Class 12th Biology 2015 Set3 Delhi Board Paper Solution
Question 11
Describe the process of Parturition in humans.
Answer
At the end of an average 9 months of gestation, vigorous uterine contractions lead to the delivery of the foetus. This process is called parturition.
Parturition is a neuroendocrine mechanism and is started by the signals from the fully developed foetus and the placenta, which produce the foetal ejection reflex.
This causes release of oxytocin from posterior pituitary, which in turn causes even stronger uterine contractions. Contraction of uterine muscles leads to the expulsion of the baby along with the placenta, and hence completes the process of parturition.
Popular Questions of Class 12th biology
- Q:- What is spermatogenesis? Briefly describe the process of spermatogenesis.
- Q:- Why is reproduction essential for organisms? Answer
- Q:- Write a short note on
(a) Adaptations of desert plants and animals
(b) Adaptations of plants to water scarcity
(c) Behavioural adaptations in animals
(d) Importance of light to plants
(e) Effect of temperature or water scarcity and the adaptations of animals. - Q:- With a neat diagram explain the 7-celled, 8-nucleate nature of the female gametophyte.
- Q:- What is DNA fingerprinting? Mention its application.
- Q:- Describe the structure of a seminiferous tubule.
- Q:- What is oogenesis? Give a brief account of oogenesis.
- Q:- What is triple fusion? Where and how does it take place? Name the nuclei involved in triple fusion.
- Q:- With a neat, labelled diagram, describe the parts of a typical angiosperm ovule.
- Q:- Explain the Law of Dominance using a monohybrid cross.
Recently Viewed Questions of Class 12th biology
- Q:- List the attributes that populations but not individuals possess.
- Q:- What is a bisexual flower? Collect five bisexual flowers from your neighborhood and with the help of your teacher find out their common and scientific names.
- Q:- In our society the women are often blamed for giving birth to daughters.
Can you explain why this is not correct? - Q:- Can you think and answer how a reporter enzyme can be used to monitor transformation of host cells by foreign DNA in addition to a selectable marker?
- Q:- Write a short note on
(a) Adaptations of desert plants and animals
(b) Adaptations of plants to water scarcity
(c) Behavioural adaptations in animals
(d) Importance of light to plants
(e) Effect of temperature or water scarcity and the adaptations of animals. - Q:- Which is a better mode of reproduction sexual or asexual? Why?
- Q:- Do you think that friends can influence one to take alcohol/drugs? If yes, how may one protect himself/herself from such an influence?
- Q:- Is sex education necessary in schools? Why?
- Q:- What is pedigree analysis? Suggest how such an analysis, can be useful.
- Q:- Two heterozygous parents are crossed. If the two loci are linked what would be the distribution of phenotypic features in F1 generation for a dihybrid cross?