Courses Lab HandBook Support Expanded Extreme Bacteria Multiple Choice Assignmen
ID: 207791 • Letter: C
Question
Courses Lab HandBook Support Expanded Extreme Bacteria Multiple Choice Assignment - due 05/04/2018 QUESTION 11 OF 12 SHOW LAB WORK What adjustment, if any, needs to be made to this spectrophotometer so you can best measure bacterial growth in liquid media? A. The mode needs to change to Vis. B. The wavelength needs to be set to 620 nm. C. Nothing needs to change. D. The mode needs to change to Vis, and the wavelength needs to be set to 620 nm. SUBMIT FOR GRADING SAVE AND FINISH LATER 2 unanswered questions Need technical support?
Explanation / Answer
C. Nothing needs to change
The purpose of growth rate measurement is to determine the the rate of change in the number of cells in a culture per unit time. This requires estimating the cell density at a series of time points. The number of cells per milliletre of culture is estimated by the turbidity of the culture. Spectrophotometres measure the fraction of light that is absorbed by the solution and report that as absorbance units. The absorption of solution depends on the wavelength of light which is at 620nm.