Molecular Basis of Inheritance — BIOLOGY STD 12 Science — Question

In ecosystem the movement of nutrients is called cycling while the term 'flow' used for energy. Why?

1. Sickel-cell anaemia in humans is a result of point mutation. Explain.
2. Write the genotypes of both the parents who have produced a sickle-cell anaemic offspring.

Give any six features of the human genome.

Explain the evolutionary theory of living form based on the observations of Charles Darwin.

1. Name the kind of diseases/ disorders that are likely to occur in humans if
   1. Mutation in the gene that codes for an enzyme phenyl alanine hydrolase occurs,
   2. There is an extra copy of chromosome 21,
   3. The karyotype is XXY.
2. Mention any one symptom of the diseases/ disorders named above.

1. Write the importance of measuring the size of a population in a habitat or an ecosystem.
2. Explain with the help of an example how the percentage cover is a more meaningful measure of population size than more numbers.

What are Cry proteins? Name an organism that produce it. How has man exploited this protein to his benefit?

"Prevention is better than cure' is an apt slogan to safeguard adolescents from drug abuse. List any six steps that could be taken in this regard.

Name the group of bacteria involved in setting milk into curd. Explain the process they carry in doing so. Write another beneficial role of such bacteria.

1. Do all pollen grains remain viable for the same length of time? Support your answer with two suitable examples.
2. How are pollen grains stored in pollen banks? State the purpose of storing pollen grains in these banks.