Class 12th Biology 2017 Set3 Delhi Board Paper Solution
How do mycorrhizae help the plants to grow better?
Symbiotic association of fungi with plants is called mycorrhiza. Many members of the genus Glomus form mycorrhiza. These fungal symbiont absorb phosphorus from the soil and passes it to the plant. In this way these fungal helps in the growth of Plants. There are other benefits of the this kind of association:
1. Resistance to root-borne pathogens.
2. Tolerance to salinity and drought
3. Overall increase in plant growth and development
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:- Define and design a test − cross?
- Q:- Examine a few flowers of any cucurbit plant and try to identify the staminate and pistillate flowers. Do you know any other plant that bears unisexual flowers?
- 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 ____________. - Q:- How do biofertilisers enrich the fertility of the soil?
- Q:- Suggest some methods to assist infertile couples to have children.
- Q:- Suggest the aspects of reproductive health which need to be given special attention in the present scenario.
- Q:- Name any five hybrid varieties of crop plants which have been developed in India.
- Q:- Draw a well-labelled diagram of an antibody molecule.
- Q:-
Explain the following terms with example
(a) Co-dominance
(b) Incomplete dominance - Q:- Name the functions of the following.
(a) Corpus luteum
(b) Endometrium
(c) Acrosome
(d) Sperm tail
(e) Fimbriae