Question 1 1A1 – natural selection and evolution 1A2 – natural selection and phenotypic variations 2D1 – all biological systems are affected by abiotic and biotic interactions 3C1 – changes in genotype and resulting changes in phenotypes 4C2 – environmental factors influence expression of genotypes
Criteria You have been asked to design a procedure to create a strain of Escherichia coli that will survive in a nutrient broth that contains 11% sodium chloride. In order to focus on the procedure itself, the use of aseptic technique will be assumed.
A. design the procedure. The procedure must include reference to the following: 4 points maximum 1 point maximum for controls 1 point maximum for defining the starting culture 1 point maximum for the procedure 1 point maximum for a method to ensure the end bacteria is the same strain as the starting bacteria
Appropriate responses but not limited to the following Controls – a single strain of E coli, temperature, humidity control, incubation time, nutrients provided Description of starting point – nutrient broth with no salt added Procedure – incremental addition of sodium chloride to successive cultures Method to ensure starting and ending bacteria are the same – PCR and electrophoresis or Gram stain
B. based upon your procedure, list three of the materials needed to conduct the procedure you developed in part a. Equipment for aseptic technique is assumed and should not be listed. For each item explain its purpose in the experiment. 6 points maximum Appropriate materials and their purpose include but are not limited to the following: 2 points each correct pair 6 points maximum
MaterialPurpose E coli cultureBacterial strain to be altered in the experiment Nutrient brothProvide the essential nutrients necessary for bacterial growth Sodium chlorideThe dependent variable Sterile culture tubesContainers where E coli will be grown Inoculating loopUsed to transfer E coli from one culture to another BalanceUsed to mass the amount of nutrient broth and salt for each step in the procedure Stirrer/hot plateUsed to prepare the salt broth IncubatorUsed to control the temperature and humidity of the experiment