Microbes in Human Welfare — BIOLOGY STD 12 Science — Question

Draw a schematic sketch of pBR322 plasmid and label the following in it:

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

What is LAB? What is its role in human stomach?

Since the origin of life on the earth, there were five episodes of mass extinction of species.

1. How is the 'Sixth Extinction', presently in progress, different from the previous episodes?
2. Who is mainly responsible for the 'Sixth Extinction'?
3. List any four points that can help to overcome this disaster.

Name the type and give the effect of the following drug in human.
LSD

A teacher wants his/her students to find the genotype of pea plants bearing purple coloured flowers in their school garden. Name and explain the cross that will make it possible.

1. Is the trait recessive or dominant?
2. Is the trait sex-linked or autosomal?
3. Give the genotypes of the parents in generation I and of their third and fourth child in Generation II.

A pea plant with purple flowers was crossed with white flowers producing 50 plants with only purple flowers. On selfing, these plants produced 482 plants with purple flowers and 162 with white flowers. What genetic mechanism accounts for these results? Explain.

Prior to a sports event blood & urine samples of sportspersons are collected for drug tests.

1. Why is there a need to conduct such tests?
2. Name the drugs the authorities usually look for.
3. Write the generic names of two plants from which these drugs are obtained.

What is parturition? Which hormones are involved in induction of parturition?

Write the three basic facts that are highlighted in Mendel's Law of Dominance.