Biology Food

Objectives for food State the Function of Food Name three reasons for requiring food Name six common chemical elements in food: C, H, N, O, P, S Name five elements present in dissolved salts: Na, Mg, Cl, K, Ca Name 3 trace elements required: Fe, Cu, Zn Define Biomolecular Structures State that simple biomolecular units are composed of a combination of elements in different ratios. Eg carbohydrates Cx(H2O)y Name the element components, biomolecular components and sources of: carbohydrates, fats & oil and proteins. State that carbohydrates are composed of indivisible units and give examples of these. Eg. Monosaccharide – glucose; Disaccharides – maltose; and Polysaccharides - starch/cellulose. State that carbohydrates & lipids act as a primary source of energy. State carbohydrates role as cellulose in cell walls State that proteins act as enzymes and are made of amino acids State proteins role as fibrous protein e.g. keratin or as myosin State that hormones (protein) act as regulators of metabolic activity. State the role of lipids as Phospholipids in cell membranes State the requirements & use of any 2 minerals in plants. State the requirements & use of any 2 minerals in animals. Explain what a vitamin is. Name one water-soluble vitamin. Name one water in-soluble (fat-soluble) vitamin. List the sources of these vitamins State that vitamin C & D are used for tissue growth, cell production and health maintenance. Name disorders associated with deficiency of a water-soluble and a water in-soluble vitamin. State 5 good reasons why water is important for organisms. Define of the terms: Anabolic and Catabolic. Give an example of each

Food is needed for: 1.Energy 2.Growth of new cells and Repair of existing cells, tissues, organs, etc. 3. Provides materials needed for metabolism

What is Food made up of? Food is made up of: Six chemical elements C, H, O, N, P, S Salts of Na, Mg, Cl, K, Ca Three trace elements Fe, Cu, Zn

Chemical Elements and their Symbols CalciumCaNitrogenN CarbonCOxygenO ChlorineClPhosphorusP CopperCuPotassiumK HydrogenHSodiumNa IronFeSulphurS MagnesiumMgZincZn

Test yourself… What are three functions of food? There are six elements present in food. Can you name them? What elements are present in salts found in our bodies? Name 3 trace elements.

By the end of today’s class you should be able to… Define Biomolecular Structures State that simple biomolecular units are composed of a combination of elements in different ratios. Eg carbohydrates Cx(H2O)y Name the element components, biomolecular components and sources of: carbohydrates, State that carbohydrates are composed of indivisible units and give examples of these. Do a test for the presence of reducing sugar in food.

Types of Food Food is made up of six different food groups WaterProteins Lipids Carbohydrates Vitamins Minerals

Humans need to consume a balanced diet which contains all of the nutrients in different amounts for the needs of the body The main nutrients the body needs are: carbohydrates for energy; proteins for growth and repair; fats to store energy; vitamins and minerals to keep the body healthy. Which food type does the body need the most of?

What is a balanced diet?

Nutrients in food

Learning check What are the six different food components? WaterProteins Lipids Carbohydrates Vitamins Minerals

Carbohydrates Carbohydrates contain the elements CarbonHydrogenOxygen The general formula for a carbohydrate is C x (H 2 O) y There are twice as many hydrogen molecules as oxygen molecules

A common carbohydrate General formula = C x (H 2 O) y When x = y = 6 We get the formula C 6 H 12 O 6 What is the name of this monosaccharide carbohydrate? Glucose

Another common carbohydrate General formula = C x (H 2 O) y When x = 12 and y = 11 We fet the formula C 12 H 22 O 11 What is the name of this disaccharide carbohydrate? Sucrose

Learning check Name the three elements that make up carbohydrates CarbonHydrogenOxygen What is the general formula for a carbohydrate? C x (H 2 O) y

Carbohydrates which are made of long chains of identical small sugar molecules. carbohydrate molecule one sugar molecule The long chains of carbohydrates are broken down into the smaller sugar molecules These are used by the body to release energy

3 Types of Carbohydrate Monosaccharides Disaccharides Polysaccharides

Monosaccharides These are single sugar molecules smallest carbohydrate unit Examples:glucose, fructose Found in:fruit

Disaccharides These are two monosaccharide sugar units joined together – known as double sugar molecules Examples: sucrose, lactose, maltose Found in:table sugar, milk

Polysaccharides These are Many sugar molecules joined together Example:starch, cellulose Found in:bread, pasta, cereals

Learning check Name the three types of carbohydrate Monosaccharides Disaccharides Polysaccharides

To test for the presence of a reducing sugar Stand the two test tubes in boiling water for about 3 minutes. If sugar is present in a food it will turn Benedict's solution from blue to red

How can you test different foods for the presence of a simple sugar.. It has to be a fair test There has to be a control experiment – a standard to compare the other experiments against.

Can you.. Name the elements present in carbohydrates? Know the ratio which describes carbohydrates? Know the ratio of oxygen to hydrogen in carbohydrates? Know the three types of carbohydrates and give examples of them? Describe how to do a test for the presence of reducing sugar in food.

To test for the presence of starch Iodine turns from yellow/brown to blue/black if starch is present

Learning check Give examples and sources of: ExamplesSources Monosaccharide s Disaccharides Polysaccharides Glucose Fructose fruit Sucrose Lactose Table sugar Milk Starch Cellulose Bread, Pasta, Cereals

The‘Structural Role of Carbohydrates The function/job of carbohydrates in making parts of living things Cellulose (polysaccharide) found in plant cell walls Chitin (polysaccharide) found in insect exoskeletons

The Metabolic Role of Carbohydrates the function of carbohydrates in the chemical reactions in cells These are the primary sources of energy for metabolism – e.g. glucose (carbohydrate) is an immediate source of energy

What a lipid is The structure of triglycerides and phospholipids How to test for fats Some sources of fat in our diet.

Lipids Are: fats (solid at room temp.) oils (liquid at room temp.) steroids which include cholesterol and some of the sex hormones waxes which cover insect bodies and plant leaves.

Structure of Lipids They are made up of the elements carbon hydrogen oxygen But dont have the same ratios as carbohydrates.

Lipids are made up of fatty acids and glycerols What are fats? fat molecule glycerol fatty acids

Triglyceride It is made up of 3 fatty acid molecules and 1 glycerol molecule This is the smallest lipid

Phospholipids If one fatty acid of a lipid molecule is replaced by a phosphate group then a phospholipid is formed

A special test for the presence of lipids Lipids make brown paper go translucent (light passes through it very easily) Sources of Lipids Fat – in and on meat Butter (80% fat) Cooking oils

Structural role of Lipids Heat insulation – e.g. under the skin Protection around body organs e.g. kidney, heart Phospholipids and lipoproteins are major parts in cell membranes

Metabolic Role of Lipids These are the primary sources of energy for metabolism – e.g. lipids are a long-term energy storage

What a lipid is The structure of triglycerides and phospholipids How to test for fats Some sources of fat in our diet. The role of fats in our diet

What a protein is How to test for proteins Some sources of protein in our diet.

Proteins Proteins contain the elements Carbon Hydrogen Oxygen Nitrogen Some may also contain sulphur, phosphorous or iron

What are proteins? protein molecule one amino acid Proteins are made up of chains of small molecules called amino acids. There are over 20 different kinds of amino acid. Amino acids are joined together by peptide bonds This results in the formation of polypeptide chains

Learning check Proteins contain the elements Carbon Hydrogen Oxygen Nitrogen Sometimes they contain sulphur, phosphorous or iron Proteins are made up of long chains of amino acids

To test for the presence of protein in food: Dissolve the food in some water. Add 2cm 3 of BIURET SOLUTION If protein is present the solution will turn from a blue to a purple colour!

Sources of protein Milk Eggs Cheese Meat Nuts

Structural role of Proteins Proteins combine with phospholipids to from cell membranes Keratin is the structural protein in skin, hair and nails Myosin is the structural protein in muscle

Metabolic Role of Proteins Enzymes ( made of protein) control the rate of chemical reactions in cells. Chlorophyll is a protein that traps the sun’s energy during photosynthesis

Metabolism (all of the chemical reactions in a living thing) Anabolic reactions Catabolic reactions Small molecules are combined to make larger molecules. Energy is needed Large molecules are broken down into smaller molecules. Energy is given out.

Respiration Glucose is burnt with oxygen in the body to make energy. Carbon dioxide and water are also made. Photosynthesis Carbon dioxide and water taken in by a plant. Light is needed. The plant makes glucose.

Metabolic Role of Hormones Hormones are made of lipids or protein Hormones regulate body functions e.g. the hormone insulin controls the amount of glucose in the blood

Metabolic Role of Vitamins Definition: Vitamins are organic substances needed in small amounts for the metabolism to function normally

Class activity Make up your own fact sheet on Vitamin C and Vitamin D Do these on PowerPoint slides. One for each Vitamin. Then save the file with your name and send it on. You should have: Sources, functions, is it water soluble, and one deficiency disease. Use pictures if you can when finished!!!

Vitamin C Solubility:water soluble Function: for building connective tissue i.e. tissue used for attaching organs together Source: Fruit

Scurvy – not enough vitamin C Loose teeth, bleeding gums

Vitamin D – Fat soluble Needed to absorb calcium from the blood which builds strong bones and teeth Source: Milk, cheese, yogurt,sunlight

Rickets in children – not enough vitamin D Softened bones or bow legs

Need to know Describe what an anabolic and a catabolic reactions are and give examples State the metabolic role of fats State the metabolic role of carbohydrates State the metabolic role of proteins State the metabolic role of hormones Define vitamin State the functions and sources of vitamin C & D Name disorders associated with deficiency of a water soluble and a fat-soluble vitamin

Water (H 2 0) 1.It is a solvent for transporting substances in blood or in plants 2.It is where chemical reactions take place in cells 3.It is a reactant/product in chemical reactions 4.Controls cell shape. It is slow to heat up and cool down – kept at a fairly steady temperature – helps to keep a constant rate of metabolism.

Minerals Minerals are salts formed from the earth’s rocks. The salts then dissolve in water and are absorbed by plants. Animals then eat the plants.

Minerals and Plants They use: Calcium (Ca) to make cell walls Magnesium (Mg) to make the pigment chlorophyll

Minerals and Animals They use Calcium (Ca) to make bones and teeth Iron (Fe) to make the pigment haemoglobin