Human Health and Disease — BIOLOGY STD 12 Science — Question

In the vector and DNA fragments are generated using the same restriction enzyme, how can self-ligation be prevented?

During which phases of cell cycle, transcription occurs in the nucleus?

Aa Bb was crossed with aa bb. What would be the phenotypic ratio of the progeny? Mention the term to denote this cross.

In the year 1963, two enzymes responsible for restricting the growth of bacteriophage in E.coli were isolated. How did the enzymes act to restrict the growth of the bacteriophage?

Why cannot DNA gain entry into a cell through the plasma membrane?

All primary productivity is not available for herbivores. Give one reason.

Give one example of natural pollutant.

Name the layers of peritoneum that surrounds the heart sequentially from outside to inside.

Introns

Viral disease of plants.