Question | Answer |
What is a signal-transduction pathway? | a series of steps by which a signal on a cell's surface is converted into a specific cellular response |
what other types of signaling? | - local regulators are messenger molecules that travel only short distances
- In long-distance signaling, plants and animals use chemicals called hormones |
What are the 3 processes that cells receiving signals go through? | - Reception
- Transduction
- Response |
what is reception? | a signal molecule binds to a receptor protein, causing it to change shape |
What are intracellular receptors? | found in cytosol or nucleus of target cells |
what are the 3 main types of membrane receptors? | - G protein linked receptors
- Receptor tyrosine Kinases
- Ion channel receptors |
What are G protein linked receptors? | - plasma membrane receptor that works with help of a G protein
- G protein acts as an on/off switch, if GDP is bound to the G protein then it is inactive |
What are tyrosine Kinase? | - membrane receptors that attach phosphates to tyrosines
- can trigger multiple signal transduction pathways at once |
What are Ion channel receptor? | - acts as a gate when the receptor changes shape
- when a signal molecule binds as a ligand to the receptor the gate allows specific ions, such as Na + or Ca+ to go through |
What are the molecules that relay a signal from receptor to response? | Proteins |
In many pathways the signal is transmitted by a cascade of protein called? | phosphorylations |
what do phosphate enzymes do? | they reverse the phosphorylation and remove the phosphate |
what are second messengers? | small, non protein, water soluble molecules or ions |