Nutrients
Name the three main categories of nutrients.
Carbohydrates, proteins and fats
What is the basic unit of starch?
Glucose
State the two places in the human body where glycogen can be found.
Liver and muscles
Which nutrient does the iodine test test for?
Starch
Which biological molecule are enzymes made of?
Proteins
Name foods that contains carbohydrates, proteins and fats respectively.
E.g. Carbohydrates-rice, sugar
Proteins-chicken, fish
Fats-butter, oil
How many glucose molecules are present in maltose?
2
Name 1 function of glucose in our cells.
Used by mitochondria for aerobic respiration to release energy.
Following the steps of the Benedict's test, a green precipitate forms in the blue solution. What is the correct conclusion?
A small amount of reducing sugar is present.
What is the name of the area of an enzyme that binds to the substrate?
Active site
Which element in the periodic table is present in proteins but absent in carbohydrates and fats?
Nitrogen (N)
What is the basic unit of glycogen?
Glucose
Both fats and carbohydrates store energy. What is the main difference in their function?
Fats are a long term store of energy while carbohydrates are a short term store of energy.
Describe the steps to the Biuret's test.
1. Add 2cm3 of food sample into the test tube.
2. Add Biuret's solution dropwise.
The enzyme amylase binds to starch to form maltose. Which is the lock and which is the key?
Amylase (enzyme) is the lock. Starch (substrate) is the key.
Name two reducing sugars.
Any two: glucose, fructose, maltose
What are the basic units of proteins?
Amino acids
Proteins are used to synthesize many compounds in our body. Name two.
Describe the steps of the Benedict's Test.
1. Add 2cm3 of food sample into a test tube
2. Add 2cm3 of Benedict's solution into a test tube
3. Heat in boiling water bath for 2 min.
What happens when enzymes are placed in a solution of very high temperature?
Enzymes will denature
Name the three polysaccharides.
What are the basic units of fats?
1 glycerol and 3 fatty acids.
Describe two functions of fats in the human body.
Used to synthesize cell membranes.
Used as a solvent for fat-soluble vitamins.
Long-term storage of energy.
Describe how you would test whether peanuts contain fats.
1. Grind up peanuts in a mortar and pestle.
2. Add 2cm3 of ethanol to the peanuts.
3. Filter the solution to remove peanut pieces.
4. Add 2cm3 of water to the peanuts. Shake well.
The enzyme amylase is added to a solution of starch and incubated for 1 hour. The Iodine test is performed on the final solution. What is the expected observation?
Brown solution remains brown. (All the starch has been digested into maltose.)