TLS Online TPP Program

#Question id: 563


Both water and glucose share an —OH that can serve as a substrate for a reaction with the terminal phosphate of ATP catalyzed by hexokinase.  Glucose, however, is about a million times more reactive as a substrate than water.  The best explanation is that:

#Unit 1. Molecules and their Interaction Relevant to Biology
  1. glucose has more —OH groups per molecule than does water.

  2. the larger glucose binds better to the enzyme; it induces a conformational change in hexokinase that brings active-site amino acids into position for catalysis.

  3. the —OH group of water is attached to an inhibitory H atom, while the glucose —OH group is attached to C.

  4. water and the second substrate, ATP, compete for the active site resulting in a competitive inhibition of the enzyme.

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TLS Online TPP Program

#Question id: 1131

#Unit 4. Cell Communication and Cell Signaling

Which of the following function(s) as an inhibitor of TGFβ signal transduction?

a. R-Smad       b. I-Smad        c. Co-Smad     d. Ski   e. SnoN

TLS Online TPP Program

#Question id: 1132

#Unit 4. Cell Communication and Cell Signaling

Which of the following become(s) active as a kinase when an activation lip residue is phosphorylated?

a. EpoR                       b. JAK             c. STAT           d. Ras              e. MAPK

TLS Online TPP Program

#Question id: 1133

#Unit 4. Cell Communication and Cell Signaling

What tertiary structure characterizes all cytokines?

TLS Online TPP Program

#Question id: 1134

#Unit 4. Cell Communication and Cell Signaling

Arrange the following proteins in the proper order in which they become activated in the MAPK signaling pathway:

a. MAP kinase                         b. MEK           c. Ras              d. Raf              e. RTK            

TLS Online TPP Program

#Question id: 1135

#Unit 4. Cell Communication and Cell Signaling

Which of the following is a direct substrate of MAP kinase?

a. TCF             b. SRF             c. SRE             d. p90RSK      e. CREB

TLS Online TPP Program

#Question id: 1136

#Unit 4. Cell Communication and Cell Signaling

Which of the following signaling pathways can be activated by activation of receptor tyrosine kinases?

a. phospholipase Cγ                b. PI-3 kinase

c. MAP kinase                         d. none of the above