Mutations

A single substitution in the third position would have the greatest probability of mutational effect on the codon

a. GUU

b. AUU

c. CGU

d. AUG

e. CCC

• GUU

• AUU

• CGU

• AUG

Which of the following is a correct statement about mutations?

• They are a source of variation for evolution

• Ther drive evolution by creating mutation pressures

• They are irriversible

• They occur in germ cells but not in somatic cells

• They are most often beneficial to the organisms in which they occur.

Suppose a gene has the DNA nucleotide sequence

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

C T G G C A T G C T T C G G A A A

(No real gene could be this short, but for our purposes, this will suffice.) Which one of the following mutations would probably produce the greatest change in the activity of the protein for which this gene codes?

• substitution of A for G in position 3

• deletion of the C at position 5

• deletion of the A at position 15

• addition of G between position 14 and 15

• substitution of A for T at position at 11

Tags

NGSS.HS-LS1-1

NGSS.HS-LS3-2

 A frameshift mutation could result from 

• a base insertion only.
• a base deletion only. 
• a base substitution only. 
• either an insertion or a deletion of a base.

Tags

NGSS.HS-LS3-2

DNA molecule segment is : TTACGCAAG
The mutated DNA segment is TTCGCAAG. This is an example of ______ mutation.

• Substitution
• Deletion
• Insertion
• Inversion

Tags

NGSS.HS-LS3-2

Are all mutations bad?

• Yes
• No

Tags

NGSS.HS-LS3-2

NGSS.HS-LS4-2

Where do mutations occur?

• DNA and RNA
• DNA 
• RNA
• mRNA and tRNA

Tags

NGSS.HS-LS3-2

NGSS.HS-LS4-2

What is the effect of a nucleotide-pair substitution that results in a nonsense mutation in a gene?

• it changes an amino acid in the encoded protein
• It has no effect on the amino acid sequence of the encoded protein
• it introduces  premature stop codon into the mRNA
• it alters the reading frame of the mRNA

Tags

NGSS.HS-LS3-2

What effect would the following mutation have on a protein?

normal mRNA: AUG CCC CGA

mutant mRNA: AUG CCG CGA

• would make the protein nonfunctional

• would not affect the function of the protein

• would give the protein new functions

Tags

NGSS.HS-LS3-2

Which of the following mutations is most likely to create a nonfunctional protein in a eukaryotic organism.

• a deletion of a nucleotide in an intron

• a deletion of a nucleotide near the beginning of an exon

• a deletion of one nucleotide in the last codon of the last exon

Tags

NGSS.HS-LS3-2