Download App

Molecular Basis of Inheritance — BIOLOGY STD 12 Science — Question

Rajasthan BoardEnglish MediumSTD 12 ScienceBIOLOGYMolecular Basis of Inheritance1 Mark
Question
For question, two statements are given-one labelled Assertion and the other labelled Reason. Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below.
  1. Both assertion and reason are true, and reason is the correct explanation of assertion.
  2. Both assertion and reason are true, but reason is not the correct explanation of assertion.
  3. Assertion is true, but reason is false.
  4. Both assertion and reason are false.
Assertion: R-type of Pneumococcus is non-virulent.
Reason: R-type of Pneumococcus can be virulent by having transformation with S -type of Pneumococcus.
✓

Answer

  1. Both assertion and reason are true, but reason is not the correct explanation of assertion.

Explanation:

Transformation is the change in the genetic constitution of an organism by picking up genes present in the environment. Pneurnococcus has two strains -virulent (S) and non-virulent (R). The virulent strain causes pneumonia. R-type bacteria form irregular or rough colonies and did not produce any disease while the S-type bacteria cause pneumonia and then death in the mice. Griffith injected a combination of live R-type and heat killed S-type bacteria into mice. While some mice survived, others developed the disease of pneumonia and died. Autopsy of the dead mice showed that they possessed both the types of bacteria in living state, though the mice had been injected with dead virulent and living non-virulent bacteria. The occurrence of living S-type virulent bacteria is possible only by their formation from R-type non-virulent bacteria, which pick up the trait of virulence from dead bacteria. The phenomenon is called 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 "Assertion (A) & Reason (B) MCQ" from Molecular Basis of Inheritance→Molecular Basis of Inheritance — all question types→BIOLOGY STD 12 Science question papers→Rajasthan Board STD 12 Science question papers→Rajasthan Board question paper generator→

Similar questions

For question, two statements are given-one labelled Assertion and the other labelled Reason. Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below.
  1. Both assertion and reason are true, and reason is the correct explanation of assertion.
  2. Both assertion and reason are true, but reason is not the correct explanation of assertion.
  3. Assertion is true, but reason is false.
  4. Both assertion and reason are false.
Assertion: B-DNA has a constant diameter of 20 A.
Reason: A pyrimidine always pairs with a purine.
→
For question two statements are given-one labelled Assertion and the other labelled Reason. Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below.
  1. Both assertion and reason are true and reason is the correct explanation of assertion.
  2. Both assertion and reason are true but reason is not the correct explanation of assertion.
  3. Assertion is true but reason is false.
  4. Both assertion and reason are false.
Assertion: Quantitative inheritance is called polygenic inheritance.
Reason: Several genes control the expression of a trait.
→
Assertion (A): Generally, a woman does not conceive during the lactation period.
Reason (R): The hormone prolactin initiates and maintains lactation in a woman.
→
For two statements are given-one labelled Assertion and the other labelled Reason. Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below.
  1. Both assertion and reason are true, and reason is the correct explanation of assertion.
  2. Both assertion and reason are true, but reason is not the correct explanation of assertion.
  3. Assertion is true, but reason is false.
  4. Both assertion and reason are false.
Assertion: In blastulation, cell masses show morphogenetic movements.
Reason: A three layered blastocyst is fanned during blastulation.
→
For two statements are given-one labelled Assertion and the other labelled Reason. Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below.
  1. Both assertion and reason are true, and reason is the correct explanation of assertion.
  2. Both assertion and reason are true, but reason is not the correct explanation of assertion.
  3. Assertion is true, but reason is false.
  4. Both assertion and reason are false.
Assertion: Now-a-days amniocentesis is banned.
Reason: Amniocentesis gives the information of any abnormality in the fetus and many other complications regarding pregnancy can be detected.
→
For question two statements are given-one labelled Assertion and the other labelled Reason. Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below.
  1. Both assertion and reason are true and reason is the correct explanation of assertion.
  2. Both assertion and reason are true but reason is not the correct explanation of assertion.
  3. Assertion is true but reason is false.
  4. Both assertion and reason are false.
Assertion : Haplodiploidy occurs in some insects.
Reason: Male insects develop parthenogenetically, while females grow from fertilised eggs.
→
For two statements are given-one labelled Assertion and the other labelled Reason. Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below.
  1. Both assertion and reason are true, and reason is the correct explanation of assertion.
  2. Both assertion and reason are true, but reason is not the correct explanation of assertion.
  3. Assertion is true, but reason is false.
  4. Both assertion and reason are false.
Assertion: PCR, ELISA, DNA hybridisation are confirmatory tests for sexually transmitted diseases.
Reason: Incidence of STDs are very high in persons above the age of 30.
→
Number of rice varieties developed by ancient Indians was:
  1. 1,00,000
  2. 40,000
  3. 21,000
  4. 10,000
→
For question two statements are given-one labelled Assertion and the other labelled Reason. Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below.
  1. Both assertion and reason are true and reason is the correct explanation of assertion.
  2. Both assertion and reason are true but reason is not the correct explanation of assertion.
  3. Assertion is true but reason is false.
  4. Both assertion and reason are false.
Assertion: In a monohybrid cross, F1 generations indicate dominant characters.
Reason: Dominance occurs only in heterozygous state.
→
For two statements are given-one labelled Assertion and the other labelled Reason. Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below.
  1. Both assertion and reason are true, and reason is the correct explanation of assertion.
  2. Both assertion and reason are true, but reason is not the correct explanation of assertion.
  3. Assertion is true, but reason is false.
  4. Both assertion and reason are false.
Assertion: Mammary gland is a modified sweat gland.
Reason: Mammary gland is functional in both male and female.
→