Testing For Biochemicals Flashcards
What is the chemical test for protein?
To test for protein, a few drops of Biuret reagent are added to the solution and the mixture is gently shaken. It start as blue and a purple colour is a positive result.
What is the chemical test for starch?
To test for starch, a few drops of iodine solution added to the solution, and the mixture is gently shaken. I starts as orange and a deep blue/black colour is a positive result.
What is the chemical test for glucose (reducing sugars)?
To test for glucose, Benedicks reagent is added to the solution, and the mixture is heated in a boiling water bath. It starts as blue and an orange/Brick red colour is a positive result.
Why might a doctor want to check for glucose?
A doctor might check a patients urine sample for glucose to find out whether he/she has diabetes (glucose is a positive result)
How would you test for lipids?
The lipid can be mixed with water and ethanol and if a milky white emulsion is formed a lipid is present. Alternatively, you could rub the food on to dry filterpaper, and if it went from opaque to translucent, that would be a positive result
How would you test for vitamins C?
You can add DCPIP and if the solution de-colourises, that you know that there is vitamin C. You can also count the amount of drops needed to find the relative concentrations of vitamin C.
