Some events that happen during phagocytosis are listed. 1 Molecules on the surface of a pathogen bind to the cell surface membrane of a phagocyte. 2 Endocytosis takes place forming a specialised vesicle. 3 Enzymes catalyse hydrolysis reactions. 4 Lysosomes migrate through the cytoplasm and fuse with an organelle. What is the correct order of these events during phagocytosis?

Biology

IGCSE&ALevel

CAIE

Exam No：9700_s25_qp_13 Year：2025 Question No：38

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