Chapter 11

Question 0

Locus

Answer 0

The specific location of a gene, DNA sequence, or position on a chromosome

Question 1

Genes

Answer 1

The basic physical unit of heredity
-a linear sequence of nucleotides along a segment of DNA that provides the coded instructions for synthesis of rna, which when translated into protein leads the expression of heredity character

Question 2

Allele

Answer 2

An alternative form of a gene

Question 3

Homozygous

Answer 3

An organisms that has two identical alleles for a gene for a given character

• YY = homozygous dominant
• yy = homozygous recessive

Question 4

Heterozygous

Answer 4

An organism that has differing alleles for a trait

-Yy

Question 5

Genotype

Answer 5

The genetic makeup of an organism with reference to a single trait, set of traits, or an entire complex of traits
-ex) if yellow is dominant, the organism can be YY or Yy

Question 6

Phenotype

Answer 6

A physiological feature, bodily characteristic, or behavior of an organism

• ie a plant’s visible characteristics
• ex) purple flowers, white flowers, yellow seeds, green seeds

Question 7

P

Answer 7

Shorthand for the parental generation in experiments

Question 8

F1

Answer 8

The offspring of the parental generation

• the first filial generation
• filial indicates a daughter or son

Question 9

F2

Answer 9

The second filial generation

-Fx is used for any succeeding generation

Question 10

Monohybrid cross

Answer 10

A genetic cross made to examine the distribution of one specific set of alleles in the resulting offspring
-ex) seed color

Question 11

Punnett square method

Answer 11

A simple graphical way of discovering all of the potential combinations of genotype a that can occur in children, given the genotype of their parents
-also shows us the odds of each of the offspring genotype a occurring

Question 12

Test cross

Answer 12

A cross between an individual exhibiting the dominant phenotype of a trait and an individual that is homozygous recessive for that trait in order to determine he genotype of the dominant individual

Question 13

Law of segregation

Answer 13

• differing characteristics in organisms result from two genetic elements (alleles) that separate in gamete formation, such that each gamete gets only one of the two alleles
• mendels first law
• the separation of homologous chromosomes during meiosis

Question 14

Dihybrid cross

Answer 14

A breeding experiment between P generation organisms that differ in two traits

• ex) green pod color and yellow seed color
• expressed in the format GgYy

Question 15

Law of independent assortment

Answer 15

During gamete formation, gene pairs assort independently of one another

• traits are transmitted to offspring independently of one another
• mendels second law

Question 16

Incomplete dominance

Answer 16

A genetic condition in which the heterozygous phenotype is intermediate between either of the homozygous phenotypes

• ex) snapdragons are pink as heterozygotes instead of red or white because neither the red nor white alleles are completely dominant
• *neither allele is expressed fully

Question 17

Codominance

Answer 17

A condition in which two alleles of a given gene have different phenotypic effects, with both effects manifesting in organisms that are heterozygous for the gene

• *both alleles are expressed fully
• ex) AB

Question 18

Continuous variation

Answer 18

Variation in phenotypic traits such as body weight or height I which a series of types are distributed on a continuum rather than grouped into discrete categories
-ex) 6.21, 6.22, 6.23, 6.24

Question 19

What blood types are expressed by each gene combination?

Answer 19

• A= AA or AO
• B= BB or BO
• AB= AB
• OO= O