tests for biological molecules Flashcards
1
Q
what is benedict’s test?
A
semi- quantitative test for reducing and non reducing sugars
2
Q
benedict’s test for reducing sugar
A
- can donate electrons
3
Q
benedict’s test for non reducing sugar
A
- add dilute of HCL (hydrogen chloride) to sample
- heat in water bath
- neutralise solution with sodium hydrogen carbonate
- carry out benedict test as usual
- add benedicts solution
- heat in water bath again for five mins
- turns red, orange and green based on concentration of non reducing sugar
4
Q
benedict’s tests for reducing sugar
A
- put solution in bioling tube
- add bendicts solution
- put boiling tube in boiling water for five mins
- blue negative
- turns red, orange , and green based on concetratin of reducing sugar
5
Q
what can calibration curve be used for?
A
- to find exact amount of sugar in different samples
- used with ‘‘unknown’’ samples to determine concentration of sugar in original sample
6
Q
process of creating calibrative curve
A
- take series of known concentrations of reducing sugar
- carry put benedict test on each sample
- use colorimeter to record the % transmission of light through each supernatant
- plot graph to show transmission of light against concentration of reducing sugar
7
Q
What is iodine test used for?
A
starch
8
Q
process of iodine test
A
- potassium iodide solution is sample
- goes from yellow to blue black if starch present
9
Q
what is the biuret test used for?
A
proteins
10
Q
result of biuret test
A
turns sample from blue to purple
11
Q
What does a biosensor do?
A
- take biological or chemical variable that cannot be measured
- converts to electrical signal
12
Q
what can biosensors be used for?
A
- detect contaminants in water
- detect pathogens and toxins in food
- detect airborne bacteria e.g in counter-bioternism programmes
13
Q
what is emulsion test used for?
A
presence of lipids
14
Q
What are outcomes of emulsion test?
A
- if present: milky emulsion; appears cloudy
- not present: remains clear
