Download App

Principles of Inheritance and Variation — BIOLOGY STD 12 Science — Question

Gujarat BoardEnglish MediumSTD 12 ScienceBIOLOGYPrinciples of Inheritance and Variation1 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: Epistasis does not show normal dihybrid ratio, i.e., 9 : 3 : 3 : 1.
Reason: A gene suppresses the phenotypic expression of a non-allelic gene.
✓

Answer

  1. Both assertion and reason are true and reason is the correct explanation of assertion.

Explanation:

The gene which inhibits or suppresses the expression of a non-allelic gene is known as epistatic gene. Epistasis reduces the number of phenotypes appearing in the F2 generation of dihybrid cross. Thus instead of normal 9 : 3 : 3 : 1 dihybrid ratio, epistasis may result in a ratio of 9 : 3 : 4 (recessive epistasis). 12 : 3 : 1 (dominant epistasis). 13 : 3 (dominant recessive epistasis) or 9 : 7 (double recessive epistasis), etc

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 Principles of Inheritance and Variation→Principles of Inheritance and Variation — all question types→BIOLOGY STD 12 Science question papers→Gujarat Board STD 12 Science question papers→Gujarat Board question paper generator→

Similar questions

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: An organism which acts as herbicide is called bioherbicide.
Reason: Phytophthora palmivora is a mycoherbicide.
→
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: Chlamydia trachomatis is a human pathogen that causes trachoma, sexually transmitted and perinatal infection.
Reason: Chlamydia trachomatis has DEFGHIJK serotypes.
→
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 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: Batesian mimicry is a protective mimicry.
Reason: Viceroy butterfly shows Batesian mimicry.
→
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 : Skin forms the first tine of defence.
Reason: It is a non-specific defence.
→
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: Heliophytes, generally have low photosynthetic, respiratory and metabolic activities.
Reason: This is an adaptation of heliophytes to high intensity of light.
→
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: Predation and parasitism are considered to be negative interactions.
Reason: Predators and parasites limit the population of their host species.
→
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 : The uptake of DNA during transformation is an active, energy requiring process.
Reason: Transformation occurs in only those bacteria, which possess the enzymatic machinery involved in the active uptake and recombination.
→
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: YAC vectors have been exploited extensively in the mapping of large genomes.
Reason: YAC vectors have a composite structure made of bacteriophage and plasmid.
→
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: Emigration is outward movement of some individuals from local population.
Reason: Emigration is caused by occurrence of deficiencies and calamities.
→