- 1(current)
Q. No.Gene regulation governing lactose operon of E. coli that involves the lac I gene products is:
| 1. | positive and inducible because it can be induced by lactose. |
| 2. | negative and inducible because repress or protein prevents transcription. |
| 3. | negative and repressible because repress or protein prevents transcription. |
| 4. | feedback inhibition because excess of β galactosidase can switch off transcription. |
Subtopic: Gene Regulation: Lac Operon |
53%
Level 3: 35%-60%
NEET - 2015
Hints
Which enzyme(s) will be produced in a cell in which there is a non-sense mutation in the lac Y gene?
| 1. | Lactose permease |
| 2. | Transacetylase |
| 3. | Lactose permease and transacetylase |
| 4. | β - galactosidase |
Subtopic: Gene Regulation: Lac Operon |
Level 3: 35%-60%
AIPMT - 2013
Hints
In an inducible operon, the genes are:
1. usually not expressed unless a signal turns them "on"
2. usually expressed unless a signal turns them "off"
3. never expressed
4. always expressed
1. usually not expressed unless a signal turns them "on"
2. usually expressed unless a signal turns them "off"
3. never expressed
4. always expressed
Subtopic: Gene Regulation: Lac Operon |
69%
Level 2: 60%+
NEET - 2013
Hints
Read the following four statements (A-D):
| A. | In transcription, adenosine pairs with uracil |
| B. | Regulation of lac operon by a repressor is referred to as positive regulation |
| C. | The human genome has approximately 50,000 genes |
| D. | Haemophilia is a sex-linked recessive disease |
How many of the above statements are right?
1. Three
2. Four
3. One
4. Two
Subtopic: Gene Regulation: Lac Operon | Human Genome Project | Transcription |
58%
Level 3: 35%-60%
AIPMT - 2012
Hints
Select the two correct statements out of the four (a-d) given below about lac operon:
| (a) | Glucose or galactose may bind with the repressor and inactivate it. |
| (b) | In the absence of lactose, the repressor binds with the operator region. |
| (c) | The z-gene codes for permease. |
| (d) | It was explained by Francois Jacob and Jacque Monod. |
1. (b) and (c)
2. (a) and (c)
3. (b) and (d)
4. (a) and (b)
Subtopic: Gene Regulation: Lac Operon |
87%
Level 1: 80%+
AIPMT - 2010
Hints
The lac Operon consists of:
| 1. | One regulatory gene and three structural genes |
| 2. | Two regulatory genes and two structural genes |
| 3. | Three regulatory genes and three structure genes |
| 4. | Four regulatory genes only |
Subtopic: Gene Regulation: Lac Operon |
88%
Level 1: 80%+
AIPMT - 2010
Hints
- 1(current)
Q. No.
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