Carbohydrates

Question 1

What are carbohydrates?

Answer 1

-Organic compounds with the general formula C x (H 2 O) y.

-They form the most important source of energy in the body.

Question 2

How can carbohydrates be classified?

Answer 2

-Monosaccharides, disaccharides, and polysaccharides.

-Monosaccharides and disaccharides are both considered sugars, which are polar and soluble in water.

-Polysaccharides are macromolecules resulting from the polymerization (condensation) of sugars and are not soluble in water.

Question 3

What are monosaccharides?

Answer 3

-The simplest types of carbohydrates.

-The number of carbon atoms can range from three to seven.

-The carbons are joined to a hydroxyl group (-OH).

Question 4

Examples of monosaccharides

Answer 4

Ribose, glucose, fructose and galactose, deoxyribose

Question 5

Monosaccharides act as ___

Answer 5

Monomers to make larger complex carbohydrate molecules.

Question 6

Two monosaccharide monomers are linked together by a ___

Answer 6

Condensation reaction which forms a glycosidic bond producing a disaccharide, releasing one water molecule.

Question 7

What do several monomer units linked together form?

Answer 7

A polysaccharide.

Question 8

What is a condensation reaction?

Answer 8

-A reaction in which two smaller organic molecules combine to form a larger molecule and a molecule of water or some other simple molecule.

-The reaction opposite to condensation is called hydrolysis.

-This is a chemical reaction in which water is used to break down the bonds of big compounds.

Question 9

What are polysaccharides?

Answer 9

Polysaccharides are large molecules, such as cellulose, glycogen and starch.

Question 10

What is the function of glycogen?

Answer 10

It is a storage substance in animals and fungi.

Question 11

Plants store ___ in their roots and stems.

Answer 11

Starch

Question 12

Examples of disaccharides

Answer 12

-Sucrose

-Maltose

-Lactose

Question 13

What are the monomers of sucrose?

Answer 13

Glucose and fructose

Question 14

What are the monomers of maltose?

Answer 14

Glucose (2 units)

Question 15

What are the monomers of lactose?

Answer 15

Glucose and galactose

Question 16

Examples of polysaccharides

Answer 16

-Starch

-Glycogen

-Cellulose

Question 17

What is the similarities and differences between starch and cellulose?

Answer 17

They are both made up of the same monomer- glucose- but they differ in the arrangement of glucose molecules and the position of the glycosidic bonds.

Question 18

Glucose is an example of a reducing sugar. Describe how a food sample could be tested to see whether or not it contained glucose

Answer 18

Add drops of Benedict’s solution to the food sample in a test tube; heat sample with
Benedict’s solution in it in a water bath; if Benedict’s solution turns green / orange / brick-red
glucose is present (greater colour change indicates greater concentration of glucose); if
Benedict’s solution remains blue no glucose is present in food sample.