Organisms and Populations — BIOLOGY STD 12 Science — Question

Why do sportspersons often fall a victim to cocaine addiction?

Name a bioactive molecule, its source organism and the purpose for which it is given to organ transplant patients.

Calculate the length of the DNA of bacteriophage lambda that has 48502 base pairs.

Why is ZIFT a boon to childless couples? Explain the procedure.

Explain broadly utilitarian argument for conservation of biodiversity.

List any three enzymes involved in the process along with their functions.

Mention the early symptoms of STDs.

The scientists believe that evolution is gradual. But extinction, part of evolutionary story, are 'sudden' and 'abrupt' and also group-specific. Comment whether a natural disaster can be the cause for extinction of species.

Point out the interaction between :
(a) Cuscuta growing on some angiospermic tree
(b) Orchid growing on a mango tree
(c) Wasp pollinating fig inflorescence
(d) Smaller branches disappeared when Balanus dominated on the coast of Scotland
(e) Mycorrhizae on the roots of higher plants
(f) Birds and Cattle

Name and explain the types of barriers of innate immunity, where some cells release interferons when infected.