11.1. The immune system
A subsection of Biology, 9700, through 11. Immunity
Listing 10 of 122 questions
Pathogens enter the body in a variety of ways, including through the gas exchange system. The body has several defence mechanisms against the entry of pathogens and their spread throughout the body. is an electron micrograph of a cross section of the lining of a bronchiole. Y X Name tissue X and cell Y. X Y With reference to the structures visible in , state three ways in which the lining of the trachea, bronchus and bronchioles provides protection against the entry of bacterial pathogens. shows part of the immune response to the first infection by a bacterial pathogen that has entered the body through the lining of a bronchiole. J and K are stages in the immune response. Key antigen bacterium secretion of cytokines J L K cytotoxic T-lymphocyte helper T-lymphocytes B-lymphocytes State what is happening at stage J. Explain the role of cell L at stage K in the immune response. With reference to , explain how the response to a second infection by this bacterial pathogen differs from the first. There are various ways in which the effectiveness of immune responses can be reduced. Suggest how each of the following reduces the effectiveness of an immune response. The number of T-lymphocytes is reduced in a person with HIV/AIDS. Some pathogens are covered in cell surface membranes from their host. B-lymphocytes do not mature properly and do not recognise any antigens.
9700_s15_qp_21
THEORY
2015
Paper 2, Variant 1
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Macrophages synthesise intracellular enzymes. is a summary diagram of events that occur in a macrophage. bacteria $ % & ' ( ) * + - Name the process at A. Name the stages of protein synthesis that occur at E and at F. E F Name organelles B, G, H and J. B G H J Describe what happens to the bacteria between C and D. Macrophages are antigen presenting cells (APCs). Antigens from pathogens such as the bacteria shown in are presented to helper T-lymphocytes as shown in . helper T-lymphocyte antigen T cell receptor APC Very few helper T-lymphocytes respond to the presence of APCs by binding in the way shown in . Suggest why this is so.
9700_s16_qp_21
THEORY
2016
Paper 2, Variant 1
View
Questions Discovered
122