Chapter 4

Why is water so important?

• Water is an important solvent.

• It controls body temperature.

• Important in photosynthesis

• Transports dissolved substances

What is the simplest unit for carbohydrate ?

Glucose

What is the chemical formula of glucose?

C6H12O6

What are the simples sugars (monosaccharides)?

• Glucose

• Fructose

• Galactose

What does monosaccharides mean?

It means that the substance cannot be broken down any further.

What are the Disaccharides?

• Maltose

• Sucrose

• Lactose

What is disaccharides?

It is formed through the joining of two monosaccharides.

What is Maltose made of?

Glucose + Glucose

What is Sucrose made of?

Glucose + Fructose

What is Lactose made of?

Glucose + Galactose

What are the Polysaccharides?

• Starch

• Glycogen

• Cellulose

What form does starch exist as and what is its function?

• It exists in a branched and unbranched form

• Its function is that it is the storage of carbohydrates in the root of the plant.

What form does Glycogen exist as and what is its function?

• It is more branched.

• It is the storage of carbohydrate in mammals.

What form does Cellulose exist as and what is its function?

• It is arranged in rows with cross sections.

• It forms a rigid cell wall to prevent bursting.

What is the simplest unit of fat?

Glycerol and Fatty Acids.

What are the elements that form protein?

Carbon, Hydrogen, Oxygen, Nitrogen/ Sulfur

What is the simplest unit of Protein?

Amino Acid

What is the full name of DNA?

Deoxyribonucleic Acid

How do you test for Reducing sugar?

• Add an equal volume or excess of benedict solution to the food sample in test tube

• Place in a hot water bath for a few minutes

• If reducing sugar is present, a brick-red precipitate is formed, if not the solution remains blue

How do you test for Proteins?

• Add a few drops of Biuret’s reagent to the food sample in a test

• Shake the solution to mix and wait for a few minutes'

• If protein is present the solution turns from blue to purple

How do you test for Carbohydrates/ Starch?

• Put some food sample into a test tube

• Add a few drops of Iodine Solution to the food sample using a pipette

• If starch is present, the solution turns from brown to black

How do you test for Fat?

• Add a few cm³ of ethanol to the food sample

• pour this mixture into a test tube of equal volumes of distilled water

• If lipids are present a white emulsion is formed on the surface of the mixture

What is the test for Protein called?

Biuret test

What is the test for Carbohydrates called?

Starch Test

What is the test for Reducing Sugars called?

Benedict Test

What is the test for Fats called?

Ethanol Emulsion Test