Wild type E. coli metabolizes the sugar lactose by expressing the enzyme ß-galactosidase. You have isolated a mutant that you call lac1–, which cannot synthesize ß-galactosidase and cannot grow on lactose (Lac–). During an condition you have a wild type (Lac+) strain carrying a Tn5 insertion known to be near several Lac genes on the E. coli chromosome. You grow P1 phage on this strain and use the resulting phage lysate to infect the lac1– strain, selecting for kanamycin resistance (Kanr). Among 100 Kanr transductants, you find that 82 are Lac– and 18 are Lac+. Express the distance between Tn5 and the lac1– mutation as a cotransduction frequency;

TLS Online TPP Program

#Question id: 24327

#Unit 4. Cell Communication and Cell Signaling

What is the major roles of Tight junctions in animal cells?

TLS Online TPP Program

#Question id: 24328

#Unit 4. Cell Communication and Cell Signaling

Tight junctions prevent the diffusion of: 

a. Macromolecules

b. Small water-soluble molecules

c. Ions 

d. Membrane proteins 

e. Glycolipids

Choose the correct set of combinations

TLS Online TPP Program

#Question id: 24329

#Unit 4. Cell Communication and Cell Signaling

_______permit the passage of molecules as large as 1.2 nm in diameter (molecules smaller than 1200 Da).

TLS Online TPP Program

#Question id: 24330

#Unit 4. Cell Communication and Cell Signaling

Ions, low-MW precursors of cellular macromolecules, products of intermediary metabolism, & small intracellular signaling molecules can pass from cell to cell through_______?

TLS Online TPP Program

#Question id: 24331

#Unit 4. Cell Communication and Cell Signaling

Select the CORRECT combination by matching the junctions with their principal CAMs or adhesion receptors.

Junctions	Principal CAMs or Adhesion receptors
1. Tight junctions	a. Integrins
2. Gap Junctions	b. Occludin
3. 3-D adhesions	c. Connexin
4. Plasmodesmata	d. Undefined

TLS Online TPP Program

#Question id: 24431

#Unit 1. Molecules and their Interaction Relevant to Biology

Which of the following option is correct regarding the ATP Synthase

1. ATP Synthase Has Two Functional Domains, Fo and F1

2. It Catalyzes the formation of ATP from ADP and Pi, driven by the flow of protons from the P to the N side of the membrane.

3. ATP synthase produces ATP as protons diffuse back through it from the lumen into the stroma.

4. The molecular structure of the mitochondrial ATP synthase has been determined by X-ray crystallography.