practical 2

Question 1

henderson hasselbach eqn

Answer 1

ph = pka + [A-]/{HA]

Question 2

why does the graph flatten on a ph curve

Answer 2

because the solution is buffering against changes in ph

Question 3

what is a buffered solution

Answer 3

one that resists changes in its pH when you add small volumes of strong acids or bases

Question 4

what is the range for ph probes

Answer 4

3-11

Question 5

what is Vmax

Answer 5

the velocity of the enzyme as the substrate concentration [S] tends to infinity

Question 6

what is Km

Answer 6

the substrate concentration when the velocity is half the maximum value.

Question 7

what affect does inhibitor have on kcat

Answer 7

it reduces the catalytic capacity

Question 8

what do you do before you start ion exchange chromatography

Answer 8

pre equibrilate the column with a weak buffer

Question 9

what is the procedure for preparing for bacterial staining

Answer 9

clean slide with methanol
add sample with loop - in water if from solid culture
hold over busen flame to dry slide and help adherance and kill bacteria

Question 10

What is the procedure for bacterial staining

Answer 10

• stain cell with a basic dye
• treat with a mordant eg. iodine to increase affinity between the cells and the dye
• decolourising agent then added such as alcohol
• cells that retain the basic dye after decolourisation are called gram positive.
• decolourised = gram neg