Which cells are primarily responsible for the activation of B lymphocytes in mammals?

A. Macrophages

B. T lymphocytes

C. Plasma cells

D. Memory cells

What is the primary role of antibodies in the immune response?

A. Activation of B lymphocytes

B. Destruction of pathogens

C. Production of histamines

D. Formation of memory cells

Which of the following statements about vaccines is correct?

A. Vaccines contain live pathogens to induce immunity.

B. Vaccines work by suppressing the immune system.

C. Vaccines introduce a weakened or inactivated form of the pathogen to stimulate an immune response.

D. Vaccines create memory cells without activating B lymphocytes.

What is the role of histamines in allergic responses?

A. Suppression of immune response

B. Activation of T lymphocytes

C. Dilation of blood vessels and increase in permeability

D. Production of antibodies

How are hybridoma cells utilised in the production of monoclonal antibodies?

A. By activating B lymphocytes

B. By fusing with memory cells

C. By fusing a B lymphocyte with a myeloma cell

D. By introducing antigens to plasma cells

a) Explain the concept of unique molecules on cell surfaces and how they contribute to immune responses. [3]

b) Discuss the role of antibodies in the identification and destruction of pathogens. [4]

a) Describe the activation of B lymphocytes by T lymphocytes in mammals and its significance in immune responses. [4]

b) Explain how the formation of plasma cells and memory cells from activated B cells contributes to immunity. [3]

a) Discuss the principles of how vaccines work and their role in providing immunity against infectious diseases. [4]

b) Explain the correlation between the length of the loop of Henle and the need for water conservation in animals. [3]

a) Discuss the difference between osmoregulators and osmoconformers and their strategies in maintaining internal balance. [3]

b) Explain the role of the Malpighian tubule system in insects in osmoregulation and nitrogenous waste removal. [4]

c) How does the composition of blood differ between the renal artery and the renal vein? [2]

a) Describe the ultrastructure of the glomerulus and Bowman's capsule and explain their role in ultrafiltration. [4]

b) Discuss the role of the proximal convoluted tubule in the selective reabsorption of useful substances. [3]

c) How does the loop of Henle maintain hypertonic conditions in the medulla? [2]