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]

What is the significance of unique molecules on cell surfaces?

A. They prevent the activation of T lymphocytes.

B. They determine the specificity of antibodies.

C. They facilitate cross-species barriers.

D. They are essential for the production of histamines.

Which of the following cells are formed from activated B cells?

A. T lymphocytes and macrophages

B. Plasma cells and memory cells

C. Hybridoma cells and myeloma cells

D. Antigens and antibodies

Why are pathogens typically species-specific?

A. Due to the similarity in cell surface molecules across species

B. Due to the universal nature of antibodies

C. Due to differences in cell surface molecules between species

D. Due to the identical nature of immune responses in all species

How do vaccines contribute to immunity?

A. By introducing live pathogens to the body

B. By stimulating the production of histamines

C. By inducing the formation of memory cells and antibodies

D. By suppressing the activation of B lymphocytes

Which statement about cross-species barriers is correct?

A. They are facilitated by the similarity in antigens between species.

B. They prevent the transmission of pathogens between different species.

C. They are irrelevant to the specificity of the immune response.

D. They are broken down by the action of antibodies.

a) Explain the role of ADH in the reabsorption of water in the collecting duct. [3]

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

c) How do hybridoma cells contribute to the production of monoclonal antibodies? [3]

a) Discuss the role of histamines in allergic responses and how they affect the body. [3]

b) Explain the mechanism of action of vaccines in providing immunity. [4]

c) How does the secretion of estrogen and progesterone by the placenta regulate pregnancy? [2]

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

b) Describe the activation of B lymphocytes by T lymphocytes in mammals and the subsequent formation of plasma cells and memory cells. [4]

c) Discuss the role of antibodies in the destruction of pathogens and provide an example. [3]

d) How do vaccines work to provide immunity, and what is their significance in public health? [3]

a) Discuss the difference between internal and external fertilisation in animals and give examples of each. [3]

b) Explain the mechanisms that prevent polyspermy during fertilisation. [3]

c) Discuss the importance of the implantation of the blastocyst in the endometrium for the continuation of pregnancy. [3]

d) How does the placenta facilitate the exchange of materials between the mother and fetus? [4]

a) Explain how the role of HCG in stimulating the ovary to secrete progesterone during early pregnancy. [3]

b) Discuss the correlation between the type of nitrogenous waste in animals and their evolutionary history and habitat. [4]

c) How does the secretion of estrogen and progesterone by the placenta, once it has formed regulate pregnancy? [3]

d) Discuss how birth is mediated by positive feedback involving estrogen and oxytocin. [3]