Biological Molecules The Chemistry of Living Things

How to take notes Molecule Type # of calories Food sources How to test for... Uses in the body Compo sed of... Other important information

Organic Compounds --Organic compounds are compounds that contain carbon and hydrogen. --99% of all living things are composed of the elements Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorous, and Sulfur (CHNOPS). --The four major molecules in living things are: 1. Carbohydrates 2. Fats 3. Proteins 4. Nucleic Acids

Carbohydrates Carbohydrates are sources of quick energy. They are composed of smaller sugar molecules. They are composed of carbon, hydrogen, and oxygen. Provide 4 cal/gram food energy.

Carbohydrates continued... Monosaccharides are single sugar carbohydrates; glucose and fructose are examples. Disaccharides are made from two sugar molecules linked together. Sucrose, maltose, and lactose are examples. Monosaccharides and disaccharides are called simple sugars.

Carbohydrates continued... Polysaccharides are made from many monosaccharides bonded together. These are called complex carbohydrates. Cellulose, glycogen, and starch are examples.

Important carbohydrates Starch is produced in plants as an energy storing molecule. Starch molecules are long, straight, twisted molecules.Glycogen is an energy storing molecule produced in the liver of animals and is made of chains of smaller carbohydrates.

Foods containing carbohydrates sugars grains and breads pasta potatoes Carbohydrates dissolve in water

Testing for carbohydrates Carbohydrates are tested by adding iodine stain. Add 5 drops to a food or a solution. If the color turns dark blue, starch is present. Press to see a carbohydrate moleculePress to see a carbohydrate molecule

Testing for glucose (simple sugar) Add 3ml of Benedict’s solution to 5ml of your sugar solution. Heat in a hot water bath on a hot plate. If there is a color change to brown then glucose is present.

Fats Fats are large molecules of carbon, hydrogen, and oxygen that store energy. Fats do not dissolve in water and are composed of 3 fatty acid molecules and one glyceride molecule.

Fats continued... Fats have 5 major functions: 1. Store and release energy 2. Make cell membranes 3. Make hormones which allow communication 4. Vitamins are carried in and out of cells by fats 5. Protection and insulation

Fats continued... Fats with no double bonds are called saturated fats. Fats with double bonds are unsaturated and easier to break down. Cholesterol and steroids are both fats. Unused carbohydrates are stored as fats. Fats provide 9 cal/gram food energy.

Foods containing fats meat nuts oils butter milk anything that tastes good!

Testing for fats Smear the food sample on a piece of brown paper bag. If a ring is left, after the substance dries, then fat is present. Pre ss Pre ss to see a fat mol ecu le

Proteins Proteins come from the Greek meaning, “of first importance ”. Proteins are the most complex of the basic molecules. Proteins provide 4 cal/gram food energy.

Proteins continued... Serve many functions in living organisms: 1. Structure: make muscles, etc. (building blocks) 2. Enzymes: help reactions occur 3. Antibodies: fight disease 4. Transportation: carry molecules around 5. Regulation: control chemical reactions

Proteins continued... Proteins are composed of many amino acids in a long chain. Proteins contain carbon, hydrogen, oxygen, and nitrogen. Proteins are made of combinations of only 20 different amino acids.

Proteins continued... Many amino acids link together to form a polypeptide. Polypeptides, once they have a three dimensional shape, are called proteins. Amino acids must be obtained from foods. Animals can not make them.

Sources of protein Meat Cheese Fish Nuts Beans (amino acids) Rice (amino acids)

Testing for proteins Add 5 drops of Biuret’s Solution to a food source. A change in color of light blue to purple indicates the presence of a protein.

Nucleic Acids Deoxyribonucleic Acid (DNA) and Ribonucleic Acid (RNA) are molecules in cells that carry the genetic code. The work done in cells is largely done by proteins but DNA directs the work being done by the proteins.

Nucleic Acids continued... DNA and RNA are made of nucleotides. 1. a five carbon sugar (deoxyribose in DNA) (ribose in RNA) 2. a nitrogen base (a pyrimidine or purine) 3. and a phosphate group

Nucleic Acids continued... ATP and ADP are nucleotides that are energy transfer molecules in cells. Press here Press to see ATP molecule

Making other molecules The human body is very efficient. It reuses molecules, and breaks many things down to rebuild needed molecules. The process of breaking down is called hydrolysis. The process of building is called dehydration synthesis or condensation. These processes go on in carbohydrates, fats, and proteins.

Making bigger molecules When two molecules bond, energy is stored and water molecules are produced. This process is called dehydration synthesis. Water is removed, thus dehydration. A new and larger molecule is made, thus synthesis.

Making smaller molecules When a large molecule is broken down a water molecule is needed. The process is called hydrolysis. A water molecule is broken (lysis) and the parts used to form the smaller molecule, thus the name hydrolysis. Hydro- meaning water, -lysis meaning to break.

You Are What You Eat ! Purpose/problem: What basic nutrients are in different foods? Hypothesis: Select 5 foods and guess what nutrients are in them. Put in If..Then format for each food, using what you know about testing for different nutrients.

Materials: Some possible materials are: beakers test tubes/test tube rack hot plate Biuret’s solution iodine solution Benedict’s solution graduated cylinder test tube clamp brown paper eye dropper

Procedure: Give a detailed set of procedures showing how you are going to test. Get approval of the teacher before testing. Data: Make a data table to show display your results.

Conclusion: Write a conclusion that answers your hypothesis, discusses the data, and suggests further study. Also, tell which foods, if any, contained more than one nutrient. And, which foods would be considered nutritious and why.