Biology essay on cell growth..

Discussion of all aspects of cellular structure, physiology and communication.

Moderators: honeev, Leonid, amiradm, BioTeam

Post Reply
addicted
Garter
Garter
Posts: 6
Joined: Fri Feb 08, 2008 1:15 am

Biology essay on cell growth..

Post by addicted » Fri Feb 08, 2008 1:18 am

I seriously need all the help I can get because I dont understand these last two questions of this essay, I got everything else figured out and done except for the two at the bottom. And its the type of question I cant really just "look" up in my text book.
Details;
"A scientist designed the following experiment to test the limits of cell population growth. Cells were grown in six flasks under different temperature conditions. Each flask contained a nutrient broth of the same concentration. The table below shows the data obtained from the experiment. Study the table and answer the questions that follow in a well devolped essay."

Flask 1: Temp: 0 Vol of nutri: 500 No of cells day 1: 1.0 Day 2: 1.0 Day 3: 1.0
Flask 2: Temp: 20 Vol of nutri: 500 No of cells day 1: 1.0 Day 2: 1.2 Day 3: 1.2
Flask 3: Temp: 30 Vol of nutri: 1000 No of cells day 1: 1.0 Day 2: 2.6 Day 3: 3.2
Flask 4: Temp: 40 Vol of nutri: 500 No of cells day 1: 1.0 Day 2: 2.2 Day 3: 2.2
Flask 5: Temp: 50 Vol of nutri: 500 No of cells day 1: 1.0 Day 2: 2.0 Day 3: 2.0
Flask 6: Temp: 60 Vol of nutri: 500 No of cells day 1: 1.0 Day 2: 1.4 Day 3: 1.4

Two questions I dont get;
D. Based on the data, what generalization can you make concerning the growth of a population of cells overtime? Exclude results from the flask with the faulty data.

E. Develop a hypothesis to account for the generalization you made in answer D.

please and thank you everybody.

blcr11
Viper
Viper
Posts: 672
Joined: Fri Mar 30, 2007 4:23 am

Post by blcr11 » Fri Feb 08, 2008 4:00 pm

This strikes me as a strange way to report cell growth. And part of the exercise, I think, is for you to identify the “faulty data” so as to exclude it, so I’m not going to tell you which trial(s) is off. It looks to me like the cell growths are recorded as proportions of cells present after a certain period when all the cultures should have been starting from the same point (same number of cells, same concentration of nutrients), but at different temperatures. So nothing happens at 0 C; the relative number of cells remains the same (1.0). At 20 C the number of cells goes up a litte, from 1.0 to 1.2, which I take to mean a 20% increase in the number of cells. Usually you just report either the number of cfu/ml or number of cells/ml, but they must be taking the ratio of, say, cfu/ml at day(i) to cfu/ml at day(0), so growth is represented by increasing ratios, with greater growth indicated by higher ratios. So then, your problem is to identify the temperature which is most favorable for growth—remembering to ignore any faulty data. A plot of relative growths at the different temperatures might help. Then you have to suggest an explanation as to why this temperature appears to be most favorable for growth for this particular strain. Thinking about the properties and characteristics of enzymes might be helpful here.

addicted
Garter
Garter
Posts: 6
Joined: Fri Feb 08, 2008 1:15 am

Post by addicted » Fri Feb 15, 2008 12:12 am

I'm gonna seem completely stupid.. but I'm not sure if I understood your explanation (I know that flask 3 is the one off.) I just really need a detailed explanation on what I'm supposed to do.. I dont really understand cells, or biology in general (probably a huge mistake to take the class.)

Cat
King Cobra
King Cobra
Posts: 635
Joined: Thu Feb 14, 2008 7:40 pm

Post by Cat » Fri Feb 15, 2008 6:41 pm

What that "No of cells day" is measured in??? cfu/ml or something else???

addicted
Garter
Garter
Posts: 6
Joined: Fri Feb 08, 2008 1:15 am

Post by addicted » Tue Feb 19, 2008 1:54 am

^^ all it says is "No. of cells (millions) day 1, day 2, day 3."

Post Reply

Who is online

Users browsing this forum: No registered users and 11 guests