The first test (unseen) was conducted in this course after conducting two open book tests earlier. This test is of 100 marks and 1hour durarion. Performance of this test is considered for assessment of the course. It was conducted during the regular lecture hour without any special seating arrangement and time table. Nearly 200 students attended the test. The question paper is posted here.
ASSESSED EXERCISE Week 6:
Please attach your working on a separate sheet, but also fill in the answers on THIS sheet.
NAME:……………………………………….………
Use scientific notation whenever appropriate.
(E.g., write 2.3 x 10 -9 instead of 0.0000000023)
1. Express 5 mM in units of:
(4 marks each)
(a) mmol / litre ……………………
(b) µmol / nl …………………
(c) nmol / µl …………………...
(d) mmol / ml …………………..
(e) µmol / ml …………………
(f) mmol / µl …………………..
2. Calculate the molarity of a solution containing:
(4 marks each)
(a) 0.25 mg of bovine serum albumin per ml (Mr of BSA = 65,000) …
(b) 6 mg NaOH/10 ml (Mr NaOH = 40) ……………….
(c) 9.25 mg KCl/50 ml (Mr KCl = 74). ……………….
(d) 2.42g Tris/20 ml (Mr Tris-121) …………….
3. Calculate the number of mols of glucose in:
(4 marks each)
(a) 50 ml of 1mM solution …….......
(b) 0.3 ml of 100 mM solution ……… ……….
(c) 1.5 ml of 3 x 10-5 M solution ……… ……….
(d) 500 µl of 0.01 M solution ..........................
(e) 0.05ml of a 0.001M solution ….. ……….
.
4. 10 ml of cell homogenate was prepared. A 0.1 ml sample was mixed with 9.9 ml of
water and was shown to contain 0.5mM of glycine. 1ml of this was mixed with 4ml
of Trichloroacetic acid. The resulting total protein precipitate was solubilised in 2ml
and was shown to contain 3mg/ml protein. (5 marks each)
(a) what was the concentration of glycine in the original sample (in mM) ? …......
(b) how many moles of glycine were present in the original sample ? ……
(c) what was the protein concentration in the original sample ? …… …………
5. 5 ml of cell homogenate was prepared. A 0.1 ml sample was mixed with 4.9 ml of water to produce solution X, which was shown to contain 0.01 mM glucose. 1ml of solution X was mixed with 4ml of Trichloroacetic acid to recover all protein. The resulting precipitate was solubilised in 5ml and was shown to contain 0.05 mg/ml BSA protein. (5 marks each)
(a) what was the concentration of BSA protein in the original sample (in mg/ml) ? …………..
(b) how much total BSA was present in the original sample (in mg) ? …............
(c) what was the molarity of BSA in the original sample (Mr of BSA = 65,000)?............
(d) what was the concentration of glucose in the original sample (in mM)?.............
(e) how many moles of glucose were present in the original sample? ……… …....
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