Class 12 Biology Chapter 18 Notes

• Important chapter 18 biology class 12  for Intermediate part-II students.
• What is follicle atresia?
• What is after birth?
• What is the role of placenta in human?
• What is seed dormancy? Give its importance.
• Important biology chapter 18 biology class 12 notes for Intermediate part-II students.
• What is the role of interstitial cells in sperm production?
• What is the structure and function of corpus luteum?
• what is a period?
• What is parthenocarpy?  OR  Define parthenocarpy with examples.  OR  How does parthenocarpy differ from parthenogenesis?
• Write down at least two important measures to prevent AIDS.
• What are Oviparous, Viviparous and Ovoviviparous animals?  OR Give difference between Oviparous and Viviparous animals.  OR  What are Ovoviviparous animals? Give examples.  OR  Differentiate between oviparity and viviparity.
• Important biology chapter 18 biology class 12 mcqs for Intermediate part-II students.
• Classify the plants according to photoperiodic requirement for flowering.  OR  Name types of plants according to photoperiodism.
• Compare sexual and asexual reproduction.
• Define photoperiodism and write its effects in plants.  OR  Give importance of photoperiodism in plants.
• Define apomixes.  OR  What is meant by apomixes?  OR  What is apomixes.
• Define vernalization.  OR  What is vernalization?
• Important class 12 biology chapter 18 important short questions for Intermediate part-II students.
• Differentiate between haploid parthenogenesis and diploid parthenogenesis.  OR  Define diploid parthenogenesis.  OR  Define diploid parthenogenesis. Give an example.
• what are period cramps?
• Differentiate between menupause and ovulation.  OR  Explain menupause and after birth.
• Differentiate between internal and external fertilization.
• Differentiate between spermatogenesis and oogenesis.
• Important biology chapter 18 biology class 12 long questions for Intermediate part-II students.
• Differentiate between identical twins and fraternal twins.  OR How identical twins and fraternal twins are produced?
• what counts as a late period?
• How can you differentiate between menstrual cycle and oestrous cycle?  OR  Define/ Explain oestrous cycle.
• How are test tube babies produced?  OR  What are test tube babies.
• what stops period cramps
• Important biology chapter 18 biology class 12 pdf for Intermediate part-II students.

• What is asexual reproduction?  Asexual reproduction requires only a single parental organism which gives rise to offspring by mitotic cell division, during which the complete adult number of chromosomes is exactly replicated and passed on, os that the offspring are genetically identical to the parent.
• Important biology chapter 4 biology class 12 important questions for Intermediate part-II students.
• What is fruit set?  Fruit set is the retention of the ovary. which becomes the fruit after fertilization. After fertilization, the ovary and the ripe seeds continue to produce auxins which stimulates fruit development.
• What are spermatocytes and spermatids?  The spermatogonia present in seminiferous tubules differentiate into primary spermatocytes which undergo meiotic division to form secondary spermatocytes and spermatids which ultimately forms sperms.
• What are sertoli cells?  Sertoli cells are present in testes. They secrete fluid that provides liquid medium, protection and nourishment to sperms while they are in the tubules.
• What is testosterone?  The interstitial cells of testes secrete testosterone. This hormone is essential for the successful production of sperms and also control the development of male secondary characteristics during puberty.
• Important biology chapter 4 biology class 12 notes for Intermediate part-II students.
• What is FSH?  The pituitary gland on the onset of puberty, releases follicle stimulating hormone (FSH) which stimulates the development of several primary follicles.
• What is foetus?  From beginning of the 3rd month of pregnancy the human embryo is referred to as the foetus. Most of the major organs are being formed in it.
• What is Genital Herpes?  It is caused by a herpes simply type 2 virus, most frequently transmitted by sexual contact causing infection of the genitalia. It produces genital soreness and ulcers in the infected area.
• Important biology chapter 4 biology class 12 mcqs for Intermediate part-II students.
• What is menstrual cycle?  In human females the periodic reproductive cycle is completed in approximately 28 days and involves changes in the structure and function of the whole reproductive system. It is called menstrual cycle and can be divided into four phases.
• Define photoperiodism.  The variations in day length are called photoperiod and the phenomenon is called photoperiodism.
• What is florigen?  Florigen is a hormone in leaves, which travel through phloem to the floral buds and initiates flowering.