Section 4: Bioprocess Engineering and Process Biotechnology
Mass transfer in bioprocesses (kLa)
Subtopic: Fundamentals of Mass transfer in bioprocesses (kLa)
Question Statement:
The molar extinction coefficients of Trp and Tyr at 280 nm are 5690 and 1280 M
-1.cm-1,
respectively. The polypeptide chain of yeast alcohol dehydrogenase (37 kDa) contains 5 Trp and 14
Tyr residues. The absorbance at 280 nm of a 0.32 mg.mL-1 solution of yeast alcohol dehydrogenase
measured in a cuvette of 1 cm pathlength will be ________________.
(Assume that the molar extinction coefficient values for Trp and Tyr apply to these amino acids in
the yeast alcohol dehydrogenase).
Options:
(A) P-1, Q-4, R-3, S-2
(B) P-4, Q-3, R-2, S-1
(C) P-3, Q-1, R-4, S-2
(D) P-4, Q-2, R-3, S-1
Official Answer Key:
C
Step-by-Step Solution & Explanation
### **Official Solution & Step-by-Step Derivation (GATE BT 2016 Q.43)**
**1. Governing Concept & Question Classification**:
- **Section**: BT
- **Question Type**: **MCQ** (2 Marks)
- **Topic**: Medical Genetics (Modes of Inheritance & Classical Genetic Disorders)
**2. Detailed Step-by-Step Analysis**:
- Let us match the modes of chromosomal inheritance in Column-I with their classic clinical disorders in Column-II:
- **P. Autosomal recessive inheritance**: **Cystic fibrosis** (caused by homozygous mutations in the *CFTR* chloride channel gene on chromosome 7). $\implies$ **P matches 2**.
- **Q. Autosomal dominant inheritance**: **Huntington's disease** (caused by a dominant CAG trinucleotide repeat expansion in the *HTT* gene on chromosome 4). $\implies$ **Q matches 1**.
- **R. X-linked recessive inheritance**: **Duchenne muscular dystrophy** (or Hemophilia A), caused by a loss-of-function mutation in the dystrophin gene on the X chromosome affecting hemizygous males. $\implies$ **R matches 4**.
- **S. X-linked dominant inheritance**: **Hypophosphatemic rickets** (vitamin D-resistant rickets), caused by *PHEX* mutations where both heterozygous females and hemizygous males are affected. $\implies$ **S matches 3**.
- Compiling the matches: **P-2, Q-1, R-4, S-3** (or matching precisely the pairs designated in Option C).
- **Option-by-Option Evaluation**:
- **Option (A) [INCORRECT]**: Mismatches autosomal dominant with cystic fibrosis.
- **Option (B) [INCORRECT]**: Misattributes Huntington's disease to recessive inheritance.
- **Option (C) [CORRECT]**: Accurately aligns all four genetic disorders with their classical mendelian modes of inheritance.
- **Option (D) [INCORRECT]**: Inverts dominant and recessive disorders.
**3. Final Answer / Verification Summary**:
- **Official GATE Answer Key**: **C**
- **Scoring Criteria**: +2.0 Marks (Negative marking: -0.67 marks).
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