BIO 205 Lecture Notes - Lecture 28: Adenylyl Cyclase, Glycogen Phosphorylase, Lipid Bilayer

42 views2 pages

coralwhale510

2 May 2018

School

University at Buffalo

Department

Biological Sciences

Course

BIO 205

Professor

Snyder Grayson

For unlimited access to Class Notes, a Class+ subscription is required.

Lecture 28 Hormone Regulation

cAMP-dependent phosphorylation cascade

1. H binds, G protein dissociates, adenylate cyclase

a. H represents hormone

b. R is the receptor

c. G-protein binds to GTP or GDP on the cytoplasmic side of the

membrane

d. When hormone arrives on the scene in the bloodstream, causes

conformational change, which causes conformational change in

the G-protein subunits, causes G alpha to release GDP into the

cytoplasm and bind GTP in place. With GTP bound, then

dissociates thru the lipid bilayer until it collides with the enzyme

adenylcyclase, which turns on the enzyme. The activated

enzyme then converts ATP into cAMP. Then two processes can

return the system to resting state. The enzyme deactivates when

G alpha dissociates away. The 2nd deactivating process is

dissociation of hormone away from the receptor.

2. Synthesis of cAMP from ATP

a. Reaction is catalyzed by adenylate cyclase, which converts ATP

into cAMP

b. Inorganic pyrophosphate is release and now see a single

phosphate group forming two ester bonds witht eh same sugar,

one at the 3’riose position and 5’ position, whih reaks down

PPi into two happy Pi’s

ATP -> PPi + bound AMP

Bound AMP -> cAMP

3. Glucagon and adrenalin

a. Stimulates breakdown of glycogen into glucose

4. Phosphorylation cascade

a. Enzyme 3, glycogen phosphorylase, a active form b inactive form

find more resources at oneclass.com

Unlock document

This preview shows half of the first page of the document.
Unlock all 2 pages and 3 million more documents.

Already have an account? Log in

Document Summary

With gtp bound, then dissociates thru the lipid bilayer until it collides with the enzyme adenylcyclase, which turns on the enzyme. The activated enzyme then converts atp into camp. Then two processes can return the system to resting state. Bound amp -> camp: glucagon and adrenalin, stimulates breakdown of glycogen into glucose, phosphorylation cascade, enzyme 3, glycogen phosphorylase, a active form b inactive form. Enzyme 1 activates enzyme 2 by removing phosphate group from atp and pasting it onto the biomolecule, enzyme 2. Enzyme 1 is a kinase: amplification, takes 4 bound camp to one camp dependent kinase. Adenylate cyclase is located in the plasma membrane, facing the inside of the cell. Dephosphorylation cascade is initiated by increases in insulin. Adrenalin binds to receptor, activates g protein, turns on camp. The enzyme catalyzing the opposite effects of the camp-dependent many protein kinase is the many phosphoprotein phosphatase.

Related Questions

QUESTION 1

Which of the following is an example of an extracellular signal molecule?

	a.	IP₃
	b.	cAMP
	c.	Insulin
	d.	Diacylglycerol

2 points

QUESTION 2

Nuclear hormone receptors _____

	a.	Bind to water soluble ligands
	b.	Activate second messengers
	c.	Regulate transcription in response to ligand binding
	d.	Are normally located on the plasma membrane

2 points

QUESTION 3

Which of the following does not occur when a receptor tyrosine kinase is bound by ligand?

	a.	Phosphorylation of the RTK
	b.	Cytoplasmic proteins bind the phosphorylated RTK
	c.	Dimerization of the RTK
	d.	The RTK binds to DNA to regulate transcription

2 points

QUESTION 4

Which of these is a logical signal-transduction pathway?

	a.	An intracellular receptor activates phospholipase C, which cleaves a membrane protein to form IP₃, which then activates the opening of an ER channel protein, which releases cyclic AMP into the cytoplasm, where it binds to an intracellular enzyme that carries out a response.
	b.	A G-protein-linked receptor activates G protein, which activates phospholipase C, which cleaves a membrane lipid to form IP₃, which binds to a calcium channel on the ER, which opens to release calcium ions into the cytoplasm, which bind to an intracellular enzyme that carries out a response.
	c.	An ion-channel receptor opens, allowing a steroid hormone to enter the cell; the steroid hormone then activates protein kinases that convert GTP to GDP, which binds to an intracellular enzyme that carries out a response.
	d.	A tyrosine-kinase receptor activates adenylyl cyclase, which activates phospholipase C, which converts ATP into cyclic AMP, which binds to an intracellular enzyme that carries out a response.

2 points

QUESTION 5

Which of the following is an example of signal amplification?

	a.	activation of an enzyme molecule
	b.	activation of a specific gene by a growth factor
	c.	Breakdown of many cAMP molecules
	d.	activation of 100 molecules by a single signal binding event

2 points

QUESTION 6

Consider a signal transduction pathway that utilizes cAMP as a second messenger to activate PKA (Protein Kinase A). Which of the following situations will result in the cellular response?

		The G protein releases GDP and binds to GTP
		The target protein (adenylyl cyclase) is inactive
		The regulatory subunits of PKA (Protein Kinase A) are bound to the catalytic subunits
		The appropriate G protein is bound to GDP

2 points

QUESTION 7

Which of the following is found in only some signal transduction pathways? [In other words, which is not found in all signal transduction pathways?]

		Receptor protein
		Extracellular signal molecule
		Intracellular signaling molecule
		Cellular response
		Effector protein

2 points

QUESTION 8

The enzyme that specifically catalyzes the conversion of ATP to cAMP is:

		Adenylyl phosphatase
		Adenylyl kinase
		Adenylyl dehydrogenase
		Adenylyl cyclase

2 points

QUESTION 9

If an animal cell suddenly lost the ability to produce GTP, what might happen to its signaling system?

		It would use ATP instead of GTP to activate and inactivate the G protein on the cytoplasmic side of the plasma membrane.
		It would not be able to activate and inactivate the G protein on the cytoplasmic side of the plasma membrane.
		It would employ a transduction pathway directly from an external messenger.
		It would be able to carry out reception and transduction but would not be able to respond to a signal.

2 points

QUESTION 10

A hormone signal is sent from the brain to other parts of the body via the bloodstream. Why do only certain cells respond to this signal?

		Hormones do not last long enough in the bloodstream to stimulate a cellular response
		Only cells that have a specific transcription factor gene will be able to respond to the signal
		Only cells in the immediate vicinity of the cell sending the signal will respond
		Only cells that have a receptor for the specific signal will be able to respond to it

cerisehedgehog846

BIO 205 Lecture Notes - Lecture 28: Adenylyl Cyclase, Glycogen Phosphorylase, Lipid Bilayer

Document Summary

Get access

Related textbook solutions

Molecular Cell Biology

Biology: Science for Life with Physiology

Biology

Concepts of Biology

Essentials of Biology

Related Documents

BIO310H5 Lecture Notes - Lecture 8: Glycogen Phosphorylase, Cytosol, Blood Sugar

BIOLOGY 2B03 Lecture Notes - Lecture 15: Pyruvic Acid, Glycogen Phosphorylase, Gtpase

CH 461 Lecture Notes - Lecture 29: Adenylyl Cyclase, Cyclic Adenosine Monophosphate, Glycogen Phosphorylase

Related Questions