Chapter 14 - Mutation and Genetic Variation

Question 1

what is genetic variation?

Answer 1

genetic differences that exist among individuals in a population at a particular time

Question 2

What is the genotype?

Answer 2

the genetic makeup of a cellular organism

Question 3

WHat is polymorphism?

Answer 3

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

Question 4

what are alleles?

Answer 4

different form of the same gene

Question 5

what does homozygous mean?

Answer 5

the same allele for a gene inherited from each parent

Question 6

WHat does heterozygous mean?

Answer 6

different allele for a gene inherited from each parent

Question 7

what is the phenotype?

Answer 7

individuals observable characteristics or traits

Question 8

what is a genetic risk factor?

Answer 8

any mutation that increases the risk of disease in the individual

Question 9

What are neutral mutations?

Answer 9

have negligible effect on survival or reproduction

Question 10

What are harmful mutations?

Answer 10

decrease the survival or reproduction in individuals - often eliminated after 1 generation

Question 11

Where are neutral mutations most likely to occur?

Answer 11

in non coding DNA or in introns

Question 12

What are beneficial mutations?

Answer 12

mutations that were discovered through their effects oin protecting from infectious disease

Question 13

What is an example of a beneficial mutation?

Answer 13

mutation to CCRS so it is no longer a HIV receptor so is a lot harder for viruses to invade

Question 14

What is the nature of mutations?

Answer 14

most are spontaneous and random

Question 15

what is the most common mutation?

Answer 15

substitution

Question 16

what are hotspots (mutations)?

Answer 16

sites in the genome that exhibit greater rates of mutation

Question 17

WHat are germ cells?

Answer 17

haploid gametes and the diploid cells that give rise to them

Question 18

WHat are somatic cells?

Answer 18

all other body cells (excluding gametes etc.)

Question 19

What does number of mutations depend on?

Answer 19

rate, size of genome, and amount of replication

Question 20

Which are the only mutations transmitted to progeny (descendants)?

Answer 20

germ line mutations (as occur in egg and sperm cells)

Question 21

What cells do most cancers result from?

Answer 21

mutations in somatic cells

Question 22

What did Joshua and Esther Lederberg study?

Answer 22

replica plating (do mutations occur randomly or are they directed by the environment?)

Question 23

What did Joshua and Esther Lederberg find?

Answer 23

showed that antibiotic resitant mutant can arise in the abscence of antibiotic

Question 24

What is a point mutation?

Answer 24

changes in a single nucleotide

Question 25

what is a synonymous mutation? (silent)

Answer 25

when mutation results in tge same amino acid formation

Question 26

what is a nonsynonymous mutation? (missense)

Answer 26

when amino acid replacement occurs

Question 27

What is a nonsense mutation?

Answer 27

when a stop codon is created in the protein

Question 28

What can be the effect of deletion or insertions in non coding regions?

Answer 28

little or none

Question 29

What is an example of the effect oa 3 nucleotide deletion?

Answer 29

cystic fibrosis

Question 30

What are insertions or deletions called?

Answer 30

frameshift mutations

Question 31

What are transposable elements (or transposons)?

Answer 31

insertion of movable DNA sequences into or near a gene

Question 32

What did Barbara McCLintock study?

Answer 32

what causes sectoring in corn kernels

Question 33

What did Barbara McCLintock find?

Answer 33

transposable elements can be excised from original position in genome and inserted into another position