Download App

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

Bihar BoardEnglish MediumSTD 12 ScienceBIOLOGYPrinciples of Inheritance and Variation5 Marks
Question
  1. Explain Polygenic inheritance and Multiple allelism with the help of suitable examples.
  2. "Phenylketonuria is a good example that explains Pleiotropy." Justify.
✓

Answer

  1. Traits that are generally controlled by three or more genes , the phenotype reflects the contribution of each allele/effect of each allele is additive 

eg. Human skin colour, controlled by three genes (A , B, C)

In multiple allelism more than two alleles , govern the same character/phenotype  eg . Human blood group (ABO system) , controlled by three different alleles (IA , IB, i)

  1. In pleiotropy a single gene can exhibit multiple phenotypic expressions , in phenyl ketonuria single mutated gene express mental retardation and reduction in hair and skin pigmentation.

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 "Long Answer Type Questions [5M]" from Principles of Inheritance and Variation→Principles of Inheritance and Variation — all question types→BIOLOGY STD 12 Science question papers→Bihar Board STD 12 Science question papers→Bihar Board question paper generator→

Similar questions

In the medium where E. coli was growing, lactose was added, which induced the lac operon. Then, why does lac operon shut down some time after addition of lactose in the medium?
→
  1. How does a chromosomal disorder differ from a Mendelian disorder?
  2. Name any two chromosomal aberration associated disorders.
  3. List the characteristics of the disorders mentioned above that help in their diagnosis.
→
Represent schematically the life cycle of a malarial parasite.
→
List the harmful effects caused by alcohol/drug abuse.
→
Explain the causes, inheritance pattern, symptoms of two Mendelian genetic disorders.
→
DNA separated from one cell, when introduced in another cell, is able to bestow some of the properties of the former to the latter. What is this change called in technical terms? Describe the experiment evidences which led to the discovery of the above phenomenon.
→
  1. Give reasons for:
  1. Both strands of DNA are not copied during transcription.
  2. Transcription and translation in bacteria can be coupled.
  1. Differentiate between the process of transcription in prokaryotes and eukaryotes.
→
Describe in detail the various levels of biodiversity.
→
Answer the following questions:
Explain the menstrual phase in a human female. State the levels of ovarian and pituitary hormones during this phase.
→
What essential features must be present in a cloning vector?
→