Microbes in Human Welfare — BIOLOGY STD 12 Science — Question

1. State how the constant internal environment is beneficial to organisms
2. Explain any two alternatives by which organisms can overcome stressful external conditions.

Why is hormone releasing IUD considered a good contraceptive to space children?

One of the twins born to parents having normal colour vision was colour blind whereas the other twin had normal vision. Work out the cross. Give two reasons how it is possible.

A non biology person is quite shocked to know that apple is a false fruit, mango is a true fruit and banana is a seedless fruit. As a biology student how would you satisfy this person.

Indicate the stages where meiosis and mitosis occur (1, 2 or 3) in the flow chart,

1. What are two types of desirable approaches to conserve biodiversity? Explain with examples bringing out the difference between two types.
2. What is the association between the bumble bee and its favourite orchid Ophrys? How could extinction or change of one would affect the other?

What are 'cry-proteins'? Explain with the help of a suitable example how it works as a biopesticide.

Draw a schematic sketch of pBR 322 plasmid and label the following in it:

1. Any two restriction sites.
2. Ori and rop genes.
3. An antibiotic resistant gene.

Answer the following questions:
What is plasmid?

Discuss briefly the following:

1. Radioactive wastes.
2. Defunct ships and e-wastes.
3. Municipal solid wastes.