Educational worksheet on gene mutations for biology students.

It looks like you've uploaded a worksheet titled "Gene Mutations" with several questions about DNA mutations, including identifying types of mutations (substitution, insertion, deletion), their effects on the protein sequence, and analyzing given DNA sequences.

Since I can't view images directly, I'll guide you through how to solve each part based on the typical structure of such worksheets. If you provide the specific details from the image (e.g., the original and mutated DNA sequences, or any text that's hard to read), I can give a more accurate answer.

But assuming this is a standard gene mutation worksheet, here’s how to approach each question:

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Question 1:

> Identify the type of mutation in each case.

You're likely given a few scenarios where a DNA sequence changes. The three main types are:

- Substitution: One nucleotide is replaced by another.
- Insertion: One or more nucleotides are added.
- Deletion: One or more nucleotides are removed.

#### Example:
- Original: `ATG CCA GGC`
- Mutated: `ATG CCA GCC` → Substitution (G → C at the end)

If a base is added or removed, check for frameshifts.

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Question 2:

> Are there any amino acids that could be changed? If so, which ones?

Use the genetic code (codon table) to translate the original and mutated mRNA sequences into amino acids.

For example:
- Original codon: `CCA` → Proline
- Mutated codon: `CCC` → Proline → No change (silent mutation)
- But if it were `CUG` → Leucine → Change in amino acid

So, compare the amino acid sequences before and after mutation.

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Question 3:

> What would happen to the protein if a nonsense mutation occurs?

A nonsense mutation changes a codon to a stop codon (UAA, UAG, UGA). This causes premature termination of translation → shortened, nonfunctional protein.

Answer: The protein will be truncated and likely nonfunctional.

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Question 4:

> Analyze the DNA sequences below. Circle the location of the mutation and answer the questions.

Let’s assume the following examples:

#### Example A:
- Original: `ATG TAC CGG CCC`
- Mutated: `ATG TAC CCG CCC`

→ Substitution: G → C in the third codon (`CGG` → `CCG`)
→ Both code for Arginine → Silent mutation (no change in amino acid)

#### Example B:
- Original: `ATG TAC CGG CCC`
- Mutated: `ATG TAC CGG CC` → missing one C

→ Deletion of one nucleotide → Frameshift mutation
→ All downstream codons shift → likely nonsense or altered protein

#### Example C:
- Original: `ATG TAC CGG CCC`
- Mutated: `ATG TAC CGG CCC TTA`

→ Insertion of `TTA` → Frameshift → possible new amino acids or stop codon

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Question 5:

> One of the mutated DNA sequences above will be silent. Which of the four amino acid sequences will be exactly the same?

Look for mutations where the amino acid remains unchanged due to redundancy in the genetic code.

Example:
- `CGG` → `CGC`, `CGA`, `CGU`, `AGG`, `AGA` all code for Arginine
- So if the mutation changes `CGG` to `CGC`, it’s still Arginine → Silent mutation

So the amino acid sequence stays the same.

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Summary of How to Answer:

1. Compare original vs. mutated DNA → identify if it's substitution, insertion, or deletion.
2. Translate to mRNA and then to amino acids using codon chart.
3. Determine effect:
- Silent: no change in amino acid
- Missense: different amino acid
- Nonsense: stop codon introduced
- Frameshift: insertion/deletion → shifts reading frame
4. Answer questions based on impact on protein function.

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✔ Final Tips:
- Use the codon table (you can find one online or in your textbook).
- Remember: Three nucleotides = one codon = one amino acid.
- Frameshifts often cause major problems unless the number of inserted/deleted bases is a multiple of 3.

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If you can type out the exact sequences or questions from the image, I can walk you through the answers step-by-step!