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Directions: Two statements are given-one labelled Assertion and the other labelled Reason. Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below.
Assertion: Lactose in lac operon is promoter gene.
Reason: Lactose inactivates the repressor gene.
- a)Both assertion and reason are true and reason is the correct explanation of assertion.
- b)Both assertion and reason are true but reason is not the correct explanation of assertion.
- c)Assertion is true but reason is false.
- d)Both assertion and reason are false.
Correct answer is option 'D'. Can you explain this answer?
Most Upvoted Answer
Directions: Two statements are given-one labelled Assertion and the o...
Lactose is not a promoter gene but an inducer of lac operon as it combines with a repressor protein formed by repressor or regulatory gene and not the gene itself. The inducer joins the repressor, forming a repressor-inducer complex. This complex prevents the repressor from binding with the operator gene of the operon. This frees the operator gene so that the RNA polymerase can move from the promoter to the structural genes.
The structural genes are then transcribed, forming a piece of polycistronic mRNA. The latter is transcribed by fRNA and ribosomes into enzymes.
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Directions: Two statements are given-one labelled Assertion and the o...
**Assertion and Reason:**
- Assertion: Lactose in lac operon is a promoter gene.
- Reason: Lactose inactivates the repressor gene.
**Explanation:**
The lac operon is a set of genes responsible for the metabolism of lactose in bacteria. It consists of three structural genes, lacZ, lacY, and lacA, along with a promoter region and an operator region.
- **Lactose as a Promoter Gene:**
The assertion states that lactose in the lac operon is a promoter gene. However, this statement is incorrect. Lactose is not a promoter gene in the lac operon. The promoter gene in the lac operon is actually the region of DNA where RNA polymerase binds and initiates transcription. It is responsible for the initiation of gene expression.
- **Lactose and Repressor Gene:**
The reason provided states that lactose inactivates the repressor gene. This statement is also incorrect. The repressor gene in the lac operon is responsible for producing the lac repressor protein. This protein binds to the operator region and prevents RNA polymerase from transcribing the structural genes in the absence of lactose.
- **Lactose and Induction of Operon:**
In reality, lactose acts as an inducer of the lac operon. When lactose is present in the environment, it enters the bacterial cell and is converted into allolactose by the enzyme β-galactosidase, encoded by the lacZ gene. Allolactose binds to the lac repressor protein and causes a conformational change, preventing it from binding to the operator region. This allows RNA polymerase to bind to the promoter region and initiate transcription of the structural genes.
- **Correct Answer:**
Based on the explanations above, it can be concluded that both the assertion and reason given in the question are false. Therefore, the correct answer is option 'D' - Both assertion and reason are false.
- Assertion: Lactose in lac operon is a promoter gene.
- Reason: Lactose inactivates the repressor gene.
**Explanation:**
The lac operon is a set of genes responsible for the metabolism of lactose in bacteria. It consists of three structural genes, lacZ, lacY, and lacA, along with a promoter region and an operator region.
- **Lactose as a Promoter Gene:**
The assertion states that lactose in the lac operon is a promoter gene. However, this statement is incorrect. Lactose is not a promoter gene in the lac operon. The promoter gene in the lac operon is actually the region of DNA where RNA polymerase binds and initiates transcription. It is responsible for the initiation of gene expression.
- **Lactose and Repressor Gene:**
The reason provided states that lactose inactivates the repressor gene. This statement is also incorrect. The repressor gene in the lac operon is responsible for producing the lac repressor protein. This protein binds to the operator region and prevents RNA polymerase from transcribing the structural genes in the absence of lactose.
- **Lactose and Induction of Operon:**
In reality, lactose acts as an inducer of the lac operon. When lactose is present in the environment, it enters the bacterial cell and is converted into allolactose by the enzyme β-galactosidase, encoded by the lacZ gene. Allolactose binds to the lac repressor protein and causes a conformational change, preventing it from binding to the operator region. This allows RNA polymerase to bind to the promoter region and initiate transcription of the structural genes.
- **Correct Answer:**
Based on the explanations above, it can be concluded that both the assertion and reason given in the question are false. Therefore, the correct answer is option 'D' - Both assertion and reason are false.
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Directions: Two statements are given-one labelled Assertion and the other labelled Reason. Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below.Assertion: Lactose in lac operon is promoter gene.Reason: Lactose inactivates the repressor gene.a)Both assertion and reason are true and reason is the correct explanation of assertion.b)Both assertion and reason are true but reason is not the correct explanation of assertion.c)Assertion is true but reason is false.d)Both assertion and reason are false.Correct answer is option 'D'. Can you explain this answer? for NEET 2025 is part of NEET preparation. The Question and answers have been prepared according to the NEET exam syllabus. Information about Directions: Two statements are given-one labelled Assertion and the other labelled Reason. Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below.Assertion: Lactose in lac operon is promoter gene.Reason: Lactose inactivates the repressor gene.a)Both assertion and reason are true and reason is the correct explanation of assertion.b)Both assertion and reason are true but reason is not the correct explanation of assertion.c)Assertion is true but reason is false.d)Both assertion and reason are false.Correct answer is option 'D'. Can you explain this answer? covers all topics & solutions for NEET 2025 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Directions: Two statements are given-one labelled Assertion and the other labelled Reason. Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below.Assertion: Lactose in lac operon is promoter gene.Reason: Lactose inactivates the repressor gene.a)Both assertion and reason are true and reason is the correct explanation of assertion.b)Both assertion and reason are true but reason is not the correct explanation of assertion.c)Assertion is true but reason is false.d)Both assertion and reason are false.Correct answer is option 'D'. Can you explain this answer?.
Directions: Two statements are given-one labelled Assertion and the other labelled Reason. Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below.Assertion: Lactose in lac operon is promoter gene.Reason: Lactose inactivates the repressor gene.a)Both assertion and reason are true and reason is the correct explanation of assertion.b)Both assertion and reason are true but reason is not the correct explanation of assertion.c)Assertion is true but reason is false.d)Both assertion and reason are false.Correct answer is option 'D'. Can you explain this answer? for NEET 2025 is part of NEET preparation. The Question and answers have been prepared according to the NEET exam syllabus. Information about Directions: Two statements are given-one labelled Assertion and the other labelled Reason. Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below.Assertion: Lactose in lac operon is promoter gene.Reason: Lactose inactivates the repressor gene.a)Both assertion and reason are true and reason is the correct explanation of assertion.b)Both assertion and reason are true but reason is not the correct explanation of assertion.c)Assertion is true but reason is false.d)Both assertion and reason are false.Correct answer is option 'D'. Can you explain this answer? covers all topics & solutions for NEET 2025 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Directions: Two statements are given-one labelled Assertion and the other labelled Reason. Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below.Assertion: Lactose in lac operon is promoter gene.Reason: Lactose inactivates the repressor gene.a)Both assertion and reason are true and reason is the correct explanation of assertion.b)Both assertion and reason are true but reason is not the correct explanation of assertion.c)Assertion is true but reason is false.d)Both assertion and reason are false.Correct answer is option 'D'. Can you explain this answer?.
Solutions for Directions: Two statements are given-one labelled Assertion and the other labelled Reason. Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below.Assertion: Lactose in lac operon is promoter gene.Reason: Lactose inactivates the repressor gene.a)Both assertion and reason are true and reason is the correct explanation of assertion.b)Both assertion and reason are true but reason is not the correct explanation of assertion.c)Assertion is true but reason is false.d)Both assertion and reason are false.Correct answer is option 'D'. Can you explain this answer? in English & in Hindi are available as part of our courses for NEET.
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Directions: Two statements are given-one labelled Assertion and the other labelled Reason. Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below.Assertion: Lactose in lac operon is promoter gene.Reason: Lactose inactivates the repressor gene.a)Both assertion and reason are true and reason is the correct explanation of assertion.b)Both assertion and reason are true but reason is not the correct explanation of assertion.c)Assertion is true but reason is false.d)Both assertion and reason are false.Correct answer is option 'D'. Can you explain this answer?, a detailed solution for Directions: Two statements are given-one labelled Assertion and the other labelled Reason. Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below.Assertion: Lactose in lac operon is promoter gene.Reason: Lactose inactivates the repressor gene.a)Both assertion and reason are true and reason is the correct explanation of assertion.b)Both assertion and reason are true but reason is not the correct explanation of assertion.c)Assertion is true but reason is false.d)Both assertion and reason are false.Correct answer is option 'D'. Can you explain this answer? has been provided alongside types of Directions: Two statements are given-one labelled Assertion and the other labelled Reason. Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below.Assertion: Lactose in lac operon is promoter gene.Reason: Lactose inactivates the repressor gene.a)Both assertion and reason are true and reason is the correct explanation of assertion.b)Both assertion and reason are true but reason is not the correct explanation of assertion.c)Assertion is true but reason is false.d)Both assertion and reason are false.Correct answer is option 'D'. Can you explain this answer? theory, EduRev gives you an
ample number of questions to practice Directions: Two statements are given-one labelled Assertion and the other labelled Reason. Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below.Assertion: Lactose in lac operon is promoter gene.Reason: Lactose inactivates the repressor gene.a)Both assertion and reason are true and reason is the correct explanation of assertion.b)Both assertion and reason are true but reason is not the correct explanation of assertion.c)Assertion is true but reason is false.d)Both assertion and reason are false.Correct answer is option 'D'. Can you explain this answer? tests, examples and also practice NEET tests.
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