Topic 2 - Cell Communication Flashcards
Why do cells communicate?
so cells can coordinate their activities properly such as cell division, responding to invaders, growing and cell death.
Examples of 3 different signalling molecules
- A hormone (e.g. insulin)
- A neurotransmitter (chemical released between neurons)
- A protein receptor (on the surface of another cell)
Why do only target cells respond to a signal and not all cells?
have a cell membrane receptor that has a matching shape to the signalling molecule, which non-target cells cannot respond to as they don’t have a matching receptor.
Examples of possible cell responses to signals
- Opening up the cell membrane to transport chemicals
- Speeding up cell division by mitosis
- Producing more proteins
Role of WBC
They defend the body by killing off invaders including bacteria and viruses. They identify and destroy abnormal cancer cells
What are self-antigens? Where are they located?
they are molecules produced by your own body’s cells that can trigger an immune response if recognised as foreign by the immune system.
- they are located on the cell membrane
What is a target cell for a signal?
is a specific cell within an organism that is capable of responding to a particular signalling molecule.
- they have receptors that recognise the signalling molecule, initiating a cellular response.
Consequences to a cell if it can’t respond in a appropriate way to a signal?
- It may not function properly. If a nerve cell can’t respond to neurotransmitters, it may struggle to transmit signals effectively, leading to communication issues
- May grow abnormally
- Cancer cells grow and divide in a uncontrolled manner
What role to self-antigens have?
It allows the body to recognise its cells from harmful pathogens (e.g. cancerous cells), that are foreign to the body.
What is a non-self antigen?
an individual, specific self-marker that is not recognised by the immune system, seeing them as foreign. They are attacked by the immune system.
- originate from outside the body’s cells.
- trigger an immune response to eliminate them
Define self marker
labels the body’s cells as a friend and are tolerated by the immune system
Why do organ transplants get rejected?
It depends on the donor and the recipient having similar self antigens or membrane proteins
- if they are very different then the donors immune system will launch an attack on the foreign transplanted tissue.
What is an autoimmune disease?
a condition in which your immune system attacks your own body’s cells (fails to recognise self cells)
- Your body should not repsond to self cells, known as self tolerance, but should only attack non-self antigens.
Examples of Autoimmune diseases
- Lupus
- Multiple Sclerosis
- Celiac Disease
Define Antigen
An antigen is an individual, specific marker/receptor protein on the surface of the cell.
