Chp 2 (cont.) Organic Molecules Spider s web and close up of capture strand - spider silk protein 1!
Molecular Diversity is Based on Carbon An organic molecule contains both carbon and hydrogen. Ex: Methane - a simple organic molecule C atoms can bond to 4 other atoms chains, rings, branches A chain of C atoms is called a carbon skeleton Methane
What is the chemical formula for Butane and Isobutane? Ethane Length. Propane Carbon skeletons vary in length. Double bonds. 1-Butene 2-Butene Skeletons may have double bonds, which can vary in location. Branching. Butane Isobutane Skeletons may be unbranched or branched. Rings. Cyclohexane Benzene Skeletons may be arranged in rings. 3!
Cells Make Lots of Large Molecules From a Limited Set of Small Molecules Large organic molecules are called macromolecules Aka. polymers b/c they are made from same units linked together (draw train cars linked) The repeating units are called monomers Nucleic acid polymer Monomer Carbohydrate polymer Monomer Monomer Protein polymer 4!
During dehydration synthesis, an enzyme binds two monomers, releasing a water molecule O O O Short polymer Unlinked monomer Dehydration reaction 2 O O O Longer polymer Building a polymer chain 5!
ydrolysis is the reverse reaction, it breaks polymers into monomers 2 O O ydrolysis O O Breaking a polymer chain 6!
Organic Molecules: Carbohydrates Carbohydrates include small simple sugars and large polysaccharides Monosaccharides are the monomers of carbs Exs: Glucose and Fructose Bees with honey, a mixture of 2 different monosaccharides What do you think a chemical formula would be for carbo hydrate? 7!
Molecular formula of a monosaccharide is a multiple of C 2 O Glucose is C 6 12 O 6 Monosaccharides are the main fuel for cellular work Monosaccharide structures 8!
Two monosaccharides can join to form one disaccharide (a dehydration synthesis reaction) Glucose bonding to fructose forms sucrose, table sugar Glucose linked to galactose = lactose, sugar found in milk What problem is associated with this disaccharide in some people? 9!
Starch and glycogen = polysaccharides in plant and animal respectively, storage of Cellulose = polysaccharide in plant cell walls, structural support Polysaccharides are long chains of carbohydrates 10!
Organic Molecules: Lipids Lipids = hydrophobic (water ) Long-term energy storage Not large Not built of monomers Fats = lipids made from glycerol and fatty acids Long hydrocarbon chains Saturated fatty acid vs. unsaturated fatty acid Formation of a fat molecule 11!
Phospholipids & Sterols are Also Lipids Phospholipids = main component of cell membranes Similar to fats, but imp. differences Two fatty acids ydrophilic head and hydrophobic tails Form stable bilayer in water 13!
Steroids = lipids with 4 fused rings Cholesterol = common component of animal cell membranes Starting material for sex hormones Too much in the blood can lead to atherosclerosis Fig. 3.9C Cholesterol, a type of steroid 14!
Atherosclerosis 15!
Organic Molecules: Proteins The monomers of proteins are amino acids Protiens; hair, cartilage, muscle, antibodies, enzymes, hemoglobin 3-D structure directly related to function Made from genetic info (DNA) found in the of the cell 16!
N C C Carboxyl group O Amino group + N C C O Dehydration reaction Peptide bond O N C C N C C O R O R O 2 O R R O Amino acid Amino acid Dipeptide Fig 3.11C Peptide bond formation Amino acids structure: amino group, carboxyl group, central carbon atom, and an R group Linked together by dehydration reactions Links called peptide bonds Carboxyl group bonded to amino group (C-N bond) 17!
Polypeptides must fold into a protein to work A polypeptide chain has hundreds or thousands of aa s linked by peptide bonds Amino acid sequence of polypeptide determines shape Shape determines its specific function Groove Groove Ribbon model of lysozyme Space-filling model of lysozyme 18!
Four Levels of Protein Structure Primary structure Amino acids ydrogen bond Secondary structure Alpha helix Pleated sheet Tertiary structure Polypeptide (single subunit of transthyretin) Quaternary structure Transthyretin, with four identical polypeptide subunits 19!
If protein s shape is altered, it may no longer function Denaturation = polypeptide chains unravel, lose their shape, and lose their function Can happen w/ changes in salt concentration, heating, changes in p Ex. Frying an egg (egg white is protein) 20!
Organic Molecules: Nucleic Acids DNA and RNA are nucleic acids Monomers of nucleic acids are nucleotides Nucleotides have 3 parts A 5-C sugar called ribose in RNA and deoxyribose in DNA A phosphate group A nitrogenous base A nucleotide 21!
There are 5 types of nucleotides Nucleotides form nucleic acids 22!
DNA - 2 polynucleotide strands wrap around each other, double helix 2 strands are held together by bonds A pairs with T, and C pairs with G, producing base pairs RNA is a single strand Figure 15C DNA double helix 23!
Clicker Question #5 Which monomer is incorrectly paired? A. protein: monopeptide B. carbohydrate: monosaccharide C. nucleic acid: nucleotide D. lipid: no monomer
2.5 Mastering Concepts Explain hydrolysis and dehydration synthesis in large molecules