fit14 Quiz Subnissims - Quiz 6: signallirg - BIOLOGY 2803: CELL BIOLOGY FALL 2013 - McMaster Unircrsity

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Quiz Submissions - Quiz 6: signalling y

ALEXANDRA MACDONALD (username: macdonat)

Attempt IWritten: Nov 3,2013 11:00 PM - Nov 3,2013 11:18 PM

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Questionl l/lpointIn the Jak-STAT signalling pathway what is the function of STAT?

It causes dimerization of the receptor.

It phosphorylates JAK.

It is the ligand for the EpoR,

Question2 l/lpointSignaling between cells usually results in the activation of protein

nucleases

lipases

kinases

proteases

Question3 l/lpointWhich of the following is NOT a Wpical event associated with cell signaling?

Activation of protein kinases

Activation of G-proteins by exchanging GDP for GTP

Production of the second messengers cAMP and IP3

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1nn4 Quiz Subrissions - Quiz 6: signalling - BIOLOGY 2803: CELL BIOLOGY FALL 2013 - McMaster Unirasity

Release of calcium ions from cell membranes

Stimulation of apoptosis

Question4 l/lpointReceptor tyrosine kinases are so called because...

They autophosphorylate on threonine in response to ligand binding.

They contain SH2 domains that bind to phosphorylated tyrosines.

They are phosphorylated by G-proteins in response to ligand binding.

Question 5 1 / 1 point

A cell secretes growth factors that have a slow diffusion rate, and interacting only with other cells in theimmediate area is an example of signaling.

exocrrne

synaptic

cell contact

Question6 l/tpointSending a signal through the cell membrane can lead to the production of second messengers inside the cell.Which of the following can serve as second messengers?

cAMF

Ca++

IP3

NO (nitric oxide)

all of the above

QuestionT l/lpoint

Which of the following statements about G protein coupled receptors is true.

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fi114 Quiz Suhrissims - Quiz 6: sig nalling - BIOLOGY 2803: CELL BIOLOGY FALL 2013 - McMaster Unirersity

GPCRs have intrinsic kinase activity and autophosphorylate in response to ligand binding,

GPCRs are found only in animal cells, they have not been found in plant cells.

GPCRs include the receptors in the eye that respond to light signals.

GPCRs act through the second messenger GTP.

QuestionS l/lpointSome receptors for growth factors activate a protein kinase cascade, with the participation of multiple enzymesto effecta change in gene expression. Which of the following statements abouta protein kinase cascade aretrue?

Multiple steps allow the amplification of the signal.

External signals can lead to changes in gene expression.

Multiple steps leading to kinase activations can result in cells having different responses, dependingon the presence or absence of target proteins.

Multiple steps in an activation mean that abnormal stimulation of a cell response such as growth canoccur with mutations in more than one gene.

All of the above are true.

Question9 l/lpointThe endogenous GTPase activity of G-proteins serves to:

synthesize GTP as an energy source.

synthesize cGMP as a second messenger.

stimulate the activity of enzymes by producing energy.

hydrolyze GTP returning the G protein to a pre-stimulated level of activity.

Questionl0 O/lpointIn a fight-or-flight response, epinephrine released by the adrenal glands binds to a membrane receptor onmuscle cells. Which of the following events result from ligand binding?

;r{ G-protein is activated by binding GTP and causing adenylyl cyclase to produce cAMP.

The second messenger, cAMP, activates protein kinase A which inhibits glycogen synthetase blockingglycogen synthesis.

Protein kinase A activates phosphorylase kinase, which transfers a phosphate that activates glycogen

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1ilt14 Quiz Silrrissiors - Quiz 6: sigrdlirg - BIOLOGY 2Bffl: CEIL BIOLOGY FALL 2013 - Mc[r6ter Uni\Ersity

phosphorylase. This leads to the breakdown of glycogen and the production of glucose-l-phosphate.

Glucose produced from glucose-l-P stimulates glycolysis, produclng energy for muscle contraction.

All of the above.+ t_i

AttemptScore:91L0Overall Grade (highest attempt)t 9 I 70

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