Ch. 13 Gene Mutations, Transposable Elements, And Dna Repair

Question 1

Base substitution

Answer 1

Changes a single DNA nucleotide

Question 2

Transition

Answer 2

Base substitution in which a purine replaces a purine or pyramiding replaces a pyramiding

Question 3

Transversion

Answer 3

Base substitution in which a purine replaces a pyramiding or a pyrimnidine replaces a purine

Question 4

Insertion

Answer 4

Addition of one or more nucleotides

Question 5

Deletion

Answer 5

Deletion of one or more nucleotides

Question 6

Frameshift mutation

Answer 6

Insertion or deletion that alters the reading frame of a gene

Question 7

In frame deletion or insertion

Answer 7

Deletion or insertion of a multiple of three nucleotides that does not alter the reading frame

Question 8

Expanding nucleotide repeats

Answer 8

Increased the number of copies of a set of nucleotides

Question 9

Forward mutation

Answer 9

Changes wild type phenotype to mutant phenotype

Question 10

Reverse mutation

Answer 10

Changes mutant phenotype back to wild type phenotype

Question 11

Missense mutation

Answer 11

Changes a sense codon into different sense codon, resulting in incorporation of different amino acid in the protein

Question 12

Nonsense mutation

Answer 12

Changes a sense codon into a nonsense (stop) codon, causing premature termination of translation

Question 13

Silent mutation

Answer 13

Changes sense codon into synonymous codon leaving amino acid sequence of protein unchanged

Question 14

Neutral mutation

Answer 14

Changes amino acid sequence of protein without altering ability to function

Question 15

Loss of function mutation

Answer 15

Mutation causes complete or partial loss of function

Question 16

Gain of function mutation

Answer 16

Causes the appearance of a new trait or function or causes the appearance of a trait in inappropriate tissue or at an inappropriate time

Question 17

Lethal mutation

Answer 17

Causes premature death

Question 18

Suppressor mutation

Answer 18

Suppresses the effect of an earlier mutation at different site

Question 19

INTRAgenic suppressor mutation

Answer 19

Suppresses the effect of an earlier mutation WITHIN the same gene

Question 20

INTERgenic suppressor mutation

Answer 20

Suppresses the effect of an earlier mutation IN ANOTHER gene

Question 21

Mutation rate

Answer 21

Frequency with which a wild type allele at a locus changes into a mutant allele

Question 22

Spontaneous mutations

Answer 22

Mutations that occur under normal conditions

Question 23

Induced mutations

Answer 23

Mutations caused by environmental chemicals or radiation

Question 24

Tautomeric shifts

Answer 24

Tautomers are isomers of a compound which exist together in equilibrium and readily interchanged by migration of an atom or group within the molecule. ***** The primary cause of spontaneous replication errors was formerly thought to be tautomeric shifts in which positions of protons in DNA bases change. But NOW research shows little evidence for this.

Question 25

Incorporated error

Answer 25

Occurs when a mispaired base has been incorporated into a newly synthesized nucleotide chain. The original incorporated error leads to a REPLICATED ERROR which creates permanent mutation.

Question 26

Strand slippage

Answer 26

This can occur when one nucleotide strand forms small loop. Insertions and deletions can result from strand slippage.

Question 27

Depurination

Answer 27

Loss of a purine base from a nucleotide.

Question 28

Deamination

Answer 28

Another spontaneously occurring chemical change that takes place in DNA is the loss of an amino group (NH2) from a base. May be spontaneous or result of mutagenic chemicals.

Question 29

Mutagen

Answer 29

Any environmental agent that significantly increases the rate of mutation above the spontaneous rate.

Question 30

Base analogs

Answer 30

Class of chemical mutagen with structires similar to those of any of the four standard bases of DNA. Can cause new analog to pair or mispair

Question 31

Hydroxylamine

Answer 31

A very specific base-modifying mutagen that adds a hydroxyl group to cytosine converting it into hydrosylaminocytosine.

Question 32

Intercalating agents

Answer 32

Produces mutations by sandwiching themselves (intercalating) between adjacent brasses in DNA, distorting the three dimension structure of the helix cause I got indels in replication. Ex: ethidium bromide

Question 33

Ames test

Answer 33

Based on the principle that both cancer and mutations result from damage to DNA results of experiments have demonstrated that 90% of known carcinogens are also mutagens.

Question 34

Transposable elements

Answer 34

JUMPING GENES _ _ _ DNA sequences that can move about the genome are often a cause of mutation. They make up at least 45% of human DNA.

Question 35

Flanking direct repeats

Answer 35

From 3-12 bps long present on both sides of most transposable elements.

Question 36

Terminal inverted repeats

Answer 36

At the ends of many but not all transposable elements. Sequences from 9 to 40 by that are inverted complements to one another.

Question 37

Transposition

Answer 37

Movement of a transposable element from one location to another.,

Question 38

DNA transposons

Answer 38

Transposable elements transposing as DNA. Also called class 2 transposable elements. More commonly found in bacteria.

Question 39

retrotransposons

Answer 39

Elements that transpose through an RNA INTERMEDIATE also called CLASS 1 transposons. Although DNA transposons and retrotransposons can both be in eukaryotes. Retrotransposons More commonly found in eukaryotes.

Question 40

Replicating transposition

Answer 40

New copy of transposable element that is introduced at a new site while the old copy remains behind at original site so number of copies of transposable element increases a a result of transposition.

Question 41

Nonreplicative transposition

Answer 41

The transposable element excises from the old site and inserts at new site without any increase in number of its copies.

Question 42

Mismatch repair

Answer 42

Type of DNA repair which corrects incorrectly inserted nucleotides that escape proofreading by DNA polymerase during replication. Methyl group recognized on template strand

Question 43

Direct repair

Answer 43

Another type of DNA repair mechanism which does not replace altered nucleotides but instead restores Their original correct structures.

Question 44

Base excision repair

Answer 44

Modified base is fairest excised and then the entire nucleotide is replaced.

Question 45

Nucleotide excision repair

Answer 45

Removes bulky DNA lesions such as pyrimidine dimers that distort the double helix.