BIOCHEM MIDTERM EXAM REVIEWER
questions and answers 2026\2027 A+ Grade
Denaturation occurs in the stomach with gastric juice as the denaturant. -
correct answer The first step in protein digestion is denaturation. Where does denaturation occur in the
body, and what is the denaturant?
Gastric juice -
correct answer What is the first digestive enzyme that protein encounters, and where does this
encounter take place?
urea cycle -
correct answer the metabolic pathway that converts ammonium ions into urea. This cycle processes the
ammonium ions in the form of carbamoyl phosphate
carbamoyl phosphate -
correct answer a compound formed from CO2, NH4, ATP, and H2O
carbamoyl phosphate -
correct answer In what chemical form do ammonium ions enter the urea cycle?
one molecule of bicarbonate, two molecules of MgATP, and one molecule of glutamine. -
correct answer What are the chemical reactants for the formation of carbamoyl phosphate?
arginine, ornithine and citrulline -
correct answer Name the three amino acids are involved as intermediates in the urea cycle..
carbamoyl phosphate -
correct answer What substance is the "fuel" for the urea cycle?
, Four -
correct answer How much energy, in terms of ATP, is expended in the synthesis of a molecule of urea?
One nitrogen atom comes from carbamoyl phosphate, the other from aspartate. -
correct answer What are the sources of the two nitrogen atoms in urea?
Arginine -
correct answer the most nitrogen-rich of the standard amino acids. It contains four nitrogen atoms.
nonstandard amino acids -
correct answer amino acids not found in protein.
False; glutamate to a-ketoglutarate. -
correct answer TRUE OR FALSE
The toxicity of ammonium ion is related to the oxidative deamination reaction by which it is formed, the
conversion of aspartate to a-ketoglutarate.
FALSE; The functional group attached to the phosphate in carbamoyl phosphate is the simple amide
functional group -
correct answer TRUE OR FALSE
The functional group attached to the phosphate in carbamoyl phosphate is OH functional group.
TRUE -
correct answer TRUE OR FALSE
the urea cycle occurs partially in the mitochondria and partially in the cytosol and that ornithine and
citrulline must be transported across the inner mitochondrial membrane.
FALSE; Hydrolysis of arginine produces urea and regenerates ornithine, -
correct answer TRUE OR FALSE
questions and answers 2026\2027 A+ Grade
Denaturation occurs in the stomach with gastric juice as the denaturant. -
correct answer The first step in protein digestion is denaturation. Where does denaturation occur in the
body, and what is the denaturant?
Gastric juice -
correct answer What is the first digestive enzyme that protein encounters, and where does this
encounter take place?
urea cycle -
correct answer the metabolic pathway that converts ammonium ions into urea. This cycle processes the
ammonium ions in the form of carbamoyl phosphate
carbamoyl phosphate -
correct answer a compound formed from CO2, NH4, ATP, and H2O
carbamoyl phosphate -
correct answer In what chemical form do ammonium ions enter the urea cycle?
one molecule of bicarbonate, two molecules of MgATP, and one molecule of glutamine. -
correct answer What are the chemical reactants for the formation of carbamoyl phosphate?
arginine, ornithine and citrulline -
correct answer Name the three amino acids are involved as intermediates in the urea cycle..
carbamoyl phosphate -
correct answer What substance is the "fuel" for the urea cycle?
, Four -
correct answer How much energy, in terms of ATP, is expended in the synthesis of a molecule of urea?
One nitrogen atom comes from carbamoyl phosphate, the other from aspartate. -
correct answer What are the sources of the two nitrogen atoms in urea?
Arginine -
correct answer the most nitrogen-rich of the standard amino acids. It contains four nitrogen atoms.
nonstandard amino acids -
correct answer amino acids not found in protein.
False; glutamate to a-ketoglutarate. -
correct answer TRUE OR FALSE
The toxicity of ammonium ion is related to the oxidative deamination reaction by which it is formed, the
conversion of aspartate to a-ketoglutarate.
FALSE; The functional group attached to the phosphate in carbamoyl phosphate is the simple amide
functional group -
correct answer TRUE OR FALSE
The functional group attached to the phosphate in carbamoyl phosphate is OH functional group.
TRUE -
correct answer TRUE OR FALSE
the urea cycle occurs partially in the mitochondria and partially in the cytosol and that ornithine and
citrulline must be transported across the inner mitochondrial membrane.
FALSE; Hydrolysis of arginine produces urea and regenerates ornithine, -
correct answer TRUE OR FALSE
