Hemoglobin Structure and Function Quiz

Hemoglobin has a lower affinity for oxygen than myoglobin. Hemoglobin is also a tetrameric protein, while myoglobin is only a monomer.

True (A)

The multiple subunits of hemoglobin enable cooperative binding of oxygen. This means that the binding of one oxygen molecule to a subunit increases the affinity of the other subunits for oxygen, allowing for efficient transport of oxygen from the lungs to the tissues.

<p>The two types of globin proteins in adult hemoglobin are alpha and beta.</p> Signup and view all the answers

<p>Both b and c (C)</p> Signup and view all the answers

<p>The two models that explain how cooperative proteins perform their function are the sequential model and the concerted model.</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>Oxygen</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>The P50 of hemoglobin is the partial pressure of oxygen at which hemoglobin is 50% saturated with oxygen. It is approximately 26 mmHg.</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>When the oxygen pressure is less than P50, hemoglobin releases oxygen to tissues.</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>Hemoglobin becomes unsaturated when it releases oxygen in tissues.</p> Signup and view all the answers

<p>The chains of hemoglobin interact with each other through hydrophobic interactions.</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>Hemoglobin exists in two forms: the T-state and the R-state.</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>Binding of oxygen to hemoglobin triggers conformational changes, moving it from the low affinity T-state to the high affinity R-state.</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>When free of oxygen, heme has a domed structure with iron outside of the plane of the heme group. When oxygen binds to heme, it adopts a planar structure and iron moves into the plane of the heme group.</p> Signup and view all the answers

<p>When oxygen binds to heme, the iron atom moves into the plane of the heme group and pulls proximal histidine (F8) along with it.</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>The cooperative binding of oxygen to hemoglobin is a protective mechanism that prevents a sudden drop in pulmonary capillary oxygen tension from dramatically affecting overall hemoglobin saturation.</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>pH can affect the shape of hemoglobin and its affinity for oxygen. A lower pH (more acidic) shifts hemoglobin from the R-state to the T-state. This results in a decrease in affinity for oxygen, allowing for easier release of oxygen to tissues.</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>CO2 can bind to the N-terminus of hemoglobin subunits, forming carbamate. This binding converts hemoglobin to the T-state, which has a lower affinity for oxygen.</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>The amino acids mainly responsible for the positive charge in the core of hemoglobin are histidine and lysine.</p> Signup and view all the answers

<p>BPG binds to a location in the core of hemoglobin where the subunits meet. This stabilizes the T-state of hemoglobin and reduces its affinity for oxygen, promoting oxygen release to tissues.</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>Fetal hemoglobin lacks the histidine residue that is involved in BPG binding. Without BPG binding, fetal hemoglobin stays in the R-state, maintaining a high affinity for oxygen.</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>Freshly donated blood is important for transfusions because BPG degrades in the blood over time. The degradation of BPG reduces the hemoglobin's affinity for oxygen and can impact the effectiveness of oxygen delivery to the tissues.</p> Signup and view all the answers

A protein that binds oxygen and transports it in the blood.

A protein that binds oxygen and stores it in muscles.

The ability of a protein to change its shape upon binding a ligand.

The state of hemoglobin with low affinity for oxygen.

The state of hemoglobin with high affinity for oxygen.

The partial pressure of oxygen at which 50% of the hemoglobin is saturated.

The process where the binding of one ligand increases the affinity for subsequent ligands.

The effect of acidity on hemoglobin, decreasing its affinity for oxygen.

A molecule that binds to hemoglobin and reduces its affinity for oxygen.

The type of hemoglobin found in fetuses, with higher affinity for oxygen than adult hemoglobin.

The phenomenon where the binding of a ligand to one site affects the binding of another ligand at a different site.

The binding of oxygen to heme causes conformational changes in hemoglobin.

The ability of hemoglobin to effectively bind oxygen in the lungs and release it in the tissues.

The interaction between hemoglobin subunits, affecting its oxygen-binding properties.

The sigmoidal shape of hemoglobin's saturation curve.

The process by which oxygen is transported from the lungs to the tissues.

The process by which oxygen is released from hemoglobin in the tissues.

The binding of carbon dioxide to hemoglobin, contributing to oxygen release.

The formation of carbamate on hemoglobin, affecting its oxygen-binding properties.

The binding of BPG to hemoglobin, decreasing its affinity for oxygen.

The difference in oxygen affinity between adult and fetal hemoglobin, crucial for oxygen transfer.

The process by which hemoglobin binds oxygen in the lungs.

The ability of hemoglobin to hold onto a large amount of oxygen at high partial pressures.

The structure of hemoglobin, consisting of four subunits.

The role of hydrophobic interactions in maintaining the stability of hemoglobin.

The role of electrostatic interactions and hydrogen bonds in stabilizing hemoglobin.

The two most abundant hemoglobin subunits in adults.

The process by which hemoglobin releases oxygen in the tissues.

The protective mechanism of hemoglobin against sudden drops in oxygen tension.

The role of hemoglobin in oxygen transport and delivery.