Cellular Signals Flashcards
(24 cards)
Endocrine signalling
A distant target cell in a different tissue
Paracrine signalling
A nearby target cell in the same tissue
Autocrine signalling
It’s target cell is itself
Exocrine signalling
A target cell in a different organism
Neurotransmitters
- Paracrine signalling
- they diffuse over synapses in between neutrons to carry the message to the next neutron
Hormones
- endocrine signalling
- secreted by glands into the bloodstream to communicate with distant cells with specific receptors
- generally peptide molecules (I.e made of proteins)
Cytokines
- may be endocrine, autocrine or paracrine signalling
- they are signalling molecules involved with the immune response
- e.g. Histamine secreted by mast cells
Pheromones
- exocrine signalling
- helps animals communicate with other members of the same species
- e.g female menstrual cycle
Plant growth regulators
- plant hormones
- endocrine signalling
- very small, organic and don’t travel in general circulation
How are plant growth regulators similar and different to animal hormones?
Similarities:
- organic
- signalling molecules with a distant target cell
Differences:
- not produced in endocrine glands
- not biomacromolecules, I.e. They are very small
- don’t travel in general circulation (bloodstream)
Where will a hydrophobic signalling molecules receptor be located?
Inside the cell
Where will a hydrophillic signalling molecules receptor be located?
On the surface of a cell, facing into the extra cellular environment
Where will a protein signalling molecules receptor be located?
On the surface of a cell
Where will a steroid or lipid signalling molecules receptor be located?
Inside a cell
What occurs during signal transduction?
The message from the signalling molecule is transferred through the cell
What occurs during signal reception?
A signalling molecule binds to a specific receptor
What occurs during a cellular response?
A cell is producing a response to the stimulus as a result of the signalling molecule
What are the 2 mechanisms in which a cellular response can be caused as a result of a signalling molecule?
- enzymes are activated which will result in a cascade effect where a lot of other proteins are produced
- gene expression can be altered
How are the mitochondrial and death receptor pathway of apoptosis different?
The mitochondrial pathway is activated by a signal that comes from inside the cell whereas the death receptor pathway is activated by a signal that comes from outside the cell
What are 3 potential triggers of apoptosis?
- A cell that has damaged DNA
- a cell has reached the end of its lifespan
- if it is infected with a virus
- if there are two many of one kind of cell
- during embryonic development
What are the stages in the mitochondrial pathway of apoptosis?
- Cell has an issue like damaged DNA
- The mitochondria will by triggered to release the enzyme cytochrome c
- Caspases will be activated
- The cell will be broken down forming bleed which will be phagocytosed
What are the stages in the death receptor pathway of apoptosis?
- A specific signalling molecule will bind to a death receptor
- This will activate a caspase which will the. Activate other executioner caspases which will break down the cell
- The cell will bleb and be engulfed by phagocytes
What happens when cells undergo apoptosis?
- the cell shrinks
- blebs form
- nucleus is condensed and then fragments
How would you tell if a cell is undergoing apoptosis?
By the blebs that are formed
