Exam (elaborations)
MCAT Biochem Ch. 1 ( Amino Acids)
- Course
- Institution
MCAT Biochem Ch. 1 ( Amino Acids)
[Show more]
Seller
Follow
Content preview
MCATBiochem
Ch.
1
(
Amino
Acids)
All
Amino
Acids
have?
-
ANS1.
Amino
group
(NH2)
2.
Carboxyl
group
(COOH)
3.
H
group
4.
R
group
*
the
r
group
determines
the
chemical
property
of
the
AA
and
therefore
its
function.
y-aminobuteric
acid
(GABA)
-
ANS-
neurotransmitter
-
the
amino
group
is
on
the
gamma
carbon,
3
carbons
away
from
the
carboxyl
group.
Proteinogenic
amino
acids
-
ANS20
alpha
amino
acids
encoded
by
the
human
genetic
code
Stereochemistry
of
AA
-
ANS-
all
aa
are
chiral
(optically
active)
EXCEPT
for
glycine.
-
all
aa
in
eukaryotes
are
L-amino
acid,
meaning
the
amino
group
is
on
the
left
side
of
the
fisher
projection.
-
therefore,
all
AA
have
S
absolute
config.
EXCEPT
for
cysteine
which
has
an
R
config.
b/c
the
-CH
₂
SH
has
priority
over
the
-COOH
group.
Nonpolar,
Nonaromatic
Side
Chains
(7)
-
ANS-
hydrophobic,
found
in
the
interior
of
proteins
-
Glycine,
Gly,
G
-
Alanine,
Ala,
A
-
Valine,
Val,
V
-
Leucine,
Leu,
L
-
Isoleucine,
Ile,
I
-
Methionine,
Met,
M
-
Proline,
Pro,
P
Glycine,
Gly,
G
-
ANS
Alanine,
Ala,
A
-
ANS
Valine,
Val,
V
-
ANS
Leucine,
Leu,
L
-
ANS
Isoleucine,
Ile,
I
-
ANS
Methionine,
Met,
M
-
ANSSulfur
atom,
but
the
methyl
group
makes
it
nonpolar
Proline,
Pro,
P
-
ANS-
the
ring
constraints
flexibility
of
proline.
Polar
Uncharged
R
Groups
(
5)
-
ANS-
hydrophillic
-
OH
group
in
serine
(Ser,
S)
and
threonine
(Thr,
T)
makes
them
highly
polar
and
able
to
participate
in
H
bonding -
cysteine
(Cys,
C)
has
thiol
(-SH)
group.
Sulfur
is
less
electronegative
than
O,
and
so
S-H
is
weaker
than
O-H,
leaving
the
S-H
prone
to
oxidation.
-
Asparagine
(Asn,
A)
and
glutamine
(
Gln,
Q)
have
amide
side
chains
(O=C-NH
₂
),
in
which
the
N
group
does
not
gain
or
lose
protons
with
changes
to
pH
as
does
the
amide
group.
Serine,
Ser,
S
-
ANS
Threonine,
Thr,
T
-
ANS
Cysteine,
Cys,
C
-
ANSR
config.
since
since
S
has
higher
priority
than
O
in
.
pKa
of
R
group=
8.18
Asparagine,
Asn,
N
-
ANS
Glutamine,
Gln,
Q
-
ANS
Aromatic
Side
Chains,
Uncharged
(3)
-
ANS-
Phenylalanine,
Phe,
F
-
Tyrosine,
Tyr,
Y
-
Tryptophan,
Trp,
W
Phenylalanine,
Phe,
F
-
ANSnonpolar,
benzyl
side
chain,
smallest
Tyrosine,
Tyr,
Y
-
ANSrelatively
polar
due
to
OH
-
pKa
of
R
group
10.07
Tryptophan,
Trp,
W
-
ANSlargest,
double-ring
with
N.
Positively
charged
R
groups
(Basic)
(3)
-
ANSLysine,
Lys,
K
Arginine,
Arg,
R
Hisitidine,
His,
H
Lysine,
Lys,
K
-
ANS-terminal
primary
amino
group
-
pKa
of
R
group
10.53
Arginine,
Arg,
R
-
ANS3
N
atoms
in
side
chain.
the
positive
charged
is
delocalized
over
all
3
N
atoms.
-
pKa
of
R
group
=
12.48
Histidine,
His,
H
-
ANS-
aromatic
ring
w/
2
N
atoms.
Ring
is
called
imidazole.
pKa
of
side
chain
is
relatively
close
to
6,
while
the
pka
itself
is
7.4
so
at
physiological
pH,
1
N
is
protonated
while
the
other
isn't.
-
under
acidic
conditions,
the
second
N
atom
is
protonated,
giving
side
chain
a
+
charge.
-
pKa
of
R
group
6.00
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller mangeni188. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $7.99. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
75759 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now