You take absorbance readings on a Madison Christian Micro Final Quest

Question 81 / 104: You take absorbance readings on a spectrophotometer across a 6 hour culture of E. coli cells growing in tryptic soy broth (TSB). Your absorbance readings clearly indicate a lag phase, a log phase, and a stationary phase. You come back in and take readings at 8, 10, 12, 14, and 16 hours, but the absorbance number remains the same. Shouldn't it start coming down as the closed batch culture enters death phase? What's the most likely thing that is happening?

A Clearly, something is wrong with the spectrophotometer and it isn't measuring the correct values.
Perhaps something is on the detector, making it register falsely high absorbance numbers.

B When we establish a growth curve, we should actually plot the log of the number of viable cells
vs. time. However, a spectrophotometer can only measure absorbance. Absorbance is NOT the same
as the number of viable cells. Many of the cells in the tube are most likely dead, but the
machine can't discriminate between a live cell and a dead one. This keeps the absorbance high
even into the death phase.

C It'll happen-E. coli just grow slowly. We haven't gotten to the end of the stationary phase
yet. Be patient!

D Perhaps there's a big smudge of something on the tube that is blocking some of the light. This
would lead to an elevated reading for every timepoint after the smudge was placed on the tube.

<< First < Previous Flashcard Next > Last >> Quiz Home Page

https://www.jobilize.com/micro-final-practice-1-ken-quiz-by-madison-christian

Micro Final Practice 1 - Ken

Author:

Madison Christian

Access: Public Instant Grading

Ask

	2 Microbiology Final 2 By Madison Christian Start Quiz
	17 Sociology 17 Government and Politics MCQ By OpenStax Start Quiz
	College physics By OpenStax Read Online Course
©flickr: Aaron	Computer Literacy Exam 1 By Lakeima Roberts Start Quiz
	Biology 302 Final By Dravida Mahadeo-J... Start Quiz
	21 AP 21 Lymphatic Immune System MCQ By OpenStax Start Quiz
	34 Biology 34 Animal Nutrition Digestive System By OpenStax Start Quiz
	32 Biology 32 Plant Reproduction MCQ By OpenStax Start Quiz
	Introduction to sociology By OpenStax Read Online Course
	46 Biology 46 Ecosystems MCQ By OpenStax Start Quiz
	3 Physiotherapy Flashcards Set 3 By Rhodes Start Flashcards

Copy and paste the following HTML code into your website or blog.