Reproduction  

What is Reproduction

The NEET biology syllabus entails the sixth unit devoted to the process of reproduction in organisms, sexual reproduction in flowering plants and human reproduction. These topics are elaborated under unit one of the NCERT textbook for class 12. You would be glad to find that reproduction is one of the easiest topics in the NEET syllabus! That is because many of the concepts from the chapter reproduction have been studied already and flow of concepts are so intriguing that you would not feel any burden while preparing the chapter reproduction. This is a matter of rejoicing that the chapter reproduction accounts for 11% weightage in the NEET exam. Therefore, you stand with a higher probability of getting them all correct if the chapter reproduction is prepared with conceptual clarity and understanding.

 

Introduction to Reproduction

I think you can say that life is a system in which proteins and nucleic acids interact in ways that allow the structure to grow and reproduce. It's that growth and reproduction, the ability to make more of yourself, that's important.
- Andrew H. Knoll

The moment you would read the above quote, based on your understanding of living organisms, biomolecules and physiological processes, it would strike your brain that reproduction is a quintessential process of living beings. Reproduction, in a nutshell, is a methodology of continuation of life, which provides with suitable variations and chances of evolution in its course of occurring. 

The NEET biology syllabus offers a profound range of reproduction topics in various living organisms. Let us have a look into the topics of reproduction as per their lay-out in the NCERT textbook for class 12.

 

 

Reproduction

 

Notes on Reproduction

1. Reproduction in Organisms: This topic of reproduction presents a general understanding of the process of reproduction. It begins by describing the life-span of different living beings and correlating the same with the reproduction process. The two broad categories of the process of reproduction are elaborated here as:

a) Asexual Reproduction: The process of reproduction that occurs by a single parent. It does not involve the process of meiosis and gamete formation. The parent reproduces by means of:

  • Binary fission -  where a cell divides into two halves and each rapidly grows into an adult (e.g., Amoeba, Paramecium).
  • Sporulation - formation of asexual spores by means of mitosis like zoospores that usually are
  • microscopic motile structures. Other common asexual reproductive structures are conidia (Penicillium) and buds (Hydra).
  • Budding - It occurs in organisms like yeast, wherein the division is unequal and small buds are produced that remain attached initially to the parent cell which, eventually gets separated and mature into new yeast organisms (cells). 
  • Gemmule - These are also asexual spores produced in bryophytes and also in animals like sponges.
  • Fragmentation - When the parent body breaks into a number of fragments and each fragment gives rise to a new organism, as seen in Spirogyra.
  • Vegetative propagation in plants - Flowering plants reproduce by asexual as well as sexual means of reproduction. The asexual reproduction occurs through the vegetative parts of the plant, such as roots, stem, leaves and axillary buds. Much of this detail has already been discussed under the topic morphology of the flowering plants.

 

Hydra Budding

 

b) Sexual Reproduction: The process of sexual reproduction is also described in general. The three phases of sexual reproduction mentioned are:

  • Pre-fertilization events: These include all the events of sexual reproduction prior to the fusion of gametes. The two main pre-fertilisation events are gametogenesis and gamete transfer.
  • Fertilization event: It is the fusion of male and female gamete to produce the diploid zygote.
  • Post-fertilization events: Events in sexual reproduction after the formation of the zygote are called post-fertilization events. These involve the embryogenesis and development of the organism.

After understanding the differences between the asexual and sexual modes of reproduction, you will be able to compare and contrast between them. The advantages and disadvantages of asexual reproduction are also dealt with at the end of the chapter.

2. Sexual Reproduction in Flowering Plants: This chapter of reproduction in flowering plants begins by describing the reproductive part of the angiosperms, that is, flower. Again, much of this detail has been covered under the morphology of the flowering plants. Further, the internal structure of anther is described along with the process of formation of male gametophytes, that is, pollen grains. This process is called microsporogenesis. The internal structures of ovary and ovule are described along with the formation of the female gametophyte. This is called the megasporogenesis. 

The topic of sexual reproduction in flowering plants progresses with the description of pollination, double fertilization, zygote, and endosperm formation and then seed setting. Hence, these topics can be summarised as:

  • Development of male and female gametophytes
  • Pollinationtypes, agencies, and examples
  • Outbreeding devices
  • Pollen-Pistil interaction
  • Double fertilization
  • Post fertilization events- Development of endosperm and embryo
  • Development of seed and formation of fruit
  • Special modes-apomixis, parthenocarpy, polyembryony 
  • Significance of seed and fruit formation

 

 

Sexual Reproduction in Flowering Plants

 

 

3. Human Reproduction: Humans are sexually reproducing organisms. The process of human reproduction is complex and requires a comprehensive understanding of the structures of the male and female sex organs. This chapter offers an exhaustive understanding of human reproduction and covers the following topics:

  • Male reproductive system - testes and accessory organs of ducts, glands and external genitalia
  • female reproductive system - main and accessory sex organs of ovaries, fallopian tubes, uterus, cervix and external genitalia
  • Microscopic anatomy of testis and ovary
  • Gametogenesis- spermatogenesis & oogenesis, the formation of sperms and ovum in the testes and ovaries respectively
  • Menstrual cycle - hormonal regulation, various events, and graphical representation
  • Insemination and fertilization
  • Embryo development up to blastocyst formation
  • Implantation of the embryo in the uterus wall, pregnancy, and placenta formation
  • Gestation period and events in this period
  • Parturition
  • Lactation and hormonal regulation

Hence, after reading this chapter, you would be able to trace the biological history of a human being from the time of inception to birth! A good number and variety of questions are asked from human reproduction, therefore, the utmost care has to be taken while preparing human reproduction.

 

 

Human Reproductive System

 

4. Reproductive Health: The process of human reproduction is subjected to various emotional, personal and ethical standards. The process is highly complex owing to the fact that humans are viviparous and human female and to survive a gestation period of nine months to bring about successful reproduction. Also, because the process of gametogenesis is subjected to hormonal regulation which, in turn, is influenced by the emotional and social stability of a person, reproductive health in humans is wider filed of understanding and practice. It does not deal with the proper functioning of the reproductive organs only. It also offers various autonomous and decision-making processes of birth control. Hence, the contraceptives that prevent reproduction also come under the purview of reproductive health. The menace of sexual abuse and the prevalence of sexually transmitted diseases are also taken care of within the reproductive health. The scope of reproductive health is not limited to this only. In the case of infertility, there are various assisted reproductive technologies that are offered to bring about successful reproduction.

 

Hence, the reproductive health can be studied under the following heads:

  • Need for reproductive health and prevention of sexually transmitted diseases (STD)
  • Birth control- Need and Methods
  • Contraception and Medical Termination of Pregnancy (MTP)
  • Amniocentesis
  • Infertility and assisted reproductive technologies – IVF (In-vitro fertilization), ZIFT (Zygote intrafallopian transfer), GIFT (Gamete intrafallopian transfer)

 

Tips on Reproduction

  • Build-up the basic understanding from the NCERT textbook of class 12.
  • A variety of conceptual questions are asked from human reproduction and sexual reproduction in flowering plants. Therefore, prepare a holistic study plan for these topics.
  • Solve previous years’ question to develop a better understanding of the pattern of questions.
  • Keep revising.

 

Books for Reproduction

  • The NCERT textbook for class 12
  • A Textbook of CBSE Biology for Class 12 by Sarita Aggarwal
  • Trueman’s Elementary Biology Volume 2

 

Biology Units-wise Notes for Medical Exams

Units No.

Units Name

Unit 1

Diversity in Living World

Unit 2

Structural Organisation in Animals and Plants

Unit 3

Cell Structure and Function

Unit 4

Plant Physiology

Unit 5

Human Physiology

Unit 7

Genetics and Evolution 

Unit 8

Biology and Human Welfare

Unit 9

Biotechnology and Its Applications 

Unit 10

Ecology and Environment 

Topics from Reproduction

  • Reproduction in organisms: Reproduction, a characteristic feature of all organisms for continuation of species ( NEET, AIIMS MBBS, JIPMER MBBS, KVPY SA, KVPY SB/SX ) (18 concepts)
  • Modes of reproduction Asexual and sexual; Asexual reproduction ( NEET, AIIMS MBBS, JIPMER MBBS, KVPY SA, KVPY SB/SX ) (27 concepts)
  • Modes-Binary fission, sporulation, budding, gemmule, fragmentation ( NEET, AIIMS MBBS, JIPMER MBBS, KVPY SA, KVPY SB/SX ) (5 concepts)
  • vegetative propagation in plants ( NEET, AIIMS MBBS, JIPMER MBBS, KVPY SA, KVPY SB/SX ) (3 concepts)
  • Sexual reproduction in flowering plants: Flower structure ( NEET, AIIMS MBBS, JIPMER MBBS, KVPY SA, KVPY SB/SX ) (1 concepts)
  • Development of male and female gametophytes ( NEET, AIIMS MBBS, JIPMER MBBS, KVPY SA, KVPY SB/SX ) (34 concepts)
  • Pollination-types, agencies and examples ( NEET, AIIMS MBBS, JIPMER MBBS, KVPY SA, KVPY SB/SX ) (15 concepts)
  • Outbreeding devices ( NEET, AIIMS MBBS, JIPMER MBBS, KVPY SA, KVPY SB/SX ) (3 concepts)
  • Pollen-Pistil interaction ( NEET, AIIMS MBBS, JIPMER MBBS, KVPY SA, KVPY SB/SX ) (8 concepts)
  • Double fertilization ( NEET, AIIMS MBBS, JIPMER MBBS, KVPY SA, KVPY SB/SX ) (4 concepts)
  • Post fertilization events-Development of endosperm and embryo, Development of seed and formation of fruit ( NEET, AIIMS MBBS, JIPMER MBBS, KVPY SA, KVPY SB/SX ) (20 concepts)
  • Special modes-apomixis, parthenocarpy, polyembryony ( NEET, AIIMS MBBS, JIPMER MBBS, KVPY SA, KVPY SB/SX ) (2 concepts)
  • Significance of seed and fruit formation ( NEET, AIIMS MBBS, JIPMER MBBS, KVPY SA, KVPY SB/SX ) (2 concepts)
  • Human Reproduction: Male and female reproductive systems ( NEET, AIIMS MBBS, JIPMER MBBS, KVPY SA, KVPY SB/SX ) (22 concepts)
  • Microscopic anatomy of testis and ovary ( NEET, AIIMS MBBS, JIPMER MBBS, KVPY SA, KVPY SB/SX ) (5 concepts)
  • Gametogenesis-spermatogenesis & oogenesis ( NEET, AIIMS MBBS, JIPMER MBBS, KVPY SA, KVPY SB/SX ) (25 concepts)
  • Menstrual cycle; Fertilisation, embryo development upto blastocyst formation, implantation ( NEET, AIIMS MBBS, JIPMER MBBS, KVPY SA, KVPY SB/SX ) (20 concepts)
  • Pregnancy and placenta formation (Elementary idea) ( NEET, AIIMS MBBS, JIPMER MBBS, KVPY SA, KVPY SB/SX ) (6 concepts)
  • Parturition ( NEET, AIIMS MBBS, JIPMER MBBS, KVPY SA, KVPY SB/SX ) (2 concepts)
  • Lactation ( NEET, AIIMS MBBS, JIPMER MBBS, KVPY SA, KVPY SB/SX ) (2 concepts)
  • Reproductive health: Need for reproductive health and prevention of sexually transmitted diseases (STD) ( NEET, AIIMS MBBS, JIPMER MBBS, KVPY SA, KVPY SB/SX ) (2 concepts)
  • Birth control-Need and Methods, Contraception and Medical Termination of Pregnancy ( NEET, AIIMS MBBS, JIPMER MBBS, KVPY SA, KVPY SB/SX ) (10 concepts)
  • Amniocentesis ( NEET, AIIMS MBBS, JIPMER MBBS, KVPY SA, KVPY SB/SX ) (1 concepts)
  • Infertility and assisted reproductive technologies IVF, ZIFT, GIFT (Elementary idea for general awareness) ( NEET, AIIMS MBBS, JIPMER MBBS, KVPY SA, KVPY SB/SX ) (7 concepts)

Important Books for Reproduction

  • Reproduction Book
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Questions