WorksheetsTesting for Biochemicals
Total questions: 15
Worksheet time: 15mins
Which of the following does not consist of organic molecules?
Carbon dioxide
Starch
DNA
Lipids
Choose the elements that make up a protein molecule
Carbon
Hydrogen
Oxygen
Phosphorus
Nitrogen
Carbon, hydrogen, oxygen, nitrogen, phosphorus.
These are elements in.....
proteins
nucleic acids
glucose
lipids
Organic molecules are molecules that must contain the elements ............... and ................... .
Choose the correct answers that fill in the blanks.
Oxygen
Carbon
Nitrogen
Hydrogen
What is not the function of proteins?
Make antibodies
Form body tissues
Source of energy
Thermal insulation of body
What is not a reducing sugar?
glucose
fructose
maltose
starch
What is the reagent to test for reducing sugars?
DCPIP
Iodine
Benedict's reagent
Biuret reagent
What is the reagent to test for the presence of starch?
DCPIP
Iodine
Benedict's reagent
Biuret reagent
When Biuret solution is added to a food sample, the mixture turns from blue to purple.
What does this show?
Reducing sugar is present
Protein is present
Lipids are present
Starch is present
How does one test for the presence of lipids in a food sample?
Mix the food sample with DCPIP
Mix the food sample with ethanol
Mix the food sample with ethanol and then water
Mix the food sample with DCPIP and then water
What results show the presence of Vitamin C in a food test?
Food sample and reagent mixture turns to dark blue
Food sample and reagent mixture decolourizes (loses all colour)
A brick red precipitate forms
A milky white emulsion forms
Olive oil is tested with iodine.
What result is to be expected?
Iodine turns from yellow to dark blue
Iodine turns from dark blue to yellow
Iodine turns from yellow to purple
Iodine remains yellow
Glucose is tested with Biuret solution.
What result is to be expected?
The solution forms a brick-red precipitate
The solution turns dark green
The solution mixture remains blue
The solution mixture turns purple
Lemon juice is mixed with DCPIP.
What happens when the mixture is stirred?
The solution's colour fades and becomes colourless
The solution's colour remains blue
The solution's colour remains yellow
The solution's colour turns red and then orange
Benedict's reagent is added to a maltose solution and the mixture is stirred.
No changes are observed. Why?
There is no reducing sugar present
The mixture is not stirred quickly enough
The mixture is not heated in a water bath
Ethanol was not added
