BS 161 - unit 1

bond

interaction between atoms

when a bond forms, energy is ________

released

when a bond forms, entropy ______ for the system

increases

2nd law of thermodynamics

covalent bonds

within molecules not between molecules

electronegativity

the ability of atoms to attract electrons

order HCON from most to least electronegative

oxygen > nitrogen > carbon = hydrogen

non polar covalent bond

shared pair of electrons between 2 atom

bond strenght in aqeous solution: strong

example: methane

polar covalent bond

difference in electronegativity leads to permanent partially negative atoms

bond strenght in aqeous solution: strong

example: H2O

ionic interaction

forms between oppositvely fully charged ions

bond strenght in aqeous solution: weak

example: NaCL

ion dipole interaction

when one atom with a permanent partial charge interacts with a fully charged atom

bond strenght in aqeous solution: weak

example: water and Na Ion

hydrogen bond

interaction between a partially positvely charged hydrogen with a more lectornegative atom with a partial negative charge

USE DASHES TO INDICATE HYDROGEN BOND

bond strenght in aqeous solution: individually weak, collectively have strong infleunce on behaviors

example: H2O and H2O

hydrophobic clustering

molecules seperate themselves out from water, no attraction bringing molecules together

bond strenght in aqeous solution: weak

example: oil and water

london dispersion forces

very weak attraction between transient opposite temporary partial charges

bond strenght in aqeous solution: weakest

example: any 2 molecules

hydroxyl

OH

polar

carbonyl

CO

polar

carboxyl

COOH or COO-

negatively charged, at pH of 7 at the cell acts as acids

amino

NH, NH2, +NH3

positively charged

acts as a base at pH of a cell

amide

C(=O)NH

CONH2

polar

sulfhydrl

SH

polar

phosphate

OPO3 2-

negatively charged, acts as an acid

methyl

CH3

nonpolar

what is a typical cell made of

water mainly, macromolecules, ions and small molecules

proteins

monomer: amino acids, have an amino group, carboxyl group, and a central group, and side chain

linking bond: peptide bond (carboxyl of one amino acid to the amino group of the next amino acid)

example: collagen, provides structure, long rod that suppports strcuture in cell walls

carbohydrates

monomer: monosachrrides, carbon, hydrogen and oxygen atoms in a 1:2:1 ratio

• glucose

linking bond: glycosidic - glucose monomers linked by hydroxyl groups (dehydration reaction)

example: cellulose, cell walls, rigid and packed making it good for cell walls

starch, energy, open making it easier to breakdwon

nucleic acid

monomer: nucleotides, phosphate group, 5 carbon sugar, nitrogenous base

• cytosine, thymine (uracil in RNA), guanine and adenine

linking bond: phosphodiester linkage (sugar, phosphate backbone)

example: DNA, storing and transmitting genetic info, bases are in teh inferior of the helix, ufncitonal groups are polar and will intearct with one another

lipids

nonpolar and hydrophobic

functions: barriers for keeping stuff in and out of a cell, energy storage

saturated fatty acid

saturated with hydrogens, no double bonds, more solid, and more IMFs

unsaturated fatty acid

bent shape, more fluid, has a couble bond