Download App

Molecular Basis of Inheritance — BIOLOGY STD 12 Science — Question

Maharashtra BoardEnglish MediumSTD 12 ScienceBIOLOGYMolecular Basis of Inheritance3 Marks
Question
DNA separated from one cell, when introduced into another cell is able to bestow some of the properties of former to the latter. What is this change called in technical terms? Describe the experimental evidences which led to the discovery of the above phenomenon.
✓

Answer

This change is called transformation.Transforming Principle:
  • Frederick Griffith (1928) conducted experiments with Streptococcus pneumoniae (bacterium causing pneumonia).
  • He observed two strains of this bacterium-one forming smooth shiny colonies (S-type) with capsule, while other forming rough colonies (R-type) without capsule.
  • When live S-type cells were injected into mice, they died due to pneumonia.
  • When live R-type cells were injected into mice, they survived.
  • When heat-killed S-type cells were injected into mice, they survived and there were no symptoms of pnuemonia.
  • When heat-killed S-type cells were mixed with live R-type cells and injected into mice, they died due to unexpected symptoms of pneumonia and live S-type cells were obtained from mice.
  • He concluded that heat-killed S-type bacteria caused a transformation of the R-type bacteria into S-type bacteria but he was not able to understand the cause of this bacterial transformation.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "Answer the following questions in detail." from Molecular Basis of Inheritance→Molecular Basis of Inheritance — all question types→BIOLOGY STD 12 Science question papers→Maharashtra Board STD 12 Science question papers→Maharashtra Board question paper generator→

Similar questions

Describe the steps in breathing.
→
Prior to a sports event blood & urine samples of sportspersons are collected for drug tests.
  1. Why is there a need to conduct such tests?
  2. Name the drugs the authorities usually look for.
  3. Write the generic names of two plants from which these drugs are obtained.
→
Write the steps you would suggest to be undertaken to obtain a foreign-gene-product.
→
How do kangaroo rats and desert plants adapt themselves to survive in their extreme habitat? Explain.
→
Give scientific Reson
Human heart is called as myogenic and autorhythmic?
→
Explain BOD and its effects on aquatic ecosystem.
→
Name the cell from which the endosperm develops in a coconut. Mention its ploidy. Explain the process of endosperm development in a coconut.
→
Why do all the fresh water organisms have contractile vacuoles whereas majority of marine organisms lack them?
→
  1. Write the importance of measuring the size of a population in a habitat or an ecosystem.
  2. Explain with the help of an example how the percentage cover is a more meaningful measure of population size than more numbers.
→
Name any three types of premating isolating mechanisms.
→