biochem test

functional groups

carbonyl: C double bonded to O; aldehyde if at the end, ketone if in the middle

hydroxyl: OH

carboxyl: COOH

amino: NH₂

sulfhydryl: SH

phosphate: PO₄

methyl: CH₃

carbohydrate functions

fast energy, raw materials, energy storage, structural materials

dehydration synthesis

one monosaccharide loses OH, another monosaccharide loses H → water is formed and the two monosaccharides combine w/ covalent bond

linkage between two monosaccharides = glycosidic linkage

polysaccharides function

energy storage: starch (plants) - easy to digest, glycogen (animals)

structure: cellulose (plants) - hard to digest, chitin (arthopods and fungi)

linear vs branched polysaccharides

linear: starch, slow release of energy

branched: glycogen, fast release of energy

cellulose

herbivores have evolved a mechanism to digest cellulose while carnivores haven’t; bc bacteria live in digestive systems

lipids

-fats, phospholipids, steroids

-do not form polymers (big molecules made of smaller molecules not repeating smaller units)

fats and their function

-glycerol + fatty acid

-dehydration synthesis → ester linkage (between hydroxyl and carboxyl)

-functions: energy storage, cushion organs, insulates body

saturated vs unsaturated fats

Saturated:

-no carbon to carbon double bonds

-long straight chain

-most animal fats

-solid at room temp.

Unsaturated:

-carbon to carbon double bonds in fatty acids

-double bond causes bending

-plant, fish fats + vegetable oil

-liquid at room temp.

phospholipids

-glycerol + 2 fatty acids + PO₄ (negatively charged)

-fatty acid tails = hydrophobic, PO₄ head = hydrophilic

-in water: head attracted but tails repel; can self-assemble into bubbles (micelle) or form a phospholipid bilayer; heads on the outside while tails in the inside

-phospholipid bilayer: form cell membranes, blocks water soluble molecules + large molecules from entering the layer

steroids

-4 fused C rings + functional group

-different steroids created by attaching different functional groups to rings

-ex. cholesterol: animal cell membranes, helps keep cell membranes fluid and flexible, precursor of all other steroids

-ex. sex hormones

protein structure

monomer = amino acid

polymer = polypeptide

-peptide bond: bonding between amino acids , formed between NH₂ of one amino acid and COOH of another, C-N bond, formed by dehydration synthesis

protein = 1 or more poly peptide chains folded and bonded together

-large, complex, 3-D structure

amino acids

-central carbon, amino group (NH₂), carboxyl group (COOH), r-group

-r group different for each amino acid; r groups can by non-polar or polar

• polar r-groups can be acidic or basic

• acidic: aspartate, glutamate, asparagine, glutamine - H⁺ donors

• basic: lysine, arginine, histidine - H⁺ acceptors

-amino acids w/ sulfur in them: form disulfur bridges (covalent cross links between sulfhydryls, stabilizes 3-D structure, H-S — S-H)

polypeptides

-N terminals = NH₂ end

-C terminals = COOH end

N-C-C = polypeptide backbone

different protein structures

-Primary (1) structure: order of amino acids in chain, dna, slight change in sequence → affect protein structure and function

-Secondary (2) structure: hydrogen bonding (between amine and carbonyl groups) of peptide backbone causes amino acids to fold in a repeating pattern

• 𝜶 helix vs 𝜷 pleated -sheet

-Tertiary (3) structure: whole molecule folding, 3-D shape, interactions between r-groups of distant amino acids, clustering of hydrophobic groups away from water (nonpolar amino acids), stabilized by H bonds + ionic bonds + disulfide bridges

-Quaternary (4) structure: more than one polypeptide chain bonded together, stabilized by H bonds + ionic bonds + disulfide bridges

• ex. hemoglobin (four protein chains), fibrous (long, straight) which includes collagen

protein denaturation

-conditions that disrupt H bonds, ionic bonds, hydrophobic interactions (peptide bonds + disulfide bridges not affected bc covalent)

-temp, pH, salinity

-affect 2, 3, 4 structure and 3-D shape

-destroys functionality (only some can return to functional shape)

chaperonin proteins

-guide protein folding

-provide shelter for folding polypeptides

-keep new protein segregated from cytoplasmic influences

geometric vs structural isomers

structural: differ in covalent arrangement of atoms, different properties

geometric: differ in spatial arrangement around carbon-carbon double bond

• cis = same side of double bond

• trans = opposite side of double bond

enantiomer: mirror images but are not the same when overlapped