BIO 311C Lecture Notes - Lecture 16: Tyrosine, Alpha Helix, G Protein–Coupled Receptor

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harlequinox937

3 Oct 2016

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Ex: hormones in animals" endocrine system the hormone gets into the blood stream and moves everywhere in the body. The only cells that respond to the hormone are those that have the right receptor. Ex: fruit that is ripening will promote ripening of the fruit around it by sending out signals. Steps of signaling: reception- a signaling molecule binds to a receptor on the membrane of the cell. Interact with g proteins that bind to gtp (in active state) or gdp (in inactive state) A signaling molecule binds to the g protein coupled receptor which causes the g protein (inactive) to bind to the g protein coupled receptor and release the. This gtp allows the g protein to activate and leave the receptor, moving to an enzyme which it activates. Then, the gtp breaks down into gdp and a phosphate group and the g protein unbinds from the enzyme and goes back to its inactive state: receptor tyrosine kinases:

Related Questions

Which of the following statements is FALSE? (choose one)

A.	Voltage-gated sodium (Na+) channels open in the dendrites and cell body during a local, graded potential.

B.	During repolarization, potassium ions are leaving the cell (K+ is diffusing out of the cell), and the inside of the cell becomes more negative

C.	If someone damaged an efferent motor neuron, they could feel pain, but not respond to move away from the pain

D.	Myelin serves as electrical insulation and increases the speed at which an action potential travels along the axon

E.	Movement of ions can be excitatory (if sodium ligand-gated channels bind the neurotransmitter), or inhibitory (if potassium ligand-gated channels bind the neurotransmitter)

1.A stronger stimulus to a neuron results in ________.

A. larger voltage changes in graded potentials and greater frequency of action potentials produced in response

B. greater frequency of graded potentials and larger voltage changes in the action potentials produced in response

C. larger voltage changes in the graded potentials, but no changes in action potentials

D. larger voltage changes in both graded and action potentials

E. larger voltage changes in graded potentials but smaller action potentials

2. Why is it more difficult to fire an action potential when the interval between stimuli decreases?

A. because sodium is flowing out of the cell

B. because potassium is flowing into the cell

C. because some sodium channels may still be in an inactivated state

D. because chloride is flowing into the cell

E. because chloride is flowing out of the cell

3. As an action potential zips down an axon,

A. voltage gated potassium channels open first followed by voltage-dependent sodium channels

B. voltage- gated sodium channels ahead of the wave and not yet activated are influenced by the depolarizing electrical field of other nearby sodium channels

C. voltage-gated potassium channels ahead of the wave and not yet activated are influenced by the depolarizing electrical field of nearby sodium channels

D. leak channels are opened by the wave of electricity passing along the axon

E. B and C

What would be most strongly affected by a drug that inhibited the opening of voltage-gated potassium channels (also known as delayed rectifiers)?

A. Falling phase of an action potential

B. Rising phase of an action potential

C. Resting membrane potential

D. Threshold for an action potential

Why does the voltage during the undershoot phase of the action potential become more negative than the resting membrane potential?

A. During the undershoot potassium ions are flowing into the cell due to the reversal of the potassium concentration gradient occurring during the action potential

B. The undershoot phase results from a delay in the activation of sodium channels, resulting in some sodium channels being open after the voltage-gated potassium channels have closed. C. The potassium conductance is higher during the undershoot than during the resting membrane potential.

D. The concentration gradient for potassium has been reversed as a result of the action potential, and the undershoot phase lasts until this the concentration gradient is restored.

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BIO 311C Lecture Notes - Lecture 16: Tyrosine, Alpha Helix, G Protein–Coupled Receptor

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