Cells and the Immune System

T-Cells are involved in Cellular Response.

Select the correct definitions of a Primary Immune Response.

Why is it beneficial to our immune system that many pathogens have several different antigens?

[blank_start]Active[blank_end] Immunity is when your own immune system manufactures its own antibodies to tackle the antigen. [blank_start]Passive[blank_end] Immunity is when you receive antibodies made by another organism.

Active Immunity is long term and offers immediate protection.

[blank_start]Natural Passive Immunity[blank_end] is when antibodies are passed from the mother to the baby through the placenta and/or breast milk. [blank_start]Natural Active Immunity[blank_end] is when antibodies are produced when you have caught the disease. [blank_start]Artificial Passive Immunity[blank_end] is when antibodies are injected into you from another organism. [blank_start]Artificial Active Immunity[blank_end] is when antibodies are produced after exposure to the antigen through a vaccine.

Antigenic Variation:

HIV is known as a [blank_start]retro[blank_end]virus because it stores its genetic information in the form of [blank_start]R[blank_end]NA.

Label this diagram of a HIV.

[blank_start]Indirect[blank_end] ELISAs test for the presence of a specific antibody. [blank_start]Direct[blank_end] ELISAs test for the presence of a specific antigen.

Label the diagram of an antibody:

Label this graph:

A phagocyte follows the trail of [blank_start]chemoattractants[blank_end] left by the pathogen up the concentration gradient. When it gets near the pathogen, the phagocyte starts stretching out its cell membrane around the pathogen. These 'arms' are known as [blank_start]pseudopodia[blank_end] and allow the phagocyte to [blank_start]engulf[blank_end] the pathogen and form a [blank_start]phagosome[blank_end] or phagocytotic vacuole. [blank_start]Lysosomes[blank_end] in the phagocyte travel to this vesicle, fuse with it (a [blank_start]phagolysosome[blank_end]) and release their [blank_start]lytic[blank_end] enzymes into it, breaking down and destroying the pathogen. The waste is released in [blank_start]exocytosis[blank_end] and often the antigen(s) of the pathogen are displayed on the cell surface of the phagocyte.

Endocytosis is when something is taken into a cell.

Put these stages of an Immune Response in order of when they occur and match the correct definition to them: [blank_start]PHAGOCYTES ENGULF PATHOGENS[blank_end] - Phagocyte ingests pathogen and displays its antigens on its cell surface membrane. [blank_start]T-CELLS ACTIVATED[blank_end] - A [blank_start]T-Cell[blank_end] with a [blank_start]complementary receptor[blank_end] to the antigen comes into contact with the phagocyte. [blank_start]CLONAL SELECTION[blank_end] - The T-Cell begins [blank_start]rapid mitosis[blank_end], producing [blank_start]daughter cells[blank_end] with the complementary receptors. [blank_start]IMMUNE RESPONSE[blank_end] - [blank_start]Cytokines[blank_end] are released by the T-Cells, stimulating [blank_start]B-Cells[blank_end] to divide to form [blank_start]plasma and memory cells[blank_end] and phagocytes to perform [blank_start]phagocytosis[blank_end]. [blank_start]Cytotoxic and Memory T-Cells[blank_end] are also created.