CHEM120 Biochemsitry - Final Assessment Review - Mod 3
2023
which amino acids are in the positively charged R groups
what are their characteristics - __100% correct answer lysine
arginine
histidi
Amino Acids & Proteins - __100% correct answer xxxxxxxxxxxxxxxxxxxx
what are the different functions of proteins - __100% correct answer blood - hemoglobin
proteins carry in oxygen
brain & nerves - ion channel proteins control brain signaling by allowing small molecules
into or out of nerve cells
enzymes - enzymes in the saliva, stomach, and small intestine are proteins that help
digest food
cellular work - huge clusters of proteins form molecular machines that do the cells
heavy work, such as copying genes during cell division and making new proteins
antibodies - antibodies are proteins that help defend your body against foreign invaders
(bacteria & viruses)
cellular messengers - receptor proteins stud the outside of cells and transmit signals to
partner proteins on the inside of the cell
muscles - muscle proteins called actin and myosin enable all muscular movement
hair & nails - a protein called alpha keratin forms your hair and fingernails
discuss the molecular basis for the chirality of amino acids - __100% correct answer
they're chiral molecules
rotated molecules that can't be superimposed on its mirror image
asymmetrical centers
four different bonds
,exist as enantiomers
discuss enantiomers in alpha amino acids - __100% correct answer they can exist as
either L- or D- conformations
*in humans, all alpha amino acids in proteins are L-*
proteins are made up of ________ different amino acids distinguished by their ______
________ - __100% correct answer proteins are made up of 20 different amino acids
distinguished by their side chains
which amino acids are in the nonpolar aliphatic R groups
what are their characteristics - __100% correct answer glycine (Gly)
alanine (Ala)
valine (Val)
leucine (Leu)
methionine (Met)
isoleucine (Ile)
proline (Pro)
nonpolar
hydrophobic
no partial charge
*proline has a unique cyclic side chain that reduces the structural flexibility of
polypeptide region*
which amino acids are in the aromatic R groups
what are their characteristics - __100% correct answer Phenylalanine (Phe)
Tyrosine (Tyr)
Tryptophan (Trp)
have a benzne ring
hydrophobic
*the hydroxyl group of tyrosine can form hydrogen bonds*
which amino acids are in the polar uncharged R groups
,what are their characteristics - __100% correct answer Serine (Ser)
Threonine (Thr)
Cysteine (Cys)
Asparagine (Asn)
Glutamine (Gln)
have no charge
hydrophilic
can form h-bonds
which amino acids are in the negatively charged R groups
what are their characteristics - __100% correct answer aspartate (Asp)
glutamate (Glu)
accepts electrons - negative charge
hydrophilic
*since they are charged, they are hydrophilic (they like water) because water has a
partial charge as well*
gives up electrons - positive charge
hydrophilic
*since they are charged, they are hydrophilic (they like water) because water has a
partial charge as well*
explain the basis for disulfide bonds - __100% correct answer cysteines can form a
covalently linked (via disulfide bond) amino acid called cystine
this is a reversible formation
oxidation: cysteine to cystine
reduction: cystine to cysteine
disulfide bonds between Cys residues stabilize the structures of many proteins
beta-mercaptoethanol (Beta-ME) is a powerful reducing agent
when a protein is exposed to Beta-ME, what is likely to occur - __100% correct answer
cystines become cysteines
recall...
reduction is cystine to cysteine
oxidation is cysteine to cystine
, how can amino acids be modified
give an example - __100% correct answer reversible amino acid modifications can occur
where a phosphate group is added
this is called phosphorylation
methylation and other modifications can occur as well
example: L-tyrosine can be modified into the neurotransmitters dopamine and
norepinephrine
what does the Henderson-Hasselbalch equation allow to be calculated - __100% correct
answer pKa - given pH and the molar ratio of proton donor and acceptor
pH - given pKa and the molar ratio of proton donor and acceptor
the molar ratio of proton donor and acceptor - given pKa and pH
what is a peptide bond - __100% correct answer covalent bond between two amino acids
via dehydration synthesis (condensation rxn)
the nitrogen (alpha amine group) of one of the amino acids will act as a nucleophile and
donates an electron pair
this nitrogen will then bond to the carbon of the other amino acids carboxyl group
O=C-N-H
which amino acid has a sweet taste - __100% correct answer aspartame
what is central dogma - __100% correct answer states that information in nucleic acid
can be perpetuated or transferred but the transfer of information into protein is
irreversible
how does information flow from DNA to proteins - __100% correct answer 1. DNA -
transcriptional control
2. RNA - RNA processing control
3. mRNA - RNA transport and localized control
4. mRNA - translation control
5. mRNA - mRNA degration control (inactive mRNA)
2023
which amino acids are in the positively charged R groups
what are their characteristics - __100% correct answer lysine
arginine
histidi
Amino Acids & Proteins - __100% correct answer xxxxxxxxxxxxxxxxxxxx
what are the different functions of proteins - __100% correct answer blood - hemoglobin
proteins carry in oxygen
brain & nerves - ion channel proteins control brain signaling by allowing small molecules
into or out of nerve cells
enzymes - enzymes in the saliva, stomach, and small intestine are proteins that help
digest food
cellular work - huge clusters of proteins form molecular machines that do the cells
heavy work, such as copying genes during cell division and making new proteins
antibodies - antibodies are proteins that help defend your body against foreign invaders
(bacteria & viruses)
cellular messengers - receptor proteins stud the outside of cells and transmit signals to
partner proteins on the inside of the cell
muscles - muscle proteins called actin and myosin enable all muscular movement
hair & nails - a protein called alpha keratin forms your hair and fingernails
discuss the molecular basis for the chirality of amino acids - __100% correct answer
they're chiral molecules
rotated molecules that can't be superimposed on its mirror image
asymmetrical centers
four different bonds
,exist as enantiomers
discuss enantiomers in alpha amino acids - __100% correct answer they can exist as
either L- or D- conformations
*in humans, all alpha amino acids in proteins are L-*
proteins are made up of ________ different amino acids distinguished by their ______
________ - __100% correct answer proteins are made up of 20 different amino acids
distinguished by their side chains
which amino acids are in the nonpolar aliphatic R groups
what are their characteristics - __100% correct answer glycine (Gly)
alanine (Ala)
valine (Val)
leucine (Leu)
methionine (Met)
isoleucine (Ile)
proline (Pro)
nonpolar
hydrophobic
no partial charge
*proline has a unique cyclic side chain that reduces the structural flexibility of
polypeptide region*
which amino acids are in the aromatic R groups
what are their characteristics - __100% correct answer Phenylalanine (Phe)
Tyrosine (Tyr)
Tryptophan (Trp)
have a benzne ring
hydrophobic
*the hydroxyl group of tyrosine can form hydrogen bonds*
which amino acids are in the polar uncharged R groups
,what are their characteristics - __100% correct answer Serine (Ser)
Threonine (Thr)
Cysteine (Cys)
Asparagine (Asn)
Glutamine (Gln)
have no charge
hydrophilic
can form h-bonds
which amino acids are in the negatively charged R groups
what are their characteristics - __100% correct answer aspartate (Asp)
glutamate (Glu)
accepts electrons - negative charge
hydrophilic
*since they are charged, they are hydrophilic (they like water) because water has a
partial charge as well*
gives up electrons - positive charge
hydrophilic
*since they are charged, they are hydrophilic (they like water) because water has a
partial charge as well*
explain the basis for disulfide bonds - __100% correct answer cysteines can form a
covalently linked (via disulfide bond) amino acid called cystine
this is a reversible formation
oxidation: cysteine to cystine
reduction: cystine to cysteine
disulfide bonds between Cys residues stabilize the structures of many proteins
beta-mercaptoethanol (Beta-ME) is a powerful reducing agent
when a protein is exposed to Beta-ME, what is likely to occur - __100% correct answer
cystines become cysteines
recall...
reduction is cystine to cysteine
oxidation is cysteine to cystine
, how can amino acids be modified
give an example - __100% correct answer reversible amino acid modifications can occur
where a phosphate group is added
this is called phosphorylation
methylation and other modifications can occur as well
example: L-tyrosine can be modified into the neurotransmitters dopamine and
norepinephrine
what does the Henderson-Hasselbalch equation allow to be calculated - __100% correct
answer pKa - given pH and the molar ratio of proton donor and acceptor
pH - given pKa and the molar ratio of proton donor and acceptor
the molar ratio of proton donor and acceptor - given pKa and pH
what is a peptide bond - __100% correct answer covalent bond between two amino acids
via dehydration synthesis (condensation rxn)
the nitrogen (alpha amine group) of one of the amino acids will act as a nucleophile and
donates an electron pair
this nitrogen will then bond to the carbon of the other amino acids carboxyl group
O=C-N-H
which amino acid has a sweet taste - __100% correct answer aspartame
what is central dogma - __100% correct answer states that information in nucleic acid
can be perpetuated or transferred but the transfer of information into protein is
irreversible
how does information flow from DNA to proteins - __100% correct answer 1. DNA -
transcriptional control
2. RNA - RNA processing control
3. mRNA - RNA transport and localized control
4. mRNA - translation control
5. mRNA - mRNA degration control (inactive mRNA)
