Which one of is associated with downstream processing?
A. Separation B. Purification C. DNA isolation D. Gene expression

Options

A. A,B
B. B,C
C. C,D
D. A,B,C,D

Answer

To determine which option is associated with downstream processing, we need to understand the concepts of upstream and downstream processing in biotechnology.

### Step-by-Step Solution:

1. **Understanding Upstream Processing**:
- Upstream processing refers to the initial steps in bioprocessing where the focus is on the preparation and cultivation of microbial or cell cultures. This includes steps like DNA isolation and gene expression.

2. **Understanding Downstream Processing**:
- Downstream processing, on the other hand, occurs after the cultivation phase. It involves the recovery and purification of the product obtained from the bioreactor.

3. **Identifying the Options**:
- A. Separation: This is a key step in downstream processing where the desired product is separated from the biomass and other impurities.
- B. Purification: This is also a crucial step in downstream processing that involves refining the product to achieve the desired purity.
- C. DNA Isolation: This is part of upstream processing, not downstream.
- D. Gene Expression: This is also part of upstream processing.

4. **Conclusion**:
- Since downstream processing is primarily concerned with the separation and purification of the product, the correct answer is A. Separation and B. Purification. Therefore, the options associated with downstream processing are A and B.

### Final Answer:
The options associated with downstream processing are **A. Separation** and **B. Purification**.

---