Topic 11: Immunity Flashcards
Definitions I:
(a) Phagocyte
(b) Antigen
(c) Antibody
(a) Phagocyte: Immune cell engulfing pathogens. (1 mark)
(b) Antigen: Molecule triggering immune response. (1 mark)
(c) Antibody: Protein binding specific antigens. (1 mark)
In a wound, describe the mode of action of macrophages. [2 Marks]
Macrophages engulf bacteria via phagocytosis (1 mark); Digest, present antigens to lymphocytes (1 mark). (2 marks)
Explain antigens and the difference between self and non-self in a human body. [2 Marks]
Antigen: Molecule on cell surface (1 mark); Self: Body’s own, non-self: Foreign, triggers response (1 mark). (2 marks)
In a flu infection, describe the primary immune response with macrophages and lymphocytes. [3 Marks]
Macrophages present antigens (1 mark); B-cells produce antibodies, T-helpers activate (1 mark); T-killers destroy infected cells (1 mark). (3 marks)
Explain the role of memory cells after a measles vaccination. [2 Marks]
Memory cells recognise measles antigen (1 mark); Trigger faster antibody production (1 mark). (2 marks)
Relate the structure of antibodies to their function in fighting bacteria. [3 Marks]
Y-shaped, variable region binds antigen (1 mark); Constant region tags for destruction (1 mark); Neutralises pathogens (1 mark). (3 marks)
Outline the hybridoma method for producing monoclonal antibodies in a lab. [2 Marks]
Fuse B-cells with myeloma cells (1 mark); Hybridomas produce specific monoclonal antibodies (1 mark). (2 marks)
In cancer treatment, outline the use of monoclonal antibodies. [2 Marks]
Bind cancer cell antigens (1 mark); Target for drugs or immune attack (1 mark). (2 marks)
Describe the differences between active and passive immunity in a newborn. [3 Marks]
Active: Body makes antibodies (1 mark); Passive: Received, e.g., mother’s milk (1 mark); Natural vs. artificial differs (1 mark). (3 marks)
Explain how a flu vaccine provides long-term immunity. [2 Marks]
Vaccine antigens stimulate immunity (1 mark); Memory cells ensure long-term protection (1 mark). (2 marks)
In a village outbreak, explain how vaccination controls cholera spread. [3 Marks]
Vaccines trigger antibody production (1 mark); Herd immunity reduces spread (1 mark); Controls cholera outbreak (1 mark). (3 marks)
Analyse the roles of T-helper and T-killer cells in a TB infection. [4 Marks]
T-helpers activate B-cells, immunity (1 mark); T-killers destroy infected cells (1 mark); Coordinate response (1 mark); Limit TB spread (1 mark). (4 marks)
Discuss how B-lymphocytes and memory cells protect against reinfection. [4 Marks]
B-cells produce antibodies (1 mark); Plasma cells amplify response (1 mark); Memory cells store immunity (1 mark); Prevent reinfection (1 mark). (4 marks)
