Ecosystems and Energy Flow — BIOLOGY STD 12 Science — Question

Regulation of lac operon can be visualised as regulation of enzyme synthesis by its substrate. Explain the statement.

Following table gives certain terms associated with ART. Fill in the space A,B,C and D.

IVF and ET	A
B	lntroduction of zygote or embryo with 8-celled blastomeres into Fallopian tube.
C	lntroduction of ova of a donor into the Fallopian tube.
D	lntroduction of semen from the husband or healthy donor into the uterus.

Shyam Lal and his wife have been advised by the gynaecologist to go for artificial insemination. What may have been the reason for the doctor to give such an advice? Explain.

1. Name the organisms that reproduce through the following structures.

1. Conidia.
2. Zoospores.

2. Mention one similarity and one difference between these two reproductive structures.

How and why is the bacterium Thermus aquaticus employed in DNA technology? Explain.
Or
Name the source of the DNA polymerase used in PCR technique. Mention why it is used?

Or
Give the name of the organism from where the thermostable DNA polymerase is isolated. State its role in genetic engineering.

How does the female gamete reach the uterus from ovary?

What is aminoacylation? State its significance.

A liverwort plant is unable to complete its life-cycle in a dry environment. State two reasons.

State the consequence when Meloidegyne incognita consumes cells with RNAi gene.