n this step, wash the cells with ice-cold PBS. Drain the PBS, then add ice-cold lysis buffer. Scrape adherent cells off the dish using a cold plastic cell scraper, then gently transfer the cell suspension into a pre-cooled microfuge tube. Maintain constant agitation for 30 minutes at 4°C. Centrifuge in a microcentrifuge at 4°C. You may have to vary the centrifugation force and time depending on the cell type. Gently remove the tubes from the centrifuge and place on ice, aspirate the supernatant and place in a fresh tube kept on ice, and discard the pellet.   Q3: To make sure that you used a similar amount of samples, what important step should be done before proceeding the electrophoresis stage?   Once you have determined the concentration of each sample, you can freeze them at -20°C or -80°C for later use or prepare for immunoprecipitation or for loading onto a gel.   Q4. Why is it necessary to store the prepared lysates in a very low temperature?     PLEASE ANSWER Q3 AND Q4

You just finished plating your electroporatio products on your YPD-Zeocin plate and you think you did everything perfectly but you come back the folloeing week and have zero colonies. Which of the following could be the reason for the absence of colonies? A) You centrifuged your electroporated cells for 30 sec at 16,000 rpm instead of 4,000 rpm before plating them B) You added sorbitol+YPD to your cells thirty minutes after pulsing your cells C) The Zeocin had not been added to the plates when they were made. D) All of the above E) Both a and b only

The following is result from a standard plate count. What is the cell density of the undiluted culture? Please follow all SPC rules. (TNTC: too numerous to count)

When testing the efficacy of an antibiotic against bacteria on an agar plate, it is important to spread the bacteria evenly across the plate before you add the antibiotic. Why do the bacteria need to be applied evenly?     None of the following are true     All of the following are true     If you add more bacteria in some areas compared to others, it might obscure the effect of the antibiotic     If the area right next to the antibiotic initially received relatively few bacterial cells, that might lead you to overestimate the effectiveness of the antibiotic     If the area right next to the antibiotic initially received a relatively large number of bacterial cells, that might lead you to underestimate the effectiveness of the antibiotic

Case Study: You are asked to inoculate lactose media (broth) with E. coli that was growing exponentially in glucose media (broth). You monitor the growth of these cells in the lactose broth using a viable plate count technique and plot the Growth Curve for E. coli growing c lactose. After a day of monitoring the cells, you note that the culture entered into lag phase growth initially and is now currently growing exponentially. In addition, you find that the cultures doubling time is 30 minutes. You know that the doubling time of E. coli in glucose media is 20 minutes. You did not change the oxygen content or temperature at Which you were growing the cells, E. coli is still aerobically respiring at 37°C. Question: If the lac operon is 'on' what does this imply about the cell? O The cell is dying and the lac operon is going to induce apoptosis. Apoptosis is truly cell death and the cells will enter into the death phase of the Growth Curve. O Lactose is being catabolized and glucose is no…