You would like to stain Cadherins and Integrins in the same

You would like to stain Cadherins and Integrins in the same cell for immunofluorescence analysis. Which of the following antibody combinations would allow you to do this staining? Combo #1: mouse-anti-rabbit, goat-anti-mouse-GREEN Combo #2: mouse anti-integrin, goat-anti-mouse-RED Combo #1: mouse-anti-Cadherin, goat-anti-mouse-RED Combo #2: rabbit-anti-Integrin, goat-anti-mouse-GREEN Combo #1: mouse-anti-Cadherin, goat: anti-mouse-RED Combo #2: goat anti-Integrin, goat anti-mouse-RED Combo #1: mouse-anti-Cadherin, goat-anti-mouse RED Combo #2; rabbit-anti-Integrin, goat anti-rabbit-GREEN Combo #1: rabbit anti-Cadherin, goat anti-rabbit GREEN Combo #2: rabbit anti-Integrin, goat anti-rabbit RED You are expressing GFP-tagged keratin in tissue culture cells in order to perform FRAP analysis on keratin bundles. Which of the following graphs (1.-4.) best describes the behavior of keratin after photobleaching, which occurs at the 0s time point? Images of a time lapse analysis are shown in the figure on the left (time is shown in seconds) 1 2 3 4 The yeast Saccharomyces cerevisae is haploid and can be grouped into two different mating types: a-cells and alpha-cells. Secretion of the mating pheromone a-factor (by an a-cell) and apha-factor (by an alpha-cell) leads to mating, during which a diploid cell is formed (see image). You have isolated an a-cell yeast mutant which grows at normal rate, but is unable to mate with an apha-cell because the mating pheromone a-factor is not secreted. Which of the following proteins is most likely mutated to produce such a phenotype? Signal Recognition Particle (SRP) A subunit of the ribosome signal peptidase Sec61, a critical component of the translocation channel a-factor itself

Solution

Answer 1. to stain the cells for cadherin and integrin simultaneously, you need to stain it with two flourescent markers seperate from each other and raised in different organisms. As per the options given above, option no (d) is correct.

Combo 1# mouse-anti-Cadherin; goat-anti-mouse:RED

Combo 2# rabbit -anti-integrin; goat-anti-rabbit:GREEN

all other options are wrong as either the secondary antibody is not against the organism in which the primary antibody is raised, or the primary antibody is the same for both cadherins and integrin and this would crreate cross reactivity and hence is not recommended.

2) correct curve showing the FRAP analysis is option 3

In FRAP analysis the area is photobleached and hence the flourescence decreases from Ft to F0 and slowly the flourscence is regained through diffusion and this pattern follows a parabolic curve not a straight line curve hence the answer cannot be option 4

correct answer is Option 3.

3) mutation in a factor itself due to mutation in the genes producing a factor, would lead to little or no production of a-factor which will not be recognised by the cell surface receptors (Ste3) on the alpha cell. and hence no shmoo would form, impairing the mating. therefore correct option is (e) a factor itself .

if SRP was mutated not just a factor a lot of proteins which required translocation would have been affected, and since the cell is growing fine, therefore SRP, ribosomal subunit , signal peptidase and sec61 cannot be mutated. as it would have affected the overall growth of the cell as well, that leaves us with option (e) i.e mutation in the a factor itself. since the only problem in the cell is a factor not being released, as it is not being synthesised.