Tags & Description
intramolecular bonds
covalent bonds - 2 non metals sharing e- equally
ionic bonds - 1 atom loses e- and the other gains the e-
polar covalent bonds - sharing of e- less equally
type of intramolecular bond is distinguished by difference in electronegativity (∆EN):
covalent = ∆EN < 0.4 → share equally
ionic = ∆EN > 1.7 → atom w greater EN takes e- from atom w lesser EN, both become charged
polar covalent = ∆EN = 0.5-1.7
polar covalent bonds
one atom has a stronger hold on shared e-
one end of molecule gets slightly + charged, one end gets slightly - charged
δ- = stronger EN end gets - charge
δ+ = weaker EN end gets + charge
influences attraction & biological interaction
water is polar, has polar covalent bonds
e- spend more time near the O than the H, difference in charge btwn poles of the molecules
δ- = O
δ+ = H
due to its polarity, it forms H bonds w itself → a lot of H bonds = a lot of strength
water forms bonds through
H bonding w itself
cohesion: water molecules are attracted to other water molecules
adhesion: water is a polar molecule and thus attracts other polar molecules
intermolecular forces
London dispersion forces: v weak attraction btwn all molecules, even non polar ones. increase w molecule size
dipole dipole attraction: attractive force btwn 2 polar molecules
H bonding: special kind of dipole dipole attraction btwn 2 polar molecules w H bonded to N, O, F
carbon, the backbone of nearly every bio molecule except for water
organic compound = compound containing C-H bonds and maybe other elements too such as N, O, etc.
often found in organisms
C-H is non polar bond → hydrocarbons are non polar but polarity can be achieved by adding other atoms called functional groups
functional groups (FG)
molecules interact w eo at specific regions of their molecules and classifies molecule types
after a rxn btwn 2 molecules’ functional groups, a linkage will be formed
alcohols
FG: -OH ~ hydroxyl
simplest = CH3OH
aldehydes
end group of fg -CO ~ carbonyl
simplest = HCOH
ketones
middle fg -CO ; middle carbon
simplest = CH3COCH3
organic acids
fg: -COOH ~ carboxyl; end group
simplest = HCOOH
amine
fg: -NH2 ~ amino
simplest = CH3NH2
phosphate group
fg: -PO4 ~ phosphate ; no official classification
hydrolysis rxns
rupture, use of water to rupture/break down, catabolic, splits a larger molecule apart ~ water required and used up
dehydration synthesis rxns
condenses smaller particles into larger ones. anabolic and builds up molecules ~ water is released as a product
ether linkages
glycosidic link btw sugars when it occurs btwn sugar molecules
btwn 2 hydroxyl groups
used in carbohydrates
pattern COC
ester linkages
btw hydroxyl and carboxyl
used in triglycerides
pattern OCO
phosphate ester linkages
btwn hydroxyl (1st) and phosphate (2nd)
used in phospholipids and nucleic acid - instructs DNA and RNA
pattern OPO
peptide linkages
btwn carboxyl (1st) and amino (2nd)
links amino acids together
pattern OCNH
carbohydrates
made of C, H, O - ratio 1:2:1
formula - (CH2O)n where n is # of carbons
short term energy source, building blocks, cell surface markers
3 kinds - monosaccharides, disaccharides, polysaccharides
monosaccharides
chain of carbons w hydroxyl groups attached
contain carbonyl groups
have diff #s of carbons - commonly 3, 5, 6 carbon sugars
isomers = compounds with same empirical formula but diff configurations
glucose, galactose, fructose are isomers - C6H12O6
glucose
galactose
fructose
disaccharides
2 simple sugars attached by ether/glycosidic linkage, dehydration synthesis rxn - 2 OH linked together
maltose
glucose + glucose → maltose + water
linkage btw c1 on glucose 1 and c4 on glucose 2
a 1-4 glycosidic linkage
lactose
b galactose + glucose → lactose + water
glucose can be a or b
linkage btw c1 on galactose 1 and c4 on glucose 2
b 1-4 glycosidic linkage
sucrose
glucose + fructose → sucrose + water
flip fructose so hydroxyl on the side for bonding
linkage btw c1 on glucose 1 and c2 on fructose 2
1-2 glycosidic linkage (either a or b depending on the glucose)
polysaccharides
large molecules - same linkage used to make a strand, several hundred-thousand monosaccharides bonded w glycosidic linkages
straight chain = a 1-4 glycosidic linkages or brained chains = a 1-6 glycosidic linkages
energy storage and structural support
all a or all b linkages
starch
plant energy storage
straight chains - amylose
branched chains - amylopectin
stored in leaves and roots
glycogen
animal energy storage
many side branches
made in liver, muscle, fat cells
cellulose
plant structural support
in cell walls
H bonds btw chains from fibres, strong
straight chain of b glucose units - b 1-4 linkages
chitin
animal structural support and fungi as well
polymer of straight chain b-N-acetylglucosamine
2nd most abundant organic material
no branches
lipids
mostly C and H, with few O
hydrophobic - repel water
few polar O-H bonds & more non polar C-H bonds
long term nrg storage, membranes, dissolving fat soluble vitamins ADEK
fats, phospholipids, sterols, waxes
nucleic acid
molecules that are polymers made of nucleotides
3 components - pentose sugar, phosphate group, nitrogenous base
proteins
structural support, storage, transport, signalling, cell response, movement, defence, catalysis of rxns
amino acids make these up
side chains determine function
4 levels of folding:
1º - N → C terminus
order determines folding
2º - coils and folds ; stabilized by H bonds btw amino and carboxyl groups
a helixes and b pleated sheets
3º - super coiling involving side groups
4º - many polypeptide chains come together
enzymes
bio catalysts - assist in chemical rxns
distort substrate chemical bonds
sometimes need cofactors
cell membrane and transport
fluid mosaic model
phospholipids = main molecule
membrane fluidity
proteins - integral and peripheral