Genetic Mutations POGIL

How many nucleotides are present in the "normal" DNA sequence in Model 1?

21 nucleotides

How many codons are contained in the mRNA that is produced by the "normal" DNA in Model 1?

7 codons

How many amino acids will be in the polypeptide produced by the normal DNA/mRNA sequence?

6 amino acids

What is the amino acid sequence of the polypeptide produced by the "normal" DNA sequence in Model 1?

Met His Gln Trp Ile Thr

Compare sequence 1&2 + effect of substitution

5a. Sequence 2 has a G that replaced a C around the middle

5b. This changed Trp to Ser

Compare sequence 3&1 + effect of insertion

6a. T was inserted before a G near the end of the first third of the DNA sequence

6b. This caused all of the amino acids after His to change, and the sequence no longer stops

Compare sequence 4&1 + effect of deletion

7a. The A after the C was deleted by slightly to the left of the middle of the sequence

7b. This also changed all of the amino acids after His, and the sequence also no longer stops

Define mutations

Substitution - A nucleotide is substituted for another

Insertion - A nucleotide is inserted into the DNA sequence

Deletion - A nucleotide is deleted from the DNA sequence

Would all substitution mutations lead to a change in the amino acid sequence?

No, because some codons can code for the same amino acid despite a nucleotide change

Would all insertion or deletion mutations lead to a change in the amino acid sequence?

Yes, because it manipulates which sections are being coded

What could potentially cause more damage (or a greater benefit) to an organism, a substitution mutation or an insertion mutation?

Insertion for the reason stated above

What could potentially cause more damage (or a greater benefit) to an organism, a deletion mutation at the beginning of a DNA sequence or at the end of a DNA sequence

(Unsure) Both are pretty bad, but probably at the end because that could mean that the translating wouldn't stop when it's supposed to

All of the DNA and mRNA sequences in Model 1 have ellipses (...) on one or both ends of the sequences shown. Propose an explanation for this use of this symbol in that context.

The strands don't end until they get the stop codon

The amino acids produced from sequence 1 and sequence 2 in Model 1 do not have ellipses on the end of them, however the amino acids produced from sequence 3 and sequence 4 do have ellipses. Propose an explanation for the use or absence of the ellipses on these sequences.

The UAG codon on mRNA stops the sequence

For each of the mutations A - D in Model 2, circle the substitution that occurred by comparing the mutated DNA with the original DNA.

Mutation A: ATA becomes AAA (near the middle right)

Mutation B: GGA becomes GCA (near the middle)

Mutation C: CCC becomes CAC (near the left)

Mutation D: TAC becomes TAG (far left)

As a group, describe the range of changes in the amino acid sequence that can result from this type of mutation.

One amino acid in the sequence can change without altering length, the sequence can be unaffected, the sequence's length could end inappropriately, the sequence's creation could be prevented

Mutation that was neutral

(Unsure) The third mutation is neutral because it didn't affect the amino acid sequence

Mutation that was positive

(Unsure) The second mutation could be positive because it could change the function of an enzyme

Mutation that was negative

(Unsure) The fourth mutation is negative because it straight up prevents the enzyme from existing

18. Which types of mutations, positive, negative or neutral, are most likely to be seen in offspring several generations after the mutation occurred? Explain your reasoning.

Positive, since positive mutations are more likely to aid for survival, so they're more likely to be passed on

19a. A single bacteria cell contains a positive mutation in its DNA.

Yeah because bacteria constantly gains resistances and other advantages by keeping beneficial mutations

19b. A skin cell on a cat contains a positive mutation in its DNA.

(Unsure) No because skin cells doesn't really need to be passed on for survival

19c. A sperm cell in a whale contains a positive mutation in its DNA.

(Unsure) Yeah because the offspring would just have it

20a. If each cell has multiple mutations, why do most of us have normally-functioning tissues and organs?

Not all mutations are bad/harmful

20b. Why is only a tiny subset of these mutations passed on to our children?

Mutations don't usually affect sperm or eggs

21. Explain why "mistakes" in transcription or translation are not as serious as mutations in a gene

DNA is often repaired through regulatory processes, and transcription errors usually just lead to a limited number of proteins

22. Explain why insertions and deletions are called frameshift mutations

Insertion and deletions change the number of codons, leading to different amino acids getting inserted, changing the reading frame for the ribosome