Lactose (Lac) operon is regulated by from Biology Molecular Basi

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201.

Lactose (Lac) operon is regulated by

  • lac repressor only

  • lac repressor and CAP-cGMP complex

  • lac repressor and CAP-cAMP complex

  • CAP-cAMP and CAP-cGMP complex


C.

lac repressor and CAP-cAMP complex

The lac operon is regulated by lac repressor and CAP cAMP complex. The inducer - repressor control of the lac operon is an example of negative control of lac-operon, in which expression is normally blocked.

CAP-cAMP system is an example of positive control because expression of the lac operon requires the presence of an activating single. In this case, the interaction of the CAP-cAMP complex with the CAP region takes place.


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202.

The enzyme peptidyl transferase of prokaryotes resides in

  • 50 S ribosome

  • 30 S ribosome

  • 40 S ribosome

  • 60 S ribosome


203.

The tRNA anticodon 3'-UAC-5' will pair with the mRNA codon

  • 5'-AUU-3'

  • 5'-UAC-3'

  • 5'-AUG-3'

  • 3'-GUA-5'


204.

Select the correct combination of statements for DNA fingerprinting,

I. It is ELISA based technique.

II. It is PCR based technique.

III. It is used by forensic scientists.

IV. It is based on the fingerprint of the individual.

V. It is a test for paternity

  • I, II and III

  • II, III and IV

  • I, IV and V

  • I, III and IV


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205.

Which of the following are not the functions of genes?

I. Cell division

II. Structure and metabolism control

III. Carrier of hereditary information

IV. Provide proof for crossing over

  • I, II, III and IV

  • I, III and IV

  • I, II and III

  • II, III and IV


206.

Read the following statements.

I. Satellite DNA is found in the region of euchromatin

II. Prokaryotes contain only non-repetitive DNA

Identify wheather the given statements are true or false

  • Both the statements are true

  • I is true and II is false

  • I is false and II is true

  • Both the statements are false


207.

Select the option for correct pairing of nitrogenous bases in dsDNA.

  • (Py)Adenine  = (Pu)Cytosine :: (Pu)Guanine = (Pu)Thiamine

  • (Pu)Adenine  Thiamine(Py) ::  (Py)Cytosine = (Py)Guanine

  • (Py)Adenine  (Pu)Thiamine :: (Py)Cytosine  (Pu)Guanine

  • Adenine(Pu) = Thiamine(Py) :: Guanine(Pu)  Cytosine(Py)


208.

The translation unit is represented by the following diagram. Select the correct answer based on this

  • Promoter/ Terminater/ Coding strand/ Structural gene

  • Promoter/ Coding strand/ Terminator/ Structural gene

  • Terminater/ Coding strand/ Structural gene/ Promoter

  • Promoter/ Structural gene/ Coding strand/ Terminator


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209.

Given below are the set of statements describing the structural details of Purines (A) and Pyrimidines (BJ.

I. Nine - membered, double ring

II. Six - membered, single ring

III. Contains Nitrogen atoms at four positions

IV. Contains Nitrogen atoms at two positions

Segregate the statements I - IV into categories A and B and choose the correct option.

  • A B
    I, IV II, III
  • Only I Only IV
  • Only II Only I
  • I, III II, IV

210.

Which type of RNA carries no coding message?

  • mRNA

  • tRNA

  • rRNA

  • tRNA and rRNA


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