(False) Oogenesis takes place in the ovary. The process of Oogenesis takes place in three phases: 13. NCERT Solutions for Class 12 Biology Chapter 3 Human Reproduction: As you know, humans are viviparous and reproduce sexually. 20. All questions have been solved in a step by step manner to you give better understanding of key concepts of Biology in NCERT Class 12. During spermatogenesis, a diploid spermatogonium (male germ cell) increases its size to form a diploid primary spermatocyte. The solutions provided here cover all exercises given at the end of the chapter Biology. When progesterone is secreted in high levels, the secretion of LH and FSH is inhibited which further prevents ovulation. (a) They produce female gametes called ova by the process of oogenesis. They help in the collection of the ovum (after ovulation), which is facilitated by the beating of the cilia. The diagram of male reproductive system is as follows: 3. Few follicle cells enlarge and are termed as egg mother cells and undergo mitosis to multiply which are referred to as oogonia. The diagrams in NCERT Solutions For Class 12 Biology Chapter 3 will help you depict the male and female reproductive systems precisely. A high level of progesterone inhibits the secretions of FSH and LH, thereby preventing ovulation. In this process, a diploid male germ cell or spermatogonium enlarges (in size) for the formation of a diploid primary spermatocyte which in turn goes through the first meiotic division or meiosis I. During the follicular phase, the levels of LH and FSH that is secreted from the anterior pituitary gland increases. How many eggs do you think would have been released if the mother gave birth to identical twins? (c) Leydig cells are found in ovary. It is lined on its inner side by two types of cells namely spermatogonia and sertoli cells respectively. (diploid/haploid) What is menstrual cycle? When the progesterone level in the blood is high, the FSH and LH secretion decreases which furthermore hinders the process of ovulation. 18. Answer Parturition is the process of giving birth to a baby as the development of the foetus gets completed in the mother’s womb. The major components of seminal plasma are: 11. Typically in a month, human ovaries release only one egg, rarely two. Incase of identical twins or monozygotic twins, one egg is released by the ovary which splits into two post-fertilization. The content provided is easy to understand. The NCERT Biology Class … Spermiation – It is the phenomena where mature spermatozoa are released from the Serotoli cells into the lumen of the seminiferous tubules of the testes. NCERT Solutions for Class 12 Biology . Give a brief account of oogenesis. (e) Fimbriae – Towards the ovarian end of the fallopian tube, finger-like projections emerge, these are the Fimbriae which assist in gathering the ovum after the ovulation process. These spermatids are transformed into spermatozoa (sperm) by the process called spermiogenesis. It also allows the endometrium of the uterus to proliferate and to prepare itself for implantation. Would your answer change if the twins born were fraternal? The major components of the seminal plasma in the male reproductive system are mucus, spermatozoa, and various secretions of accessory glands. Secretions of the accessory sex glands of males – prostate gland, seminal vesicles, bulbourethral glands. Answer. NCERT Solutions for Class 12 Biology Chapter 12 in PDF form to free download is given below updated for new academic session 2020-21. Human males have 22 pairs of autosomes and contain one or two types of sex chromosome. (external/internal) Spermiogenesis – It is the phenomena of transformation of non-motile spermatids to mature, motile spermatozoa. The phenomena of sperm production from the immature germ cell in males are termed as spermatogenesis. On the contrary, male accessory glands are seminal vesicles, prostate glands, and bulbourethral glands. NCERT Solutions for Class 12 Biology Chapter 3 – Human Reproduction is framed by subject experts and comprises detailed answers for reference. Give a brief account of oogenesis. Question 18: What is parturition? Get chapter wise solutions. This diploid primary spermatocyte undergoes first meiotic division (meiosis I), which is a reductional division to form two equal There is a gradual increase in the level of LH which causes the follicle to grow, also causing the secretion of estrogen. (asexually/sexually) It contains all the chapters in the Class 11 Biology textbook. The hormones involved in this process are oxytocin and relaxin. NCERT Solutions for Class 12 Biology Chapter 3 Human Reproduction in PDF format to free download is given here updated for new session 2020-21. This is facilitated by the beating of the cilia. You will have enough reasons to buy NCERT solutions when you go through the contents of the solutions. Answer The menstrual cycle is a series of cyclic physiologic changes that take place inside the female reproductive tract in primates. (a) Humans reproduce _____________ (asexually/sexually), (b) Humans are _____________ (oviparous, viviparous, ovoviviparous), (c) Fertilisation is _____________ in humans (external/internal), (d) Male and female gametes are _____________ (diploid/haploid), (e) Zygote is _____________ (diploid/haploid), (f) The process of release of ovum from a mature follicle is called _____________, (g) Ovulation is induced by a hormone called _____________, (h) The fusion of male and female gametes is called _____________, (i) Fertilisation takes place in _____________. These solutions for Plant Kingdom are extremely popular among Class 11 Science students for Biology Plant Kingdom Solutions come handy for quickly completing your homework and preparing for exams. NCERT Solutions for Class 11 Biology Chapter 3 – Plant Kingdom NCERT solutions for class 11 Biology chapter 3 Plant kingdom is categorized under Unit 1 Diversity in the Living World. It contains hyaluronidase enzyme, which hydrolyses the outer membrane of the egg, thereby helping the sperm to penetrate the egg at the time of fertilization. (e) Fimbriae What is oogenesis? The seminal plasma is rich in fructose, calcium, ascorbic acid, and certain enzymes. Correct each false statement to make it true. 10. Define spermiogenesis and spermiation. (a) They produce male gametes called spermatozoa by the process of spermatogenesis. (True/False) Estrogen aids the development of secondary sex characteristics in females. Hence, in the process of oogenesis, a diploid oogonium produces a single haploid ovum while two or three polar bodies are produced. (h) The fusion of the male and the female gametes is called __________. (True/False), (c) Leydig cells are found in the ovary. Answer. Estrogen inhibits the secretion of FSH and stimulates the secretion of luteinizing hormone. The detailed, step-by-step solutions will help you understand the concepts better and clear your confusions, if any. (a) Androgens are produced by Sertoli cells. If you have any problem in finding the correct answers of Biology Textbook then you can find here. What are the major functions of male accessory ducts and glands? myCBSEguide provides sample papers with solution, test papers for chapter-wise practice, NCERT solutions, NCERT Exemplar solutions, … (diploid/haploid) (a) Androgens are produced by Sertoli cells. In these species, more than one ovum is released from the ovary at the time of ovulation. progesterone are the various hormones that regulate the menstrual cycle. It helps one see the bigger and clear picture of the planet and know what happens on the inside of the bodies of various organisms. This is why it is incorrect to blame women for the gender of the child. Both of these cases are attributed to the sperm that carries the chromosome fertilizing the ovum. Just adjacent to the seminiferous tubules, there are large polygonal cells referred to as leydig cells or interstitial cells which secrete testosterone – the male hormone. The NCERT Class 12th Biology textbooks are well known for it’s updated and thoroughly revised syllabus. The follicle stimulating hormone (FSH), luteinizing hormone (LH), estrogen, and NCERT Books Class 12 Biology: The National Council of Educational Research and Training (NCERT) publishes Biology textbooks for Class 12. vagina. The NCERT Biology Books are based on the latest exam pattern and CBSE syllabus. Subject: Biology (b) Humans are__________. (f) Menstrual cycle ceases during pregnancy. Lutenising hormone (LH) – serves as Leydig cells triggering synthesis & secretion of androgens, Gonadotrophin-releasing hormone (GnRH) – it is a hypothalamic hormone that is secreted at the age of puberty, acting at the anterior pituitary gland and stimulating the secretion of LH & FSH, Follicle stimulating hormone (FSH) – acts on sertoli cells, stimulating the secretion of factors which aid in spermiogenesis process, Androgens – triggers inhibin production regulating the spermatogenesis process. Each secondary spermatocyte then undergoes second meiotic division (meiosis II) to form two equal haploid spermatids. The sex of an individual is determined by the type of the male The end of the cycle is accompanied by the breakdown of uterine endothelium, which gets released in the form of blood and mucous through the Each module is carefully prepared for a more relaxed and effective learning process. Once the male and female gametes have fused to form the zygote, it would carry either XX chromosome or XY chromosome, depending on whether sperm carrying X or Y fertilized the ovum. (c) Acrosome Students can refer to these answers to prepare for the examinations. (f) The process of release of the ovum from a mature follicle is called__________. Maturation phase – The diploid primary oocyte in this phase passes through two maturation divisions. Identify True/False statements. (e) Oogenesis takes place in corpus luteum. NCERT Solutions for Class 12 Biology Chapter 12 Biotechnology and its Applications Biotechnology deals with industrial-scale production of biopharmaceuticals. gamete (X or Y), which fuses with the X chromosome of the female. Advantages of referring to NCERT Solutions For Class 12 Biology Chapter 3 Human Reproduction. Download NCERT Books 2020-21 for UP Board, CBSE, MP Board, Gujrat Board and all other boards who are following the … The corpus luteum facilitates the endometrium of the uterus to proliferate and prepare for the process of implantation. Book: National Council of Educational Research and Training (NCERT) The fusion of male and female gametes is called fertilization. Reproduction is a huge topic which involves the process of fertilization and hence the birth of offsprings. (g) Presence or absence of the hymen is not a reliable indicator of virginity or sexual experience. They play an important role in the transport and temporary storage of sperms. There is an increase in the size of the differentiated isolated oogonium as it gets nourished from the girdling follicle cells thereby transforming into a diploid primary oocyte. NCERT Books chapter-wise Solutions (Text & Videos) are accurate, easy-to-understand and most helpful in Homework & Exam Preparations. On the other hand, in fraternal twins or dizygotic twins, two eggs are released which are fertilized by two different sperms causing the fraternal twins to exhibit different genetic characters. How many eggs are released by a human ovary in a month? The level of LH increases gradually leading to the growth of follicle and secretion of estrogen. We hope the NCERT Solutions for Class 12 Biology Chapter 3 Human Reproduction help you. Question 12: What is oogenesis? This diploid primary oocyte undergoes first meiotic division i.e., meiosis I or reductional division to form two unequal haploid cells. This process is discontinuous which is initiated during the period of foetal development that is terminated only after puberty sets in. Students who are in class 12th or preparing for any exam which is based on Class 12 Biology can refer NCERT Biology Book for their preparation. Subsequently, four haploid spermatids are formed from a diploid spermatogonium. The primary spermatocytes furthermore undergo meiotic divisions for the formation of secondary spermatocytes and ultimately spermatids. The whole cycle takes around 28 days to complete. Ncert solution class 12 Biology includes text book solutions from both part 1 and part 2. It provides nourishment and On the contrary, human females have 22 pairs of autosomes and contain only the X sex chromosome. Students can refer to these answers to prepare for the examinations. The different hormones that regulate the menstrual cycle are LH – leutinizing hormone, FSH – follicle-stimulating hormone, progesterone, estrogen. When you focus on the NCERT solutions you will know about the benefits of following CBSE Class 12 Biology Chapter 3 Solutions PDF files. Estrogen obstructs the FSH secretion, triggering the secretion of the LH, which also results in the thickening of the uterine endometrium. There were 22 questions of biology comprising of 88 marks and 15 questions of zoology with a net worth of 60 marks in the NEET 2019. (d) Sperm tail (c) Leydig cells are found in ovary. This will clear students doubts about any question and improve application skills while preparing for board exams. Question 21: How many eggs do you think were released by the ovary of a female dog which gave birth to 6 puppies? From evolution theory, gene therapy, advances in biotechnology, and the biopharmaceuticals development for treating various illnesses a thorough understanding of biology help one become a better student of life. (True/False), (g) Presence or absence of hymen is not a reliable indicator of virginity or sexual experience. (j) The zygote divides to form __________, which is implanted in uterus. On the other hand, females are homogametic – they produce only one type of gamete, the ova, each of which carries the ‘X’ chromosome only.
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