Chapter 19 Intro To Genetics

Front 1

Genes

Back 1

units of information about specific traits

Front 2

Genes are passed from?

Back 2

Parents to offspring

Front 3

what are genes chemical instructions for?

Back 3

buliding proteins

Front 4

specific location of a gene on a chromosome?

Back 4

locus

Front 5

diploid cells have how many copies of each gene?

Back 5

two copies of each gene, on pairs of homologous chromosomes

Front 6

all copies of a gene deal with the same trait, why might their information about it vary?

Back 6

due to chemical differences between them

Front 7

allele

Back 7

each version of a gene

Front 8

what do contrasting alleles produce?

Back 8

much of the variations we see in traits

Front 9

homozygous condition

Back 9

two copies of a gene are identical alleles

Front 10

heterozygous condition

Back 10

two allele copies are different

Front 11

when is an allele dominant?

Back 11

when its effect on a trait masks that of any recessive allele paired with it (Aa)

Front 12

homozygous dominant

Back 12

pair of dominant alleles (AA)

Front 13

homozygous recessive

Back 13

pair of recessive alleles (aa)

Front 14

heterozygous

Back 14

pair of non-identical alleles (Aa)

Front 15

genotype

Back 15

alleles a person inherits

Front 16

phenotype

Back 16

observable functional or physical traits

Front 17

example of a phenotype

Back 17

attached ear lobes

Front 18

segregation

Back 18

seperation of gamete pairs

Front 19

probability

Back 19

a measure of the chance that some particular outcome will occur

Front 20

what is probabilty a factor in?

Back 20

the inheritance of single-gene traits

Front 21

punnet square

Back 21

grid for determining the probable outcome of genetic crosses

Front 22

laws of probability

Back 22

1.the most probable outcome doesnt have to occur
2.in a given genetic situation, probability doesn't change

Front 23

testcross

Back 23

used to learn the genotype of a (nonhuman) organism

Front 24

independent assortment

Back 24

the reason most traits are inherited independently and it occurs during meiosis

Front 25

when considering more than one trait, the gene for each trait is inherrited..?

Back 25

independently of the gene for other traits

Front 26

how many ways can each pair of homologous parent chromosomes line up before the pairs become seperated?

Back 26

two ways, how each lines up is a random process

Front 27

two possible allignments in independent assortment chromosomes

Back 27

AAaa Aaaa
BBbb bbBB

Front 28

possible combinations of alleles in gametes

Back 28

AB,ab,Ab,aB

Front 29

what does a punnet square show?

Back 29

the probabilities a child will inherit a particular combination of single-gene traits

Front 30

how many gamete unions are possible when each parent is heterozygous for the two genes in question?

Back 30

16 different gamete unions
9/16 3/16 3/16 1/16

Front 31

when is a gene "expressed"?

Back 31

when its instructions are carried out and the cell make the protein

Front 32

pleiotropy

Back 32

wide-ranging effect of a single gene

Front 33

codominance

Back 33

both alleles are expressed

Front 34

multiple allele system

Back 34

gene that has three or more alleles

Front 35

penetrance

Back 35

probability that someone who inherits an allele will have the phenotype associated with it

Front 36

polygenetic traits

Back 36

result from the combine expression of several genes

Front 37

continuous variation

Back 37

members show a range of continuous differences in some trait

Front 38

multifactorial trait

Back 38

complex phenotypes that are shaped by more than one gene and also by some aspect of the individuals enviorment

Front 39

height is an example of?

Back 39

continuous variation and a multifactorial trait

Front 40

the enviorment can effect?

Back 40

phenotypes