required practical 1(enzyme reaction rates)
Questions from the examier
Graphical skills
Could be asked to plot a graph
Sharp pencil for accurate plotting
Dependant variable of the y-axis (The rate of reaction) Quantity of product made or substrate hydrolysed / time
Straight line and ruler to join up points
Indipendant variable on the x-axis (The pH) no units of measure becuase it is pH
The scale would have to be linear.
Scale: s-1 if measuring in seconds
y=mx+c
y= y-axis read off, m is the gradient, x is the x-axis read off, c is the y intersect
rate= change in volume / change in time (cm3s-1)
AT= A Tangent which means you draw a tangent from whatever point is said in the question
Plotting a graph needs to cover more than half the paper
Tables
Look for significant figures and make sure they are all the same
Don't put units in the table they will already be in the header
C.S.M.R
C= Change
S= Same
The pH
Temperature
Things we change- The independant variable
Enzyme
Substrate
Control variable- Things we keep the same
Constant temperature water bath leave in water bath unitl an equilibrium is reached
M= Meaure
Things we measure- The dependant variable
R= Repeat
Relaible accurate mean value
Uncertainties
Resolution (precision)
Is the smallest unit you can measure to or that the intrement can make
- eg. Ruler- 23mm is 23+- 0.5 mm (+- half of the smallest unit)
- measuring error at the start + error at the end = 23+-1mm
percentage uncertainty
(uncertainty / measurement) x 100
23+-1mm = (1 / 23) x 100
Reapeat readings
(Look on VLE)
Statistical tests and the null hypothesis
Spearman's rank correlation coefficent
t- test
chi2 test
Compares 2 mean values
Catergories. Eg. bule eyes green eyes, Brown hair, Black hair
Bar Charts are related to catergories
Association
null hypothesis
Null = no difference between or no corrolation
Compare calculated value to critical value
If the caluclated is larger than the critical then there is a significant difference and you reject the null hypothesis as there is a significant difference or corrolation
If there is a significant difference
There is a less than 5% probability that the difference or corrolation is due to chance
If the caluculated is less than the critical then there is not a significant difference and you accept the null hypothesis as there is no significant difference or corrolation
If there isnt a significant difference
There is a more than 5% probability that the difference or corrolation is due to chance
Topic links
Digestion
Lipid digestion- Glycerol and 2 fatty acids
Dipeptidases
Endodipeptidases
Amalase
Maltase
Lipase
DNA
DNA and protein sythesis
Proteins and enzymes
Enzyme substrate complexes
The active site of the enzyme has a specific 3D teritiary structure
ATP
Enzymes in membranes
Channel protein acts as an enzyme to join beta gluecose molecules to form cellulose
Proteins in membranes
Ribosomes and organelles
Exocytosis
DNA helicase
DNA polymerase
Inhibitors
Competitve and non competitive inhibitors
Channel proteins
Golgi Apparatus packages proteins