Immunity Flashcards
Where are B and T cells formed?
Bone marrow
How do B and T cells clone?
Mitosis
How does HIV infect the body?
GP120 molecules on the HIV bind to the CD4 receptors on T helper cell
Viral envelope fuses with cell membrane and enters the cell
Reverse transcriptase converts the virus’ RNA into DNA
This DNA is integrated into host cell’s DNA by intergrase
This allows new viral proteins to be produced via transcription/translation
After many viral proteins have been produced, cell bursts and proteins go on to infect other T helper cells
What type of virus is HIV?
Retro virus
How do T killers cells kill cells?
Release enzymes that make holes in membrane of infected cell
This causes cell lysis
What is a lymphocyte?
White blood cell
Two types of white blood cell?
B and T cells
How do B cells fight infection?
Produce antibodies (immunoglobulins)
These bind to the antibodies and help to identify the pathogen
They also neutralise bacteria toxins
Type of receptors on T helper cells
CD4
Type of receptors on T killer cells
CD8
How do macrophages fight infection?
Digest cell
Displays cell’s antigens on its surface ;becomes an antigen presenting cell
Steps of clonal selection
Antigens bind to B cell that has correct receptor
B cell becomes an antigen presenting cell
Active T helper cell with complimentary receptor binds to the B cell and releases cytokines which stimulate B cell
B cell divides to produce B memory cells and B effector cells
B effector cells differentiate into plasma cells which produce antibodies
Explain how infection by HIV could increase the risk of a person developing a disease such as tuberculosis
- HIV affects T helper cells
- Lack of functional white blood cells mean a person is more susceptible to disease
What does AIDS stand for?
Acquired immune deficiency syndrome
What does HIV stand for?
Human immunodeficiency virus