The following techniques will be used for purification of an enzyme from cultured cells; salt fractionation, affinity chromatography, ion-exchange chromatography, homogenization and gel filtration chromatography. The protocol states that the techniques should be used in the order listed above.
a) What is wrong with the order of techniques as they are listed?
b) How does each technique contribute to the process of obtaining a pure enzyme?
In: Biology
In a 50µl reaction containing 0.25 pmol of a Michaelis enzyme with Km = 4.0 x 10-7 M and substrate concentration of 2 x 10-7 M, product was formed at an initial velocity of 5.0 x 10-5 Mmin-1 .
a. If the enzyme concentration is doubled to 0.5 pmol in the reaction, how much will the velocity increase? Show mathematically
In: Biology
Why aren't all amino acid R groups ionizable?
In: Biology
How will I find the pI for a non-ionizable amino acid?
In: Chemistry
For each of the following tRNA anticodon sequences, determine which amino acid would be charged onto the tRNA. (note: these are ANTIcodon sequences, not codon sequences) If more than one tRNA is necessary to recognize all codons for that amino acid, state the anticodon sequences of the other tRNAs that would also be charged with that amino acid. If a given sequence is not a possible tRNA anticodon sequence, explain why not.
A. 5’- IAU - 3’
B. 5’- GCC - 3’
C. 5’- CCG - 3'
D. 5’- UAU - 3’
E. 5’- AGG - 3’
F. 5’- ICA - 3’
Now, for any one of the possible tRNAs, sketch a ribosome with the charged tRNA interacting with an appropriate codon in the A site. Then show two things that must happen before that tRNA can be found in the ribosome’s P-site.
In: Biology
| 16. A human nephron A. is one of the two kidneys B. is the functional excretory unit C. is about the size of your fist D. all of the above |
17. The proximal convoluted tubule A. is lined by microvilli B. excrete salt ions of sodium and potassium C. secretes unneeded proteins D. absorbs organic acids |
18. Urine entering the collecting duct A. will have salt added as it descends B. will have urea added as it descends C. will have water added as it descends D. none of the above |
19. The multiplier effect A. increases the salt concentration of the cortex B. decreases the salt concentration of the urine C. is due to the absorption of salt into the urine D. none of the above |
20. Alcohol and caffeine increase urine volume by
A. decreasing blood pressure and increasing ADH production
B. increasing blood pressure and decreasing ADH production
C. increasing blood pressure and increasing ADH production
D. decreasing blood pressure and decreasing ADH production
In: Biology
Ubiquitination relies on 3 enzymes E1, which activate ubiquitin; E2, which are the conjugating enzymes, and E3 enzymes, which help guide the E2 enzymes to specific substrates. In any given cell there are just a couple types of E1 enzymes, several types of E2 enzymes that partner with small subsets of E3 enzymes, and even more types of E3 enzymes, which bind with small subsets of specific protein substrates. Given this information, which of these mutations would you hypothesize to be the most harmful to a cell?"
| a. |
a mutation in one type of E1 enzyme |
|
| b. |
a mutation in one type of E2 enzyme |
|
| c. |
a mutation in one type of E3 enzyme |
|
| d. |
all of these mutations would be equally harmful |
In: Biology
Initial rate data for an enzyme that obeys Michaelis-Menten kinetics are shown in the following table. When the enzyme concentration is 3 nmol ml−1, a Lineweaver-Burk plot of this data gives a line with a y-intercept of 0.00426 (μmol−1ml s).
| [S] μM | v0 (μmol ml−1 s−1) |
| 320 | 169 |
| 160 | 132 |
| 80.0 | 92.0 |
| 40.0 | 57.2 |
| 20.0 | 32.6 |
| 10.0 | 17.5 |
a. Calculate Kcat for the reaction
b. Calculate Km for the enzyme
cWhen the reactions in part (B) are repeated in the presence of 12 μM of an uncompetitive inhibitor, the y-intercept of the Lineweaver-Burk plot is 0.352 (μmol−1 ml s). Calculate K′I for this inhibitor.
In: Chemistry
How is lactate generated? What is the role of NADH + H+ in the production of lactate?
How is lactate used?
Define the following terms: glycolysis, glycogenolysis, glycogenesis, gluconeogenesis.
What is beta oxidation?
What role does beta oxidation play during exercise?
In: Biology
What is the FUNCTION (what it does, not what it is) of the following terms?
1. Promoter –
2. ORF –
3. Compatible solute–
4. Pasteurization –
5. Bacteriostatic agent –
6. Exposure of food to strong ionizing radiation–
7. Fermentation of food –
8. Glycolysis –
In: Biology