Biomolecules: Structure Function

Most of the molecules in your body are one of four things: - carbohydrates - lipids - proteins - nucleic acids a d b c

 General formula is (CH 2 O) n  Classified as Simple or Complex  Simple = one carbohydrate unit (glucose) = monosaccharide  Complex = many carbohydrate units (starch) = polysaccharide  Provide major source of easily accessible energy  Water soluble

 Glucose is the monosaccharide most readily used by cells, and the only source of energy for the brain  Starch is a polysaccharide stored in roots and seeds for future energy needs  Cellulose is indigestible in humans and is used by plants to provide rigidity  Glycogen is how animals store carbohydrates for future needs

 Cereal grains such as wheat and rice contain many complex carbohydrates  Root crops such as potatoes and carrots contain large quantities of carbohydrates  Fruits contain many sugars (monosaccharides and disaccharides)  Candy, soda, and other sweets are very high in monosaccharides

 A lipid is the technical name for a triglyceride (fat) or steroid (cholesterol)  Triglycerides are a glycerol attached to 3 fatty acids  The fatty acids are non-polar, long hydrocarbon chains  A chain with all single bonds is saturated  A chain with one or more double bonds is unsaturated.

 Saturated fats have the maximum number of hydrogen atoms on them  Saturated fats tend to be solids at room temperature

 Unsaturated fats, with their double bonds, can hold more hydrogen atoms  Unsaturated fats tend to be liquids at room temperature

 Very large molecules  Fundamental to structure and function of all organisms  Often consist of 2 or more subunits held in place by covalent bonds  Each subunit is made of a very long chain of amino acids which folds up on itself  Bond joining amino acids is called a peptide bond

 Basic structure of an amino acid: Acid group Functional Group Amine Group

The amino acid is determined by the “R” group, shown here in blue. Note that small differences in the “R” structure result in a totally different amino acid.

 The structure of a protein is determined by the order of the amino acids and their respective polarities  Non-polar functional groups attract non-polar functional groups  Polar functional groups attract polar functional groups  The protein folds as the different functional groups are attracted to each other and the protein takes its shape in this manner

 Meats, eggs, seafood are all excellent sources of protein but contain significant amounts of fat  Dairy products are also good sources of protein but contain sugar (lactose) and fat  Legumes, including beans and lentils, are excellent sources of protein  Soy products such as tofu are excellent sources of protein  Egg whites are pure protein; all the fat in an egg is in the yolk

 Proteins have many functions  Provide structure (hair, nails, muscle)  Enzymes = catalyze chemical reactions  Hormones = signaling between tissues  Antibodies = recognizing pathogens (germs)  Storage and Transport  Across cell membrane  Hemoglobin

 With your seat partner: 1. Without looking at your notes, name 3 different foods that contain each of the 3 biomolecules we’ve discussed so far? 2. Why do you think it is important for our bodies to get a balanced diet of all of these foods?

 Nucleic acids are found in the nucleus  Contain information that is passed from generation to generation – genetic material  Two forms  Deoxyribonucleic acid (DNA)  Ribonucleic acid (RNA)

 DNA stays in nucleus  Double helix  EXTREMELY large  Nitrogenous bases  Adenine  Guanine  Cytosine  Thymine  RNA leaves nucleus  Single strand  Large, but not very  Nitrogenous bases:  Adenine  Guanine  Cytosine  Uracil

 1. What are the 4 macromolecules most common in living organisms?  2. Which macromolecule includes starches and sugars?  3. What is the difference between saturated and unsaturated fats?  4. What are the building blocks of proteins called?  5. What are 3 things our body uses proteins for?  6. Which type of nucleic acid uses deoxyribose sugar?