2 Life’s molecular diversity is based on the properties of carbon Most compounds in living organisms are organic – composed of carbon bonded to other elements. Functions of organic compounds:Main structural components of cells and tissuesParticipate in and regulate many chemical reactionsProvide energy
3 By sharing electrons, carbon can bond to four other atoms. This allows for branching in up to four directions.
4 A chain of carbon atoms is called a carbon skeleton. Carbon skeletons can be branched or unbranched.Therefore, different compounds with the same molecular formula but different properties can be produced.These structures are called ISOMERS.
8 An organic compound has unique properties that depend upon: The size and shape of the molecule andThe groups of atoms (functional groups) attached to it.A functional group affects a biological molecule’s function in a characteristic way.Compounds that contain functional groups are hydrophilic (water-loving)
9 Cells make a huge number of large molecules from a small set of small molecules Four classes of biological molecules:CarbohydratesLipidsProteinsNucleic Acids
10 The four classes of biological molecules contain very large molecules They are often called macromolecules because of their large sizeThey may also be called polymers when they are made from identical building blocks strung togetherThe building blocks of polymers are called monomers.
11 Dehydration synthesis (condensation) is the linking of monomers by the removal of water. This reaction builds polymers.
12 Hydrolysis (“to break, with water”) breaks down polymers to monomers by adding water. A good example of hydrolysis is when you digest your food!
13 Carbohydrates Serve as fuel and structural components for cells General structure: contain carbon, hydrogen and oxygen in a ratio of about1:2:1
14 Classification of Carbohydrates Monosaccharides: contain one type of sugar unitDisaccharides: contain two types of sugar unitsPolysaccharides: contain many sugar units
15 Monosaccharides Also known as simple sugars Example: glucose is an important fuel molecule in living cellsMonosaccharides are also used as raw materials to manufacture other organic moleculesMonosaccharides are the monomers for disaccharides and polysaccharides.
16 Polysaccharides Composed of repeating monosaccharide units They can function in the cell as a storage molecule or as a structural compound
17 Storage Polysaccharides Starch – storage polysaccharide of plantsGlycogen – storage polysaccharide of animals
18 Structural Polysaccharides Cellulose is a polymer of glucose that forms plant cell walls.Chitin is a polysaccharide that is a structural component of the exoskeleton of insects and crustaceans. (also used in surgical thread for stitches that dissolve!)
19 Lipids (fats)Lipids are water insoluble (hydrophobic – “water fearing”) compounds that are made from glycerol and fatty acids.They contain twice as much energy as a polysaccharide, so their main function is long-term energy storage.
20 Lipids differ from other organic compounds in that they are neither huge macromolecules nor polymers.Three types of lipids:FatPhospholipidsSteroids
21 Types of Fats:Unsaturated – corn oil, olive oil, and other vegetable oils. Liquid at room temperature.Saturated – have the maximum number of hydrogens. Examples include beef fat and butter. Solid at room temperature.Trans fat – made by adding hydrogen to unsaturated fats. Associated with health risks.
22 Phospholipids – a modified fat that is the main structural component of cell membranes. Steroids – cholesterol is a common component of cell membranes. Animal cells use it as a precursor for making other steroids, including hormones.
23 ProteinsA protein is a polymer built from various combinations of 20 amino acid monomers.
24 Proteins are essential to the structures and functions of life Structural proteins provide associations between body parts.Contractile proteins are found within muscle.Defensive proteins include antibodies of the immune system.
25 Signal proteins are best exemplified by the hormones Receptor proteins serve as ‘antenna’ for outside signalsTransport proteins carry oxygen.Enzymes regulate the chemical reactions within cells.
26 Proteins are made from amino acids linked by peptide bonds This is done by means of an enzyme-mediated dehydration synthesis.A polypeptide chain contains hundreds or thousands of amino acids.The amino acid sequence causes the polypeptide to assume a particular shapeThe shape of a protein determines its specific function.
27 Levels of protein organization Primary structure – unique sequence of amino acidsCorrect amino acid sequence is determined by the cell’s genetic informationThe slightest change in this sequence affects the protein’s ability to function.
28 Secondary structure – coiling or folding of the peptide chain Coiling results in a helical structure called an alpha helixFolding may lead to a structure called a beta pleated sheet.