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Syllabus and Exam Weightage for Class 12 Biology

Students can face challenges while dealing with the chapters from the Biology Class 12 CBSE syllabus as there is a new pattern for CBSE Class 12 Biology. The Biology CBSE Class 12 syllabus is full of sophisticated topics and chapters. Extramarks has all the relevant content related to those topics from the CBSE 12 Biology syllabus. Below are some of the topics that are included in the CBSE Class 12 Biology syllabus.

Chapter 1 Reproduction in Organism 
Chapter 2 Sexual Reproduction in Flowering Plants 
Chapter 3 Human Reproduction 
Chapter 4 Reproductive Health 
Chapter 5 Principles of Inheritance and Variation
Chapter 6 Molecular Basis of Inheritance 

Reproduction in Organism
Lifespan can vary from less than a day to more than 400 years of age. Whatever the life span, the death of every individual organism is a certainty, i. e. No human, even single-celled organisms, is immortal. Reproduction is a biological process of continuation of a population in which adult individuals give rise to springs identical to them.
It performs the following functions: 
(i) Enables ecosystem continuity.
(ii) Maintain life on the earth.
(iii) It creates variations in population.
The process for producing offspring exhibits large variations, based on the environment of the species, the internal morphology, and several other influences.
Based on the participation of one or two organisms, the reproduction may be of the following two types: (i) asexual reproduction; (ii) sexual reproduction. 
Asexual reproduction is the mode by which a single parent is capable of producing offspring. As a rule, the offspring are physically and morphologically similar to each other and to their parents. We are often referred to as clones. The reproductive unit is commonly developed from the somatic cells of the parent. Meiosis does not occur in the reproduction of asexuals.
Asexual reproduction is common in single-celled organisms and in plants and animals with simple organizational structure. Cell division itself is a method of replication in protists, e.g. bacteria and monerans, e.g. Amoeba (the parent cell is divided into two to give rise to new individuals).  Fission can be further defined as
(i) Binary fission. The body of the person is separated into two separate halves.
The following forms may be:
(a) Simple binary fission. If separation happens in any direction, but there is always a right angle to the elongated dividing nucleus, e.g. Amoeba.
(b) Longitudinal binary fission The separation happens along the longitudinal axis, e.g. Euglena, Vorticella, man.
(c) Oblique binary fission When division occurs at the angle of the transverse axis, e.g. Ceratium, Gonyalax, man.
(d) Transverse binary fission When division occurs along an individual's transverse axis, e.g. Paramecium, diatoms, bacteria, Planaria.
(ii) Multiple fission. The division of the parent body into a variety of daughter cells, e.g. Amoeba, Plasmodium, Monocystis (all of the Protozoa).

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