NCERT Solutions for Class 12 Biology Chapter 3 Human Reproduction FREE to Study Online or download in PDF form. NCERT Books and NCERT Solutions based on latest CBSE Curriculum is given to download. Join the Discussion Forum and place your views for the questions of others.
|Chapter 3:||Human Reproduction|
NCERT Solutions for class 12 Biology Chapter 3
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Solutions for 12 Biology Chapter 3
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Class 12 Biology Chapter 3 Question Answers
Important Terms on Chapter 3
- Gestation Period: A period between fertilisation of ovum and the birth of a baby.
- Implantation: Fixing of ernbryo/fertilized egg in uterus. It leads to pregnancy.
- Menarche: The beginning of first menstruation in female on attaining puberty.
Menopause: Permanent ceasation of menstrual cycle in female. It occurs between the age 45 to 50 years in human female.
- Puberty: A stage at which immature reproductive system of boy or girl becomes mature. Period of puberty is 10-14 years in girls and 13-16 years in boys.
- Ovulation: Process of release of mature ovum (Secondary oocyte) from the ovary.
- Parturition: Process of delivery of the foetus (Child birth), through birth canal.
- Spermiogenesis: Transformation of spermatids into sperms.
- Spermiation: A process by which spermatozoa are released from the seminiferous tubules.
- Spermatogenesis: Process of formation of sperm from male germ cell in the testes.
- Lactation: The fluid secreted by mammary glands soon after birth is called colostrum. It contains proteins, lactose and antibodies (e.g. IgA). This provides nutrition and help the new born baby to develop resistance for healthy development.
Questions for revision
- Failure of testes to descend into sacrotal sacs leads to sterility. Why?
- How many sperms will be produced from 10 primary spermatocytes and how many eggs will be produced from 10 primary occytes?
- What is meant by L.H. Surge? Write the role of L.H.
- T.S. of mammalian testis revealing seminiferous tubules show different types of cell.
(i) Name the two types of cells of germinal epithelium.
(ii) Name of cells scattered in connective tissue and lying between seminiferous tubules.
- High temperature of abdomen kills the spermatogenic tissue of the testes, so no sperm are formed.
- 40 sperms, 10 eggs.
- LH surge refers to maximum level of luteihising hormone living middle of menstrual cycle. LH couses ovulation.
- (i) Germinal epithelium have two types of cells. 1. Spermatogonium. 2. Sertoli cells
(ii) Leydig’s cell or Interstitial cells.
Write two major functions each of testis and ovary.
They produce male gametes called spermatozoa by the process of spermatogenesis.
The leydig cells of the seminiferous tubules secrete the male sex hormone called testosterone. Testosterone aids the development of secondary sex characteristics in males.
Functions of the ovary
They produce female gametes called ova by the process of oogenesis.
The growing Graffian follicles secrete the female sex hormone called estrogen. Estrogen aids the development of secondary sex characteristics in females.
Name the hormones involved in regulation of spermatogenesis.
Define spermiogenesis and spermiation.
It is the process of transforming spermatids into matured spermatozoa or sperms.
It is the process when mature spermatozoa are released from the sertoli cells into the lumen of seminiferous tubules.