Theme 4A

Question 1

genotype

Answer 1

the genetic makeup of a cell or organism

Question 2

phenotype

Answer 2

its observed characteristics

Question 3

polymorphism

Answer 3

any genetic difference among individuals that is sufficiently common that it would almost certainly be present in a group of 50 randomly chosen individuals
i.e. a mutation that is not commonly found in a population

Question 4

a phenotype results from:

Answer 4

an interaction between the genotype and the environment

Question 5

allele

Answer 5

different forms of any gene, correspond to different DNA sequences (polymorphisms) in the genes

Question 6

homozygous

Answer 6

an individual who inherits an allele of the same type from each parent

Question 7

heterozygous

Answer 7

individuals who inherit different types of alleles from their parents

Question 8

the effect of an allele usually depends on:

Answer 8

whether the mutation is homozygous or heterozygous, and the effect of the genotype in the context of a particular environment

Question 9

alpha-1 antitrypsin

Answer 9

an enzyme that inhibits elastase which breaks down connective-tissue protein elastin in the lungs, loses function if individual smokes or in the case of mutations ex. PiZ mutated allele

Question 10

genotype-by-environment interaction

Answer 10

a phenotype that is the result of an interplay between genes and the environment (ex. combination of homozygous PiZ and smoking)

Question 11

neutral mutations are likely to occur in…:

Answer 11

organisms with large genomes and abundant noncoding DNA regions

Question 12

transmission genetics

Answer 12

the manner in which genetic differences among individuals are passed from generation to generation

Question 13

trait

Answer 13

characteristic

Question 14

blending inheritance

Answer 14

traits in the offspring resembles the average of those in the parents

Question 15

Principle of Segregation

Answer 15

segregation of alleles into different games: each gamete gets one allele and the other gets the other allele

Question 16

incomplete dominance

Answer 16

phenotype of the heterozygous genotype is intermediate between those of the homozygous genotype

Question 17

Principle of Independent Assortment

Answer 17

segregation of one set of alleles of a gene pair is independent of the segregation of another set of alleles of a different gene pair
i.e. the hereditary transmission of either gene has no effect on the hereditary transmission of the other

Question 18

independent assortment reflects:

Answer 18

the random alignment of chromosomes in meiosis (metaphase I)

Question 19

not all genes undergo independent assortment, for example…

Answer 19

genes that are sufficiently close together in one chromosome do not assort independently of one another

Question 20

genes on the same chromosome that fail to demonstrate independent assortment are known as:

Answer 20

linked

Question 21

epistasis

Answer 21

genes that modify the phenotypic expression of other genes (ex. genes that code for proteins that act in the same biochemical pathway)