Exam 19: Allosterism and Receptor-Ligand

Heterotropic regulation I. occurs with a molecule other than the protein's substrate II. occurs with regulator binding at a site other than the active site III. influences substrate binding IV. is a type of competitive inhibition

Proteins/enzymes that can be regulated allosterically I. show a hyperbolic Michaelis-Menten curve II. can be regulated by molecules that differ structurally from a substrate III. can be both activated and inhibited IV. undergo only competitive inhibition

In its reduced form, the central ion of the heme group of hemoglobin is _____.

In hemoglobin of sickle cell anemia patients, a valine residue binds to a(n) ___ patch causing ___ of the hemoglobin.

How does CO₂ affect hemoglobin-oxygen binding?

Enzymes that are allosterically regulated

The graph to the right, where YO2 represents %O2 saturation, will be used for the following questions -The sigmoidal nature of the plot of oxygen binding to hemoglobin indicates ___ among hemoglobin's subunits.

In the sequential model of allosterism, as regulatory molecules bind to allosteric sites,

Hemoglobin's subunits bind oxygen in a ______ manner.

The aggregation of hemoglobin of sickle cell anemia patients occurs in the ___ state, thus the formation of aggregates is most likely to occur in the ___.

The structure of the globin protein plays an important role in the affinity of hemoglobin for oxygen.

The absence of 2,3-bPG causes hemoglobin's affinity for oxygen to______.

Which is NOT true of enzyme-linked receptors?

Molecules that act identically like a receptor's natural ligand I. are termed agonists II. may compete with the natural ligand for the receptor binding site III. as inverse agonists activate the receptor to a lesser extent IV. as partial agonists can cause a different cellular effect than the natural Ligand

Which is NOT true of nuclear receptors?

G protein-coupled receptors

While the composition of hemoglobin in adult humans is $\alpha$ ₂ $\beta$ ₂, in the developing fetus, _____ is observed

An antagonist and an inverse agonist are similar in that

Cl- ion plays a role in the transport of CO2 in plasma

The graph to the right, where YO2 represents %O2 saturation, will be used for the following questions -The plot above describes the Bohr effect. If a third plot were added, a sigmoidal one between plots A and B,