BIO 1140 Lecture Notes - Lecture 12: Lipid-Anchored Protein, Gtpase, Reuptake

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ivoryhippopotamus335

5 Mar 2018

School

University of Ottawa

Department

Biology

Course

BIO 1140

Professor

Caroline Petit- Turcotte

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Document Summary

Thu, february 25 - lecture 12 signal transduction part 2. Slide 3 cells don"t send transcription factors, but some messengers can act as transcription messengers (i. e: thyroid hormones, steroids) Intracellular receptors can be in the cytosol or in the nucleus. Depending on how far the target cell is, it can use different paths (last lecture). Once it binds to the receptor, it forms a complex (which acts as the transcription actor). Response elements - patterns in the genes that it recognizes. As long as its bound to its target, mrna can be released etc. Cortisol is distributed by the endocrine pathway, is going to reach cells that have cortisol receptors. The receptor is inactive, waiting for its messenger to arrive and bind to a specific binding area (lock & key), lets go of chaperone protein, cell is now active (transcription factor). Goes to nucleus, find ones that have sequences/genes that recognize transcription factor for cortisol.

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

1. In order for a hormone to cause a response, it must first bindto an appropriate receptor on its target cell. (Points: 1)
True
False

2. Disorders associated with the endocrine system can be caused byproblems with hormone production or lack of receptors for thehormones on the target cells. (Points: 1)
True
False

3. The levels of potassium and sodium in the body are regulatedprimarily by the hormone aldosterone. (Points: 1)
True
False

4. Nitric oxide is produced by cells lining the blood vessels; thischemical messenger regulates the contraction of smooth muscle inthe digestive tract as well as local blood flow in various tissuesof the body. (Points: 1)
True
False

5. Uptake of blood glucose by liver cells is stimulated by (Points:1)
ADH
prolactin
parathyroid hormone
glucagon
insulin

6. Which of the following is true regarding estrogen andprogesterone? (Points: 1)
They are secreted by the ovaries.
They are released during a female's reproductive years.
They regulate the menstrual cycle.
They stimulate the development of female secondary sexcharacteristics.
all of the above

7. Which of the following is not a symptom of diabetes mellitus?(Points: 1)
blurred vision
high sodium concentration in the blood and urine
excessive thirst
tingling in the feet or hands
fatigue

8. Which of the following is required in the diet in order foractive thyroid hormones to be produced? (Points: 1)
calcium
phosphorus
iodine
zinc
iron

9. Which of the following nonhormonal chemical messengers isimportant in local control of blood flow and blood clotting?(Points: 1)
prostaglandins
nerve growth factor
tumor angiogenesis growth factor
histamine
epidermal growth factor

10. If diabetes is left untreated, which of the following coulddevelop as a result? (Points: 1)
neural disorders
kidney failure
blindness
cardiovascular disorders
all of the above

11. The process by which the blastocyst becomes buried within theendometrial lining of the uterus is: (Points: 1)
fertilization.
implantation.
morphogenesis.
differentiation
embryonic development.

12. The placenta forms from embryonic tissue and (Points: 1)
bone marrow
amniotic fluid
embryonic disk
endometrium
yolk sac

13. Which of the following organs is not fully developed in a fetusand is therefore bypassed by the ductus aerteriosus? (Points:1)
liver
pancreas
heart
lungs
bladder

14. During puberty, the secretion of GnRH causes the secretion of________, which in turn stimulate(s) the production of sexhormones. (Points: 1)
LH and FSH
oxytocin and prolactin
insulin
growth hormone
oxytocin and growth hormone

15. Research on the aging process shows that wounds of the elderlyheal more slowly and that they are more susceptible to disease.These are problems associated with an aging ________ system.(Points: 1)
respiratory
immune
integumentary
digestive
endocrine

________________________________________

cyanwoodchuck896

1. A mutation in the gene encoding the integrase enzyme rendersthe protein non-functional. How would the affect the HIV infectioncycle?

Formation of the provirus would bestopped.

Reverse transcription would nolonger be possible.

The gp120 glycoprotein would nolonger be able to bind to the CCR5 receptor.

Cutting and assembling the capsid would be halted.

2. If the viral gene is AUGCCCAGG and the mRNA used to make theviral protein is UACGGGUCC, then the virus is a :

Negative strand RNA virus

Double stranded DNA virus

Retrovirus

Positive strand RNA virus

3. Would treating prions with enzymes that digest nucleotides bean effective neutralization method?

No, prions lack amino acids.

Yes, prion nucleic acids would besusceptible to enzymatic digestion.

No, prions lack phosphodiesterbonds and would not be subject to digestion by these types ofenzymes.

Yes, the bonds between the amino acids would be hydrolyzed.

4. Most Americans born before 1970 have a permanent scar ontheir shoulders from the smallpox vaccine. Why don't youngerAmericans have one?

Smallpox has been eradicated by aworldwide vaccination program.

Smallpox is no longer lethal.

A safer less damaging vaccine wasdeveloped in the early 1970's.

The vaccine is no longer effective due to antigenic shift.

5. What kind of pathogen would retain its ability to causeinfections after being treated with powerful proteolytic chemicalsthat would destroy all proteinaceous material?

A viroid

6. Select all of the false statements concerning AIDS.

AIDS kills the patient.

Patients die as a result ofopportunistic infections.

AIDS shuts down the immunesystem.

HIV therapy (HAART) can clear thevirus from the bloodstream.

HIV therapy (HAART) can clear the virus from the patient'sbody.

7. Why do viruses only infect specific types of cells?

Viruses only attack epithelialcells, such as the cells lining the lungs.

If a host cell is weakened, viruseshave an easier time infecting it.

The initial choice is random butonce a cell type is chosen it becomes the preferred host.

The host cells have the correctsurface receptor that the virus can fit into.

Viruses infect the first cells they encounter.

8. Nucleotide analogs are a class of drugs that are highlyeffective against many types of viruses. They work by halting thereplication of viral genes. They are equally effective at stoppingthe spread of prion diseases.

True

False

9. An experimental chemical has been shown to selectively cleavephosphodiester bonds. How would the affect a virus?

Dissociate the envelope

Fragment the genome

Hydrolyze the protein coating

Alter the host binding site

Digest the capsid

10. HIV uses cell surface receptors to enter host cells. Whydoes switching from a CCR5 co-receptor to a CXCR4 co-receptoreventually shut down the immune system?

	Macrophages have CCR5co-receptors.
	T-helper cells have CXCR4co-receptors.
	T-helper cells are not involved incoordinating immune responses.
	Only macrophages are killed byHIV.

crimsonsalmon160

BIO 1140 Lecture Notes - Lecture 12: Lipid-Anchored Protein, Gtpase, Reuptake

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