Nutrition Is the way organisms obtain and use food Nutrients are the chemical substances present in food which are used by organisms. They are essential for »metabolism and continuity of life Uses are »Source of energy »To aid metabolism »For growth and repair

14 Food Elements 6 Common elements Carbon Hydrogen Oxygen Nitrogen Phosphorus Sulfur 5 Dissolved salts Sodium Magnesium Chlorine Potassium Calcium 3 Trace elements Iron Copper Zinc

Biomolecules Biomolecules: molecules in which atoms of the 14 elements bond together in various ratios. 4 Major types found in food –Carbohydrates –Lipids –Proteins –Vitamins ( Remember L.C.V.P.)

Features Carbohydrates are the body's source of fuel. It provides energy for daily metabolic activities. Simple carbohydrates are found in simple sugars, such as table sugar, honey, corn syrup, cane sugar, brown sugar. Complex carbohydrates are cereals, breads, pastas, and vegetables. Fruit contains both simple and complex carbohydrates. Simple carbohydrates are rapidly digested; complex carbohydrates are digested slowly. *Carbohydrates

Carbohydrates What are Carbohydrates ??? Composed of Carbon, Hydrogen and Oxygen Ratio of C:H:O is 1:2:1 e.g. C 6 H 12 O 6 Exist in the form of: - simple sugars such as fructose, glucose - double sugars as sucrose (cane sugar) lactose (milk sugar), maltose (malt sugar) - multiple sugars such as starch or glycogen.

Glucose Molecule C 6 H 12 O 6

3 Categories of carbohydrates 1)Monosaccharide's - single sugar unit e.g. Glucose and Fructose - sweet to taste - soluble in water 2)Disaccharides - double sugar unit e.g. Sucrose, Maltose and Lactose - sweet to taste - soluble in water 3)Polysaccharides* - many sugars units e.g. Starch (amylose), Glycogen, Cellulose - insoluble/slightly soluble in water

Sources

Test for reducing sugar - simple sugars

Chemicals used: Benedicts solution (blue) Heat required: yes ( water bath) Results: colour change from blue to BRICK RED if sugar is present Control: water

Test for Starch

2. Lipids (Fats and Oils) Contain Carbon, Oxygen and Hydrogen No simple ratio of composition Contain very little oxygen Fats are lipids that are solid at room temp Oils are lipids that are liquid at room temp Sources of lipids – butter, oils, margarine, cream, lard, fat on meat, olives

Structure of Lipids Triglycerides The smallest lipids contain one molecule of glycerol linked to 3 fatty acid molecules Phospholipids One fatty acid is replaced by a phosphate group. Play an NB role in cell membrane structure

Test for fat

Fat Test Worksheet on Food Test

Materials used: brown paper Result: if permanent stain remains on paper, fat is present Control: water

3. Proteins Contain Carbon, Oxygen, Hydrogen and Nitrogen May also contain small amounts of sulfur and phosphorus No ratio Very large and complex molecules Constructed from building blocks called Amino Acids

Amino acids are biochemical building blocks.biochemical Twenty amino acids are encoded by the standard genetic code and are called standard amino acids.genetic code Rarer, more complicated amino acids are produced by the body and are called nonstandard. *Structure of Proteins

Amino acid structure Amine group Carboxylic acid group The R group. This group differs between AA

Amino acids form short polymer chains called peptides or polypeptides which in turn form structures called proteins.polymerpeptides polypeptidesproteins Peptide Polypeptide Protein

Each type of protein has a different AA sequence The folding of the AA chain impacts on the function of the protein: o Fibrous proteins show little or no folding. Form strong fibres e.g. keratin, collagen o Globular proteins have well defined folding – specific shape e.g. enzymes o Prions: proteins which do not fold correctly. These proteins are responsible for brain and nervous system diseases – BSE, CJD Protein Function

Sources of Proteins Sources of proteins are meat, fish, eggs, nuts, milk Note: the body doesn’t store AA. Broken down in the liver, and the amine group is converted to urea for excretion in the urine.

Test for Protein - Biuret test

Chemicals used: sodium hydroxide & copper sulphate Heat required: No Results: colour change from blue to violet if protein is present Control: water

4. Vitamins Complex organic compounds that the body can’t make Needed in tiny amounts Vitamin C (ascorbic acid) Water soluble Sources: fruit and veg Forms connective tissue, bone and teeth, Helps healing and immune system. Deficiency - Scurvy Vitamin D (calciferol) Fat soluble Sources: cod liver oil, milk, UV Helps absorb Ca for bones and teeth Deficiency – rickets or osteomalacia (brittle bones)

Types of energy transfer reactions Metabolism is the full set of chemical processes (anabolic + catabolic) carried out by a living organism Anabolic reactions convert smaller molecules into larger molecules. They require energy input. »e.g.. Photosynthesis Catabolic reactions involve the breakdown of large complex molecules into smaller simpler molecules. Catabolic reactions release energy. »e.g.. Aerobic respiration

Roles of Biomolecules Biomolecule Carbohydrate Lipid Protein Vitamin Structural role Cellulose in cell walls Energy stores Protection (kidneys) Insulation (under skin) Formation of cell membranes Keratin in hair, nails, hooves Myosin in muscle Metabolic role Primary source of energy Enzyme, Antibody and Hormone formation. 2 nd source of energy Healthy tissue, bone and tooth formation. Healing and immune system function.

14 Food Elements 6 Common elements Carbon Hydrogen Oxygen Nitrogen Phosphorus Sulfur 5 Dissolved salts Sodium Magnesium Chlorine Potassium Calcium 3 Trace elements Iron Copper Zinc

Minerals Minerals are inorganic nutrients obtained within mineral salts Functions are  To form rigid structures e.g. Ca in bones, teeth and cell walls of plants  To form soft body parts e.g. S in muscle formation  To function in cellular and body fluids e.g. Fe formation of haemoglobin. Mg formation of Chlorophyll. P formation of ATP

Water Water is essential for life for three reasons: 1)liquid in which all metabolic reactions take place. 2)provides the basis for transport systems in organisms. 3)environment in which many organisms live

Water Importance of Water for living things A)Component of cytoplasm and body fluids: - water makes up 75 – 90% of the mass of most cells. - mainly found in the cytoplasm. - humans 1/3 of body’s water found outside cells. B) Good Solvent: Water can dissolve a wide range of molecules and as a result: - allows chemical reactions to take place in water, in the cytoplasm and in cell organelles. - allows many molecules to dissolve in water for transport in plants and animals.

Importance of Water for living things C) Participates in chemical reactions: Water is involved in several biochemical reactions - Condensation Reactions – smaller molecules join to form larger molecules with the loss of water e.g. formation of maltose. - Hydrolysis Reactions – a molecule gains water and is broken down to form smaller molecules e.g. breaking of a dipeptide bond. - Photosynthesis* - Respiration* D) Movement through membranes: Water can easily pass in and out of cells giving them the correct shape.

Importance of Water for Living things E) Good absorber of heat: Water is a good absorber of heat energy which provides stable temperatures for living things and their reactions.

Food Test Summary Table Food tested Chemicals usedPositive result StarchIodineBlue Black GlucoseBenedict's solnRed FatBrown paperPermanent stain ProteinSodium hydroxide + copper sulphate purple