PYQSide ExamsMy practice

Molecular Basis of Inheritance · Question 131

AIPMT 2005MCQEasy📈 Topic in 88% papers+4−1
1

E. coli cells with a mutated z gene of the lac operon cannot grow in medium containing only lactose as the source of energy because -

  1. They cannot transport lactose from the medium into the cell
  2. They cannot synthesize functional -galactosidase
  3. In the presence of glucose, E. coli cells do not utilize lactose
  4. The lac operon is constitutively active in these cells

Answer

(2) They cannot synthesize functional -galactosidase

Solution

As per NCERT, the lac operon has three structural genes: z codes for -galactosidase, y for permease and a for transacetylase.

⇒ -galactosidase hydrolyses lactose into glucose and galactose, which the cell can use for energy.

⇒ A mutated z gene gives no functional -galactosidase (permease from the y gene is still made, so lactose can enter).

∴ Lactose cannot be broken down and the cells cannot grow on lactose alone.

Answer: (2)

AIPMT 2005

Keep practising — Molecular Basis of Inheritance

2

Telomerase is an enzyme which is a -

  1. RNA
  2. Repetitive DNA
  3. Simple protein
  4. Ribonucleoprotein
AIPMT 2005
3

Protein synthesis in an animal cell occurs -

  1. On ribosomes present in the nucleolus as well as in cytoplasm
  2. On ribosomes present in cytoplasm as well as in mitochondria
  3. Only on the ribosomes present in cytosol
  4. Only on ribosomes attached to the nuclear envelope and endoplasmic reticulum
AIPMT 2005
4

Which one of the following makes use of RNA as a template to synthesize DNA -

  1. Reverse transcriptase
  2. DNA dependent RNA polymerase
  3. RNA polymerase
  4. DNA polymerase
AIPMT 2005
5

During transcription holoenzyme RNA polymerase binds to a DNA sequence and the DNA assumes a saddle like structure at the point. What is the sequence called?

  1. TATA box
  2. GGTT box
  3. CAAT box
  4. AAAT box
AIPMT 2005
6

Production of a human protein in bacteria by genetic engineering is possible because

  1. The human chromosome can replicate in bacterial cell
  2. The genetic code is universal
  3. Bacterial cell can carry out the RNA splicing reactions
  4. The mechanism of gene regulation is identical in humans and bacteria
AIPMT 2005
7

During replication of a bacterial chromosome DNA synthesis starts from a replication origin site and

  1. RNA primers are involved
  2. is facilitated by telomerase
  3. moves in one direction of the site
  4. moves in bi-directional way
AIPMT 2004
8

Which form of RNA has a structure resembling clover leaf ?

  1. r-RNA
  2. m-RNA
  3. t-RNA
  4. hn-RNA
AIPMT 2004
9

During transcription, if the nucleotide sequence of the DNA strand that is being coded is ATACG, then the nucleotide sequence in the mRNA would be -

  1. UAUGC
  2. TCTGG
  3. UATGC
  4. TATGC
AIPMT 2004
10

The following ratio is generally constant for a given species :-

  1. A+CT+G
  2. G+CA+T
  3. A+GC+T
  4. T+CG+A
AIPMT 2004
11

DNA fingerprinting refers to :-

  1. Techniques used for molecular analysis of different specimens of DNA
  2. Analysis of DNA samples using imprinting devices
  3. Molecular analysis of profiles of DNA samples
  4. Techniques used for identification of fingerprints of individuals
AIPMT 2004

All Molecular Basis of Inheritance PYQs →

PDFDownload Molecular Basis of Inheritance PYQs as PDF Free, with answer key and a QR code to every solution — print it or study offline⬇
All NEET Botany chapters
Class 11The Living WorldBiological ClassificationPlant KingdomMorphology of Flowering PlantsAnatomy of Flowering PlantsCell: The Unit of LifeCell Cycle and Cell DivisionTransport in PlantsMineral NutritionPhotosynthesis in Higher PlantsRespiration in PlantsPlant Growth and Development
Class 12Reproduction in OrganismsSexual Reproduction in Flowering PlantsPrinciples of Inheritance and VariationMolecular Basis of InheritanceStrategies for Enhancement in Food ProductionMicrobes in Human WelfareOrganisms and PopulationsEcosystemBiodiversity and ConservationEnvironmental Issues
Other chaptersBiomolecules (Biology)