CBSE Class 12 Biology — Principles of Inheritance and Variation

All previous year questions from Chapter: Principles of Inheritance and Variation

6 questions found

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2026(6 questions)

8
$In the following figure, two ways of pairing of two homologous pairs of chromosomes are shown. Which of the following phenomena is expressed ?$
1 mark· A· $Independent Assortment of Chromosomes$
20
$(a) Analyse the following two cases of sex determination in different organisms: Case I : Males have (XO) sex chromosomes and females have two copies of same sex chromosome (XX). Case II : Females have two different sex chromosomes (ZW) and males have two copies of same sex chromosome (ZZ). Identify the type of heterogamety in each case, giving one example of each. [1+1] OR (b) (i) Differentiate between a DNA and RNA nucleotide. [1] (ii) Name the two types of bonds present within a single nucleotide. [1]$
2 marks· B· $Sex determination and heterogamety$
23
$(a) What is pedigree analysis? Mention its importance in human genetics. (2 pts.) [1+1] (b) Analyse the following pedigree and write the (i) Pattern of inheritance. [½] (ii) Give one example of disease showing such an inheritance pattern. [½] [Pedigree chart provided below the question.]$
3 marks· C· $Pedigree analysis and autosomal recessive inheritance$
32
$(a) What can you infer about the genotype of parents in crosses I and II? [1] OR (a) Which genetic cross is represented by these crosses? [1]$
1 mark· D· $Genotype of Parents in Monohybrid Crosses$
33
$(b) Looking at bar graph of cross III, identify the type of cross performed and its importance in genetics. [2]$
2 marks· D· $Test Cross and Its Importance$
34
$(c) What conclusion can you draw from the results of bar graphs of crosses I and II? Name the genetic principle illustrated. [1]$
1 mark· D· $Law of Dominance and Segregation$