#Question id: 31025
#Unit 4. Cell Communication and Cell Signaling
#Question id: 4459
#Unit 3. Fundamental Processes
Give correct explanation, why RNA polymerase can initiate a new RNA chain on a DNA template without any primer?
A. Because RNA polymerase starts most transcripts with an A, and that ribonucleotide binds the template nucleotide (T) with only two hydrogen bonds.
B. The enzyme has to make specific interactions with one or all of the DNA template strand, the initiating ribonucleotide, and the second ribonucleotide—holding one (or all) rigidly in the correct orientation to allow chemical attack on the incoming NTP.
C. The structure of the open complex shows that the s region 3/4 linker interacts with the template strand, organizing it in the correct conformation and location to allow initiation.
D. Consistent with this, in experiments using an RNA polymerase containing a s70 derivative lacking this part of s, initiation requires much lower than normal concentrations of one or both of the first two ribonucleotides.
#Question id: 32338
#Unit 2. Cellular Organization
#Question id: 28799
#Unit 2. Cellular Organization
Arp2/3 needs to be activated by interacting with a nucleation promoting factor (NPF). Although there are many different NPFs, The major NPF family is characterized by the presence of a region called___
#Question id: 2580
#Unit 2. Cellular Organization
Following statements are regarding to mechanism of kinesin-1 movement.
A. Initially leading head tightly bound to the microtubule and not bound by any nucleotide, while the trailing head is weakly bound to the microtubule and has ADP bound.
B. Binding of ATP induces a conformational change causing the linker to swing forward and dock into the head. This motion swings the former trailing head to become the leading head.
C. Binding of ATP induces a conformational change causing the linker to swing forward and dock into the head. This motion swings the former leading head to become the trailing head.
D. When leading head releases ADP and coordinately the trailing head hydrolyzes ATP to ADP + Pi. Pi is released and the linker becomes undocked.
E. When trailing head releases ADP and coordinately the leading head hydrolyzes ATP to ADP + Pi. Pi is released and the linker becomes undocked.
Which of the following combination is correct?