Class 12th Biology 2016 Set1 Outside Delhi Board Paper Solution
Why must a cell be made ‘competent’ in biotechnology experiments ? How does calcium ion help in doing so ?
DNA being a hydrophilic molecule, can not pass through cell membranes, hence the cells should be made competent to accept the DNA molecules as competency is the ability of a cell to take up foreign DNA. Calcium ion helps in increasing the pore size in cell wall which enables the cell to take up the recombinant DNA.
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:- Offspring formed due to sexual reproduction have better chances of survival. Why? Is this statement always true?
- Q:- Differentiate between microsporogenesis and megasporogenesis. Which type of cell division occurs during these events? Name the structures formed at the end of these two events.
- Q:- Why do you think the zygote is dormant for sometime in a fertilized ovule?
- Q:- What measures, as an individual, you would take to reduce environmental pollution?
- Q:- Explain (in one or two lines) the function of the followings:
(a) Promoter
(b) tRNA
(c) Exons - Q:- Describe briefly the followings:
(a) Origin of replication
(b) Bioreactors
(c) Downstream processing - Q:- Give an account of energy flow in an ecosystem.
- Q:- Define and design a test − cross?
- Q:- What is apomixis and what is its importance?
- Q:-
Fill in the blanks:
(a) Humans reproduce __________. (asexually/sexually)
(b) Humans are__________. (oviparous/viviparous/ovoviviparous)
(c) Fertilization is __________ in humans. (external/internal)
(d) Male and female gametes are __________. (diploid/haploid)
(e) Zygote is __________. (diploid/haploid)
(f) The process of release of the ovum from a mature follicle is called__________.
(g) Ovulation is induced by a hormone called the __________.
(h) The fusion of male and female gametes is called _____________.
(i) Fertilisation takes place in _____________.
(j) Zygote divides to form _____________which is implanted in uterus.
(k) The structure which provides vascular connection between fetus and uterus is called ____________.