Overview of DNA mutations, highlighting silent mutations and point mutations with codon examples.

Let’s go step by step to understand what’s happening in this problem.

We’re looking at a DNA sequence that has changed — this is called a mutation. Specifically, we’re told it’s a point mutation, which means just one base (letter) was swapped for another.

The original DNA sequence given is:
> GGA CAC CTC

And the mutated version is:
> GCA CAC CTC

Wait — actually, looking again at the image, it says:

Original DNA:
GGA CAC CTC

Mutated DNA:
GCA CAC CTC? No — wait, let me check carefully.

Actually, in the image, under “Mutated Sickle Cell”, it shows:

DNA:
GGA CAC CTC → then below it, with red letters:
CCU GUG GAG

But hold on — that doesn’t match directly. Let’s read it again.

It says:

> Mutated Sickle Cell
> DNA: GGA CAC CTC
> Then underneath: CCU GUG GAG
> Amino Acids: Proline - Valine - Glutamic Acid

Wait — that seems backwards. Normally, DNA is transcribed to mRNA, which is then translated to amino acids.

In standard biology:

- DNA template strand is used to make mRNA.
- mRNA codons are read to build proteins (amino acids).

But here, they might be showing the coding strand or simplifying.

Looking more closely:

They write:

DNA: GGA CAC CTC
Then below: CCU GUG GAG ← these look like mRNA codons (because they have U instead of T)

And then amino acids: Proline - Valine - Glutamic Acid

So likely, they mean:

Original DNA (coding strand): GGA CAC CTC
→ mRNA would be: CCU GUG GAG? Wait no — if DNA is GGA, mRNA should be CCU? That doesn’t match base pairing.

Hold on — let’s fix this.

Standard base pairing:

DNA → mRNA:

A → U
T → A
C → G
G → C

So if DNA is GGA, mRNA should be CCU

If DNA is CAC, mRNA should be GUG

If DNA is CTC, mRNA should be GAG

Yes! So:

DNA: GGA CAC CTC
mRNA: CCU GUG GAG
Amino acids: Proline - Valine - Glutamic Acid

Now, the mutation part — they show in red:

In the DNA line, they wrote “GGA” but then crossed out the second G and put a C? Or maybe they meant the mutation is in the first codon?

Wait — look at the text:

It says: “one base swapped for another” — green underline.

And in the DNA line: “GGA CAC CTC” — but then below, in red, they have “CCU GUG GAG” — and under GUG, they have “Valine” in red.

Also, in the amino acid line: “Proline - Valine - Glutamic Acid” — and “Valine” is in red.

This suggests that normally, without mutation, it should be something else — but in sickle cell, it’s Valine instead of Glutamic Acid? Wait no — in real sickle cell anemia, the mutation changes Glutamic Acid to Valine in hemoglobin.

But here, they show:

Amino acids: Proline - Valine - Glutamic Acid

That’s three amino acids. In sickle cell, the famous mutation is in the sixth amino acid of beta-globin, changing from Glutamic Acid to Valine.

But here, they have Valine as the second amino acid? That doesn’t match.

Perhaps there’s a mistake in how I’m reading it.

Let me re-read the image description.

Under “Mutated Sickle Cell”:

DNA: GGA CAC CTC
Then below: CCU GUG GAG
Amino Acids: Proline - Valine - Glutamic Acid

And in red, they highlight “Valine”.

But in reality, for sickle cell, the normal sequence has Glutamic Acid, and mutant has Valine.

Here, they show Valine as present — so perhaps this IS the mutant version.

But then what was the original?

Maybe the DNA shown is the mutant DNA.

Let’s think differently.

Perhaps the DNA sequence given is the mutant one, and we need to find what changed.

But the problem isn't clearly stated — the user didn't ask a specific question. They just uploaded an image.

Looking back at the user's message: "You are an educational assistant helping a student solve homework problems." and "The user uploaded an image containing a task."

But in the image, there's no explicit question. It's notes about mutations.

However, in the context, it seems like the task might be to identify the type of mutation or explain what happened.

Given that, and since the user said "solve the problem accurately", I need to infer what the problem is.

From the content, it appears to be illustrating a point mutation that causes sickle cell disease.

In sickle cell anemia, a single nucleotide change in the DNA leads to a different amino acid being incorporated into the protein.

Specifically, in the beta-globin gene, the sixth codon changes from GAG (which codes for Glutamic Acid) to GTG (which codes for Valine) in the DNA coding strand.

In terms of mRNA, it changes from GAG to GUG.

In the image, they show:

DNA: GGA CAC CTC — but that doesn't match the standard sickle cell mutation.

Standard sickle cell mutation:

Normal DNA coding strand: ...GTG CAC CTG... or something — let's recall.

Actually, the normal sequence for the sixth codon in beta-globin is GAG (DNA coding strand), which gives mRNA GAG, amino acid Glutamic Acid.

Mutant is GTG (DNA), mRNA GUG, amino acid Valine.

In the image, they have DNA: GGA CAC CTC

If we assume this is the coding strand, then mRNA would be:

GGA → CCU → Proline
CAC → GUG → Valine
CTC → GAG → Glutamic Acid

So amino acids: Proline - Valine - Glutamic Acid

But in sickle cell, the mutation is supposed to change Glutamic Acid to Valine, not have Valine already.

Unless this is showing the mutant version where Valine is present, but in the wrong position.

Perhaps there's a typo in the image or in my understanding.

Another possibility: maybe the DNA sequence shown is for the template strand, not coding strand.

Let's try that.

If DNA template strand is GGA CAC CTC, then mRNA would be complementary:

GGA → CCU? No.

Template strand is read 3' to 5', mRNA synthesized 5' to 3'.

If template DNA is 3'-GGA CAC CTC-5', then mRNA is 5'-CCU GUG GAG-3'

Same as before.

Amino acids still Proline - Valine - Glutamic Acid.

But for sickle cell, we expect the sixth amino acid to change from Glu to Val.

Here, the second amino acid is Valine, which is unusual.

Perhaps the sequence is abbreviated or miswritten.

Looking back at the image description: it says "Mutated Sickle Cell" and then DNA: GGA CAC CTC, and below CCU GUG GAG, and amino acids Proline-Valine-Glutamic Acid, with Valine in red.

Also, in the DNA line, they have "GGA" but then in red, they might have indicated a change.

In the text, it says: "one base swapped for another" and in green.

And in the DNA, they have "GGA" but perhaps it's meant to be that the first base of the second codon changed or something.

Let's look at the amino acids: Proline - Valine - Glutamic Acid.

In normal hemoglobin, the sequence around position 6 is ...Proline - Glutamic Acid - Glutamic Acid... or something.

I recall: the normal beta-globin chain has at position 5-7: Proline - Glutamic Acid - Glutamic Acid.

Position 6 is Glutamic Acid.

In sickle cell, position 6 is Valine.

So normal: ...Pro - Glu - Glu...

Mutant: ...Pro - Val - Glu...

In the image, they have Proline - Valine - Glutamic Acid, which matches the mutant version.

So the DNA shown is for the mutant.

What is the mutation?

Normal DNA for that region: for amino acids Pro - Glu - Glu.

Codons:

Proline: can be CCU, CCC, CCA, CCG

Glutamic Acid: GAA or GAG

So normal DNA coding strand might be: CCT GAA GAG or something.

For simplicity, often it's shown as:

Normal DNA: ...CCT GAG GAG... for Pro-Glu-Glu

mRNA: ...GGA CUC CUC... no.

Let's do it properly.

If amino acid is Proline, codon in mRNA is CCN, so DNA coding strand is CCN.

Glutamic Acid, mRNA GAA or GAG, DNA coding strand GAA or GAG.

So for Pro-Glu-Glu, DNA coding strand could be: CCT GAG GAG

mRNA: GGA CUC CUC? No.

DNA coding strand same as mRNA except T/U.

So if DNA coding strand is CCT GAG GAG, then mRNA is CCU GAG GAG, amino acids Pro-Glu-Glu.

In sickle cell, the middle Glu is changed to Val.

Valine codons: GUU, GUC, GUA, GUG

So mutant DNA coding strand: CCT GTG GAG

mRNA: CCU GUG GAG, amino acids Pro-Val-Glu.

Yes!

So in the image, they have DNA: GGA CAC CTC — that doesn't match.

GGA CAC CTC would give mRNA CCU GUG GAG, which is Pro-Val-Glu, but the DNA should be CCT GTG GAG for coding strand.

Perhaps they have the template strand.

If DNA template strand is GGA CAC CTC, then mRNA is CCU GUG GAG, same thing.

But typically, when we say "DNA sequence", we mean the coding strand.

In the image, they wrote "DNA: GGA CAC CTC", but for the mutant, it should be something like CCT GTG GAG for coding strand.

GGA CAC CTC is not matching.

Unless it's a different representation.

Perhaps "GGA CAC CTC" is the mRNA or something.

Let's calculate what DNA would give mRNA CCU GUG GAG.

If mRNA is CCU GUG GAG, then DNA template strand is GGA CAC CTC (since A-U, T-A, G-C, C-G).

DNA coding strand would be CCT GTG GAG.

In the image, they wrote "DNA: GGA CAC CTC", which is likely the template strand.

And they have amino acids Pro-Val-Glu, which is correct for sickle cell mutant.

The mutation is that in the DNA, the second codon changed from GAG (for Glu) to GTG (for Val) in the coding strand, or from CTC to CAC in the template strand? Let's see.

Normal template DNA for Glu at position 6: if mRNA is GAG, template DNA is CTC.

Mutant mRNA is GUG, so template DNA is CAC.

Yes! So in the template strand, it changed from CTC to CAC.

In the image, they have DNA: GGA CAC CTC — but that's for the whole thing.

For the second codon, normal template DNA should be CTC (for Glu), but in mutant, it's CAC (for Val).

In the sequence given, it's GGA CAC CTC, so the second codon is CAC, which is mutant.

The third is CTC, which would be for Glu, but in sickle cell, only the sixth amino acid changes, so the seventh should still be Glu, so CTC is correct for template strand for Glu.

mRNA for third codon: if DNA template is CTC, mRNA is GAG, amino acid Glu.

Perfect.

So the mutation is in the second codon of this segment: from CTC (normal, for Glu) to CAC (mutant, for Val).

In terms of bases, in the template strand, the first base of the codon changed from T to A? CTC to CAC — so the second base changed from T to A.

CTC → CAC: the middle base changed from T to A.

In DNA template strand, position: C-T-C to C-A-C, so the T changed to A.

This is a point mutation: substitution of T to A in the template strand.

Which corresponds to a change in the coding strand from GAG to GTG (since coding strand is complementary).

Coding strand normal: for template CTC, coding is GAG.

Mutant template CAC, coding is GTG.

So in coding strand, GAG to GTG, which is A to T change.

But in any case, it's a single base substitution.

Now, in the image, they have highlighted "Valine" in red, indicating that this is the changed amino acid.

Also, they mention "Silent Mutation" earlier, but this is not silent; it's a missense mutation because it changes the amino acid.

Silent mutation is when the amino acid doesn't change, like in the leucine example: CUU, CUC, CUA, CUG all code for Leucine, so if you change from CUU to CUC, it's still Leucine — silent.

But here, changing from Glu to Val is not silent; it's a missense mutation.

So for the sickle cell example, it's a point mutation (substitution) that causes a missense mutation.

Now, to answer the implied question: probably, the task is to identify the type of mutation or explain what happened.

Since the user didn't specify, but based on common homework, likely they want to know what kind of mutation this is and why it matters.

From the image, it's clear that a single base change led to a different amino acid, causing sickle cell disease.

So, stepping through:

1. There is a DNA sequence provided for the mutated sickle cell case.

2. The DNA (likely template strand) is GGA CAC CTC.

3. This transcribes to mRNA: CCU GUG GAG.

4. Which translates to amino acids: Proline - Valine - Glutamic Acid.

5. In the normal version, the second amino acid should be Glutamic Acid, not Valine.

6. So the mutation changed the codon from one that codes for Glu to one that codes for Val.

7. Specifically, in the DNA template strand, the codon changed from CTC (for Glu) to CAC (for Val).

8. This is a point mutation — a substitution of one base for another (T to A in the template strand).

9. Because it changes the amino acid, it is a missense mutation.

10. This single change causes the hemoglobin protein to malfunction, leading to sickle cell disease.

So, the final answer should summarize this.

But since the user might expect a specific format, and given that the options are false, I just need to provide the final answer after reasoning.

Final Answer: The mutation shown is a point mutation (specifically a substitution) in the DNA that changes the amino acid from glutamic acid to valine in the protein, which causes sickle cell disease. This is a missense mutation because it results in a different amino acid being incorporated.