NCERT Solutions for Class 12 Biology, Chapter 5 - Principles of Inheritance and Variation

The NCERT Solutions For Class 12 Biology Chapter 5 is available at UrbanPro. This book will help you understand the concepts of Chapter 5 of Biology. The chapter discusses the process of genetic evolution and its various aspects. It also provides information regarding the variations and similarities that exists between a parent and their offsprings. You will learn in details regarding the process of inheritance of genes and gender determination in this chapter.

The Contents of Chapter 5- Principles of Inheritance and Variation are as follows:

5.1. Mendel’s Laws of Inheritance

5.2. Inheritance of One Gene

5.3. Inheritance of Two Genes

5.4. Polygenic Inheritance

5.5. Pleiotropy

5.6. Sex Determination

5.7. Mutation

5.8. Genetic Disorders

Let us take a look at the contents and sub-topics of Principles of Inheritance and Variation Class 12 NCERT.

Section 5.1: This section tells you that people began to grasp and understand the concept of Inheritance in the mid 19th century. It was Gregor Mendel who conducted the experiment of hybridisation on garden peas for approximately seven years and went on to propose the laws of Inheritance in living organisms. Mendel studied the different traits that occurred in peas such as colour, height, shape, and position.

Section 5.2: In this section, the concept of Inheritance of one gene has been explained. This section has been explained with the help of examples and diagrams from experiments that were conducted by Gregor Mendel. Mendel generated the first hybrid generation, and it was called Filial 1 progeny. Terms like genes and alleles have been discussed in this section along with homozygous recessive with the help of test cross.

Section 5.3: In this section of Chapter 5 of Biology, the Inheritance of Two Genes has been explained thoroughly. This section deals with explaining the Law of Independent Assortment, Chromosomal Theory of Inheritance, Linkage and Recombination in 5.3.1, 5.3.2, 5.3.3, respectively.

Section 5.4: In this section, you will learn about Polygenic Inheritance. This happens when two or more genes control one characteristic trait of a human being.

Section 5.5: In this section, Pleiotropy has been discussed. This happens when one gene influences two or more unrelated phenotypic traits.

Section 5.6: For this section of chapter 5, the mechanism of sex determination has been explained thoroughly.

Section 5.7: In this Section, the phenomenon of mutation is taught to you. The mutation is a phenomenon where a change in DNA sequence occurs, which results in changes in the phenotype and the genotype of an organism.

Section 5.8: In this Section, the various genetic disorders have been explained, and the analysis of such disorder is done with the help of Pedigree Analysis. Mendelian Disorders-colour blindness, haemophilia, sickle-cell anaemia, phenylketonuria, and thalassemia are discussed in this section.

Chromosomal Disorders- Down’s syndrome, Turner’s syndrome, and Klinefelter’s syndrome have been explained in this section.

You can also find Principles of Inheritance and Variation Class 12 NCERT Pdf at UrbanPro.