Production of a human protein in bacteria by genetic engineering is possible because

Options

A. bacterial cell can carry out the RNA splicing reaction
B. the human chromosome can replicate in bacterial cell
C. the mechanism of gene regulation is identical in humans and bacteria
D. the gentic code is universal

Explanation

To solve the question about why the production of a human protein in bacteria by genetic engineering is possible, we can break it down step by step:

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks why we can produce human proteins in bacteria using genetic engineering techniques.

2. **Analyzing the Options**: We have four options to consider:
- A) Bacterial cells can carry out RNA splicing reactions.
- B) Human chromosomes can replicate in bacterial cells.
- C) The mechanism of gene regulation is identical in humans and bacteria.
- D) The genetic code is universal.

3. **Evaluating Each Option**:
- **Option A**: Bacterial cells do not perform RNA splicing as eukaryotic cells do. This option is incorrect.
- **Option B**: Human chromosomes cannot replicate in bacterial cells because they are fundamentally different in structure and function. This option is incorrect.
- **Option C**: While there are similarities in gene regulation, the mechanisms are not identical between humans and bacteria. This option is also incorrect.
- **Option D**: The genetic code is universal, meaning that the same codons code for the same amino acids across different organisms, including bacteria and humans.

4. **Conclusion**: The best option is D, "the genetic code is universal." This universality allows bacteria to read human genes and produce human proteins when the corresponding DNA is introduced into the bacterial system.

### Final Answer:
The production of a human protein in bacteria by genetic engineering is possible because the genetic code is universal.

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