Genetics

Question 1

What is a character?

Answer 1

a heritable feature that varies among individuals

ex. flower color

Question 2

what is a trait

Answer 2

each variant for a character such as purple or white colors

Question 3

What is a genetic cross

Answer 3

the mating of haploid gametes

Question 4

what is the P generation

Answer 4

The parents used in a cross are part of the parental generation they are both true-breeding

Question 5

What is the F1 generation

Answer 5

the offspring of the P generation. They are a product of hybridization

Question 6

What is the F2 generation?

Answer 6

Offspring of the F1 generation

Question 7

What is true-breeding

Answer 7

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

Question 8

What is hybridization

Answer 8

The mating of two contrasting, true-breeding varieties

Question 9

What is the genotype

Answer 9

genetic makeup

Question 10

what is the phenotype

Answer 10

the physical expression of the genotype

Question 11

whats the relationship of phenotype and genotype

Answer 11

an organisms phenotype may not always reveal its genetic composition because of dominant and recessive alleles

Question 12

If two alleles at a locus differ, which one determines the appearance and which has no effect?

Answer 12

the dominant allele determines the organism’s appearance

the recessive allele has no effect on appearance

Question 13

what does the law of segregation state?

Answer 13

the two alleles for a heritable character (on homo chromos) separate during meiosis and end up in different gametes

Question 14

What is a homozygote

Answer 14

an organism with two identical alleles for a character

Question 15

What is a heterozygote

Answer 15

an organism that has two different alleles for a gene

the dominant allele in this controls the phenotype

Question 16

are dominant alleles always the most common

Answer 16

no

Question 17

What is a monohybrid

Answer 17

individuals that are heterozygous for one character (Aa)

Question 18

what is a monohybrid cross

Answer 18

the cross between heterozygotes

Aa x Aa

Question 19

What is cystic fibrosis

Answer 19

a recessive human genetic disease (heterozygotes do not show the disease and are carriers)

Question 20

What is a test cross

Answer 20

it is used to distinguish between homozygous dominant and heterozygote genotypes

if any offspring display the recessive phenotype, the mystery parent must be heterozygous

Question 21

What is a dihybrid and how is it produced

Answer 21

the crossing of two two-breeding parents differing in two characters produces dihybrids in the F1 generation

dihybrids are heterozygous for both characters

Question 22

What are dihybrid crosses

Answer 22

crosses that involve two traits

Question 23

what does the law of independent assortment apply to

Answer 23

genes on different chromosomes

Question 24

what is true about the inheritance of genes located near eachother on the same chromosome

Answer 24

they are inherited together

Question 25

what are the extensions to mendelian genetics

Answer 25

incomplete dominance/co-dominance

multiple alleles

pleiotropy

Question 26

incomplete dominance

Answer 26

when alleles are not completely dominant or recessive

the phenotype is an intermediate between the two parents

Question 27

multiple alleles

Answer 27

when a gene has more than two alleles (ex. blood type)

Question 28

pleiotropy

Answer 28

when a gene produces multiple phenotypes

Question 29

what is codominance

Answer 29

two dominant alleles affect the phenotype in separate distinguishable ways

both alleles are dominant and both phenotypes are expressed

Question 30

most genes exist in populations

Answer 30

with more than two allelic forms

Question 31

what are Y-linked genes

Answer 31

involved in male determination and development

Question 32

Which chromosome are sex linked human disorders carried on?

Answer 32

X chromosome

Question 33

What are human sex-linked disorders due to and who does it affect?

Answer 33

they are often due to recessive alleles and they mostly affect males since they only have 1x chromosome

Question 34

What are carriers

Answer 34

carriers express the normal trait phenotypically but are heterozygous for the recessive allele

Question 35

who is a carrier of X-linked recessive traits?

Answer 35

Only females because they have two X chromosomes and can be heterozygous for the allele

Question 36

what is polygenic

Answer 36

a trait affected by multiple genes

Question 37

what does it mean to be multifactorial

Answer 37

it means that a phenotypic character is influenced by multiple genes and environmental factors

Question 38

what is epistasis

Answer 38

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