Transcript Modern Biology: Chapter 3

Modern Biology: Chapter 3
Biochemistry
Carbon Compounds
• Organic compounds – primarily Carbon atoms
– Large, complex molecules essential for life
– Contributes to diversity of life
• Carbon bonding
– Has 4 valence electrons
– Can form single, double, or triple covalent bonds
– Can form straight or branched chains of itself
– Can form rings of itself
Functional Groups
• Influence characteristics of molecules
– Make polar with addition of charged entities
• Affect chemical reactions molecules undergo
– Allow bond formation between molecules
• Some of these groups are –
– Hydroxyl
– Carboxyl
– Phosphate
– Amine
(R-OH)
(R-COOH)
(R-PO4)
(R-NH2)
Large Carbon Molecules
• Monomers
– Small, simple molecules
– Amino acid, fatty acid, nucleotide, monosaccharide
• Polymer
– Monomers join via condensation reactions
• Polypeptides
• Disaccharides
– Polymers break down with hydrolysis reaction
• Macromolecules
-- Formed from large polymers
-- Protein, lipids, nucleic acids, carbohydrates
Energy Currency
• Compounds store energy in chemical bonds
• Certain ones’ overall structure stores energy
– ATP (Adenosine triphosphate)
– NADH (Nicotinamide adenine dinucleotide)
– NADPH (Nicotinamide adenine dinucleotide
phosphate)
– FADH2 (Flavin adenine dinucleotide)
Molecules of Life
• Carbohydrates
– (CH2O)n general formula n = 3–8 monosaccharides
– Hundreds of glucose monomers make glycogen
(animals) or starch & cellulose (plants)
• Proteins
– Composed of amino acids (C, H, O, N et al)
– 20 essential amino acids, differ in –R groups
– Amino acids joined via peptide bond between amino
side of 1 & carboxyl side of another
– Enzymes are protein catalysts
Molecules of Life, continued
• Lipids
– Large, nonpolar organic molecules
– Higher ratio of C & H atoms to O atoms than sugar
• Types
– Fatty acids (12-28 C chain with –COOH group)
– Triglycerides (3 fatty acids attach to glycerol)
– Phospholipids (2 fatty acids attach to phosphate on
glycerol’s 3rd carbon)
– Waxes (long fatty acid attaches to long alcohol chain)
– Steroids (Four fused carbon rings + functional groups)
Molecules of Life, continued
• Nucleic acids
– Store and transmit important info in the cell
• DNA: determines traits & directs cell activities
• RNA: stores/transmits info from DNA
• Composed of nucleotides
– Adenine, guanine, cytosine, thymine or uracil
• Made of 3 compartments
– Phosphate group
– 5-C sugar [(deoxy)ribose]
– Ring-shaped nitrogenous base