30 Questions
What is the first amino acid incorporated into any new protein?
Methionine
In which direction are amino acid residues listed when describing a chain of amino acids?
N-terminus to C-terminus
What feature defines an oligopeptide?
12-20 amino acids
What is the spatial arrangement of atoms that can result from movement without breaking bonds called?
Conformation
Which type of proteins have a spherical shape with as little surface area per volume as possible?
Globular proteins
What feature makes globular proteins highly soluble in water?
Hydrophilic amino acids on the surface
What symptom might occur if a vessel carrying sickled cells is blocked in the lungs?
Fever and difficulty breathing
Why are carriers of sickle cell disease more resistant to malaria?
Sickle RBCs have an irregular shape that makes it difficult for malaria parasites to thrive
Which type of bond is NOT a weak non-covalent interaction that helps in protein folding?
Covalent bond
What can disrupt the interactions that keep proteins folded and cause them to denature?
Guanidine hydrochloride
What can protein misfolding lead to?
Toxic protein clump
What are prions composed entirely of?
Protein aggregates
What is the rate expression for a first order reaction?
$v = -k\frac{d[A]}{dt}$
Which type of reaction has a rate expression involving the square of the reactant concentration?
Second order reaction
What does the gradient of [P] vs. Time represent in an enzyme-catalyzed reaction?
Rate of reaction (velocity)
Why is initial velocity often used in the study of enzyme kinetics?
To prevent depletion of substrate as a confounding factor
How does the velocity of an enzyme-catalyzed reaction change with increasing [substrate]?
Velocity increases and approaches a limiting value
At high substrate concentrations, what determines the limit on the velocity of an enzyme-catalyzed reaction?
Conditions like temperature, pH, and amount of enzyme present
How do changes in pH affect enzyme activity at the active site?
Alter the ionization of amino acid residues
What happens to enzyme activity above an optimal temperature?
Denaturation occurs, leading to decreased activity
In enzyme kinetics, what is the significance of determining the order of reaction?
It reveals how substrate concentration impacts the reaction rate
How does an increase in thermal energy affect enzyme-catalyzed reactions?
Increases the proportion of substrates reaching the transition state
What effect does heat have on enzymes when above an optimal temperature?
Disrupts molecular interactions and leads to denaturation
How is the rate of reaction in enzyme kinetics expressed?
$v = \frac{d[P]}{dt}$ or $v = -\frac{d[A]}{dt}$
What is the theoretical value of Vmax in Michaelis-Menten kinetics?
Occurs at very high substrate concentrations when the enzyme is completely saturated
Which characteristic makes Michaelis-Menten plots difficult for determining Vmax and Km?
Small substrate concentration required
What does the Michaelis constant Km measure?
Affinity of the enzyme for its substrate
What does the turnover number Kcat represent in Michaelis-Menten kinetics?
Number of substrates converted into product per enzyme molecule per unit time
In Michaelis-Menten kinetics, what does a small Km indicate about an enzyme's affinity for its substrate?
High affinity
Why does the large substrate concentration requirement pose a disadvantage in Michaelis-Menten kinetics?
Increases experimental complexity
Test your knowledge about proteins and amino acids chains. Learn about the roles of amino acids in building protein structures and how amino acid sequences are described in proteins. Understand the direction of amino acid residues in a chain from N- to C-terminus.
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