Question

1. given the following mrna, gua ccg uau gcu, what is the complementary dna template? what is the aa

Explanation:

Step1: Recall base - pairing rules

In DNA - mRNA base pairing, A (adenine) pairs with U (uracil) in mRNA, but in DNA - DNA (template - non - template strand), A pairs with T (thymine). C (cytosine) pairs with G (guanine) and vice - versa. Since we are going from mRNA to DNA template, we reverse the mRNA - DNA non - template (coding) strand pairing. The mRNA - DNA non - template strand pairing is A - U, U - A, C - G, G - C. And the DNA template - non - template strand pairing is A - T, T - A, C - G, G - C. So for mRNA to DNA template, it's A - T, U - A, C - G, G - C.

Step2: Apply base - pairing to each mRNA base

For the mRNA sequence GUA CCG UAU GCU:

• G in mRNA pairs with C in DNA template.
• U in mRNA pairs with A in DNA template.
• A in mRNA pairs with T in DNA template.
• C in mRNA pairs with G in DNA template.
• C in mRNA pairs with G in DNA template.
• G in mRNA pairs with C in DNA template.
• U in mRNA pairs with A in DNA template.
• A in mRNA pairs with T in DNA template.
• G in mRNA pairs with C in DNA template.
• C in mRNA pairs with G in DNA template.
• U in mRNA pairs with A in DNA template.

The DNA template sequence is CAT GGC ATA CGA.

Step3: Use the genetic code table

The genetic code table (codon - amino acid table) is used. The mRNA codons (read in groups of 3) are GUA (valine), CCG (proline), UAU (tyrosine), GCU (alanine).

Answer:

The DNA template sequence is CAT GGC ATA CGA and the amino - acid (AA) sequence is Valine - Proline - Tyrosine - Alanine.