a measure of the distance between linked genes

when 2 genes are found on separate chromosomes the ratio of 1:1:1:1

Question 27

how likely are two genes found on the same chromosome located very far apart for crossover to occur.

Answer 27

likely to occur. would be unlikely if closer together

Question 28

why is the frequency of recombination 0 - 50%

Answer 28

because only 2 chromatids from two chromosomes can crossover (only 2 out of 4 bunny ears)

Question 29

what is multiple allelism

Answer 29

when there are more than 2 alleles of a gene in a population

ex: humans have 3 common alleles for blood types o,a,b

Question 30

what is codominance

Answer 30

neither allele is dominant or recessive to the other. heterozygous display the phenotype of both alleles

Ex: AB blood type

Question 31

what is incomplete dominance

Answer 31

other alleles display incomplete dominance

heterozygotes have an intermediate phenotype

ex: pink flowers and white flowers made light pink flowers (Rr)

Question 32

what is epistasis

Answer 32

the expression of many genes depends on the presence of absence of other genes

two or more genes work together to control a single trait.
genes that modify the phenotypic expression of other genes is said to show epistasis

ex: chickens and their combs

Question 33

what is a pedigree

Answer 33

a family tree that describes the interrelationships of parents and children across generations

inheritance patterns of a particular traits can be traced and described using pedigrees

pedigrees can also be used to make predications about future offspring using multiplication and addition rules

Question 34

define carriers

Answer 34

heterozygous individuals who carry the recessive allele but are phenotypically normal

Question 35

dominant alleles that cause lethal disease are ___ and arise by _____

Answer 35

rare, mutation