Food and diet Chapter 4 – part 1

Specifications 2.5 identify the chemical elements present in carbohydrates, proteins and lipids (fats and oils) 2.6 describe the structure of carbohydrates, proteins and lipids as large molecules made up from smaller basic units: starch and glycogen from simple sugar; protein from amino acids; lipid from fatty acids and glycerol 2.7 describe the tests for glucose and starch 2.23 understand that a balanced diet should include appropriate proportions of carbohydrate, protein, lipid, vitamins, minerals, water and dietary fibre 2.24 identify sources and describe functions of carbohydrate, protein, lipid (fats and oils), vitamins A, C and D, and the mineral ions calcium and iron, water and dietary fibre as components of the diet 2.25 understand that energy requirements vary with activity levels, age and pregnancy

What’s in our food? When you look at food labels, what kind of things are interested in?

Some vocabulary Give your definition, where possible, for these terms:

What would you consider a healthy, balanced, diet to be?

All of these molecules, apart from minerals, have three elements in common. Can you name them? 

Carbohydrate Name some sources of carbohydrates.

Carbohydrates Carbohydrate Carbon (C) Water (H 2 O) What is the chemical formula of glucose? Does this agree with the above description?

Carbohydrates are the main source of energy for the body. Suggest a process in which they may be broken down to produce energy. Hint: Think of how cells get their energy.

Glucose and other sugars are one type of carbohydrate. Can you name other common sugars? Look at the table below to help you: SugarWhere it is found GlucoseIn sweet-tasting foods such as fruit and vegetables. In fruit. In milk. Table sugar (obtained from sugar cane) What do all of these compounds have in common?

Sugar structures galactose

Problems with high sugar- diets  Tooth decay  Obesity  Diabetes  …

Lipids (fats and oils) Name a few examples of fats and/or oil. Do you know what the difference between a fat and an oil is? What is the use of fat in our body?

Lipids’ general structure Lipids are made up of glycerol and fatty acids

Saturated vs. unsaturated lipid Do you know the difference between saturated and unsaturated fats?

No need to learn this yet.

Proteins Name a few sources of protein in our diet. Do you remember a type of protein we have come across before? What does our body use them for?

Protein structure Proteins are composed of amino acids.

Protein deficiency and surplus.  Kwashiorkor  Kidney disease

No need to learn this yet.

Minerals MineralMass in an adult /grams Location and role in body Examples of food Calcium1000Making teeth and bone. Dairy products, fish, bread, vegetables Phosphorus650Making teeth and bones and part of many chemicals. E.g.: DNA. Most foods Sodium100In body fluids such as blood Common salt and most foods Chlorine100In body fluids such as blood Common salt and most foods Magnesium30Making bones, found in cells. Green vegetables Iron3Found in red blood cells, helps carry O 2. Red meat, liver, eggs, some vegetables.

Mineral deficiencies  Rickets  Anaemia

Vitamins

Links – FYI and revision iGCSE and GCSE resources: Article on food waste and loss: