Midterm 1 Flashcards
which functional group is acidic
carboxyl
which functional group(s) are/is basic
amine
which functional group has a nitrogen
amine, amide
which functional groups have a sulphur
thiol
sulfhydrl
what functional groups have a carbonyl carbon
carboxyl, amide,
what functional groups have both carbon and hydroxyl
carboxyl
what functional group has a carbonyl carbon and and an amine
amide
what functional group has an h-donor but isn’t acidic
hydroxyl, amine, amide
what functional groups has an H-bond acceptor
carboxyl
hydroxyl
sulfhydryl
amide
why is benzene flat but cyclohexane is kinked
benzene : each C has identical sp2 orbitals that lie at 120 degree angles. all atoms lie in same plane
cyclo: has sp3 orbitals so they have tetrahedral geometry so they don’t lie in same plane (tetrahedral geometry)
why is a covalent bond stronger than an H-bond
since covalent bonds result from shared e- while h -bonds e- arent shared so they’re further apart
what kind of geometry do sp3 C have
tetrahedral
109 degree
what kind of geometry do sp2 C have
trigonal
120
what causes a polar molecule
asymmetrical charge distribution due to unequal e- sharing
what happens to polarity with the more similar the electronegativity
smaller
what are amino acids joined by
peptide bonds (covalent bond)
what is the opposite of a aromatic compound
aliphatic
what is an isomer
non identical compounds with the same molecular formula
what is a constitutional isomer
same formula
different arrangement
what is a sterioisomer
same linkage
3d orientation differ
what makes a molecule chiral
like -hands (non-superimposable)
NO plane of symmetry
4 DIFFERENT substituents
what is an enatiomer
chiral molecules that are mirror images
what is a dipole moment
vector sum of magnitude and direction of bond dipoles
what are molecules in a cell primarily made of
C,H,O
what is dna/rna primarily made of
H C O P
what is proteins primarily made of
H C N O S
what are lipids mainly made of
H C N O P S
are are carbs mainly made of
H C O
what does intermolecular mean
between molecules
What does intramolecular mean
within a molecule
what holds atoms together in a molecule
covalent bonds
what are the specialized covalent bonds
phosphodiester - hold phosphates together and nucleotides
glycolosidic bond - joins ribose to base in ATP
peptide bond- holds amino acids together in a protein
disulphide bonds / bridges - covalent bonds between thiol groups
what kind of reaction are the most of the ones that stabilize a protein fold
non - covalent
what are the kinds of weak chemical reactions
H bonds
electrostatic
van der Waals
hydrophobic interactions
what is a van der Waals interactions
all intermolecular focus between electrically neutral molecules
what is one of the causes of protein folding
hydrophobic effect
why is water a good solvent
its polar
what is the distance between h - bonds
2 A
what is the difference between covalent bonds
1A
what holds DNA in a helical shape
H-bonds
what is a dielectric constant (D)
indicates reduction in attraction of 2 opposed charged ions in a solvent relative to in a vacuum (D=1)
what is enthalpy
heat energy
what is Gibbs free energy
amount of energy from reaction that is available to do useful work
what is standard states
T= 25 C
P= I atm
concentration = 1M for reactants and products
r = 8.314 JKm-1 mol-1
for ‘
ph=7
[Mg 2+] = 1 mM
[h2o] = 55.5 M
what does pH at midpoint = ``
ph = pKa
what does keq =
[products] / [reactants]
when is something exergonic
when S<1 (favoured)
what is a reaction that another can be coupled with
ATP -> ADP
(atp hydrolysis)
when do weak acids have highest buffering capacity
when pH = pKa
what kind of ka and pka will strong acids have
large ka and small pka
At midpoint which is larger concentration of products or reactants
equal
what is buffering range
1 above/below pka
what are the two enzyme recognition theories
lock and key : substrate is perfect fit for active site
induced fit: both substrate and active site change shape to fit conformations close to their transition state
what do enzymes do to energy
convert it from one form to another
ex: atp hydolysis
what direction do enzymes increase reaction rate
both directions
