Chapter 13 Review Flashcards
Most signals occurs because of _________.
hormones
Insulin forces the glucose to be _______ by the body.
uptaken
What kind of protein receives hormones?
Transmembrane proteins
Transmembrane Proteins
- Signal is outside the cell
- Chemical process that occurs inside the cell
Target cells have ______ that receive the hormone signals.
receptors
Only the cells with the receptor of a ______ hormone will react with the __________.
specific ; hormones
Signal Transduction
is the conversion of an informational signal into a chemical process. Signaling molecules bind to a receptor protein.
Signal Transduction Process
1) a cell receives an external informational signal from the environment or another cell
2) These signals cause changes in the cell’s composition and function
3) Signal transduction may rely on secondary signals or relay molecules to produce a change. (The change may also occur in the cytoplasm, shown here, or affect gene expression in the nucleus)
Signal Transduction is highly specific due to __________ interactions.
receptor/signal
Receptors are ______ specific.
cell
Three factors that account for sensitivity of signal transduction:
1) High affinity
2) Cooperativity
3) Amplification
What is “high affinity”?
Kd is 10^-10 M or less. Signals are picked up at extremely low concentrations because they are super specific and super sensitive.
What is cooperativity?
- Large changes in receptor activation with small changes in [ligand]
- Binding one ligand increase affinity for a second ligand molecule in positive cooperativity.
What is Amplification?
- results when an enzyme associated with a signal receptor is activated.
- One signaling hits the receptor. The activated enzyme catalyzes the activation of many molecules of a second enzyme.
- Beginning of an enzyme cascade
The sensitivity of a receptor system is subject to modification called ____________.
desensitization
