Antibodies are produced by plasma cells. Fig. 6.1 shows antigens bound to antigen-binding sites of an antibody molecule. Explain how the structure of an antigen-binding site makes it specific to a particular antigen, as shown in Fig. 6.1. ....................................................................................................................................... . ....................................................................................................................................... . ....................................................................................................................................... . ....................................................................................................................................... . ................................................................................................................................. (ii) State the function of the hinge region of the antibody shown in Fig. 6.1. ................................................................................................................................. (iii) Antibodies can bind to membrane receptors on cells of the immune system, such as macrophages. Suggest an advantage of antibodies binding to receptors on macrophages. ....................................................................................................................................... . ....................................................................................................................................... . .................................................................................................................................

Biology

IGCSE&ALevel

CAIE

Exam No：9700_s24_qp_21 Year：2024 Question No：6(a)

Answer:

11.1.1 describe the mode of action of phagocytes (macrophages and neutrophils)

11.1.2 explain what is meant by an antigen (see 4.1.3) and state the difference between self antigens and non-self antigens

11.1.3.1 macrophages

11.1.3.2 B-lymphocytes, including plasma cells

11.1.3.3 T-lymphocytes, limited to T-helper cells and T-killer cells

11.1.4 explain the role of memory cells in the secondary immune response and in long-term immunity