Bio Ch 11

Question 1

Monohybrid cross

Answer 1

cross of a single trait with organisms that are hybrid; expected phenotypic results are 3:1

Question 2

Law of Segregation

Answer 2

(1) Each individual has 2 factors for each trait (2) The factors segregate/separate during the formation of the gametes (3) Each gamete contains only one factor from each pair of factors (4) Fertilization gives each new individual two factors for each trait

Question 3

Locus

Answer 3

physical location of a trait (or gene) on a chromosome

Question 4

Alleles

Answer 4

alternative versions of a gene

Question 5

Dominant allele

Answer 5

DNA sequence that comprises the gene makes a fully functional protein

Question 6

Recessive allele

Answer 6

contains a slightly different DNA sequence and produces a protein with little or no function

Question 7

Homozygous

Answer 7

when an organism has 2 identical alleles (TT or tt)

Question 8

Heterozygous

Answer 8

when an organism has 2 different alleles at a gene locus (Tt)

Question 9

Genotype

Answer 9

refers to the alleles an individual receives at fertilization

Question 10

Phenotype

Answer 10

refers to the physical appearance of the individual, which is made from the proteins produced by the corresponding alleles

Question 11

Dihybrid cross

Answer 11

cross between parents that differ in 2 traits; expected phenotypic ratio is always 9:3:3:1

Question 12

Law of Independent Assortment

Answer 12

Each pair of factors segregates/assorts independently of the other pairs; all possible combinations of factors can occur in the gametes

Question 13

Punnett square

Answer 13

diagram that allows for calculation of the chances/probability of genotypes and phenotypes among the offspring

Question 14

Testcross

Answer 14

cross between an individual with a dominant phenotype and an individual with a recessive phenotype to determine whether the dominant individual is homozygous or heterozygous

Question 15

Autosome

Answer 15

any chromosome other than a sex (X or Y) chromosome

Question 16

Carriers

Answer 16

when the parent does not express the trait but is capable of having a child with the genetic disorder

Question 17

Family pedigrees

Answer 17

chart of genetic relationship of family individuals across generations

Question 18

Family pedigrees

Answer 18

chart of genetic relationship of family individuals across generations

Question 19

Multiple alleles

Answer 19

gene exists within several allelic forms within a population

Question 20

Incomplete dominance

Answer 20

exhibited when the heterozygote has an intermediate phenotype between that of either homozygote

Question 21

Incomplete penetrance

Answer 21

dominant allele does not always determine the phenotype of the individual

Question 22

Pleiotropy

Answer 22

occurs when a single mutant gene affects 2 or more distinct and seemingly unrelated traits

Question 23

Polygenic inheritance

Answer 23

occurs when a trait is governed by two or more sets of alleles (ex. human height and prevalence of diabetes)

Question 24

Polygenic traits

Answer 24

controlled by many genes and may be influenced by environmental factors

Question 25

X-linked

Answer 25

used for genes that have nothing to do with gender, and yet they are carried on the X chromosome

Question 26

Hemizygous

Answer 26

possessing only one allele for a gene in a diploid organism; males are this for genes on the X chromosome