If the base sequence of one starand of DNA is CAT, TAG, CAT, CAT, GAC. What would be the base sequence of its complementary mRNA?

Options

A. GUA, GUA, CUG, AUC, CUG
B. AUG, CUG, CUC, GUA, CUG
C. GUA, AUC, GUA, GUA, CUG
D. GUC, CUG, CUG, CUA, CUU

Answer

To find the base sequence of the complementary mRNA from the given DNA sequence, we need to follow these steps:

### Step 1: Identify the DNA Base Sequence
The given DNA base sequence is:
- CAT, TAG, CAT, CAT, GAC

### Step 2: Write Down the Complementary DNA Bases
In DNA, the complementary base pairing rules are:
- Adenine (A) pairs with Thymine (T)
- Thymine (T) pairs with Adenine (A)
- Cytosine (C) pairs with Guanine (G)
- Guanine (G) pairs with Cytosine (C)

Using these rules, we can find the complementary DNA bases for each base in the given sequence:
- C (Cytosine) pairs with G (Guanine)
- A (Adenine) pairs with T (Thymine)
- T (Thymine) pairs with A (Adenine)

So the complementary DNA sequence would be:
- GTA, ATC, GTA, GTA, CTG

### Step 3: Convert the Complementary DNA Sequence to mRNA
When transcribing DNA to mRNA, the base pairing rules change slightly:
- Adenine (A) pairs with Uracil (U) in RNA instead of Thymine (T)
- Thymine (T) pairs with Adenine (A)
- Cytosine (C) pairs with Guanine (G)
- Guanine (G) pairs with Cytosine (C)

Now, we will convert the complementary DNA bases to mRNA bases:
- G (Guanine) pairs with C (Cytosine)
- T (Thymine) pairs with A (Adenine)
- A (Adenine) pairs with U (Uracil)
- C (Cytosine) pairs with G (Guanine)

Using these rules, we can find the mRNA sequence:
- G (C) -> C
- T (A) -> A
- A (U) -> U
- T (A) -> A
- C (G) -> G
- T (A) -> A
- A (U) -> U
- T (A) -> A
- C (G) -> G
- T (A) -> A
- G (C) -> C

Thus, the mRNA sequence corresponding to the original DNA sequence is:
- GUA, AUC, GUA, GUA, CUG

### Final mRNA Sequence
The final base sequence of the complementary mRNA is:
- GUA AUC GUA GUA CUG

---