Cells: Cell recognition and the immune system Flashcards
What is antigen?
A protein in the cell surface membrane that triggers an immune response.
Where are B cells produced?
Bone marrow
What are non-self cells?
Not our body’s cells and molecules
Name two pathogens can stimulate an immune response:
- Virus
- Bacterium
What are the two types of phagocytes?
Neutrophils
Macrophages
What does a neutrophil do?
Engulfs and digests pathogens
What does a macrophage do?
- Punch holes in bacteria.
- Stick proteins to the outside of bacteria to make them more appealing for the neutrophils to destroy.
What is phagocytosis?
Engulfing pathogens.
Describe how phagocytes destroy non-self antigens in the blood:
1) Complementary protein receptors on the cell-surface membrane of the phagocyte binds to non-self antigens.
2) Cell membrane forms around the pathogen, engulfing it.
3) The pathogen is internalised in a phagosome.
4) Lysosomes fuse with the phagosome, releasing lysozymes, which digest the pathogen.
5) Non-self antigens are presented on the cell-surface membrane of the phagocyte.
Why must patients who receive organ donations take anti-rejection medicines?
Donor cells are non-self antigens, which will be destroyed by phagocytes.
State the four types of non-self cells that lymphocytes can recognise:
- Toxins
- Tumour cells
- Transplanted cells
- Pathogens
What are cells that belong to us called?
Self cells
What are cells that can trigger an immune response called?
Non-self cells
What are pathogens?
Any microorganism that causes disease
Lymphocytes are _________ to one antigen.
Specific
How are lymphocytes able to recognise antigens?
They have complementary receptors that bind to antigens
How many antigens can a lymphocyte recognise?
One (specific antigen)
When lymphocytes bind to an antigen, they trigger a _______ immune response.
Specific
Why are phagocytes non-specific?
Their receptors are complementary to the molecular patterns found on all pathogens.
When a pathogen invades the body, the pathogen releases _______ that attract phagocytes towards it.
Chemicals
When a pathogen has released chemicals that attracts the phagocyte, the phagocyte moves towards it along a _____________.
Concentration gradient
When the phagocyte reaches the pathogen, it binds to the pathogen via complementary _________.
Receptors
How to lysozymes aid in the digestion of a pathogen?
They speed up the hydrolysis reaction.
Do phagocytes or lymphocytes carry out a nonspecific response against a pathogen?
Phagocytes
Where are B cells matured?
Bone marrow
Where are T cells matured?
Thymus
What is the role of the disulphide bridge in forming the quaternary structure of an antibody?
Holds and stabilises the polypeptides together
What are the two types of white blood cells that lymphocytes can differentiate into?
T lymphocytes
B lymphocytes
If lymphocytes mature in the bone marrow, they are __-lymphocytes.
B
If lymphocytes mature in the thymus, they are __-lymphocytes.
T