molecules - exam 1 Flashcards
covalent bond
involves sharing of electron pairs between atoms
nonpolar
share electrons equally
no charge
CC & CH bonds
polar
don’t share electrons equally
partial charge
water soluable
polar covalent bonds important in molecules
OH
NH
SH
hydrogen bond
attraction of partial charges (positive & negative)
break easily – that’s why water is fluid
water can H bond to other polar molecules but not other H20
why can salt dissolve in water & oil can’t
salt is polar - polar molecules are water soluble
oil is nonpolar - water can’t break down its bonds
hydrolysis
water in, monomer out
using water to break a bond in a molecule
need hydrolytic enzymes
dehydration synthesis
monomer in, water out
monosaccharide
monomer
single subunit
disaccharide
dimer
2 monomers
polysaccharide
many monosaccharides
oligosaccharide
carbohydrate comprised of a relatively small number of monosaccharides
starch
function: energy storage in covalent bonds
found in plants
glycogen
function: energy storage in muscle & liver cells
found in animals & fungi
cellulose
function: structural
found in the cell wall of plants, helps them stay upright
chitin
structural
how can cows digest cellulose
they have a special bacteria that can break down cellulose & then the bacteria eats it
primary structure
sequence of a chain of amino acids
amino end & carboxyl end
“2D”
secondary structure
localized folding created by hydrogen bonding
interactions between R-groups
still “2D”
tertiary structure
3D shape
interactions between r groups maintain structure
central carbons on polypeptide backbone
r groups bond via h bonds, ionic bonds, covalent bonds, hydrophobic exclusion – giving it curly shape
blob of curly ribbon
chaperones
help proteins fold in the proper way (tertiary)
quaternary structure
aggregation of 2 or more polypeptides
separate they don’t work, together they do
substrate
what is going to be acted on by enzyme
enzyme substrate complex
enzyme = active site
substrate (2 molecules bonded) enters enzyme
H2O added to reaction
enzyme breaks down bond & produces 2 products
physical conditions affect enzyme function
temp or pH shifts
denaturation = unfolding – nonfunctional
changes on protein structure & function if amino acid is changed
change in primary structure does not have to change everything, but it can
what happens if you swap a hydrophobic amino acid for hydrophilic in primary structure
primary structure will be changed - completely different amino acid
will also change 2nd, 3rd, 4th structures (& maybe function) because the proteins will have to fold differently
saturated fatty acid
animal fats
straight
no double bond
pack tightly, solid at room temp, less fluid
increases level of LDL
unsaturated fatty acids
plant fats
double bond causes bending
loosely packed, liquid at room temp, more fluid
decrease in LDL, increase in HDL
LDL
low density lipoprotein
carries cholesterol from liver to cells
“bad” cholesterol
you need some but a lot can clog ur arteries
HDL
high density lipoprotein
more apo proteins
picks up extra cholesterol from cells
delivers to liver for disposal / recycling
“good” cholesterol
cis vs trans fat
cis - unsaturated is best for you, bent
hydrogen & carbon on same side of double bond
then saturated
then trans unsaturated
hydrogens & carbons on opposite side of double bond
partially hydrogenated
explain why phospholipids form bilayers while triglycerides form insoluble droplets
phosolipids - hydrophobic tails & hydrophilic heads, put tails together on inside & heads on outside
triglycerides - very hydrophobic
