Biological Molecules (Excluding Enzymes)

Question 1

What are the three categories most molecules in food and much of what is in our bodies fall into?

Answer 1

Carbohydrates, Proteins, Lipids

Question 2

Which chemical elements are present in carbohydrates?

Answer 2

Carbon, Hydrogen and Oyxgen

Question 3

Which chemical elements are present in proteins?

Answer 3

Carbon, Hydrogen, Oxygen and Nitrogen (Some contain small amounts of Sulphur)

Question 4

Which chemical elements are present in lipids?

Answer 4

Carbon, Hydrogen and Oxygen

Question 5

What are carbohydrates digested down to?

Answer 5

Glucose (a monosaccharide) which is absorbed into the bloodstream

Question 6

What is a single unit of carbohydrate?

Answer 6

A monosaccharide, being glucose or fructose

Question 7

What are two units of carbohydrates called?

Answer 7

Disaccharides, being sucrose which is a fructose unit and a glucose unit, or maltose which is two glucose units

Question 8

What are many units of carbohydrates called?

Answer 8

Polysaccharides like starch, glycogen or cellulose, which are comprised of many glucose units

Question 9

What is the bond that holds single units of carbohydrates together called?

Answer 9

Glycosidic

Question 10

What are proteins digested down to?

Answer 10

Amino acids

Question 11

How many different types of amino acids are there?

Answer 11

20

Question 12

What are the bonds inbetween amino acids called which make up a protein molecule?

Answer 12

Peptide bonds

Question 13

How can amino acids be arranged?

Answer 13

In any order, to form many different shapes which perform different functions. For example, each enzyme will have a very specific shape which is its specific arrangment of amino acids

Question 14

What is the difference between fats and oils? (The two sections all lipids are divided into)

Answer 14

Fats are solid at room temperature, oils are liquid at room temperature

Question 15

What is a unit of lipid comprised of?

Answer 15

One glycerol molecule bonded to three fatty acid molecules

Question 16

What are the bonds that hold lipid molecules together called?

Answer 16

Ester bonds

Question 17

What is the test for reducing sugars?

Reducing sugars = all monosaccharides + disaccharides (Except Sucrose)

Answer 17

• Add benedicts solution to the food sample
• Heat in a boiling bath for 2 minutes
• If positive, it will turn brick red

Question 18

What is the test for protein?

Answer 18

• Add biurets solution to the food sample
• If positive, it will turn purple (from blue)

Question 19

What is the test for starch?

Answer 19

• Add iodine to the food sample
• If positive, it will turn to blue-black

Question 20

What is the test for lipids?

Answer 20

• Add ethanol to the food sampleto dissolve the lipids
• Add water
• If positive, a white and cloudy emulsion will form