Chapter 3 – Biochemistry The chemistry of Life

Organic Chemistry Organic compounds must have C and H Hydrocarbons have only C and H All living things are composed of organic compounds Other than water they are the most common compounds in the bodies of living things All Organic substances come from, are part of or are produced by living things.

Carbon Based Life Forms .. why? C can bond to 4 other atoms Bonds short and strong Small size of atom Can from double bonds, rings and chains

Organic Compounds are made up of smaller molecules/groups of atoms Functional Groups – clumps of atoms that give chemical properties to anything they bond to Monomers – small organic molecules that can be joined together to form larger molecules Polymers/macromolecules – large molecules that are formed by joining many smaller molecules

Functional Groups Know structure, name and key properties of each functional group from figure 3.4 on page 36. Note if each is soluble or insoluble in H2O If they are acidic or basic Examples of molecules that they are part of

Types of Chem Rxns 1. functional group transfer 2. electron transfer (redox rxn) 3. Rearrangement of atoms fig 3.5 4. Condensation rxn. (condensation dehydration reaction) fig 3.6 5. Hydrolysis rxn fig 3.6

Condensation dehydration rxn Remove water (in form of H from one molecules and OH from the other) In order to stick to molecules together

Hydrolysis rxn Using water to break 2 molecules apart Put water (in form of H and OH back in)

1.Saccharides (sugars) All are made of Monosaccharides All are carbohydrates Only C, O & H All have –OH (hydroxyl) and C = O (carbonyl) groups Most dissolve easily in H2O Differences in properties due to different bonding patterns/ chain shapes

Monosaccharides & disaccharides Glucose Fructose Lactose -> Sucrose (Table sugar)

Oligosaccharides Oligosaccharides = made of a few monosch. Often found as part of glycoproteins or glycolipids in cell membrane that serve as membrane receptors or identification markers.

Polysaccharides Different properties based on bonding patterns and chain shape

Folding patterns of chains also change properties Hydroxyl groups facing out = soluble Hydroxyl groups facing in = insoluble

Chitin = modified polysaccharide N-acetyl functional group added

2. Lipids Macromolecules because they are large but not polymers (not repeating units) Grouped together due to hydrophobic nature The few polar groups vastly outnumbered by nonpolar hydrocarbon structure

Types of lipids Fats (oils) – store energy long term Phospholipids – membranes Steroids – membrane, hormones Waxes – repel water, lubricate, protection

Fats/oils = (triglycerides) Made by attaching fatty acids to gylcerol Fatty acid: carboxyl + hydrocarbon chain Glycerol is an alcohol that can bind up to 3 monomers ( one on each 0H group)

Types of fatty acids Saturated = no double bonds(full H) solid most animal fats(compact E storage takes less room than glycogen) Unsaturated = double bonds so bend (oil) Most plant & fish fats (fish oil, seed oil)

Trans fatty acids Created by hydrogenating unsaturated FA Create trans shape double bonds that are implicated in atherosclerosis (plaque deposits in blood vessels)

Phospholipids Glycerol bonds with 2 FA & 1 Phosphate Fatty acid tails hydrophobic Phosphate/glycerol head hydrophillic

Steroids Made of 4 fused Carbon rings with different functional groups attached Cholesterol in animal cell membranes & precursor for steroid hormones, vit. D & bile salts

Waxes Long chain FA tightly packed to long chain alcohols or carbon rings Repel water..beewax, plant cuticle

3. Proteins (polypeptides) Polymers made of amino acid monomers Bonds btwn amino acids =peptide bonds Formed by condensation rxn Proteins make up 50% dry mass of cell Include almost all enzymes, hormones, structural support, motor proteins, muscle, cytoskeleton

Each amino acid is a carbon bonded to.. *1 amino group *1 carboyxl group *1 hydrogen *and one of 20 different R groups R group gives the amino acid characteristics (polar or non-polar) (acidic neg. charge or basic + charge)

Levels of protein structure 1˚= chain of aa 2˚= chain of aa folds over on itself and sticks due to H-bonds 3˚=3-D shape due to disulfide bonds 4˚>one chain of aa bonded together

Denaturation of Proteins 3-D shape of protein altered Protein no longer functions properly H-bonds and disulfide bonds broken

Nucleotides Nucleotides are macromolecules made of 3 different types of monomers.. 1. a sugar (ribose or deoxyribose) 2. a phosphate group 3. a nitrogen base (A, T, G, C, or U)

Neucleotides can Function alone as… a. coenzymes that transfer e- or H to activate enzymes (NAD+ or FAD) b. ATP adensodine triphosphate transfers phosphate group to energize molecules Or form polymers of nucleotides called nucleic acids (DNA/RNA)

Nucleic Acids are polymers made of many nucleotides Nucleotides are covalently bonded into chains 2 type of nucleic acid DNA or RNA DNA = made of nucleotides with the sugar deoxyribose, and bases A,T,G,or C RNA = made of nucleotides with the sugar ribose and bases A,U,G or C

DNA Found only in nucleus Forms double helix structure made of 2 chains of nuclotides hydrogen bonded together

RNA = single chains of nucleotides Produced in nucleus then moves into cytoplasm 3 types…. 1) rRNA = ribosomal RNA makes up one subunit of ribosome 2) mRNA = messenger RNA carries directions to ribosome 3) tRNA = trnasfer RNA brings amino acids to ribosomes