Presentation on theme: "2.3 Carbon-Based Molecules KEY CONCEPT Carbon-based molecules are the foundation of life."— Presentation transcript:
2.3 Carbon-Based Molecules KEY CONCEPT Carbon-based molecules are the foundation of life.
2.3 Carbon-Based Molecules Carbon atoms have unique bonding properties. Carbon forms covalent bonds with up to four other atoms, including other carbon atoms: building block of life Carbon-based molecules have three general types of structures –straight chain –branched chain –ring
2.3 Carbon-Based Molecules Many carbon-based molecules are made of many small subunits bonded together. –Monomers are the individual subunits. –Polymers, large molecules or macromolecules, are made of many monomers
2.3 Carbon-Based Molecules Four main types of carbon-based molecules are found in living things. Carbohydrates are made of carbon, hydrogen, and oxygen, and include sugars and starches
2.3 Carbon-Based Molecules Four main types of carbon-based molecules are found in living things. Carbohydrates are made of carbon, hydrogen, and oxygen. –Monomer is called a monosaccharide or simple sugar: glucose –Disaccharide is TWO monosaccharide: sucrose –Polysaccharides include starches, cellulose, and glycogen.
2.3 Carbon-Based Molecules Function: Carbohydrates can be broken down to provide energy for cells. Function: Some are part of cell structure. Polymer (starch) Starch is a polymer of glucose monomers that often has a branched structure. Polymer (cellulose) Cellulose is a polymer of glucose monomers that has a straight, rigid structure monomer
2.3 Carbon-Based Molecules –Many contain carbon chains called fatty acids. –Fats and oils contain fatty acids bonded to glycerol. Lipids are nonpolar molecules made of carbon, hydrogen & oxygen & include fats, oils, and cholesterol. Triglyceride Four main types of carbon-based molecules are found in living things.
2.3 Carbon-Based Molecules Lipids have several different functions. –broken down as a source of energy –make up structure of cell membranes – used to make hormones
2.3 Carbon-Based Molecules Fats and oils have different types of fatty acids. –Saturated: maximum # of H possible in the chain; solid animal fats like butter & in meat –Unsaturated: NOT saturated with H; liquid oils like plant oils (olive, peanut, corn, etc.)
2.3 Carbon-Based Molecules Phospholipids make up all cell membranes. –Polar phosphate “head” –Nonpolar fatty acid “tails” Phospholipid Cholesterol is a lipid with a ring structure. –A certain amount of cholesterol is necessary for life –Hormones: Control stress (e.g. cortisol) and sexual development (e.g. testosterone & estrogen)
2.3 Carbon-Based Molecules Proteins are polymers of amino acid monomers and are the most varied of the carbon-based molecules. –contain carbon, hydrogen, oxygen, nitrogen and sometimes, sulfur. Four main types of carbon-based molecules are found in living things.
2.3 Carbon-Based Molecules –Amino acids have similar structure: an amine group (NH 2 ) and a carboxyl group (COOH) but differ in side groups, or R groups. Proteins are polymers of amino acid monomers. –Twenty different amino acids are used to build proteins in organisms. The body can make 12; others come from foods like meat, beans & nuts.
2.3 Carbon-Based Molecules –Amino acids form covalent bonds, called peptide bonds, between C-N –Amino acids are linked into chains called polypeptides –A protein is one or more polypeptides Proteins are polymers of amino acid monomers.
2.3 Carbon-Based Molecules Proteins differ in the number and order of amino acids. –Amino acids interact to give a protein its specific shape (structure) and, therefore, function (job) –Incorrect amino acids change a protein’s structure and function. hydrogen bond Hemoglo bin
2.3 Carbon-Based Molecules A protein can have just about any function, depending on its structure –Contractile proteins actin and myosin function in muscle movement –Hemoglobin is a protein, globin, bonded to a pigment, heme, which binds & transports oxygen in the body –Skin, hair & nails contain the protein keratin which provides structure, strength & water-proofing –Enzymes are protein catalysts for chemical reactions in all living things
2.3 Carbon-Based Molecules Nucleic acids are polymers of monomers called nucleotides composed of C, H, O, N and phosphorus (P). Four main types of carbon-based molecules are found in living things.
2.3 Carbon-Based Molecules –Nucleotides are made of a sugar, phosphate group, and a nitrogen base. A phosphate group nitrogen-containing molecule, called a base deoxyribose (sugar) Nucleic acids contain the instructions or code to build proteins.
2.3 Carbon-Based Molecules –DNA stores genetic information –Basis for genes & heredity Two basic types of nucleic acids –Several kinds of RNA molecules build proteins based on the DNA code DNA RNA