Human Reproduction — BIOLOGY STD 12 Science — Question

State the role of T lymphocytes and B lymphocytes in developing acquired immunity against certain diseases.

OR

Name the different types of cells that are responsible for producing the acquired immune response in a human body. How do these cells respond when a pathogen enters the body?

OR

 Name the two special types of lymphocytes in humans. How do they differ in their roles in immune response?

Name the four levels of organisation that ecology is basically concerned with.

Draw a well-labelled diagram of an antibody molecule.

List the events that lead to biogas production from waste water whose BOD has been reduced significantly.

Explain with the help of a suitable example the naming of a restriction endonuclease.

Give an example of an autosomal recessive trait in humans. Explain its pattern of inheritance with the help of a cross.

How LABs are useful to us explain.###Give a brief account on importance of lactobacillus bacteria in house hold products.

State the respective ratio of given genetic phenomenon.

1. Complementary gene ratio.
2. Dihybrid test cross ratio.

Write the function of adenosine deaminase enzyme. State the cause of ADA deficiency in humans. Mention a possible permanent cure for an ADA deficiency patient.

Mention the common bacterium found in the anaerobic sludge during sewage treatment and also in the rumen of cattle. How is this bacterium commercially useful?