Genetic Variation

Question 1

Genes

Answer 1

Regions of DNA that contain sequences coding for RNA and protein products; humans have around 22,000 genes

Question 2

Genome

Answer 2

The complete set of DNA in an organism where genes are structured in; humans have a genome of 23 pairs of chromosome

Question 3

Exons

Answer 3

Coding regions

Question 4

Introns

Answer 4

Non coding regions

Question 5

Are non coding regions more prevalent in the genome compared to coding regions?

Answer 5

Non coding regions make up most of the genome (exons make up 1.5%); many of these non coding (intergenic) elements are nonfunctional

Question 6

Mutation

Answer 6

A change in DNA sequence relative to some standard or previously existing sequence

Question 7

Mutant

Answer 7

An individual whose genome contains a mutation at some location of interest

Question 8

Mutations occur randomly and does not respond to an organism’s “needs”. T or F?

Answer 8

True

Question 9

Where do new mutations come from?

Answer 9

1. Errors during DNA replication
2. Errors during chromosomal separation during meiosis (nondisjunction)
3. Mutagens

Question 10

Mutagens

Answer 10

Accelerates mutation; Ex: reactive oxygen species, UV light, ionizing radiation that can damage DNA and increase the rate of errors

Question 11

Mutations arise…

Randomly from errors in chromosomal segregation

Non-randomly from errors in replication or in chromosomal segregation

Non-randomly when they are caused by mutagens

Randomly from errors in DNA replication

A and D

Answer 11

A and D

Question 12

Point mutation

Answer 12

If one nucleotide pair changes; also called substitution

Question 13

Nondisjunction

Answer 13

Chromosomes fail to correctly separate during meiosis

Question 14

Aneuploidy

Answer 14

Duplicate or missing chromosome causes unequal numbers of chromosomes

Question 15

Which statement is NOT true about mutation?

Mutations occur randomly

Each individual has at least some new mutations

Mutation rates can differ between species

Natural selection causes useful mutations to arise

Answer 15

Natural selection causes useful mutations to arise

Question 16

Somatic mutations

Answer 16

Occur in body tissues of an organism and are not transmitted to the next generation

Question 17

Germline mutations

Answer 17

Occur in gametes and are transmitted to offspring; these mutations matter for evolution

Question 18

How many new mutations occur in each individual?

Answer 18

Approx. 34 new mutations

Question 19

How many mutations are deleterious, neutral, or beneficial?

Answer 19

70% deleterious

20% neutral

10% beneficial

Question 20

Silent mutation

Answer 20

No effect because the amino acid is the same

Question 21

Missense mutation

Answer 21

Changes one amino acid to another one

Question 22

Nonsense mutation

Answer 22

The change creates a STOP codon

Question 23

Frameshift mutation

Answer 23

Caused by insertions or deletions, which changes the reading frame during transcription (shifts the whole sequence)

Question 24

If a silent mutation occurs in the germ line, the next generation…

Answer 24

Will have the mutation but it will not affect the amino acid production

Question 25

Phenotypic variation

Answer 25

Variation in phenotypes such as morphology, behavior, physiology, etc. among members of a group of organisms

Question 26

Genetic variation

Answer 26

Variation in mutations/alleles among members of a group of organisms

Question 27

Error correction mechanisms

Answer 27

Cellular/molecular mechanisms that correct most errors in DNA replication/meiosis

Question 28

Fitness

Answer 28

The contribution an individual makes to the gene pool of the next generation, relative to the contributions of other individuals in the population