Short Answer TypeSome organisms suspend their metabolic activities to survive in unfavourable conditions. Explain with the help of any four examples.
(a) State the role of DNA ligase in biotechnology.
(b) What happens when Meloidegyne incognitia consumes cells with RNAi gene?Draw a schematic diagram of a part of double stranded dinucleotide DNA chain having all the four nitrogenous bases and showing the correct polarity.
Name of parasite the causes filariasis in humans. Mention its two diagnostic symptoms. How is this transmitted to others?
Name the source of streptokinase. How does this bioreactor molecule function in our body?
How do mycorrhizae act as biofertilizers? Explain. Name a genus of fungi that forms a mycorrhizal association with plants.
(a) State the difference between meiocyte and gamete with respect to chromosome number.
(b) Why is a whiptail lizard referred to as parthenogenetic?Explain the work carried out by Cohen and Boyer that contributed immensely in biotechnology.
Where is sporopollenin present in plants? State its significance with reference to its chemical nature.
Sporopollenin is present in exine of pollen grains in plants. It is one of the most resistant organic substances and can withstand high temperature, strong acids and alkali. No enzyme has been found that degrades sporopollenin is so far known. This sporopollenin helps the pollen grain to be well preserved.
It is established that RNA is the first genetic material. Explain giving three reasons.
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