BIOCHEM C785 BIOCHEMISTRY
PREASSESSMENT FINAL TEST 2026
QUESTIONS WITH CORRECT ANSWERS
GRADED A+
◍ If acetic acid (pKa = 4.8) is dissolved in solution with pH 8, what happens?.
Answer: We have a very basic solution, with OH- more desperate for the
proton than the acetic acid. OH- will take away all the protons, and we have
acetate in solution for a charge of -1The pKa of the carboxy side chain will
vary between amino acids, depending on what else is nearby, thus the
specific charges will vary
◍ If an amino group doesn't have a pKa for its side chain (such as glycine),
how do you find pI?.
Answer: pI = (pKa1 + pKa2) / 2Take the avg of the pKa valuespI(glycine) =
(2.3 + 9.6)/2 round > (2+10)/2 = 6
◍ Membrane proteins:- Are sometimes peripheral- Are sometimes integral-Are
types of lipids - Both A and B- None of the above.
Answer: - Both A and B
◍ has the ability to form a covalent bond with another of the same aa.
Answer: cysteine2 cysteines can oxygenate their SH groups, allowing the
resulting S- to bind to each other in a covalent bond -- creating a disulfide
bridge
◍ relationship between pH & pKa.
Answer: pKa = -logKapH = pKa + log[conjugate base]/[acid]
<<Henderson-Hasselbach equationIn pH vs pKa, it is like a 'battle' for the
proton. The higher value has a stronger desire for the proton. If the pH is
, higher, the solution wins, and if the pKa is higher, the molecule wins.
◍ These two amino acids 'should' be basic but are not.
Answer: Asparagine (Asn, N) & Glutamine (Gln, Q)Their NH2 groups
should be basic, due to lone pair of electrons on N, but sp2 Ns are far less
basic than sp3 - bc electrons that would reach out & attack a proton are too
busy resonating onto the carbonyl group.
◍ Which notation indicates a 14-carbon omega-3 fatty acid that contains no
other double bonds?A) 14:1 Δ 11)( B) 17:1 Δ 14)( C) 14:1 Δ3)( D)
13:1(Δ11)E) 14:0( Δ 11).
Answer: A) 14:1 Δ 11)
◍ If glycine (COO- pKa = 2.3, NH2 pKa = 9.6) is in solution of pH1, what
happens?.
Answer: pH 1 is less than both pKa values. Thus the solution has more
protons, and will give them to both the amine and carboxyl groups. Thus the
groups exist as NH3+ and COOH. If we add both charges, we get +1 and 0,
for a net charge of +1.
◍ PUFA.
Answer: polyunsaturated fatty acid- 2 or more double bonds
◍ only covalent bond seen in tertiary/quaternary structures is _. What is the
purpose of this type of bond?.
Answer: disulfide bridge (between 2 cysteines, or 'cystine')helps stabilize the
3D structure of proteins/enzymes
◍ What does pKa tell us?.
Answer: the likelihood of a molecule to take or donate a proton from/to
solution
◍ A lipid is __________.- A fat- An oil- A molecule that dissolves in a
non-polar solvent- Is made from isoprene units- Is water soluble.
Answer: - A molecule that dissolves in a non-polar solvent
◍ Basic amino acids are found in _ bonds & _ of proteins/enzymes.
, Answer: salt bridges (ionic bonds, just like acidic aa's)outside
◍ Only achiral amino acid.
Answer: GlycineBecause it is not attached to 4 different groups, glycine
does not have R/S configurations or D/L
◍ As you raise the pH between pKa units, the charge _.
Answer: goes down by 1
◍ basic amino acids.
Answer: HistidineLysineArginine
◍ A particular lipid is a liquid at room temperature, so it is called a(n)
________. - Oil- Fat- Lipid - Membrane - Sphingolipid.
Answer: - Oil
◍ If pH = pKa, what does that tell us?.
Answer: buffer zone >> 50:50 - half molecules will be protonated and half
will be deprotonated.
◍ Ideal places for glycine.
Answer: twists/bends, anywhere you can't fit a larger side chainAlanine may
also be found in these situations, as its methyl R group is also tiny in
comparison to the other R groups.
◍ play a key role in synthesis of nitrogen-containing compounds.
Answer: Asparagine (Asn, N) & glutamine (Gln, Q)The fact that they have a
N in both their side chain & R group, and thus act as a N storage for living
molecules. The N groups can be removed thru transamination.
◍ pKa for amine group of amino acids.
Answer: 10
◍ Triacylglycerols are made from a ________ and ________.- glycerol;
cholesterol Correct!- glycerol; three fatty acids- ceramide; three fatty acids -
ceramide; three cholesterols- carotenoid; two cholesterols.
Answer: - glycerol; three fatty acids
◍ has largest & most complex R group.
PREASSESSMENT FINAL TEST 2026
QUESTIONS WITH CORRECT ANSWERS
GRADED A+
◍ If acetic acid (pKa = 4.8) is dissolved in solution with pH 8, what happens?.
Answer: We have a very basic solution, with OH- more desperate for the
proton than the acetic acid. OH- will take away all the protons, and we have
acetate in solution for a charge of -1The pKa of the carboxy side chain will
vary between amino acids, depending on what else is nearby, thus the
specific charges will vary
◍ If an amino group doesn't have a pKa for its side chain (such as glycine),
how do you find pI?.
Answer: pI = (pKa1 + pKa2) / 2Take the avg of the pKa valuespI(glycine) =
(2.3 + 9.6)/2 round > (2+10)/2 = 6
◍ Membrane proteins:- Are sometimes peripheral- Are sometimes integral-Are
types of lipids - Both A and B- None of the above.
Answer: - Both A and B
◍ has the ability to form a covalent bond with another of the same aa.
Answer: cysteine2 cysteines can oxygenate their SH groups, allowing the
resulting S- to bind to each other in a covalent bond -- creating a disulfide
bridge
◍ relationship between pH & pKa.
Answer: pKa = -logKapH = pKa + log[conjugate base]/[acid]
<<Henderson-Hasselbach equationIn pH vs pKa, it is like a 'battle' for the
proton. The higher value has a stronger desire for the proton. If the pH is
, higher, the solution wins, and if the pKa is higher, the molecule wins.
◍ These two amino acids 'should' be basic but are not.
Answer: Asparagine (Asn, N) & Glutamine (Gln, Q)Their NH2 groups
should be basic, due to lone pair of electrons on N, but sp2 Ns are far less
basic than sp3 - bc electrons that would reach out & attack a proton are too
busy resonating onto the carbonyl group.
◍ Which notation indicates a 14-carbon omega-3 fatty acid that contains no
other double bonds?A) 14:1 Δ 11)( B) 17:1 Δ 14)( C) 14:1 Δ3)( D)
13:1(Δ11)E) 14:0( Δ 11).
Answer: A) 14:1 Δ 11)
◍ If glycine (COO- pKa = 2.3, NH2 pKa = 9.6) is in solution of pH1, what
happens?.
Answer: pH 1 is less than both pKa values. Thus the solution has more
protons, and will give them to both the amine and carboxyl groups. Thus the
groups exist as NH3+ and COOH. If we add both charges, we get +1 and 0,
for a net charge of +1.
◍ PUFA.
Answer: polyunsaturated fatty acid- 2 or more double bonds
◍ only covalent bond seen in tertiary/quaternary structures is _. What is the
purpose of this type of bond?.
Answer: disulfide bridge (between 2 cysteines, or 'cystine')helps stabilize the
3D structure of proteins/enzymes
◍ What does pKa tell us?.
Answer: the likelihood of a molecule to take or donate a proton from/to
solution
◍ A lipid is __________.- A fat- An oil- A molecule that dissolves in a
non-polar solvent- Is made from isoprene units- Is water soluble.
Answer: - A molecule that dissolves in a non-polar solvent
◍ Basic amino acids are found in _ bonds & _ of proteins/enzymes.
, Answer: salt bridges (ionic bonds, just like acidic aa's)outside
◍ Only achiral amino acid.
Answer: GlycineBecause it is not attached to 4 different groups, glycine
does not have R/S configurations or D/L
◍ As you raise the pH between pKa units, the charge _.
Answer: goes down by 1
◍ basic amino acids.
Answer: HistidineLysineArginine
◍ A particular lipid is a liquid at room temperature, so it is called a(n)
________. - Oil- Fat- Lipid - Membrane - Sphingolipid.
Answer: - Oil
◍ If pH = pKa, what does that tell us?.
Answer: buffer zone >> 50:50 - half molecules will be protonated and half
will be deprotonated.
◍ Ideal places for glycine.
Answer: twists/bends, anywhere you can't fit a larger side chainAlanine may
also be found in these situations, as its methyl R group is also tiny in
comparison to the other R groups.
◍ play a key role in synthesis of nitrogen-containing compounds.
Answer: Asparagine (Asn, N) & glutamine (Gln, Q)The fact that they have a
N in both their side chain & R group, and thus act as a N storage for living
molecules. The N groups can be removed thru transamination.
◍ pKa for amine group of amino acids.
Answer: 10
◍ Triacylglycerols are made from a ________ and ________.- glycerol;
cholesterol Correct!- glycerol; three fatty acids- ceramide; three fatty acids -
ceramide; three cholesterols- carotenoid; two cholesterols.
Answer: - glycerol; three fatty acids
◍ has largest & most complex R group.
