Biologically functional gene coding for tyrosine t-RNA of E.coil synthesized by Khorana in 1979 had:

Options

A. 333 nucleotide pairs
B. 312 nucleotide pairs
C. 77 nucleotide pairs
D. 207 nucleotide pairs

Answer

To solve the question regarding the biologically functional gene coding for tyrosine t-RNA of E. coli synthesized by Khorana in 1979, follow these steps:

### Step-by-Step Solution:

1. **Identify the Context**: Understand that the question is about a specific gene synthesized by Hargobind Khorana and his team in 1979, which encodes for the tyrosine t-RNA in E. coli.

2. **Research the Synthesis**: Recall that Khorana and his co-workers were pioneers in the field of biotechnology and were known for synthesizing functional genes. They used a method involving protected nucleosides and mononucleotides to construct the gene.

3. **Determine the Length of the Gene**: The question specifically asks for the number of nucleotide pairs in the synthesized gene. From the information provided, it is noted that the gene synthesized was 207 nucleotides long.

4. **Analyze the Options**: The options provided are:
- A) 333 nucleotide pairs
- B) 312 nucleotide pairs
- C) 77 nucleotide pairs
- D) 207 nucleotide pairs

5. **Select the Correct Answer**: Based on the information gathered, the correct answer is D) 207 nucleotide pairs, as this matches the length of the gene synthesized by Khorana.

### Final Answer:
The biologically functional gene coding for tyrosine t-RNA of E. coli synthesized by Khorana in 1979 had **207 nucleotide pairs**.

---