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Molecular Basis of Inheritance

AIPMT 2002MCQMedium📈 Topic in 88% papers+4−1
Ques. 1AIPMT 2002

Jacob and Monod studied lactose metabolism in E. coli and proposed operon concept. Operon concept is applicable for :

  1. All prokaryotes and all eukaryotes
  2. All prokaryotes and some protozoans
  3. All prokaryotes
  4. All prokaryotes and some eukaryotes

Answer

(4) All prokaryotes and some eukaryotes

Solution

As per NCERT, the lac operon of E. coli (a regulator gene, a promoter, an operator and the structural genes z, y and a) explains the regulation of gene expression in prokaryotes.

An operon is a group of genes for one metabolic pathway that are transcribed together as one polycistronic mRNA under the control of a single promoter and operator.

∵ In prokaryotes, genes are commonly organised into operons ⇒ the operon concept applies to all prokaryotes.

∵ In eukaryotes, genes are usually monocistronic and gene regulation is more complex (at transcriptional, processing, transport and translational levels) ⇒ operons are not the general rule.

However, a few operon-like gene clusters transcribed together are known in some eukaryotes (e.g., the nematode Caenorhabditis elegans).

∴ The operon concept is applicable for all prokaryotes and some eukaryotes.

Answer: (4)

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Ques. 2AIPMT 2002

In E. coli, during lactose metabolism repressor binds to : -

  1. Promoter gene
  2. Operator gene
  3. Structural gene
  4. Regulator gene
Ques. 3AIPMT 2002

Out of 64 codons, 61 codons code for 20 types of amino acids; it is called : -

  1. Wobbling of codon
  2. Universality of codons
  3. Overlapping of gene
  4. Degeneracy of genetic code
Ques. 4AIPMT 2002

Which of the following reunites the exon segments after RNA splicing ?

  1. RNA polymerase
  2. RNA proteases
  3. RNA primase
  4. RNA ligase
Ques. 5AIPMT 2002

Exon parts of mRNA have code for : -

  1. Lipid
  2. Protein
  3. Phospholipid
  4. Carbohydrate
Ques. 6AIPMT 2001

m-RNA is synthesised on DNA template in which direction : -

  1. Any
  2. Both (3) and (4)
  3. 5' → 3'
  4. 3' → 5'
Ques. 7AIPMT 2001

In Negative operon : -

  1. cAMP has negative effect on lac operon
  2. Co-repressor binds with inducer
  3. Co-repressor binds with repressor
  4. Co-repressor does not bind with repressor
Ques. 8AIPMT 2001

Gene and cistron words are sometimes used synonymously because : -

  1. One gene contains one cistron
  2. One cistron contains many genes
  3. One gene contains no cistron
  4. One gene contains many cistrons
Ques. 9AIPMT 2001

Types of RNA polymerase required in nucleus for RNA synthesis : -

  1. 2
  2. 3
  3. 1
  4. 4
Ques. 10AIPMT 2001

A mutant strain of T4 bacteriophage, R-II, fails to lyse E. coli, but when two strains R-IIX and R-IIY are mixed, they lyse E. coli. What may be the possible reason?

  1. Both strains have different cistrons
  2. Both strains have similar cistrons
  3. It is not mutated
  4. Bacteriophage transforms into wild type
Ques. 11AIPMT 2000

Method of DNA replication in which two strands of DNA separate and synthesize new strands

  1. Conservative
  2. Non conservative
  3. Dispersive
  4. Semiconservative

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