Chapter 14

Question 1

Alleles

Answer 1

Alternative version of a gene Arise by mutation

Question 2

Character

Answer 2

A heritable feature that varies amount individuals

Question 3

Trait

Answer 3

Each variant of a character (purple or white flowers)

Question 4

True breeding

Answer 4

Produced same variety as parent

Question 5

Hybridization

Answer 5

Crossing or mating of two true breeding varieties

Question 6

P generation

Answer 6

The true breeding parents

Question 7

F1 generation

Answer 7

Hybrid offspring of true breeding parents

Question 8

F2 generation

Answer 8

Offspring of two f1 generations crossing breeding or mating

Question 9

What four related concepts make up Mendels model?

Answer 9

1. Alternative versions of genes account for variations in inherited characters 2. For each character, an organism inherits two versions (alleles) of a gene, one from each parent 3. If the two alleles at a locus differ then one dominant allele determine the organisms appearance 4. The two alleles for a heritable character segregate during gamete formation and end up in different gametes

Question 10

Dominant allele

Answer 10

Determines the organisms appearance

Question 11

Recessive allele

Answer 11

Has no noticeable effect on organisms appearance

Question 12

Law of segregation

Answer 12

2 alleles for a heritable character segregate during gamete formation and end up in two different gametes

Question 13

Punnett square

Answer 13

Diagram device for predicting the allele composition of offspring from a cross between individuals of genetic make up

Question 14

Homozygote

Answer 14

An organism that has a pair of identical alleles for a gene encoding character

Question 15

Heterozygote

Answer 15

An organism that has two different alleles for a gene

Question 16

Phenotype

Answer 16

An organisms appearance or observable traits

Question 17

Genotype

Answer 17

An organisms genetic makeup

Question 18

Test cross

Answer 18

Breading a organism of unknown genotype with a recessive homozygote

Question 19

Monohybrids

Answer 19

They were heterozygous for the one particular character being followed in the cross Monohybrid cross

Question 20

Dihybrids

Answer 20

Individuals heterozygous for two characters being followed in the cross

Question 21

Law of independent assortment

Answer 21

Two or more genes assort independently— that is each pair of alleles secretes independently of any other pair of alleles during gamete formation Applies only to genes located on different chromosomes

Question 22

Multiplication rule

Answer 22

To determine the probability of one event and the other occurring, we multiply the probability of one event by the probability of the other event.

Question 23

Addition rule

Answer 23

The probability that any one or more mutually exclusive events will occur is calculated by adding their individual probabilities

Question 24

Complete dominance

Answer 24

The observable characteristics of the heterozygote and the dominant homozygote are indistinguishable

Question 25

Incomplete dominance

Answer 25

Neither allele is completely dominant and F1 hybrids have a phenotype somewhere between those of the two parental varieties

Question 26

Codominance

Answer 26

The two alleles each affect the phenotype in separate distinguishable ways

Question 27

Pleiotropy

Answer 27

the production by a single gene of two or more apparently unrelated effects.

Question 28

Sex linked gene

Answer 28

A gene located on either sex chromosome

Question 29

X linked genes

Answer 29

Genes on the X chromosomes

Females have 2 males have 1

Question 30

Barr body

Answer 30

The inactive X in each cell of females condenses into a compact object called bar body, which lies along the inside of the nuclear envelope

Question 31

Epistasis

Answer 31

when the phenotupic expression of a gene at one locus alters that of a gene at a second locus

Question 32

Quantitative characters

Answer 32

A quantitative trait is a measurable phenotype that depends on the cumulative actions of many genes and the environment.

Question 33

polygenice inheritance

Answer 33

Polygenic inheritance occurs when one characteristic is controlled by two or more genes.

Question 34

Multifactorial

Answer 34

many factors both genetic and environmental collectively influence phenotype

Question 35

Family pedigree

Answer 35

A family tree describing traits across generations

Question 36

Carriers

Answer 36

heterozygotes may transmit the recessive allele to their offspring

Question 37

Chorionic villus sampling

Answer 37

a physician inserts a narrow tube through cervix into the uterus and suctions out a tiny sample of tissue from the plecenta

Question 38

Amniocentesis

Answer 38

a diagnostic test that can determine whether the developing fetus has a seriouse recessive disease