Chap 3- Food and Nutrition

Biomolecules

Biomolecules

The chemical sub-units that make up foods

Nutrition

This is the way in which organisms obtain and eat food

Functions of food

Triggers and maintains metabolic rate, and the continuity of life

Metabolism

The total of all chemical reactions happening within and organism

Six non-metal elements

Carbon, Hydrogen, Oxygen, Nitrogen, Sulphur, and Phosphorus

Five elements present in salts

Sodium, Magnesium, Chlorine, Potassium and Calcium

Trace elements found in organisms

Iron, Copper, Zinc

Macro-Nutrients

Needed by the body in large amounts (Carbohydrates, Lipids, Proteins)

Micro-Nutrients

Needed in far smaller amounts (Vitamins and Minerals)

Carbohydrates

CxHyOx - divided into three groups of monosaccharides, disaccharides, and polysaccharides

Monosaccharides

Single sugar units, glucose, fructose, and galactose

Disaccharides

Double sugar units, formed when 2 monosaccharides join. Glucose + glucose = maltose, glucose + fructose = sucrose, glucose and galactose = lactose

Polysaccharides

Many sugar units, made of many monosaccharides joined together in long chains. Starch, cellulose, glycogen

Test for starch

Iodine in starch solution

Test for sugar

Benedicts solution using heat in sugar solution

Structure of lipids

All lipids contain one glycerol and fatty acids

Two types of lipids

Triglycerides and phospholipids

Triglycerides composition

One glycerol, three fatty acids in an E like shape

Phospholipid composition

One glycerol, two fatty acids and a phosphate

Test for the presence of fat

Brown paper test

Protein elemental composition

Carbon, Hydrogen, Oxygen, Nitrogen. Some include Sulphur or Phosphorus

Metabolic Functions of protein

Hormones: regulate different functions in the body, e.g. menstruation, Antibodies: fight infection

Structural functions of protein

Growth and repair of cells, keratin is a protein found in skin, hair, and nails

Sources of protein (animal)

Meat, fish, eggs, milk, cheese

Sources of protein (plant)

Peas, beans, nuts, lentils, cereals

Structure of protein

Long chains of amino acids held together with peptide links

Fibrous proteins

Have little to no folding, long and strong fibres, e.g. keratin

Globular proteins

Lots of folding, found in enzymes and egg whites

Test for protein

Sodium Hydroxide and Copper Sulphate

Vitamins are

needed by organisms in small amounts, made in plants, and grouped into two distinct categories, classified by solubility

Vitamin classifications

Fat-soluble and water-soluble

Fat Soluble vitamin examples

A, D, E, K

Water Soluble vitamin examples

B group, C

Metabolic role of vitamin D

Absorption of the calcium into the digestive system, to help form strong bones and teeth

Metabolic Role of vitamin C

Formation of collagen, helps firm cell membranes and linings, healthy gyms and prevents colds and flus

Minerals in plants

Calcium (middle lamella), Magnesium (Chlorophyll)

Minerals in animals

Calcium (bones and teeth, Phosphorus), Iron (haemoglobin)

Function of water

Hydrates cells, good solvent, transports dissolved minerals, carrys out hydrolysis, allows cells to maintain shape