Question

mutations worksheet
there are several types of mutation:
deletion (a base is lost)
insertion (an extra base is inserted)
deletion and insertion may cause whats called a frameshift, meaning the reading \frame\
changes, changing the amino - acid sequence.
substitution (one base is substituted for another)
if a substitution changes the amino acid, its called a missense mutation.
if a substitution does not change the amino acid, its called a silent mutation.
if a substitution changes the amino acid to a \stop,\ its called a nonsense mutation.
complete the boxes below. classify each as either deletion, insertion, or substitution and as either
frameshift, missense, silent or nonsense (hint: deletion or insertion will always be frameshift).
original dna sequence: t a c,a c c,t t g,g c g,a c g,a c t
mrna sequence:
amino acid sequence:
mutated dna sequence #1: t a c,a t c,t t g,g c g,a c g,a c t (circle the change)
whats the mrna sequence?
what will be the amino acid sequence?
will there likely be effects? what kind of mutation is this?
mutated dna sequence #2: t a c,g a c,c t t,g g c,g a c,g a c,t (circle the chan)
whats the mrna sequence
what will be the amino acid sequence?
will there likely be effects? what kind of mutation is this?
mutated dna sequence #3: t a c,a c c,t t a,g c g,a c g,a c t (circle the ch)
whats the mrna sequence
what will be the amino acid sequence?
will there likely be effects? what kind of mutation is this?
mutated dna sequence #4: t a c,a c c,t t g,g c g,a c t,a c t
whats the mrna sequence?
what will be the amino acid sequence?
will there likely be effects? what kind of mutation is this?

Explanation:

Step1: Transcribe original DNA to mRNA

In transcription, A pairs with U, T with A, G with C and C with G. Original DNA: T A C A C C T T G G C G A C G A C T. mRNA: A U G U G G A A C C G C U G C U G A.

Step2: Translate mRNA to amino - acid sequence

Using the genetic code, AUG is Methionine (Met), UGG is Tryptophan (Trp), AAC is Asparagine (Asn), CGC is Arginine (Arg), UGC is Cysteine (Cys), UGA is a stop codon. Amino - acid sequence: Met - Trp - Asn - Arg - Cys - stop.

Mutated DNA Sequence #1: T A C A T C T T G G C G A C G A C T

Step1: Transcribe mutated DNA to mRNA

Mutated DNA: T A C A T C T T G G C G A C G A C T. mRNA: A U G U A G A A C C G C U G C U G A.

Step2: Translate mRNA to amino - acid sequence

AUG is Met, UAG is a stop codon, AAC is Asn, CGC is Arg, UGC is Cys, UGA is a stop codon. Amino - acid sequence: Met - stop - Asn - Arg - Cys - stop.

Step3: Identify mutation type

A single base change (from C to T in DNA, changing the mRNA codon from UGG to UAG) is a substitution. Since it changes the amino - acid (from Trp to a stop codon), it is a nonsense mutation. There will likely be effects as the protein will be prematurely terminated.

Mutated DNA Sequence #2: T A C G A C C T T G G C G A C G A C T

Step1: Transcribe mutated DNA to mRNA

Mutated DNA: T A C G A C C T T G G C G A C G A C T. mRNA: A U G C U G G A A C C G C U G C U G A.

Step2: Translate mRNA to amino - acid sequence

AUG is Met, CUG is Leucine (Leu), GAA is Glutamic acid (Glu), CGC is Arg, UGC is Cys, UGA is a stop codon. Amino - acid sequence: Met - Leu - Glu - Arg - Cys - stop.

Step3: Identify mutation type

There are multiple base insertions. This is an insertion mutation, which is a frameshift mutation. There will likely be major effects as the reading frame is shifted, changing all subsequent amino - acids.

Mutated DNA Sequence #3: T A C A C C T T A G C G A C G A C T

Step1: Transcribe mutated DNA to mRNA

Mutated DNA: T A C A C C T T A G C G A C G A C T. mRNA: A U G U G G A A U C G C U G C U G A.

Step2: Translate mRNA to amino - acid sequence

AUG is Met, UGG is Trp, AAU is Asparagine (Asn), CGC is Arg, UGC is Cys, UGA is a stop codon. Amino - acid sequence: Met - Trp - Asn - Arg - Cys - stop.

Step3: Identify mutation type

A single base change (from G to A in DNA, changing the mRNA codon from AAC to AAU). Since both AAC and AAU code for Asn, it is a silent mutation. There will likely be no effects as the amino - acid sequence is not changed.

Mutated DNA Sequence #4: T A C A C C T T G G C G A C T A C T

Step1: Transcribe mutated DNA to mRNA

Mutated DNA: T A C A C C T T G G C G A C T A C T. mRNA: A U G U G G A A C C G C U G A U G A.

Step2: Translate mRNA to amino - acid sequence

AUG is Met, UGG is Trp, AAC is Asn, CGC is Arg, UGA is a stop codon, UGA is a stop codon (but the extra codon is added). Amino - acid sequence: Met - Trp - Asn - Arg - stop - (incomplete translation due to extra codon).

Step3: Identify mutation type

A single base insertion (extra T in DNA). This is an insertion mutation, a frameshift mutation. There will likely be major effects as the reading frame is shifted.

Answer:

Original DNA Sequence: T A C A C C T T G G C G A C G A C T
mRNA Sequence: A U G U G G A A C C G C U G C U G A
Amino Acid Sequence: Met - Trp - Asn - Arg - Cys - stop

Mutated DNA Sequence #1: T A C A T C T T G G C G A C G A C T
mRNA sequence: A U G U A G A A C C G C U G C U G A
Amino acid sequence: Met - stop - Asn - Arg - Cys - stop
Will there likely be effects? Yes
What kind of mutation is this? Nonsense mutation

Mutated DNA Sequence #2: T A C G A C C T T G G C G A C G A C T
mRNA sequence: A U G C U G G A A C C G C U G C U G A
Amino acid sequence: Met - Leu - Glu - Arg - Cys - stop
Will there likely be effects? Yes
What kind of mutation is this? Insertion (frameshift) mutation

Mutated DNA Sequence #3: T A C A C C T T A G C G A C G A C T
mRNA sequence: A U G U G G A A U C G C U G C U G A
Amino acid sequence: Met - Trp - Asn - Arg - Cys - stop
Will there likely be effects? No
What kind of mutation is this? Silent mutation

Mutated DNA Sequence #4: T A C A C C T T G G C G A C T A C T
mRNA sequence: A U G U G G A A C C G C U G A U G A
Amino acid sequence: Met - Trp - Asn - Arg - stop - (incomplete translation)
Will there likely be effects? Yes
What kind of mutation is this? Insertion (frameshift) mutation