Chem basics and Biomolecules

Covalent bonds

electron is shared between two atoms share one (or many) electrons

Oxygen electronegativity

3.5

Nitrogen electronegativity

3.0

Sulfur and Carbon electronegativity

2.5

Phosphorus and Hydrogen electronegativity

2.1

Non-polar covalent bonds

atoms with similar electronegativity, electrons are equidistant

polar covalent bond

dissimilar electronegativity between atoms, electrons are closer to the atom with higher electronegativity

Potential energy in covalent bonds

PE is greater in bonds with w/ equal electronegativity (polar) than bonds w/ unequal electronegativity (non-polar)

Build up of the cell system

electrons—> atoms —> molecules —> macromolecules —> organelles —> cell!

Structural isomer

same chemical formula, differs in structure (ex: branch point)

Cis-trans isomers

same formula, different geometric (3-D) structure due to double bonds restricting rotation

enantiomers

same formula, inverted/right and left hand images of each other

Hydroxyl group

—OH, hydrophilic (hydrogen bonds w/ water) alcohols

Carboxyl group

hydrophilic acids, can donate H+ bc O—H is polar

Amino group

—NH2, hydrophilic amines, act as base and can pick up H+,

Phosphate group

phosphate,

Polysaccharides

Sugars

Lipids

Glycerol and fatty acids

Amino acids

proteins

Nucleic acids

sugars and nucleotides

Carbohydrates functions

fuels (source of energy, breaking down sugar, glucose hydrolysis), storing energy (ex: glycogen, starch), structure (maintain integrity of cells, ex: cellulose)

Triose sugar

Pentose sugar

Hexose sugar

Aldose vs. ketose sugar

C-O group (carbonyl) location

Glycosidic linkage

Bond connecting monosaccharides, caused by dehydration reaction connecting C 1-4 (maltose) or C 1-2 (sucrose)

1-4 linkage glucose

alpha consistent orientation, beta alternating orientation

Cellulose traits

beta glucose, 1-4, No branching

Starch- amylose

alpha glucose, 1-4, no branching

Starch- amylopectin

alpha glucose, 1-4 and 1-6, branching ~ 20 units

Glycogen

animals, alpha glucose, 1-4 and 1-6, branching ~ 10 units

Lipid functions

strongly hydrophobic bc of lots of non-polar C-H bonds, fuel (break down lipids slowly), storage (store in adipocytes/fat), some support structure of cell membranes

Triglyceride structure

glycerol and fatty acids, ester linkages bond fatty acids to glycerol (3 carbon alcohol)

Phospholipid structure

2 fatty acids bonded to a glycerol bonded to a phosphate and functional group (hydrophillic head, hydrophobic tail)

Steroid structure

Generally a 4 ring hydrophobic structure, hydrophilic hydroxyl left side, functional group right side

Sex hormones

derived from cholesterol

Peptide bond

connects amino acids into a polypeptide chain with a dehydration reaction