Section 4: Bioprocess Engineering and Process Biotechnology
Mass transfer in bioprocesses (kLa)
Subtopic: Fundamentals of Mass transfer in bioprocesses (kLa)
Question Statement:
A variety of genetic elements are used in the transgenic plant research. Match the genetic elements
(Column-I) with their corresponding source (Column-II).
Column-I
Column-II
P. Ubiquitin1 promoter
1. Agrobacterium tumefaciens
Q. Nos transcriptional terminator
2. Streptomyces hygroscopicus
R. bar selection marker gene
3. Escherichia coli
S. gus reporter gene
4. Zea mays
Options:
(A) P-2, Q-1, R-3, S-4
(B) P-2, Q-3, R-4, S-1
(C) P-3, Q-4, R-1, S-2
(D) P-4, Q-1, R-2, S-3
Official Answer Key:
D
Step-by-Step Solution & Explanation
### **Official Solution & Step-by-Step Derivation (GATE BT 2016 Q.42)**
**1. Governing Concept & Question Classification**:
- **Section**: BT
- **Question Type**: **MCQ** (2 Marks)
- **Topic**: Plant Genetic Engineering (Transgenic Cassette Elements & Biological Origins)
**2. Detailed Step-by-Step Analysis**:
- Let us match the genetic elements in Column-I with their source organisms in Column-II:
- **P. Ubiquitin1 (ubi1) promoter**: A widely used constitutive promoter for high-level transgene expression in monocotyledonous crops, cloned from maize, **Zea mays**. $\implies$ **P matches 4**.
- **Q. Nos transcriptional terminator**: The polyadenylation signal sequence of the nopaline synthase gene, derived from the soil bacterium **Agrobacterium tumefaciens**. $\implies$ **Q matches 1**.
- **R. bar selection marker gene**: Encodes phosphinothricin acetyltransferase (PAT), which confers resistance to the herbicide glufosinate/bialaphos, originally isolated from the actinomycete **Streptomyces hygroscopicus**. $\implies$ **R matches 2**.
- **S. gus ($\beta$-glucuronidase) reporter gene**: The *uidA* gene encoding the widely used visual GUS enzymatic reporter, derived from the bacterium **Escherichia coli**. $\implies$ **S matches 3**.
- Compiling the matches: **P-4, Q-1, R-2, S-3**.
- **Option-by-Option Evaluation**:
- **Option (A) [INCORRECT]**: Assigns ubiquitin promoter to Streptomyces.
- **Option (B) [INCORRECT]**: Inverts origins.
- **Option (C) [INCORRECT]**: Assigns ubiquitin promoter to E. coli.
- **Option (D) [CORRECT]**: P-4 (*Zea mays*), Q-1 (*A. tumefaciens*), R-2 (*S. hygroscopicus*), S-3 (*E. coli*).
**3. Final Answer / Verification Summary**:
- **Official GATE Answer Key**: **D**
- **Scoring Criteria**: +2.0 Marks (Negative marking: -0.67 marks).
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