wiz-icon
MyQuestionIcon
MyQuestionIcon
1607
You visited us 1607 times! Enjoying our articles? Unlock Full Access!
Question

In the lac operon of E.coli, which of the following happens when the repressor binds to the operator?

A
Transcription occurs
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
Transcription is blocked
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
C
RNA polymerase binds to the promoter
No worries! We‘ve got your back. Try BYJU‘S free classes today!
D
Transcription is slowed down
No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution

The correct option is B Transcription is blocked
Repressors are proteins that prevent transcription and thus, are said to take negative control of the respective structural genes. When lactose concentration in the medium is low, the repressor binds to the operator in such a way that RNA polymerase is prevented from binding to the promoter. This prevents transcription of the structural genes by RNA polymerase. Thus, repressors ensure that transcription of the genes happens only when required. In the absence of lactose, the enzymes to digest it would not be required and hence, transcription is prevented.

flag
Suggest Corrections
thumbs-up
0
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
DNA
BIOLOGY
Watch in App
Join BYJU'S Learning Program
CrossIcon