Question

..Il Verizon LTE 10:36 PM 7 40% O X Virtual_Lab_Bacterial_Growth.d... ... Virtual Lab: The Bacterial Growth Curve BIOL221 - Spring 2020 Go to the following website to access the virtual lab: http://vlab, amrita edu/?sub=3&brch=73&sim=1105&cnt=1 You may need to create an account, go ahead and do so, its free, we will be using this site a lot over the next few weeks. Part 1: Theory and Background Make sure you are on the "Theory" Tab, read the entire page, then come back and answer the following questions: (27 points total). Note: This document will be submitted into Blackboard, please make sure to fill this document in directly and write your answers in a different color than black for submission. 1. What are the two factors that influence bacterial growth? (2pts) 2. List examples of each of those factors (2pts) 3. What is the name of the process by which bacteria divide? (1 pt) 4. What is a spectrophotometer and how is it used to monitor bacterial growth? (2pts) 5. What is turbidity? And how is it related to bacterial growth? (2pts) 6. Explain figure 1 in your own words, using a sentence to describe each part of the figure (total of 4 sentences) (4pts) 7. What are the 4 phases of the bacterial growth curve and explain in your own words what is happening in each one of those stages. In addition, relate what is happening to the Y-axis in figure 2 (Spts). 8. Define generation time (1pt) 9. In figure 3, they explain how to calculate generation time from a growth curve, follow the math and write step-by-

Answer 1

1 Temperature is important factor that affects bacterial growth. High temperature denature proteins and very low temperature inactivate enzyme activity.

pH is the another imp factor for function of enzymes optimum pH should be maintained.

2 - Bacteria like mesophile shows maximum growth at 30° C temperature if they put in very cold condition like 10° C they slower down their growth and at high degree temperature they dies due to denaturing thier Enzymes.

E. Coli grows in 5.5 to 8 pH if it is placed in high pH or alkaline then it won't grow because thier Enzymes will not work and thier function of replication stops.

3- Binary Fission

4- Spectrophotometer basically measures turbidity of solution.

When bacteria grows thier will increase in cell mass thus solution become more turbid thus it is measure by Spectrophotometer.

5 - Turbidity is cloudiness present in solution due to suspension in solution.

Bacteria is mainly of single cell thus when they grows their number increase solution become more turbid and it is measure.

6 - Figure is not shown

7 - Four stage

Lag phase - when bacteria enters in new environment it takes nutrition and develop themselves. In this phase they can not replicate.

Log phase - In this phase bacteria replicate continuously. Bacteria continuously Grows and divide. This phase also know as exponential phase.

Stationary phase - After using all nutrition bacteria slower down its growth. In this phase bacteria stops dividing.

Decline or death phase - after using all the nutrition or depletion in nutrition bacteria starts dieing. Their number starts decreasing.

8 - The time taken by bacteria to doubling their number.

9- Figure not shown