You are studying a new strain of E. coli that can utilize the disaccharide melibiose very efficiently. You find that utilization depends on the enzyme melibiase, which is encoded by the gene Mel1. Mel1 is not expressed unless melibiose is present in the growth medium. You have isolated a mutation that causes constitutive melibiase activity, which you designate MelA–. P1 phage mapping experiments using a Tn5 insertion linked to Mel1 show that MelA– is not linked to Mel1. Moreover you find that when an amber suppressor is introduced into a MelA– mutant, normal melibiase regulation is restored. Classify the MelA– mutation on the basis of genetic properties,  make a proposal for the type of regulatory functions affected by the MelA– mutation?

TLS Online TPP Program

#Question id: 24271

#Unit 4. Cell Communication and Cell Signaling

Integrins are involved in following processes, except:

a. Extravasation

b. Cell-to-cell adhesion

c. Cell migration

d. Receptors for certain viruses

e. Angiogenesis

f. Apoptosis

g. Necroptosis

TLS Online TPP Program

#Question id: 24272

#Unit 4. Cell Communication and Cell Signaling

.__________ are integrin-containing anchoring junctions that attach cells to elements of the underlying extracellular matrix.

TLS Online TPP Program

#Question id: 24273

#Unit 4. Cell Communication and Cell Signaling

Which of the following physiological function perform by integrins?

TLS Online TPP Program

#Question id: 24274

#Unit 2. Cellular Organization

Nucleosome DNA wraps around the histone protein 1.65 times, so create a writhe of –1.65 and so DLk should be -1.65. But when the change in linking number associated with each nucleosome was measured, the number was lower than this, approximately –1.2 for each nucleosome added. This discrepancy is referred to as the 

TLS Online TPP Program

#Question id: 24281

#Unit 4. Cell Communication and Cell Signaling

Which of the following statement describes inside-out signaling?

TLS Online TPP Program

#Question id: 24282

#Unit 4. Cell Communication and Cell Signaling

Which of the following statement describes outside-in signaling?