BIOL 102 VOCAB TEST 2

Question 1

genetic variation

Answer 1

differences in genotype among individuals in a population

Question 2

mutations

Answer 2

any heritable change in the genetic material, usually a change in the nucleotide sequence of a gene

Question 3

genotype

Answer 3

the genetic makeup of a cell or organism; the particular combination of alleles present in an individual

Question 4

polymorphism

Answer 4

any genetic difference among individuals that is present in multiple individuals in a population

Question 5

alleles

Answer 5

the different forms of a gene, corresponding to different DNA sequences in each different form

Question 6

homozygous

Answer 6

describes an individual who inherits an allele of the same type from each parent, or a genotype in which both alleles for a given gene are of the same type

Question 7

heterozygous

Answer 7

describes an individual who inherits different types of alleles from the parent, or genotypes in which the two alleles for a given gene are different

Question 8

phenotype

Answer 8

the expression of a physical, behavioral, or biochemical trait; an individual’s observable phenotypes include height, weight, eye color, and so forth

Question 9

genetic risk factor

Answer 9

any mutation that increases the risk of a given disease in an individual

Question 10

Does a risk factor cause the disease?

Answer 10

no it does not cause the disease, but rather makes the disease more likely to occur.

Question 11

neutral mutations

Answer 11

genetic changes that have no effect or negligible effects on the organism, or whose effects are not associated with differences in survival or reproduction.

Question 12

what is the most frequent allele?

Answer 12

the A allele

Question 13

what determines a genotype?

Answer 13

a genotype is the genetic composition of a cell or organism, which can differ based on the nucleotide sequence in the region(s) of interest. Although there can be many different forms (alleles) of a gene or sequence, each cell or individual normally has only two copies of each sequence, and they can either be identical to each other (homozygous) or different from each other (heterozygous)

Question 14

What determines a phenotype?

Answer 14

A phenotype of a cell or organism refers to its observable features, which are determined in part by its genotype, but can also be influence by environmental factors. Some phenotypes are easily seen and vary widely among individuals, such as hair color or height, but a phenotype may also involve less easily observable characteristics such as blood type, which fall into a few distinct groups.

Question 15

With regards to mutations, what is meant by the terms “harmful,” “beneficial,” and “neutral”?

Answer 15

Beneficial mutations are those that provide some sort of advantage to the organism in its environment.

Neutral mutations provide neither benefit nor harm to the individual

Harmful mutations are those that may cause genetic disorders

Question 16

A mutation arises in a bacterium that confers antibiotic resistance. Is this mutation harmful, beneficial, or neutral?

Answer 16

mutations that cause antibiotic resistance are clearly beneficial to bacteria when antibiotic is present, but are neutral or can even be harmful in the absence of antibiotic. The effect of a mutation on an organism often depends on the environment

Question 17

spontaneous mutations

Answer 17

occurring in the absence of any assignable cause; most mutations are spontaneous

Question 18

Most mutations are __________, occurring by chance in the absence of any assignable cause.

Answer 18

spontaneous

Question 19

Are mutations random?

Answer 19

yes, that are unconnected to an organism’s needs and makes no difference whether a given mutation would benefit the organism.

Question 20

what is the most common mutation?

Answer 20

the substitution of one nucleotide for a different nucleotide

Question 21

hotspots

Answer 21

a site in the genome that is especially mutable

Question 22

germ cells

Answer 22

the reproductive cells that produce sperm or eggs and the cells that give rise to them

Question 23

somatic cells

Answer 23

a non-reproductive cell, the most common type of cell in the body of a multicellular organism

Question 24

germ-line mutations

Answer 24

a mutation that occurs in eggs and sperm or in the cells that give rise to these reproductive cells and therefore is passed on to the next generation

Question 25

what are germ-line mutations important to the evolutionary process?

Answer 25

they are passed from one generation to the next and may eventually come to be present in many individuals descended from the original carrier

Question 26

what are somatic mutations?

Answer 26

a mutation that occurs in somatic cells

Question 27

are somatic mutations transferred to offspring?

Answer 27

no they are not transmitted to future generations, they are transmitted to the daughter cells in mitotic cell divisions

Question 28

Mutations in which types of cell are most likely to contribute to evolutionary change in populations of organisms?

Answer 28

Mutations that contribute to evolutionary change must be capable of being transmitted from generation to generation. Thus, they must be mutations in cell lineages that give rise to reproductive cells.

Question 29

If mutations occur at random with respect to an organism’s needs, how does a species become more adapted to its environment over time?

Answer 29

Mutant genes that are harmful or neutral are much less likely to persist in a population than ones that result in increased survival or reproduction, because the latter mutations result in greater fitness.