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WorksheetsBiochem Exam I_Fall 2022: Max and Serena
Total questions: 41
Worksheet time: 23mins
Which is Not considered an evolutionary life kingdom?
Animalia
Protista
Plantae
Bacteria
Trick question: all of the previous choices are kingdoms
Depending on their source of energy, organisms can be
chemoautotrophs or chemoheterotrophs
Chemotrophs or phototrophs
Chemoheterotrophs and photoheterotrophs
Photoautotrophs and chemoautotrophs
Which is NOT an accurate statement?
All cells have a plasma membrane
All living organisms are in a dynamic steady state far from equilibrium
The ribosome is solely a eukaryotic organelle
Living cells exchange matter and energy with their surroundings
Supramolecular structures in the cell are often held together by
Covalent interactions
Non-covalent interactions
Water has several interesting properties that support life. Which ones are they? Check all that apply.
Cohesiveness
Adhesiveness
Low specific heat
Higher density of ice compared to liquid water
Hydrogen bonds are unique to water.
True
False
Water has a smaller dielecteric constant than most hydrophobic solvents. This is why water is able to dissolve salts.
True
False
Whic is the true statement? In the context of water...
Ionic bonds are stronger than covalent bonds
Hydrogen Bonds are weaker than Van der Waals interactions
Ionic bonds are weaker than covalent bonds
Which of these are colligative properties? Check all that apply
Surface tension
Boiling point
Color
Osmolarity
Melting point
Blood pH is maintained in the normal range by the bicarbonate buffer system.
True
False
Which of the pairs below show the correct amino acid name and single letter code (select all that apply)?
Tyrosine- Y
Arginine- R
Glutamine- Q
Alanine- A
Tryptophan- W
All amino acids are alpha-amino acids and have common backbone elements. Which is Not a common backbone component of an amino acid?
Amino group
Carboxylic group
Hydroxyl group
Central alpha -carbon
Which of these amino acid and R groups are associated incorrectly?
V---- Aliphatic Group
E---- Acidic Group
Q----Basic Group
F----Polar Group
Which of the following amino acids has a net negative charge at physiologic pH (~7.4)?
Glutamic acid
Histidine
Lysine
Asparagine
Amino acids found in hemoglobin (or any other protein) uniformly have which configuration?
L
R
S
D
Gel-filtration chromatography separates on the basis of...
Size and Shape
Net charge
Affinity
How cool you are
You are attempting to isolate Protein A from a patient sample that contains several proteins. Protein A has a molecular weight of 50 kDa and has a distinct charge at lower pH. What technique could best isolate Protein A?
Edman Degradation
Size Exclusion Chromatography
Affinity Binding Chromatography
SDS-PAGE and isoelectric focusing
Which of these amino acids would you expect to find in the core of a protein? (Check all that apply)
L
K
V
F
Q
The enzyme chymotrypsin only targets the bond on the C-side of amino acids with aromatic R-Groups. Which of the following peptides can chymotrypsin cleave? The sequences are written starting at the N-terminal to the C-Terminal.
G-A-K-L-L-L-F
P-I-G-Y-G-G-Q
G-L-A-D-D-A-D
A-V-I-L-L-I-L
What is the PI of this amino acid? What is the identity of the Amino Acid (Check 2 answers)
PI=10.75
PI=5.55
PI=7
Aspartic Acid
Arginine
When an amino acid is at a pH below its pI value, the amino acid has a net positive charge.
True
False
If you add a mixture of proteins into a cation exchange column, what would you expect to elute out first if you use a neutral mobile phase?
Proteins high in basic amino acids
Positively Charged Proteins
Negatively Charged Proteins
None of the proteins would elute
Which of these statements about Keratin is False?
The super-twisted coiled-coil structure is left-handed
Keratin fibers form intermediate filaments
Keratin is composed of hydrophilic amino acids
Individual keratin chains are right-handed alpha-helices
Which of the following properties of a protein is least likely to be affected by changes in pH?
Primary Structure
Secondary Structure
Tertiary Structure
Net Charge
Which of the following can stabilize protein structures? (Check all that apply)
Salt Bridges
Disulfide Bonds
Hydrophobic Effect
Hydrogen Bonds
Chaperone Proteins
How are secondary structures stabilized?
Hydrogen bonds between polar R-Groups
Ionic interaction between carbonyl backbone and R-Groups
Hydrogen bonds between acidic and basic R-Grou
Hydrogen bonds between carbonyl oxygen and amide groups
These structures do not stabilize proteins
You denature a pure enzyme sample using urea and a reducing agent. You observe no activity when the substrate is added, however, once the added reagents are removed there is a return in enzymatic activity. Which of the statements is true?
The enzyme does not have disulfide bonds
The enzyme does not require a chaperone to fold properly
The folding is random
The protein's structure is not vital to its enzymatic function
The cytoskeleton component filamentous actin is made of many subunits, all of which are globular actin. Which term refers to globular actin in this context?
Prosthetic group
Protomer
Ligand
Cofactor
polymorphism
A higher Kd indicates a higher affinity for the protein to bind to the ligand.
True
False
In Hemoglobin, T is the low affinity state.
True
False
2. BPG helps in low oxygen environments by binding to hemoglobin and increasing its affinity to oxygen.
True
False
The binding of oxygen to hemoglobin is an example of cooperative binding.
So true, so true
Nah bro, that's false
Which of these statements about Enzymes are true? (choose all that apply)
Enzymes increase the amount of free energy in a reaction
Enzymes are not regulated within cells
Enzymes increase the rate of reactions
Enzymes increase the amount of activation in order to increase the rate of reaction
Enzymes are able to catalyze several reactions without being degraded
Based of this graph, where, in the reaction progression, would an enzyme directly affect the reaction? How would it affect the reaction? (Select all that apply)
A and C
B
Lower the activation energy
Destabilize the transition state of the substrate
Make the reaction spontaneous
Which of these statements are true? check all that apply.
With enzymes, specificity for substrate is lowered
Enzymes allow for product formation regulation
Most enzymes are globular proteins
The binding energy between the enzyme and the substrate helps lower the activation energy
A low Km value indicate a high affinity for the substrate.
True
False
The standard free energy of a reaction is not affected by the Keq
True
False
In the lineweaver-Burk linear plot,
Km/Vmax is the y-intercept of the curve
1/Vmax is the x-intercept
Km/Vmax is the slope
Vmax/Km is the slope
Enzymes that exhibits allosterism
Obey Michealis -Menten kinetics
Are subject to conformational change upon binding of a modulator
Which statements are Not true?
The sequential and pingpong mechanisms can be distinguished easily using the Lineweaver-Burk plot
Competitive inhibitors affect the Vmax of the reaction
Non-competitive inhibitors increase the Vmax and decrease the Km
Toxins often cause reversible inhibition of enzymes
Competitive inhibitors are a type of mixed inhibitors
In terms of regulation,...
Oxygen can be considered a homotropic allosteric regulator of hemoglobin
Phosphorylation is the most common non-covalent modification for enzyme regulation
