Ch. 12

Question 1

Mutation

Answer 1

change in DNA sequence is rare in a population and typically affects the phenotype

“loss of function” mutations - recessive
“gain of function” mutations - dominant

Question 2

SNP vs. Mutation

Answer 2

Mutations are like rare typos in your DNA book that can sometimes cause problems or changes.
SNPs are like common tiny changes that lots of people have, and most of the time, they don’t cause problems.

Question 3

Polymorphism

Answer 3

gene variant (allele) present in more than 1% of a population

Question 4

Gene variant

Answer 4

refers to both polymorphisms and mutations

Question 5

Mutant

Answer 5

refers to phenotype and describes an allele

Question 6

Gremline Mutation

Answer 6

change occurs during the DNA replication that precedes meiosis

transmitted to the next generation of individuals

Question 7

Somatic Mutation

Answer 7

happens during DNA replication before a mitotic cell division

affect only cells that descend from changed cellS

Question 8

Somatic Mosaicism

Answer 8

a person with somatic mutation

when somatic cells mutate in an individual, not all cells in individual have that mutation

Question 9

Spontaneous Mutations

Answer 9

errors in normal cellular processes such as DNA replication, can be caused by natural changes in the molecular structure of the bases in DNA (chemical instability

de novo (new mutations)

Question 10

Induced Mutations

Answer 10

caused by mutagens or carcinogens, such as radiation and chemicals, that affect DNA and cellular processes

Question 11

Radon

Answer 11

naturally occuring radioactive gas that can cause lung cancer, second leading cause of lung cancer in US

Question 12

Conversion of Cytosine to Uracil by nitrous acid (hno2)

Answer 12

nitrates and nitriles used in preservation of meat are converted into nitrous acid in the body

Question 13

Silent Mutation

Answer 13

changes a single nucleotide in the DNA sequence but does not alter the amino acid sequence of the resulting protein.

Question 14

Missense Mutation

Answer 14

occurs when the change in nucleotide results in subtitling one amino acid for another in the final protein

Question 15

Nonsense Mutation

Answer 15

occur when the change in results in submitting a stop codon for an amino acid in the final protein

Question 16

Frameshift mutation (1 bp deletion)

Answer 16

when nucleotides are inserted or deleted from genome. shifts the reading grade usually and results in premature truncation of the protein ; can be insertion or deletion mutations

Question 17

Splice Site Mutations

Answer 17

alters a site where an intron is normally removed from mRNA

can affect phenotype if:
- intron is translated into amino acids
- exon is skipped (exon skipping)

Question 18

Deletion

Answer 18

removes genetic material

Question 19

Insertion

Answer 19

adds genetic material

Question 20

Tandem Duplication

Answer 20

two complete copies of a gene next to each other

Question 21

Pseudogenes

Answer 21

DNA sequence similar to a gene but not translated, may be transcribed into mRNA

gene sequence duplicated when DNA strands misaligned during meiosis

Question 22

Transposons

Answer 22

“jumping genes”
DNA polymerase can make mistakes during DNA replication, but at a very low rate; proofreading mechanisms also help prevent mutations

Transposons can insert and remove themselves from the genome; if insert code in middle of sequence mutation can disrupt the gene

Question 23

Expanding repeats

Answer 23

gene grows as small part of DNA sequence is copied and inserted

more repeats = more severe

Question 24

Anticipation

Answer 24

expansion of triplet repeat with an increase in severity of phenotype with subsequent generations

<40 repeats = not associated w. symptoms, but larger repeats = unstable

Question 25

A __ is a change in a DNA sequence that can cause varying effects.

Answer 25

mutation

Question 26

The term ___ is increasingly being used to mean both polymorphism and mutation.

Answer 26

variant

Question 27

A mutation that occurs during the DNA replication preceding meiosis is called a

Answer 27

germline mutation

Question 28

A mutation that occurs during the DNA replication preceding a mitotic cell division is called a

Answer 28

somatic mutation

Question 29

A ___ mutation will be present in some of the cells in an individual’s body but will be absent from other cells.

Answer 29

somatic

Question 30

You have performed exome sequencing and have identified a gene in which two different mutant forms are prevalent. Each mutation is a missense mutation, but they are found in different parts of the gene.

What can you conclude about these mutations?

Answer 30

They may each cause a different disease.

Question 31

When a gene is disrupted by a DNA sequence “jumping” into it and disrupting the reading frame, the DNA sequence that jumps into the gene is called a

Answer 31

transposon

Question 32

A mutation that can be passed on to all the cells in a person’s progeny is a _________ mutation.

Answer 32

germline

Question 33

In sickle cell disease, a _________blank that is normally in the beta globin polypeptide is replaced with a _________blank.

Answer 33

glutamic acid; valine

Question 34

Exposure to radioactive substances in the Earth’s crust is an example of

Answer 34

natural exposure to mutagens

Question 35

Consider the following gene:

Exon H - Intron 1 - Exon I - Intron 2 - Exon J - Intron 3 - Exon K - Intron 4 - Exon L.

The gene undergoes 2 splice-site mutations, one causes Intron 4 to be retained, and another that causes skipping of Exon K.

Select the correct structure of the translated protein.

Answer 35

H-I-J-4-L

Question 36

A tautomer is

Answer 36

an alternate structure of a molecule.

Question 37

DNA Repair Mechanisms

Double-strnaded break repair

Answer 37

ionizing radiation oxidative damage

Question 38

DNA Repair Mechanisms

Excision repair: nucleotide excision repair or base excision repair

Answer 38

UV exposure

Question 39

DNA Repair Mechanisms

Damage tolerance

Answer 39

small errors ignored

Question 40

DNA Repair Mechanisms

Mismatch Repair

Answer 40

Replication errors