T4M4

Question 1

Mutations can be created by

Answer 1

environmental factors, spontaneous mutations, errors during process of DNA replication

Question 2

Why do RNA viruses have the highest probability of mutation?

Answer 2

delicate nature of the RNA backbone of RNA viruses and retroviruses (being more prone to damage and breakage), in addition to the fact that there is no proofreading capability in RNA genomes

Question 3

Joshua and Esther Lederberg in 1952 showed that

Answer 3

mutations such as those of antibiotic resistance in bacteria are random and not directed

Question 4

Mismatching of single nucleotide pairs during
DNA replication can be corrected by the
proofreading capabilities of

Answer 4

DNA polymerase

Question 5

A mismatched nucleotide pair creates

Answer 5

a kink in the DNA molecule that is recognized by proteins that scan the DNA for damage and errors

Question 6

Base excision repair

Answer 6

incorporation of a uracil in DNA that signals that
there is the need for DNA repair to be done

Question 7

If any DNA molecules accidently incorporate a
uracil into their elongating strands

Answer 7

the presence of uracil is a signal that is detected by a DNA uracil glycosylase enzyme which will cleave the uracil from the sugar DNA backbone itself

Question 8

DNA synthesis facilitated by

Answer 8

enzymes such as DNA polymerase and DNA ligase

Question 9

Nucleotide excision repair

Answer 9

can remove and replace more than one
damaged nucleotide bases. It is the damaged
bases which signal to specific enzymes to cleave
the DNA backbone on either side or flanking the
region of damaged or mismatched bases

Question 10

single nucleotide polymorphisms (SNPs)

Answer 10

Point mutation, a single nucleotide pair substitution where one base pair is incorrectly replaced by another pair of nucleotides

Question 11

non-synonymous or missense mutation which causes a single amino acid substitution in the beta-globin protein subunits of the hemoglobin molecules that carry oxygen in our red blood cells causes what disease?

Answer 11

Sickle cell anemia

Question 12

Insertion mutations occur when

Answer 12

One or more extra nucleotides are inserted into replicating DNA

Question 13

Deletion mutations

Answer 13

involve the skipping, or sometimes removal of one or more nucleotides during DNA replication

Question 14

Individuals that have a three-nucleotide deletion in their genes that code for the CFTR transporter develop

Answer 14

thick, sticky mucus as a result of the inability to transport chloride ions across their cells

Question 15

Frameshift mutation

Answer 15

occur whenever the number of nucleotides inserted or deleted is not in a multiple of three

Question 16

Chromosomal mutations

Answer 16

mutations that affect a larger region of the DNA and leads to visible changes in chromosomal structures that are distinguishable under the microscope

Question 17

four major types of changes that can occur to
chromosome structure that can result in
chromosomal abnormalities

Answer 17

deletions, duplications, inversions and reciprocal translocations

Question 18

Deletion can occur when a

Answer 18

chromosomal fragment is lost

Question 19

duplication and divergence

Answer 19

Regions of a chromosome
may be able to acquire small duplications during DNA replication, don’t harm diploid organisms because the normal homologous chromosome provides a backup, extra copies due to mutations can be advantageous and lead to the formation of new genes with similar functions.

Question 20

Inversion

Answer 20

a chromosome fragment breaks off and then reattaches to the same chromosome, but in the reverse order

Question 21

Translocations

Answer 21

a portion of one chromosome is able to attach to a non-homologous chromosome

Question 22

Reciprocal translocations tend to occur in

Answer 22

noncoding regions of DNA in larger genomes, so these types of mutations generally do not disrupt gene function