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In: Biology

You performed spectrophotometric measurements to determine the grow rate of a Caulobacter crescentus cell culture and...

You performed spectrophotometric measurements to determine the grow rate of a Caulobacter crescentus cell culture and obtained the data shown below. Please plot the absorbance versus time on a logarithmic (base 10) scale to show the growth curve as a straight line. Find the slope of the line and calculate the generation time from the slope. You will first need to calculate the time elapsed (duration) for some of the data points shown in the table below. (4 points) Please show work

Time	Duration (min)	OD₆₀₀
10:30 a.m.	0	0.025
12:45 p.m.	135	0.081
2:30 p.m.		0.193
4:15 p.m.		0.420
6:30 p.m.		1.240

Expert Solution

Converting the duration into minutes we get the following:

Time/Duration/OD600

10.30am/0/0.025

12.45pm/135/0.081

2.30pm/240/0.193

4.15pm/345/0.420

6.30pm/480/1.240

We can plot the graph in excel and change the Y axis (OD) into log 10 values to get the following graph.

From the graph we get the slope equation as this:

y = 0.0024x-0.1803

From this graph and equation we can calculate doubling time as follows:

Given two O.D values within the straight line (0.05 and 0.1), and find the itercepts on X axis. The intercept and the difference between them will be the doubling time.

When y = 0.5

the equation rearranged to find X becomes like this:

x = (y+0.1803)/0.0024

x = (0.5+0.1803)/0.0024 gives you a value of 283.45 minutes

The doubled OD of 1 from 0.5 will be calculated as:

x = (1+0.1803)0.0024 gives you a value of 491.79 minutes

The difference between the two time points is 208.34 minutes.

As doubling time is expressed in hours, coverting this to hours = 3.472Hrs is the doubling time of Caulobacter.

gladiator answered 2 years ago

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You performed spectrophotometric measurements to determine the grow rate of a Caulobacter crescentus cell culture and...

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