Cellular Communication Flashcards
What are the two types of perception in cellular communication?
1) Perception of the environment
2) Perception of signals from other cells
Describe Perception of the environment
cells receive signals from the environment which cause a response appropriate to the environment
Examples of signals from the environment?
- single celled organisms – eg. Light, nutrients
- multicellular organisms – via specific sense organs
Describe Perception of signals from other cells
cells perceive signals from other cells – intercellular communication
Examples of signals from other cells?
- single celled organisms – reproduction
- multicellular organisms - development/homeostasis/cellular interaction
To accomplish mating yeast cells secrete …
…‘mating factors’
Yeast come in two…
… ‘sexes’, ‘a’ and ‘α’.
the two types of yeast cell (a and alpha) cause …
…protrusions which grow towards each other (a shmoo) and fuse.
Define a shmoo
protrusions which grow towards each other
How are the mating factors perceived and how do they make the yeast cells form the shmoo?
The a type secrete a protein called ‘a factor’ which attracts α cells.
Cells depend on …
…signals to survive
In complex organisms cells receive…
…multiple signals and in many cases these are required for continuing cell survival.
Signals ensure cells respond by:
1) Surviving
2) Growing/dividing
3) Differentiating
4) Dying (lack of signals)
5) Movement
In multicellular organisms signals act over a…
…range of distances.
Paracrine in this case may also include …
…‘autocrine’ where the cell signals to itself.
- e.g. T lymphocytes
If the cell does not recognise the other cell…
… it will kill it.
Where organisms are particularly complex they may …
…employ endocrine signals from special organs
Endocrine signals are…
…perceived by target cells
- e.g. insulin, adrenaline
Signals are perceived in two ways:
1) Signalling molecule binds at the cell surface
2) Signalling molecule binds an internal receptor
Signalling molecule binds at the cell surface and the signal is then …
…transmitted into the cell where the cell responds to the signal
Signalling molecule binds an internal receptor and transported to the …
… nucleus where it has its effect directly on gene expression
Nuclear receptors are found in …
…both the cytoplasm and the nucleus
Where receptors are in the cytoplasm …
…binding of ligand exposes Nuclear Localisation Sequence.
Exposure of Nuclear Localisation Sequence causes the receptor/ligand complex to …
…migrate to the nucleus where it acts directly on gene regulation.