Question 1-3 of 3: Operon (Organization of Genes and Chromosomes) | SWAYAM Cell Biology | Includes PYQs | Get Solutions with Detailed Explanations
Choose Programs
📹 Video Course 2025 (34 Lectures [16 hrs : 33 mins]): Offline Support
Rs. 100.00
Price Per Month, Add to Cart for 3/6/12-Month Discounts
Preview All LecturesDetails
🎓 Study Material (71 Notes): 2025-2026 Syllabus
Rs. 150.00
3 Year Validity
Topic-wise Notes & SampleDetails
🎯 122 MCQs (& PYQs) with Explanations (2025-2026 Exam)
Rs. 150.00
3 Year Validity
CoverageDetailsSample Explanation
Help me Choose❓Already Subscribed?
Question 1
MCQ
Read the question, then carefully choose the correct answer(s).
Appeared in Year: 2023
In a lac operon, a nonsense mutation in the gene encoding beta-galactosidase was found to interfere with the expression of downstream permease and transacetylase genes. Which one of the following may explain this observation most appropriately? (June)
Choices
| Choice (4) | Response | |
|---|---|---|
a. | trans-effect of the mutation | |
b. | polar effect of the mutation | |
c. | Formation of a stem-loop structure in the upstream cistron prevents translation of downstream cistrons. | |
d. | Binding of the release factor to the nonsense codon prevents translation of the downstream cistrons | |
Question 2
MCQ
Read the question, then carefully choose the correct answer(s).
Appeared in Year: 2024
The trp operon can be induced by the addition of indole propionic acid (IPA), which binds to the trp repressor but does not allow the change in conformation. Upon the addition of IPA, what will be the order of the translation of the enzymes encoded by the operon?
Choices
| Choice (4) | Response | |
|---|---|---|
a. | TrpA, TrpB, TrpC, TrpD, TrpE | |
b. | TrpE, TrpD, TrpC, TrpB, TrpA | |
c. | Only TrpE will be translated | |
d. | Only TrpA will be translated | |
Question 3
MCQ
Read the question, then carefully choose the correct answer(s).
Appeared in Year: 2024
Following are a few statements made regarding the lac operon.
A. The LacZ, LacY and LacA are encoded by a single transcript.
B. The three proteins are translated as a single precursor and then processed.
C. In the presence of glucose, lactose can upregulate the operon.
D. lsopropylthio β-D-galactoside (IPTG) is a gratuitous inducer.
Which one of the following options represents the combination of all correct statements?
Choices
| Choice (4) | Response | |
|---|---|---|
a. | A, B and D | |
b. | B, C and D | |
c. | A, B and C | |
d. | A and D only | |