Lac-operon
Lac-operon
A
is an inducible operon
B
is a repressible operon
C
Active in presence of glucose
D
All of these
Text Solution
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### Step-by-Step Solution for the Question on Lac Operon:
1. **Understanding the Concept of an Operon**:
- An operon is a cluster of genes under the control of a single promoter and is regulated as a unit. It consists of structural genes, an operator, a promoter, and regulatory genes.
2. **Defining Lac Operon**:
- The lac operon is a specific example of an operon found in E. coli and some other enteric bacteria. It is involved in the metabolism of lactose.
3. **Identifying the Type of Operon**:
- The lac operon is classified as an **inducible operon**. This means it is usually off but can be turned on (induced) in the presence of a specific substrate, which is lactose in this case.
4. **Analyzing the Options**:
- **Option A**: Lac operon is an inducible operon. (Correct)
- **Option B**: Lac operon is a repressible operon. (Incorrect; it is not repressible.)
- **Option C**: Lac operon is active in the presence of glucose. (Incorrect; it is less active when glucose is present.)
- **Option D**: All of these. (Incorrect; since options B and C are wrong.)
5. **Conclusion**:
- The correct answer is that the lac operon is an **inducible operon**.
### Final Answer:
The lac operon is an **inducible operon**.
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Similar Questions
Explore conceptually related problems
Match the following genes of the Lac operon with their respective products {:((a),"i gene",(i),beta-"galactosidase"),((b),"z gene",(ii),"Permease"),((c),"a gene",(iii),"Repressor"),((d),"y gene",(iv),"Transacetylase"):} Select the correct option.
Which of following statement is true for lac operon in E-coli (a) lac operon consists of one regulatory gene and five structural gene. (b) The i gene codes for inducer (c) The z-gene codes for beta -galacosidase (d) A very low level of expression of lac operon has to be present in cell all the time
Read the following statements for lac operon: i. Each operon has its specific operator and specific repressor. ii. The y gene codes permease, which increases the permeability of the cell to beta-galactosides. iii. Regulation of lac operon can be visualized as regulation of enzyme synthesis by its substrate. Select the option with the correct statements.
Study the schematic representation of the genes involved in the lac operon given below and answer the questions that follow : {:(p,i,p,o,z,y,a):} (a) Identify and name the regulatory gene in this operon. Explain its role in 'switching off' the operon. (b) Why is the lac operon's regulation referred to as negative regulation ? (c ) Name the inducer molecule and the products of the genes 'z' and 'y' of the operon. Write the functions of these gene products.
Match column I with II column II and select the correct option from the given codes . {:("Column I","Column II"),(A."Griffith",(i)"Lac operon"),(B."Hershey and Chase",(ii)"Semi-conservative DNA replication"),(C."Meselson",(iii)"Transduction"),(D."Jacob and Monod",(iv)"Transformation"):}
Read statements a-d . (a) In transcription, adenosine pairs with uracil (b) Regulation of lac operon by repressor is positive regulation (c) Human genome has approximate 50,000 genes (d) Haemophilia is sex-linked recessive disease How many of above statement are correct ?
Read following statements (1-4). 1. In transcriptoin, adenine pairs with uracil. 2. Regulation of lac operon by repressor is referred to as positive regulation. 3. The human genome has approximately 50,000 genes. 4. Haemophilia is a sex - linked recessive disease. How many of the above statements are right ?
Go through the following statements (i) 2'-OH group present at every nucleotide in RNA makes RNA labile and easily degradable. (ii) The transcription and translation can be coupled in bacteria (iii) the promoter is located towards the 5'-end while terminator is located towards the 3'end of the template strand. (iv). In lac operon, the z gene codes for beta galactosidase, y gene codes for permease while i gene codes for the inducer. Which of these are correct statement:
(a) State the arrangement of different genes that in bacteria is referred to as operon. (b) Describe the role of lactose in lac operon. (c) Draw a schematic labelled illustration of lac operon in a switched on state.
Select the two correct statements out of the four (1-4) given below about lac operon. 1. Glucose or galactose may bind with the repressor and inactivate it 2. In the absence of lactose the repressor binds with the operator region 3. The z-gene codes for permease 4. This was elucidated Francois Jacob and Jacque Monod The correct statements are :