Lipids, Proteins, Vitamins, and Water

What are liquid fats called?

Oils.

What are solid fats called?

Fats.

What is one function of lipids in the body regarding energy?

As a store of energy, used only after carbohydrates have been utilised.

Why are lipids stored in adipose tissue?

To reduce heat loss.

What protective function do lipids serve?

Lipids act as a shock absorber to protect organs.

What structural role do lipids play in cells?

Lipids are a component of the cell membrane.

Name two examples of lipids found in plants.

Maize (corn) and nuts.

Name two examples of lipids found in animals.

Butter and fatty meat.

What are the steps of the ethanol emulsion test for liquid food?

Add 2 cm³ of ethanol to a few drops of a liquid food sample, shake for about 5 minutes, then add 2 cm³ of water and observe.

What are the steps of the ethanol emulsion test for solid food?

Cut the sample into small pieces, add 2 cm³ of ethanol, shake for 5 minutes, let solids settle, then pour the ethanol portion into 2 cm³ of water.

What are proteins made of?

Proteins are made of amino acids.

How many types of amino acids make up proteins?

There are 20 types of amino acids that make up proteins.

Name examples of foods rich in protein.

Cheese, beef, egg, fish, and bean.

What is a major function of proteins in the body?

For body growth and repair of body tissues.

What do proteins help form in the body?

Proteins are used to form antibodies, enzymes and hormones.

What happens to excess amino acids in the body?

Excess amino acids are deaminated (broken down) to give urea.

What are the steps of the Biuret test for proteins?

Add 2 cm³ of Biuret solution to 2 cm³ of the sample, shake well, then observe and record after 5 minutes.

What are the steps of the DCPIP test for vitamin C?

Add 1 cm³ of DCPIP solution to a test tube, then add vitamin C solution drop by drop until the DCPIP becomes colourless.

What is a positive result in the DCPIP test for vitamin C?

A colourless DCPIP solution is a positive result for vitamin C.

What are the key characteristics of vitamins?

Vitamins are needed in small amounts, have no energy value, and help regulate metabolic reactions.

What is one function of water as a solvent in the body?

Water acts as a solvent so that metabolic and chemical reactions, such as respiration, can occur in body cells.

How does water function as a transport medium?

Water transports substances such as glucose and urea in the blood.

What role does water play in digestion?

Water acts as a solvent for digestive enzymes and nutrients in the digestive tract so digestion can occur.

When are lipids used as an energy source?

Lipids store energy and are used only after carbohydrates are used up.

What is the main storage site for fats in the body?

Adipose tissue stores fat for insulation and shock absorption.

What is the common name for liquid fat?

Oil is a liquid fat.

What is the common name for solid fat?

Fats are solid fats.

Which solution is used to test for vitamin C?

Vitamin C is detected using DCPIP solution.

Which solution is used to test for proteins?

Biuret solution is used to test for proteins.