BIOL 300 Lecture Notes - Lecture 31: Protein Kinase, Membrane Protein, Threonine

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beigewhale811

28 Sep 2020

School

American River College

Department

Biology

Course

BIOL 300

Professor

Ramones

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Document Summary

G proteins are key molecular switched in second-messenger pathways: Signal molecule binds to the receptor (first messenger) the signal activates the cytoplasmic end of the receptor causing the g protein to become active by inducing to bind with gtp. When g protein has gdp bound to it, its inactive and when it has gtp bound to it, its active and the association with gtp and gdp is why it"s called g protein. The activated g protein activates a plasma membrane-associated enzyme called the effector. The effector produces a non-protein internal signal molecule called the second messenger. The second messenger directly or indirectly activate protein kinases that phosphorylate target produce which then cause a cellular response. The protein kinases all add phosphate to the serine or threonine amino acid in the target proteins which are usually: Regulatory proteins that control gene activity and cell division. There"s a variety of g proteins that cause different cellular responses.

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

33 Different glycoproteins can have a diverse array of oligosaccharides. Which of the statements below for making glycoproteins on plasma membrane is true?

(a) Extensive modification of oligosaccharides occurs in the extracellular space.

(b) Initial oligosaccharide chains are made by addition of one sugar at a time onto the protein in the ER lumen.

(c) Each layer of Golgi membrane structures contains identical modification enzymes for modifying sugar chain on proteins.

(d) ER lipids can be modified by sugar chain, which can be used for sugar chain modification of the proteins.

34 In a multicellular organism, when a signal needs to be sent to most cells the signal most suited for this is a ___________.

(a) neurotransmitter.

(b) hormone.

(d) plasma membrane anchored ligands.

35 Typically, members of the steroid hormone receptor family __________________.

(a) are cell-surface receptors.

(b) do not undergo conformational changes by binding to their ligands.

(d) interact with signal molecules that diffuse through the plasma membrane

36 Which of the following statements about what happens when a G-protein-coupled receptor activates a hetero trimeric G protein is true?

(a) The Î² subunit exchanges its bound GDP for GTP.

(b) The GDP bound to the Î± subunit is phosphorylated to form bound GTP.

(d) It activates the Î± subunit and inactivates the Î²Î³ complex

37 Which of the following statements about signal transduction is false

(a) Ca2+ concentration in cytosol will increase when PLC (Phospholipase C) is activated by signal.

(b) Cyclic GMP is made in smooth muscle cells when they received NO signal.

(d) Ligand binding to RTK activates its enzyme activity then the activated RTK phosphorylates tyrosine residues on itself.

greywoodchuck816

Need help with biology questions:

1. To increase the excretion of an acidic drug, what would you do to the urine?

	A.	Make it more basic
	B.	None of the above
	C.	Make it neutral
	D.	Make it more acidic

2. G-Protein coupled receptors directly act on which of the following secondary messenger molecules:

	A.	cAMP
	B.	ATP
	C.	ADP
	D.	GTP
	E.	None of the above or more than one of the above

3. Drug A and Drug B both produce the same level of biological/physiological response. Drug A produces this effect with 100 mg/kg dose. Drug B produces this effect with 50 mg/kg dose. Which of the following is true?:

	A.	Drug B is more efficacious than Drug A. Both drugs are equally potent.
	B.	Drug A is more efficacious than Drug B. Both drugs are equally potent.
	C.	Drug A and B are equally efficacious. Drug A is more potent than Drug B.
	D.	Drug A and B are equally efficacious. Drug B is more potent than Drug A.

4. The stomach has a ______ pH, whereas the small intestines have a _______ pH. The colon has an approximately ___________ pH.

	A.	High; low; neutral
	B.	Low; high; neutral
	C.	Low; neutral; neutral
	D.	None of the above

5. Which receptor is most likely to reduce norepinephrine levels when activated?

	A.	alpha 2 adrenergic
	B.	alpha 1 adrenergic
	C.	dopamine D1 receptors

6. Which of the following statements are FALSE?

	A.	If the Vd of a drug is between 60 and 80 L the drug has likely distributed to the total body water of a 200 kg man.
	B.	In the enterohepatic system the activity of bacteria to remove conjugates from a drug in the gut will decrease the clearance of the drug.
	C.	Lipid drugs are more likely to be reabsorbed by the kidney from the urine.
	D.	A weak basic drug (pKa = 6) will be mostly ionized in urine of a pH= 3 and only the non- ionized drug will be eliminated.
	E.	The major conjugate in Phase 2 metabolism is glucuronide.

7. Isoproterenol (Î²-agonist) is a vasodilator that increases HR. What happens to systolic and diastolic pressures upon IV administration of isoproterenol?

	A.	â systolic; â diastolic
	B.	â systolic; â diastolic
	C.	â systolic; â diastolic
	D.	â systolic; â diastolic
	E.	None of the above

8. If you want to increase the blood concentration of a drug A, you can perform which of the following procedures:

	A.	Inhibit Drug A metabolism with Drug B
	B.	Enhance Drug A reabsorption from renal proximal tubule by changing ionization of Drug A with Drug B
	C.	Allow competition of Drug B with Drug A for active renal secretion processes
	D.	Increase the binding of Drug A to serum albumin
	E.	All of the above

9. Which of the following describes Phase I metabolism?

	A.	Inactive products are always produced in this phase.
	B.	Large molecules such as glucuronic acid are conjugated to drugs in this phase.
	C.	This phase may produce active metabolites from prodrugs.
	D.	This phase only occurs in the liver.

10. Which of the following is NOT an enzyme involved in the biosynthesis of biogenic amines?

	A.	Phenylethanolamine N-methyl Transferase
	B.	Dopamine Î²-hydroxylase
	C.	Tyrosine dehydroxylase
	D.	DOPA decarboxylase
	E.	All of the above

11. Why would an antibiotic at the same concentration be more active against bacteria in water than in serum or plasma? (Activity is measured in a test tube)

	A.	activity of the antibiotic is increased in water.
	B.	due to drug-protein interaction in serum
	C.	the antibiotic is more stable in water
	D.	all of the above
	E.	none of the above

12. Ion channels are targets for drugs. Which drug class targets Na+ channels?

	A.	Benzodiazepines
	B.	Beta blockers
	C.	Local anesthetics
	D.	Antihypertensive drugs (cardiac and smooth muscle)
	E.	Glibenclimide (diabetic drug)

13. _________________ not metabolized by catechol-O-methyltransferase (COMT).

	A.	Dopamine
	B.	Epinephrine
	C.	Phenylephrine
	D.	Norepinephrine
	E.	All of the above are metabolized by COMT.

BIOL 300 Lecture Notes - Lecture 31: Protein Kinase, Membrane Protein, Threonine

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