BCH4024 EXAM 1 QUESTIONS WITH
CERTIFIED ANSWERS
Transfer RNA (tRNA) secondary structure: - Answer-tRNA "reads" genes information
encoded in mRNA (3 nucleotide codon) copied from DNA
What does tRNA transfer during protein synthesis - Answer-the appropriate amino acid
to a growing polypeptide chain
Transcription creates a: - Answer-complementary RNA copy (mRNA) of a sequence of
DNA
Translation steps: - Answer-mRNA decoded by ribosomes and tRNA is used to produce
a specific amino acid chain, or polypeptide, that will later fold into an active protein
Phenotype of an organism is determined by: - Answer-proteins
What defines function by interaction? - Answer-the three dimensional structure of
proteins
what defines the type of amino acid? - Answer-side chain
what kind of molecule are amino acids - Answer-ampholytic molecule (contains both
acidic and basic groups)
Charge of an amino acid is dependent on: - Answer-the pH of a solution
What happens to the net charge of an amino acid as you increase the pH - Answer-net
charge decreases
Which of the 20 common amino acids is achiral? - Answer-Glycine
Isoelectric point - Answer-pI=pH, average charge equals zero.
two equilibrium dissociation reactions w/ isoelectric points - Answer-HAH+ ----> HA + H
HA ----> A- + H+
pI formula if no ionizable side chain - Answer-pI = ¹/₂ (pK₁ + pK₂)
simplest amino acid? - Answer-glycine
Ways to classify amino acids based on properties: - Answer--size/shapes
-charges
,-polarity
-hydrophilic/phobic
-aromaticity (stacking interactions)
-conformation (determined by side chain)
-propensity to adopt a particular conformation in proteins (combo of all above)
what determines conformation of an amino acid - Answer-the side chain
Encoded proteins have which configuration, and what is a way to remember it? -
Answer-L configuration; can be remembered as the CORN law.
Which proteins tend to cluster together on the inside of proteins? And what happens -
Answer-Ala, Val, Ile, Leu. Clustering together stabilizes the protein structure, via
hydrophobic interactions.
AA's with nonpolar, aliphatic R groups - Answer-Glycine
Alanine
Proline
Valine
Leucine
Isoleucine
methionone
AA's with aromatic R groups - Answer-Phenylalanine
Tryptophan
Tyrosine
hydroxyl group of ____ can form hydrogen bonds and play important role in enzymes -
Answer-Tyrosine, Tyr, Y
AA's with polar, uncharged R groups - Answer-Serine, Threonine, Cysteine,
Asparagine, Glutamine.
Disulfide bond example - Answer-cystine
How does cystine happen? and through which bond - Answer-when pairs of cysteines
oxidize to form cystine through a disulfide bond.
Cystine features: p/np? hydrophilic/phobic? - Answer-nonpolar/hydrophobic
AA's with positively charged R groups - Answer-Lysine, Arginine, Histidine
Histine: - Answer-only amino acid with ionizable side chain that has a pka near
neutrality. Therefore, His can serve as a proton donor or acceptor in many enzyme-
catalyzed reactions.
, The most hydrophilic R groups are: - Answer-either positively or negatively charged.
AA's with negatively charged R groups: - Answer-Aspartate, Glutamate (neg charge as
pH 7)
Characterization of Biomolecules by Light
Absorption Using a Spectrophotometer - Answer-Detect the presence of particular
biomolecules and estimate concentration
Which amino acids have a characteristic UV absorbance? - Answer-the aromatic ones;
tyrosine, tryptophan > phenylalanine
General pKa's on amino acids
Carboxyl ≈ ?
Amino ≈ ? - Answer-carboxyl ~ 2.2
amino ~ 9.6
Human diets must include adequate amounts of nine amino acids, which ones? WTF
Very Hot MILK - Answer-WTF= Tryptophan, Threonine, Phenylalanine
VH= Valine, Histidine
MILK= methionine, isoleucine, leucine, lysine
Cysteine can meet the needs for: - Answer-methionine (both contain sulfur)
tyrosine can partially substitute for: - Answer-phenylanaline
conditionally essential amino acids for dietary needs: - Answer-arginine, cysteine,
glutamine, glycine, tyrosine
(not necessarily required)
most common amino acid - Answer-leucine
least common amino aid - Answer-tryptophan
Alanine - Answer-hydrophobic
Arginine - Answer-free amino group makes it basic and hydrophilic
Asparagine - Answer-carbohydrate, can be covalently linked to its -NH
Aspartic acid - Answer-free carboxyl group makes it acidic and hydrophilic
Cysteine - Answer-oxidation of their -SH groups link 2 Cys (S-S)
Glutamic Acid - Answer-free carboxyl group makes it acidic and hydrophilic
CERTIFIED ANSWERS
Transfer RNA (tRNA) secondary structure: - Answer-tRNA "reads" genes information
encoded in mRNA (3 nucleotide codon) copied from DNA
What does tRNA transfer during protein synthesis - Answer-the appropriate amino acid
to a growing polypeptide chain
Transcription creates a: - Answer-complementary RNA copy (mRNA) of a sequence of
DNA
Translation steps: - Answer-mRNA decoded by ribosomes and tRNA is used to produce
a specific amino acid chain, or polypeptide, that will later fold into an active protein
Phenotype of an organism is determined by: - Answer-proteins
What defines function by interaction? - Answer-the three dimensional structure of
proteins
what defines the type of amino acid? - Answer-side chain
what kind of molecule are amino acids - Answer-ampholytic molecule (contains both
acidic and basic groups)
Charge of an amino acid is dependent on: - Answer-the pH of a solution
What happens to the net charge of an amino acid as you increase the pH - Answer-net
charge decreases
Which of the 20 common amino acids is achiral? - Answer-Glycine
Isoelectric point - Answer-pI=pH, average charge equals zero.
two equilibrium dissociation reactions w/ isoelectric points - Answer-HAH+ ----> HA + H
HA ----> A- + H+
pI formula if no ionizable side chain - Answer-pI = ¹/₂ (pK₁ + pK₂)
simplest amino acid? - Answer-glycine
Ways to classify amino acids based on properties: - Answer--size/shapes
-charges
,-polarity
-hydrophilic/phobic
-aromaticity (stacking interactions)
-conformation (determined by side chain)
-propensity to adopt a particular conformation in proteins (combo of all above)
what determines conformation of an amino acid - Answer-the side chain
Encoded proteins have which configuration, and what is a way to remember it? -
Answer-L configuration; can be remembered as the CORN law.
Which proteins tend to cluster together on the inside of proteins? And what happens -
Answer-Ala, Val, Ile, Leu. Clustering together stabilizes the protein structure, via
hydrophobic interactions.
AA's with nonpolar, aliphatic R groups - Answer-Glycine
Alanine
Proline
Valine
Leucine
Isoleucine
methionone
AA's with aromatic R groups - Answer-Phenylalanine
Tryptophan
Tyrosine
hydroxyl group of ____ can form hydrogen bonds and play important role in enzymes -
Answer-Tyrosine, Tyr, Y
AA's with polar, uncharged R groups - Answer-Serine, Threonine, Cysteine,
Asparagine, Glutamine.
Disulfide bond example - Answer-cystine
How does cystine happen? and through which bond - Answer-when pairs of cysteines
oxidize to form cystine through a disulfide bond.
Cystine features: p/np? hydrophilic/phobic? - Answer-nonpolar/hydrophobic
AA's with positively charged R groups - Answer-Lysine, Arginine, Histidine
Histine: - Answer-only amino acid with ionizable side chain that has a pka near
neutrality. Therefore, His can serve as a proton donor or acceptor in many enzyme-
catalyzed reactions.
, The most hydrophilic R groups are: - Answer-either positively or negatively charged.
AA's with negatively charged R groups: - Answer-Aspartate, Glutamate (neg charge as
pH 7)
Characterization of Biomolecules by Light
Absorption Using a Spectrophotometer - Answer-Detect the presence of particular
biomolecules and estimate concentration
Which amino acids have a characteristic UV absorbance? - Answer-the aromatic ones;
tyrosine, tryptophan > phenylalanine
General pKa's on amino acids
Carboxyl ≈ ?
Amino ≈ ? - Answer-carboxyl ~ 2.2
amino ~ 9.6
Human diets must include adequate amounts of nine amino acids, which ones? WTF
Very Hot MILK - Answer-WTF= Tryptophan, Threonine, Phenylalanine
VH= Valine, Histidine
MILK= methionine, isoleucine, leucine, lysine
Cysteine can meet the needs for: - Answer-methionine (both contain sulfur)
tyrosine can partially substitute for: - Answer-phenylanaline
conditionally essential amino acids for dietary needs: - Answer-arginine, cysteine,
glutamine, glycine, tyrosine
(not necessarily required)
most common amino acid - Answer-leucine
least common amino aid - Answer-tryptophan
Alanine - Answer-hydrophobic
Arginine - Answer-free amino group makes it basic and hydrophilic
Asparagine - Answer-carbohydrate, can be covalently linked to its -NH
Aspartic acid - Answer-free carboxyl group makes it acidic and hydrophilic
Cysteine - Answer-oxidation of their -SH groups link 2 Cys (S-S)
Glutamic Acid - Answer-free carboxyl group makes it acidic and hydrophilic
