NBME Form 4 ?

Prep for USMLE Forum

» Log in | Register

Forum

Step 1

Match

Prep4USMLE Forum » USMLE Step 1 Forum » Biochemistry Forum

NBME Form 4 ?

Author

16 Posts

pearljam59
Forum Guru
avatar

Topics: 120
Posts: 273

03/28/06 - 07:52 AM

7. Some oncogenes are mutants of normal cell-surface receptors that have tyrosine protein kinase motifs in their cytoplasmic domairs. The type of mutation of such a receptor that is most likely to result in cell transformation is a mutant protein with which of the following characteristics?

A) Constitutive activation of cellular transcription
B) Deletion of the cytoplasmic domain
C) Failure to become phosphorylated upon receiving the signal
D) Failure to receive the signal that normally activates cellular transcription
E) Recognition of a different signal than usual

robin082006
Forum Hero
avatar

Topics: 471
Posts: 5,125

03/28/06 - 09:35 AM

??????? Where can we get the answer?

I guess B

___________________
The Key to Succeed is Patience.

huzefa
Forum Junior

Topics: 2
Posts: 66

03/28/06 - 10:39 AM

A. Constitutive activation of cellular transcription. My reasoning is that an oncogene with intrinsic tyrosine kinase activity (as described in the question stem) will lead to constitutive activation of cellular transcription. I was also thinking E could be the answer, but mutating the receptor so that it recognizes some different signal doesn't necessarily cause production of an oncogene. However, making the receptor activate itself automatically does.

What do u think?

Jinx
Forum Elite
avatar

Topics: 17
Posts: 316

04/01/06 - 09:45 PM

agree with huzefa

also think a or e--prob a raised eyebrow

___________________
Life is a journey--enjoy the drive!!

amer_almohssen
Forum Junior

Topics: 13
Posts: 38

05/23/06 - 08:17 AM

why not :

C) Failure to become phosphorylated upon receiving the signal
?!?!?!?!

___________________
email me @: thesolobluesplayer@hotmail.com

guest007
Forum Senior

Topics: 11
Posts: 106

05/30/06 - 03:02 PM

answer is c......my reasoning is tyrosine kinase only effects phosphorylarion or dephosphorylation......so i will go with C.good job ameen.

guest007
Forum Senior

Topics: 11
Posts: 106

05/30/06 - 03:03 PM

sorry...good job amer...

study_ing
Forum Fanatic
avatar

Topics: 180
Posts: 2,511

06/04/06 - 02:01 AM

doesnt phosphorylation usually mean activation of tyrosine kinases....hence failure of phosphorylation is less likely to ccause activation in tyrosine kinase...i'd go for a

___________________
If you yourself are at peace, then there is at least some peace in the world.

xwxf
Forum Senior
avatar

Topics: 16
Posts: 71

06/05/06 - 04:29 AM

A.

Tyrosine kinase usually faciliated cell cycle and cell survival. Loss of funciton won't influence cell cycle.

ndspider
Forum Senior
avatar

Topics: 5
Posts: 69

06/05/06 - 09:48 AM

#10

Its A

docsrinu
Forum Elite

Topics: 26
Posts: 213

09/26/06 - 11:34 PM

#11

i think A is the ans..

drbin
Forum Guru
avatar

Topics: 27
Posts: 535

09/27/06 - 01:19 AM

#12

what is the answer pearljam? i would go for c

___________________
action speaks better than words

klimt
Forum Guru

Topics: 27
Posts: 605

10/01/06 - 10:02 AM

#13

hard q. I'm even more confused...is it C?

___________________
Traveler, there are no roads. Roads are made by walking.

selsibeel
Forum Newbie

Topics: 1
Posts: 10

10/02/06 - 06:43 PM

#14

I would go with A. Doesnt an oncogene when it get activated and out of control cause cancer?

proctalgia
Forum Senior
avatar

Topics: 2
Posts: 209

10/14/06 - 07:01 PM

#15

Confused. I thought C was correct.

But pls explain the meaning of Constitutive activation of cellular transcription.

Thank U

dr_sangv
Forum Newbie

Topics: 0
Posts: 4

10/14/06 - 11:32 PM

#16

I also think C is correct ans.
Anyway who ever knows the correct ans pl let us know asap.
thanx smiling face

You don't have permission to post.