AQA A Level Biology復習筆記2.5.6 The Role of Helper T cells
The Role of Helper T cells Activated T-lymphocytes (those that have receptors specific to an antigen)?divide?by?mitosis?to increase in number (similar to the?clonal selection and clonal expa...
AQA A Level Biology復習筆記2.5.5 The Role of Antigen-Presenting Cells
The Role of Antigen-Presenting Cells T-lymphocytes produce an immune response when they are exposed to a specific antigen T cells will only bind to an antigen if it is present on the surface...
AQA A Level Biology復習筆記2.5.4 The T Lymphocyte Response
The T Lymphocyte Response Lymphocytes?are another type of white blood cell They play an important part in the?specific?immune response They are?smaller?than phagocytes They have a?large nucl...
AQA A Level Biology復習筆記2.5.3 Phagocytosis
Phagocytosis Phagocytes are white blood cells that are produced continuously in the?bone marrow They are stored in the bone marrow before being?distributed around the body in the blood They ...
AQA A Level Biology復習筆記2.5.2 Antigens
Antigens Every cell in the human body has?markers?that?identify?it Microorganisms (both pathogenic and non-pathogenic), such as bacteria and viruses, also have their own unique markers These...
AQA A Level Biology復習筆記2.4.13 Factors Affecting Membrane Fluidity
Required Practical: Factors Affecting Membrane Permeability The?permeability?of?cell membranes?is affected by different?factors?or conditions, such as: Temperature Solvent concentration &nbs...
AQA A Level Biology復習筆記2.4.12 Specialised Cells
Explaining Adaptations in Specialised Cells Specialised cells for diffusion Root hair cells?and?epithelial cells of the small intestine?are examples of cells that are?adapted?for the rapid t...
AQA A Level Biology復習筆記2.4.11 Adaptations for Rapid Transport
Adaptations for Rapid Transport The rate at which?diffusion?(including both?simple?diffusion and?facilitated?diffusion) occurs across external and internal cell membranes?varies Some cells a...
AQA A Level Biology復習筆記2.4.10 Active Transport & Co-transport
The Process of Active Transport & Co-transport Active transport is the?movement of molecules and ions through a cell membrane from a region of lower concentration to a region of higher c...
