Answered

### Codons Found in Messenger RNA

| First Base | U | C | A | G | Third Base |
|------------|----|-----|-----|-----|-------------|
| U | Phe | Ser | Tyr | Cys | U |
| | Phe | Ser | Tyr | Cys | C |
| | Leu | Ser | Stop| Stop| A |
| | Leu | Ser | Stop| Trp | G |
| C | Leu | Pro | His | Arg | U |
| | Leu | Pro | His | Arg | C |
| | Leu | Pro | Gln | Arg | A |
| | Leu | Pro | Gln | Arg | G |
| A | Ile | Thr | Asn | Ser | U |
| | Ile | Thr | Asn | Ser | C |
| | Ile | Thr | Lys | Arg | A |
| | Met | Thr | Lys | Arg | G |
| G | Val | Ala | Asp | Gly | U |
| | Val | Ala | Asp | Gly | C |
| | Val | Ala | Glu | Gly | A |
| | Val | Ala | Glu | Gly | G |

### Question:
LaNeya needs help with Biology because she is having trouble understanding the process of protein synthesis. She was given a DNA strand with the nucleotide sequence TAA CGC ACT and wrote the mRNA sequence as ATT GCG TGA. Explain the correct mRNA sequence and the corresponding amino acid sequence.



Answer :

LaNeya has misunderstood the transcription process from DNA to mRNA. Let's walk through the steps in detail to help clarify the correct transcription sequence.

### Step 1: Understanding DNA to mRNA Transcription
DNA is transcribed into mRNA by pairing complementary bases. The base-pairing rules are as follows:
- Adenine (A) in DNA pairs with Uracil (U) in mRNA.
- Thymine (T) in DNA pairs with Adenine (A) in mRNA.
- Cytosine (C) in DNA pairs with Guanine (G) in mRNA.
- Guanine (G) in DNA pairs with Cytosine (C) in mRNA.

### Step 2: Split the DNA Strand into Codons
The given DNA strand is:
```
TAA CGC ACT
```
We first divide it into codons (groups of three nucleotides):
```
TAA, CGC, ACT
```

### Step 3: Transcribe DNA Codons to mRNA Codons
Using the base-pairing rules from Step 1, we transcribe each DNA codon into an mRNA codon:
- TAA (DNA) transcribes to AUU (mRNA)
- T -> A
- A -> U
- A -> U
- CGC (DNA) transcribes to GCG (mRNA)
- C -> G
- G -> C
- C -> G
- ACT (DNA) transcribes to UGA (mRNA)
- A -> U
- C -> G
- T -> A

### Step 4: Form the mRNA Strand
Combine the mRNA codons to get the complete mRNA strand:
```
AUU GCG UGA
```

### Step 5: Reviewing LaNeya's Incorrect Answer
LaNeya had written the mRNA sequence as "ATT GCG TGA". Upon reviewing:
- ATT should have been AUU
- GCG is correct
- TGA should have been UGA

### Conclusion
By carefully following the transcription rules and checking each step, we can see that the correct mRNA sequence is:
```
AUU GCG UGA

```
The DNA codons are:
```
TAA, CGC, ACT

```
And the corresponding mRNA codons are:
```
AUU, GCG, UGA
```
This corrects LaNeya's misunderstanding.