Help with question 8 is it correct You were to take all of t

You were to take all of the DNA chains from all of the chromosomes in your body and them all together into one gigantic linear double helix, how long would that helix be? Use the fact that a 1 kilobase pair (kbp) double helix of DNA is 340 nanometers in length (340 nm) and that the haploid human genome contains 3.3 times 10^9 bp of DNA of make your calculation (and remember that human calls are diploid!). Assume that the human body contains 10^13 cells and use the conversion factor 1 Meter = 6.2 times 10^-4 Miles. Show your work (with all appropriate unit conversions) and express your answer in solar units (1 solar unit = distance from earth to the sum = 9.1 times 10^7 miles). E Coil has a doubling time of 20 minutes under optimal growth conditions. Compute the of E. coli (in pounds) that would accumulate when a single cell of E. coli grows exponentially for 2 days (48 hours) in these conditions, assuming that nutrients are not limiting. Show your work (The weight of a single E. coli cell is 10^-12 gram/cell). The HIV (viral particle) is a sphere that is roughly 140 nm in diameter. What particular kind of microscope is required to visualize an HIV and what is the basis of this microscope s ability to provide the resolution required to visualize HIV .10. You are in microbiology lab and are approached by another member of the class who asks you to help him with a Gram stain He tells you that he has performed the first 4 steps of the procedure (as shown in Fig 2.22 of the textbook) but just remembered he needs to make an important phone call and asks if you will complete the procedure as he is running out the door. You complete the procedure for him but after he returns and reviews his notes, he realizes that he omitted the step in which the cells are stained with crystal violet. The specimen that your friend was staining contained the Gram-positive organism B subtilis. a. When the Gram stain procedure is done properly, what color should these cells be when viewed in the microscope? b. What color will the cells that you stained be? Suppose you ingest 20 cells of Salmonella typhimurium in a chicken taco. Some of the bacteria are killed as they pass through the stomach but 10 viable cells survive and reach the intestine. Suppose further that the sum total of subsequent bacterial replication and death(caused by host immune mechanisms) produces an average generation time of 2.7 hours and that you will feel sick when there are 1,000,000 bacteria in your gut. How much time will elapse before your feel sick? Show your work.

Solution

your answer is almost correct, but the conversion to pounds is incorrect.

In 48 hrs, there are 144 cycles/generations [(48x60)/20]as per the doubling time. So, the number of bacteria are 2ⁿ=2¹⁴⁴=2.23x10⁴³

As one bacteria has a weight of 10^-12gms, so 2.23x10⁴³x10^-12 gives the whole weight of the bacteria produced after 144 generations, i.e = 2.23x10³¹gms

Conversion of grams into pounds

1000gms=2.2 lbs, therefore 2.23x10³¹gms=4.9x10²⁸ pounds.

Hence, the biomass of E.Coli after 2 days is 4.9x10²⁸ pounds.