Grewth Curve ont a What is happening at time sero on the graph b. What is cuerin
ID: 212481 • Letter: G
Question
Grewth Curve ont a What is happening at time sero on the graph b. What is cuering daring the eclipse period? Does your curve resemble the growth curve in figure 24.1? If no, describe how it differs from the expected curve d. Define burst size, and indicate the burst size for T4 coliphage in this experi for the unex- e. Dxes the burst size match expected values for this phage? If not, suggest some reasons h pected burst value B. Short-Answer Questions 1. What is the assumption for how a phage plaque is formed? 2. What is the m.oi. and why was a low value used in this experiment? 3. How was phage adsorption to bacterial cells stopped in this experiment? 4. What was the purpose of plating a sample of E. coli before phage was added?Explanation / Answer
a) Time zero is the period where bacteriophages are added to the culture of bacteria .In this step the phages adjusts to the environment and adhers to bacteria .
b) Eclipse period is the time period for the appearance of first intracellular phages.We cannot detect phage particles in this period as the phages are Uncoated and phage DNA is injected into bacterium for replication.
c) Fig missing to answer the question.
d) Burst size is the average yield of infectious virus per cell.It can be calculated by
Burst size =Final titre of virus /Initial viral titre.
e) Fig missing to answer the question.
B) a) Phage plaques are formed by the lysis of bacteria and release of new phages after the bacteriophage replication.
b) m.o.i is the multiplicity of infection or the number of infectious particles added per cell.Infection depends on the random collision of virions per cell or to guarentee single infections.
c) Phage adsorbtion is stopped by diluting the mixture or adding antivirus antiserum so that the phage particles fail to meet the susceptable bacteria.
d) plating of bacteria is done to improve the probability of plaque formation.
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