Mutations

Question 1

Gene expression 2 steps

Answer 1

Transcription
Translation

Question 2

• the process of DNA being copied to generate a single-strand RNA

Answer 2

Transcription

Question 3

• the process of the RNA nucleotide sequence being converted into the amino acid sequence of a protein.

Answer 3

Translation

Question 4

Transcription occurs in the____; translation occurs in the______.

Answer 4

nucleus

cytoplasm

Question 5

Sense vs Antisense strans

Answer 5

Sense - coding; non tenplate

Antisense - non coding; template

Question 6

THE GENETIC CODE

Each “______” is composed of_____ three-letter codes,____ in all.

______codons are recognized by_____ for the incorporation of the____ common amino acids.

Answer 6

codon box; four; 64

Sixty-one; tRNAs; 20

Question 7

“________” proposed by_____

The hypothesis states that the pairing between codon and anticodon at the first two codon positions always follows the usual rule for complementary base pairing, but that exceptional “wobbles” (non-Watson-Crick base pairing) can occur at the third position.

Answer 7

Wobble Hypothesis; Francis Crick

Question 8

• Some sites on chromosomes are “_______” where mutations arise at a higher frequency than other regions of the DNA.

Answer 8

hotspots

Question 9

are those that occur as a result of interaction of DNA with an outside agent or mutagen that causes DNA damage.

Answer 9

• Induced mutations

Question 10

is one that occurs as a result of natural processes in cells, for example DNA replication errors.

Answer 10

spontaneous mutation

Question 11

• result from changes in the nucleotide sequence of DNA or from deletions, insertions, or rearrangements of DNA sequences in the genome.

Answer 11

Mutations

Question 12

Mutations are of fundamental importance in molecular biology for several reasons:

Answer 12

Mutations are important as the major source of genetic variation that drives evolutionary change.

Mutations may have deleterious or (rarely) advantageous consequences to an organism or its descendants.

Mutations in germ cells can lead to heritable genetic disorders, while mutations in somatic cells may lead to acquired diseases such as cancer or neurodegenerative disorders.

Mutant organisms are important tools for molecular biologists in characterizing the genes involved in cellular processes.

Question 13

Mutations are important as the major source of ______that drives evolutionary change.

Answer 13

genetic variation

Question 14

______may have deleterious or (rarely) advantageous consequences to an organism or its descendants.

Answer 14

Mutations

Question 15

Mutations in_____ cells can lead to heritable genetic disorders, while mutations in_____ cells may lead to acquired diseases such as cancer or neurodegenerative disorders.

Answer 15

germ

somatic

Question 16

Mutant organisms are important tools for _____in characterizing the genes involved in cellular processes.

Answer 16

molecular biologists

Question 17

TYPES OF MUTATION

Answer 17

Gene Mutation
Chromosome Mutation
Genome Mutation

Question 18

Mechanism of Gene Mutations

Answer 18

Substitution
Deletion
Insertion

Question 19

Insertion-

Answer 19

addition of a base

Question 20

Deletion

Answer 20

• removal of a base

Question 21

Substitution

Nucleotide Substitution or Point Mutations-

Answer 21

The most common nucleotide mutations are those that affect a single base pair, in which one base is replaced by another.

Question 22

(Insertions/Deletions

Answer 22

Base INDELS

Question 23

3 types of gene mutation

Answer 23

Point
Frameshift

Question 24

Point

Answer 24

Silent
Missense
Nonsense

Question 25

Frameshift

Answer 25

Deletion Insertion

Question 26

- usually due to a substitution in the third base of a codon, known as the _______, which often represents the same amino acid as the original codon.

Answer 26

Silent Mutations (Synonymous) Wobble position

Question 27

- Mutations that change the nucleotide sequence ***without changing the amino acid sequence***

Answer 27

Silent Mutations (Synonymous)

Question 28

- Nucleotide substitutions in protein-coding regions that do result in changed amino acids

Answer 28

Missense mutations (Nonsynonymous)

Question 29

- cause ***premature chain termination*** during protein synthesis, the remaining polypeptide fragment is nearly always nonfunctional

Answer 29

Nonsense mutations-

Question 30

- A nucleotide substitution that creates a ***new stop codon***

Answer 30

Nonsense mutations-

Question 31

Nonsense mutations- cause premature chain termination during protein synthesis, the remaining polypeptide fragment is nearly always______

Answer 31

nonfunctional

Question 32

Sickle Cell Anemia • Mutation in a_____ codon of______ gene which results in the substitution of _____ with _____ • Formation of abnormal hemoglobin molecules cause sickle-shaped RBCs.

Answer 32

6th beta-globin glutamic acid with valine

Question 33

- Results in ***abnormal protein products*** with an ***incorrect amino acid sequence*** that could ***lead to severe genetic diseases***

Answer 33

Frameshift Mutations

Question 34

- shifting the reading frame of the codons ***due to deletion or insertion of one nucleotide.*** Thus, altering the subsequent sequence of amino acids.

Answer 34

Frameshift Mutations

Question 35

• Genetic disorder caused by mutations in the ***HEXA gene.*** • ***Deletion of cytosine*** in the coding sequence which causes premature termination.

Answer 35

Tay-Sachs Disease:

Question 36

Tay-Sachs Disease: • Genetic disorder caused by mutations in the____ • Deletion of_____ in the coding sequence which causes premature termination.

Answer 36

HEXA gene cytosine

Question 37

: the altered codon codes for the same amino acid.

Answer 37

Silent mutation

Question 38

: the altered codon ***codes for a different amino acid and the protein*** is often ***nonfunctional.***

Answer 38

Missense mutation

Question 39

the new codon is a termination codon. Protein synthesis stops and the protein is nonfunctional.

Answer 39

Nonsense mutation:

Question 40

the addition or deletion of one or more base pairs results in a shift in the reading frame of the resulting mRNA, and leads to production of a nonfunctional protein.

Answer 40

Frameshift mutation

Question 41

Change in a single nucleotide No shift in the reading frame May be silent, missense, or nonsense Often mild or neutral

Answer 41

Point mutation

Question 42

Shifts the reading frame Usually results in a ***nonfunctional protein*** Usually severe and damaging

Answer 42

Insertion or deletion of nucleotides

Question 43

Chromosome Mutation (4)

Answer 43

Deletion Duplication Inversion Translocation

Question 44

Chromosme Segment Lost

Answer 44

Deletions

Question 45

A segment from chromosome is transferred to another

Answer 45

Translocation

Question 46

A segment from one chromosme is transferred to its homologous chromosme, giving it a duplicate of some genes

Answer 46

Duplication

Question 47

A segment of a chromosme arm is inverted

Answer 47

Inversion

Question 48

Genome Mutation

Answer 48

Aneuploidy Polyploidy

Question 49

Changes in whole sets of chromosomes Having more or less than normal number of sets Monoploid and Polyploids

Answer 49

Aberrant Euploidy

Question 50

Other Types of Mutations

Answer 50

• Expansions of trinucleotide repeats • Extensive insertions and deletions • Major chromosomal rearrangements