Cell Biology Lab Essay Sample
1. (14 points) The HeLa S3 cancer cell line is considered to be “continuous” due to acquired mutations that enable the cells to evade senescence. This property is one of several hallmark characteristics of cancer cell lines. Describe three hallmark characteristics of cancer cells and summarize the history of the HeLa S3 cell line (be sure to describe the origin of the cells, the approximate year of their extraction and the required growing conditions – all of which can be found on the ATCC website).
2. (20 points) Cell culture media typically contain a blend of glucose, amino acids, salts, and a buffer. Majority of cell lines also require the addition of blood serum nutrients. Using the article “Managing Serum Requirements in Cell Culture”, discuss the advantages and disadvantages of using serum for cell culture.
Animal blood serum in a factor needed in the cell culturing of mammalian cells for its nutritional content of growth factors, proteins, enzymes and other factors that are crucial for cell development. However, there are several obvsticles for its production since it is usually collected from the fetus of slaughtered cattle, which usually do not contain more than half a liter of blood each, from which half is serum. Not only is this not cost efficient, but because so little comes from every individual fetus, and not every fetus has the exact biological composition, there is much variability from serum to serum, which might affect the results of any given experiment that requires generous amounts of serum solution. Also, because serum is a biochemical that may carry very infectious agents it can not be taken from places were these agents are known to exist which reduces its availability even more.
3. (10 points) Your lab partner made three 20 mL volumes of glucose at the following concentrations: 10 mg/mL, 24 mg/mL, and 37 mg/mL. Your lab protocol requires a large amount of 15 mg/mL gluocse, so you decide to combine all of the three solutions to make as much at that concentration as possible. How much 15 mg/mL glucose can you make? How much water will you need to add?
4. (12 points) You started with a cell count of 9.3 x 105 cells / ml in a total volume of 5.2ml. You need to seed a six-well plate with the following numbers. Calculate the volume of cell suspension you will need to transfer into 1 well. Each letter represents a different scenario.
a. 1 x 104 cells/mL and up to 2 mL / well
b. 4 x 104 cells/mL and up to 2 mL / well
c. 2 x 105 cells/well and up to 2 mL / well
d. 3.5 x 105 cells/well and up to 2 mL / well
5. (24 points) Your colleague in the laboratory was able to collect all his raw data from a growth curve on the Hela S3 cell line, but had to leave unexpectedly and has asked you to perform cell calculations and prepare a growth curve to show your professor. This what your colleague did: he seeded cells into a 24-well plate (allows for replicate sampling and it is much easier to handle one 24-well plate rather than 24 flasks), and on each of the days indicated in the table on the following page, trypsinized and counted live/dead cells from three individual wells to allow for statistical accuracy. The information in the data table includes: day counted, media volume, dilutions, and number of live and dead cells counted (these numbers represent the average count from the three wells counted each day) with a Neubauer hemocytometer.