What properties allow for bacteria to survive inside of the stomach?
Are gastrointestinal bacteria tolerant to low PH or do they posses other qualities that allow for them to tolerate stomach acids?
Are there any coupled reactions that are useful to make products that we use for technology?
Do you suspect nutrients such as vitamins and minerals could induce, aggregate, and/or possibly prevent the misfolding of proteins?
Vegans must combine amino acids from different sources to form a complete protein, do all the essential amino acids need to be eaten at once or can a ‘complete protein’ be comprised of different meals throughout the day?
In the space provide below, draw a four-nucleotide piece (e.g. ATGC) of DNA, drawing out the FULL structure showing the four different nitrogenous bases that occur in DNA and showing it in its ionization state at physiological pH. Draw the four bases (A, C, T, G) and their full structure so the backbone of the DNA and the nitrogenous bases.
Describe the difference between the genomic DNA you isolated in this experiment and “plasmid” DNA used in recombinant DNA technology.
1.6 to 2.0 Ratio = Pure DNA
What is the A260 value for your DNA sample? ____0.334___________ .
What is the A280 value for your DNA sample? ____0.325___________ .
What is the A260/A280 ratio for your DNA sample?
Based upon the A260/A280 ratio of your sample, what can you say about the purity of your isolated DNA?
What was the weight of the DNA you isolated?
You started with 2g of raw wheat germ. Using this knowledge calculate the apparent % of your raw wheat germ that is supposedly DNA. Show your work below.
Apparent % DNA in wheat germ: ____________.
Here is a rule of thumb used to calculate the approximate DNA concentration in a solution, based upon the A260 value: A DNA solution of concentration 50 µg/ml gives an A260 value of 1.
Calculate the total amount of DNA in your isolated wheat germ DNA sample based upon your measured A260. Take into account any dilutions you may have made. Show your calculations below.
Total amount of DNA in wheat germ (based on A260): ____________.
% DNA in wheat germ (based on A260): ____________.
Which method of measuring the amount of DNA in your wheat germ gives the larger amount of DNA?
Which method do you think is a more accurate way of measuring the amount of DNA in a sample?Why?
How might our diets influence the misfolding of proteins?Discuss
Question
How are trace elements vital to the life processes occurring on Earth and within the physiology of various organisms?
Can you think of any disease or health complication related to the mutation of an amino acid within a peptide chain?
Write a brief objective for this experiment in your own words.
The amino acids A and B used in this lab are from the following list: glycine, aspartic acid, glutamic acid and lysine. Look up the structure of each of these in the Biochemistry text.
Identify the R group (the variable part) of each and draw the structural formulae (acidic, basic and zwitterionic) of each as the titration proceeds. Note that some of the amino acids will have three forms and others will have four.
Prepare a graph of your results, plotting mL of NaOH versus pH. Plot each of the two titrations (not the dry run) using standard graph paper or Excel. Remember to label the graph axes and provide enough tick marks along each axis to be useful. It is easy to forget these steps when using software; write the information in by hand, if necessary.
From a titration curve it is easy to discern the inflection point (pI). This is the point when 1 equivalent of base has been added. In this experiment you use 10 mL of 0.1 M amino acid or 1 millimole of amino acid (fully protonated). As stated in the introduction, the completely protonated amino acid can donate two protons during the titration.
It will take one equivalent (1 millimole) of base to titrate the first proton (on the acid group) and another equivalent to titrate the second proton (on the amine group). Find the pI and label it on each graph.
Note- An equivalent refers to the moles of OH- or H+ added with each addition of NaOH. It is determined by multiplying the volume of NaOH added by the concentration of the NaOH.
Since the pKacid is the midpoint on the first leg, you can find the pKacid at 0.5 equivalents of base. Likewise, the pKamine can be found at 1.5 equivalents of base. Find and label the pKacid and pKamine for each graph (if possible).
Calculate the pI by finding the average between the average pKacid value and the average pKamine value. This should be a better method of determining the pI of the amino acid.
Identify your amino acid from the following list: glycine, aspartic acid, glutamic acid and lysine. Look up the “true” pI of the amino acid from a reliable source (list your source) and calculate a percent error between your pI value and the “true” pI value.
Write down the final pH of your buffer measured by pH-meter.
Does the pH determined by Henderson-Hasslebach equation method agree with the desired pH of 7.5? If not, can you explain why?
The final pH of the buffer measured by the pH meter was 6.5. The pH of 6.5 does not agree with the desired pH of 7.5. It appears that our group’s calculations were off by a little and this could have been due to weighing out the incorrect amount of buffer.
