MCAT Biology the Princeton
Reviewed Exam 2026/2027 Updated
Verified Questions and Solutions A+
Pass Guaranteed
What are the 4 biological macromolecules?
- ANS - 1. Proteins.
2. Carbohydrates.
3. Lipids.
4. Nucleic Acids.
What class of enzymes makes the biological macromolecules?
- ANS - Polymerases.
What are 3 names for the type of reactions polymerases use to
make biological macromolecules?
- ANS - 1. Polymerization.
2. Dehydration synthesis.
3. Condensation.
,What type of reaction breaks a macromolecule into its
monomers?
- ANS - Hydrolysis reactions.
What is the generic structure of amino acids?
- ANS -
What are 2 common types of covalent bonds between amino
acids?
- ANS - 1. Peptide bonds.
2. Disulfide bridges.
Peptide bond
- ANS -
What is hydrolysis of a protein by another protein called?
- ANS - Proteolysis or proteolytic cleavage.
What class of proteins hydrolyze other proteins?
- ANS - Proteolytic enzymes or proteases.
What type of bond is a disulfide bridge?
- ANS - Covalent.
,Disulfide bond
- ANS -
After a cysteine residue becomes disulfide-bonded to another
cysteine residue, what is it called?
- ANS - Cystine.
Which is more oxidized, the sulfur in cysteine or the sulfur in
cystine?
- ANS - Cystine.
Unlike cysteine which is bound to a hydrogen and a carbon,
the sulfur in cystine is bonded to a sulfur and a carbon and is
thus more oxidized.
The inside of cells is known as a reducing environment
because cells possess antioxidants. Where would disulfide
bridges be more likely to be found, in extracellular proteins,
under oxidizing conditions, or in the interior of cells, in a
reducing environment?
- ANS - In a reducing environment the S-S group is reduced to
two SH groups. Disulfide bridges are found only in
extracellular polypeptides where they will not be reduced.
, Denaturation
- ANS - Disruption of a protein's shape without breaking
peptide bonds.
What are 4 ways to cause denaturation?
- ANS - 1. Urea, which disrupts hydrogen bonding.
2. Extremes of pH.
3. Extremes of temperature.
4. Changes in salt concentration, or tonicity.
What is a protein's primary structure?
- ANS - The order of the amino acid sequence.
What is a protein's secondary structure?
- ANS - Initial folding of a polypeptide stabilized by local
hydrogen bonds between backbone NH and CO groups.
What are the 2 most common secondary protein structures?
- ANS - The alpha helix and beta sheets.
What is a protein's tertiary structure?
- ANS - Hydrophobic/hydrophilic interactions between amino
acid residues located more distantly from each other.
Reviewed Exam 2026/2027 Updated
Verified Questions and Solutions A+
Pass Guaranteed
What are the 4 biological macromolecules?
- ANS - 1. Proteins.
2. Carbohydrates.
3. Lipids.
4. Nucleic Acids.
What class of enzymes makes the biological macromolecules?
- ANS - Polymerases.
What are 3 names for the type of reactions polymerases use to
make biological macromolecules?
- ANS - 1. Polymerization.
2. Dehydration synthesis.
3. Condensation.
,What type of reaction breaks a macromolecule into its
monomers?
- ANS - Hydrolysis reactions.
What is the generic structure of amino acids?
- ANS -
What are 2 common types of covalent bonds between amino
acids?
- ANS - 1. Peptide bonds.
2. Disulfide bridges.
Peptide bond
- ANS -
What is hydrolysis of a protein by another protein called?
- ANS - Proteolysis or proteolytic cleavage.
What class of proteins hydrolyze other proteins?
- ANS - Proteolytic enzymes or proteases.
What type of bond is a disulfide bridge?
- ANS - Covalent.
,Disulfide bond
- ANS -
After a cysteine residue becomes disulfide-bonded to another
cysteine residue, what is it called?
- ANS - Cystine.
Which is more oxidized, the sulfur in cysteine or the sulfur in
cystine?
- ANS - Cystine.
Unlike cysteine which is bound to a hydrogen and a carbon,
the sulfur in cystine is bonded to a sulfur and a carbon and is
thus more oxidized.
The inside of cells is known as a reducing environment
because cells possess antioxidants. Where would disulfide
bridges be more likely to be found, in extracellular proteins,
under oxidizing conditions, or in the interior of cells, in a
reducing environment?
- ANS - In a reducing environment the S-S group is reduced to
two SH groups. Disulfide bridges are found only in
extracellular polypeptides where they will not be reduced.
, Denaturation
- ANS - Disruption of a protein's shape without breaking
peptide bonds.
What are 4 ways to cause denaturation?
- ANS - 1. Urea, which disrupts hydrogen bonding.
2. Extremes of pH.
3. Extremes of temperature.
4. Changes in salt concentration, or tonicity.
What is a protein's primary structure?
- ANS - The order of the amino acid sequence.
What is a protein's secondary structure?
- ANS - Initial folding of a polypeptide stabilized by local
hydrogen bonds between backbone NH and CO groups.
What are the 2 most common secondary protein structures?
- ANS - The alpha helix and beta sheets.
What is a protein's tertiary structure?
- ANS - Hydrophobic/hydrophilic interactions between amino
acid residues located more distantly from each other.
