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Biological Classification · Question 93

AIPMT 2004MCQEasy📈 Topic in 25% papers+4−1
1

Which of the following statements is not true for retroviruses?

  1. DNA is not present at any stage in the life cycle of retroviruses.
  2. Retroviruses carry gene for RNA-dependent DNA polymerase.
  3. The genetic material in mature retroviruses is RNA.
  4. Retroviruses are causative agents for certain kinds of cancer in man.

Answer

(1) DNA is not present at any stage in the life cycle of retroviruses.

Solution

Retroviruses (e.g. HIV) have RNA as their genetic material.

⇒ They carry the gene for reverse transcriptase (RNA-dependent DNA polymerase), which copies the viral RNA into DNA inside the host cell.

∴ A DNA stage (viral DNA, provirus) is present in their life cycle, so statement (1) is false.

As per NCERT, oncogenic viruses are among the causes of cancer, so statement (4) is true.

Answer: (1)

AIPMT 2004

Keep practising — Biological Classification

2

Viruses that infect bacteria multiply and cause their lysis, are called

  1. lysozymes
  2. lipolytic
  3. lytic
  4. lysogenic
AIPMT 2004
3

Lichens are well known combination of an alga and a fungus where fungus has

  1. a saprophytic relationship with the alga
  2. an epiphytic relationship with the alga
  3. a parasitic relationship with alga
  4. a symbiotic relationship with alga
AIPMT 2004
4

When a fresh-water protozoan possessing a contractile vacuole, is placed in a glass containing marine water, the vacuole will

  1. increase in number
  2. disappear
  3. increase in size
  4. decrease in size
AIPMT 2004
5

Which one of the following statements about viruses is correct?

  1. Viruses possess their own metabolic system.
  2. All viruses contain both RNA and DNA.
  3. Viruses are obligate parasites.
  4. Nucleic acid of viruses is known as capsid.
AIPMT 2003
6

Tobacco mosaic virus is a tubular filament of size

  1. 300 10 nm
  2. 300 5 nm
  3. 300 20 nm
  4. 700 30 nm
AIPMT 2003
7

Viruses are no more "alive" than isolated chromosomes because

  1. they require both RNA and DNA
  2. they both need food molecules
  3. they both require oxygen for respiration
  4. both require the environment of a cell to replicate.
AIPMT 2003
8

In which kingdom would you classify the archaea and nitrogen-fixing organisms, if the five-kingdom system of classification is used?

  1. Plantae
  2. Fungi
  3. Protista
  4. Monera
AIPMT 2003
9

The chief advantage of encystment of an Amoeba is

  1. the ability to survive during adverse physical conditions
  2. the ability to live for some time without ingesting food
  3. protection from parasites and predators
  4. the chance to get rid of accumulated waste products.
AIPMT 2003
10

In five kingdom system, the main basis of classification is

  1. structure of nucleus
  2. mode of nutrition
  3. structure of cell wall
  4. asexual reproduction.
AIPMT 2002
11

Which statement is correct for bacterial transduction?

  1. Transfer of some genes from one bacterium to another bacterium through virus.
  2. Transfer of genes from one bacterium to another bacterium by conjugation.
  3. Bacterium obtained its DNA directly from mother cell.
  4. Bacterium obtained DNA from other external source.
AIPMT 2002

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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)