Kaplan: Biochemistry: Chapter One Flashcards
Where are amino acids found?
They are found in proteins.
What are alpha-amino acids?
Alpha-amino acids are those in which the amino group and the carboxyl group are bonded to the same carbon.
How the fuck do we know where the alpha-position is?
The alpha carbon will always be the carbon that is ADJACENT to the carboxyl carbon ( the carbon that is double-bonded to the oxygen AND bonded to the hydroxyl).
Describe the four groups that make-up an amino acid! GO
an amino (-NH2), the carboxyl group (-COOH), the hydrogen (H), AND the sidechain ( denoted R)
What makes each amino acid different from the other???
THE MF SIDECHAIN
Say it with me now!
STRUCTURE DETERMINES FUNCTION
True or False: Amino acids do not need to have the amino group and the carboxyl group attached to the same carbon. Explain why or why not.
This is obviously false babes… BECAUSE take methionine for example, the nitrogen is attached to the cyclic pentagon group but not attached to the alpha carbon.
Bitch is this true or false? Every amino acid found in the human body is specified by a codon in the genetic code or incorporated into proteins.
FALSE
What are we describing when we say proteinogenic amino acids???
There are various amino acids HOWEVERRR, there are 20 alpha-amino acids that the human body encodes.
Is glycine a chiral molecule?
NOSIREE! that bitch contains a hydrogen as its sidechain making two of the groups ze same.
Why is the amino group drawn on the left in Fischer projections?
The amino group is drawn to the left because all chiral amino acids used in eukaryotes are L-amino acids.
What is the configuration for all CHIRAL amino acids (not including glycine and cysteine)?
S-configuration
Which amino acid has an R-configuration?
Cysteine
What is a D-amino acid?
A D-amino acid is one in which the amino group is drawn to the right in a Fischer projection.
What does it mean to be non polar?
There is no overall charge.
What does it mean to be non-aromatic?
There is no hexagonal ring and there are no pi bonds.
What are the seven amino acids that are non polar and non-aromatic?
glycine, alanine, valine, leucine, isoleucine, methionine, AND proline
Which is the smallest amino acid?
The smallest amino acid is glycine
Describe the sidechain of glycine
The sidechain of glycine is hydrogen which is why the amino acid is NOT chiral
Describe the sidechain of alanine, valine, leucine, and isoleucine
They have alkyl side chains containing one to four carbons. Alkyl groups are alkane groups that are missing a hydrogen. CH4——–>CH3
Describe the sidechain of methionine.
The sidechain of methionine contains a sulfur atom ( 1 of the 2 amino acids who have one) IN its sidechain
Why is methionine considered non polar?
Even though it has a big fat sulfur atom in it, the methyl group keeps it relatively non-polar.
Describe the sidechain of proline
It forms a cyclic amino acid, the amino nitrogen becomes a part of the side chain forming a five-membered ring.
Describe the side chain of tryptophan
Tryptophan is the biggest of the aromatic group, it has a double-ring system and one of the rings contain a nitrogen giving this compound 2 nitrogen’s in its structure
describe the sidechain of phenylalanine
This amino acid only has one benzyl ring ( meaning a benzene ring + a ch2 group)
describe the sidechain of tyrosine
tyrosine’s sidechain sort of resembles phenylalanine but it has a hydroxyl group attached to the benzyl side chain
How many amino acids are non-polar and non-aromatic?
seven
How many amino acids have non-polar aromatic sidechains, what are they?
there are three of them, tryptophan, phenylalanine AND tyrosine
How many amino acids have polar side chains? What are they?
There are five of them, serine, threonine, asparagine, glutamine, cysteine
Describe the side chains of serine and threonine
Their side chains have a hydroxyl group which makes them POLAR AF and able to participate in hydrogen bonding, member NOF
Describe the side chains of asparagine and glutamine
Their side chains have lovely amides ( -NH2 + double-bonded O on the same carbon) The amides do not become charged, leave those bitches alone
How can you remember the difference between serine and threonine, structurally?
serine has one alkyl group (CH2) and threonine has one alkyl group ( CH3)
Describe the side chains of cysteine
Cysteine is the other 1 of 2 aminos that have sulfur in its structure BUT the major difference is that the sulfur atom is bonded to a hydrogen which makes it a thiol
What makes asparagine and glutamine structurally different?
Asparagine has one alkyl group (CH2) and glutamine has two alkyl groups ( CH2 x2)
How many negatively charged (acidic) side chained amino acids? What are they?
There are two of them, aspartic acid AND glutamic acid. They anions are aspartate and glutamate, respectively.
What are the three amino acids that have positively charges (basic) side chains
arginine, lysine, and histidine
Which amino acids are hydrophobic and why?
The ones with long alkyl chains ( alanine, isoleucine, leucine, valine, and phenylalanine). They are most likely to be found in the interior of proteins.
Which amino acids are hydrophilic and why?
All the amino acids with charged ( - or +) side chains are hydrophilic, these include arginine, histidine, lysine and the IONS aspartate and glutamate.
