General exam knowledge

Question 1

Control variables / precautions for valid results

Answer 1

Always look at concentration, volume, temperature, calibrating colorimeter and length of time

Question 2

How should procedure be altered

Answer 2

Repeat steps of original procedure but with altered parts and refer to graph if one given

Question 3

Does graph show/ prove that

Answer 3

Talk about correlation, remember correlation doesn’t equal causation and remember other factors which could contribute

Question 4

What conclusions can you make from data

Answer 4

State what you see, don’t make assumptions eg don’t say. ‘… Are more likely ‘ instead, say ‘…. More people.. ‘

Question 5

Why are solutions put in waterbaths before mixing

Answer 5

Acclimatisation

Question 6

Some common inaccuracies

Answer 6

Maintain temp → thermostatically charged waterto
Results are subjective e.g. Colour change I →clear → colorimeter → not all volume transferred
Accuracy of equipment

Question 7

Purpose of thermostatically charged water bath

Answer 7

Maintain temp / acclimatise to same temperature

Question 8

Explain competitive inhibitors

Answer 8

Molecules which have similar shape / structure to normal substrate molecule so complementary to active site and bind to it forming enzyme- inhibitor complex preventing normal substrate from entering by blocking active site so number of enzyme-substrate complexes forming and ROR are both reduced

Question 9

Explain effect of substrate concentration on level of inhibition for non-competitive inhibitors

Answer 9

As conc of substrate increases, level of inhibition decreases because as increased substrate conc increases chance of normal substrate binding to active site so at very high substrate concentration is same as without inhibitor as with because substrate molecule much more likely to bind to active late so effect of inhibitor is negligible

Question 10

What does small range bars mean

Answer 10

More reliable results