Induced Fit and Ligand Binding

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Which molecule binds to hemoglobin and decreases its affinity for oxygen?

2,3-BPG

What is the effect of carbamylation on hemoglobin?

It decreases the affinity of hemoglobin for oxygen

What is the pH in the tissues where hemoglobin reacts with CO2?

7.2

What is the pH in the lungs where HbCO2- is converted to HbO2?

<p>7.6</p> Signup and view all the answers

What is the molecule responsible for the resistance of fetal hemoglobin to 2,3-BPG action?

<p>2,3-BPG</p> Signup and view all the answers

What causes sickle cell anemia?

<p>Aggregation of deoxygenated hemoglobin S into polymers</p> Signup and view all the answers

Which of the following is true about protein function?

<p>Proteins function by interacting with other molecules</p> Signup and view all the answers

What is a molecule bound reversibly by a protein called?

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

What is a specific site on a protein where a ligand binds called?

<p>Binding site</p> Signup and view all the answers

What is the term for the reversible binding of ligands to proteins?

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

In multisubunit proteins, conformational changes in one subunit can affect the others. What is this phenomenon called?

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

What is the heme prosthetic group in myoglobin and hemoglobin composed of?

<p>Fe2+ (ferrous) and protoporphyrin</p> Signup and view all the answers

Which protein binds carbon monoxide (CO) 20000 times tighter than oxygen (O2)?

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

Which amino acid in myoglobin does not directly bind to Fe2+ but helps stabilize the O2 binding to Fe2+?

<p>His64</p> Signup and view all the answers

What is the main function of hemoglobin?

<p>Transport of O2 from lungs to tissues</p> Signup and view all the answers

Which state of hemoglobin is more stable when O2 is not present?

<p>T state</p> Signup and view all the answers

What is the phenomenon called when the affinity of a protein for O2 varies with local pO2?

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

How does the pH difference between lungs and metabolic tissues affect the efficiency of O2 transport?

<p>Increases efficiency</p> Signup and view all the answers

Which type of antibody is the most abundant in the blood?

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

What is the structure of an IgG antibody?

<p>Two heavy chains and two light chains composed of constant domains and variable domains</p> Signup and view all the answers

What is the function of antibodies in the immune response?

<p>To target and recognize extracellular pathogens</p> Signup and view all the answers

What is the mechanism of action of antibodies in the immune response?

<p>Antibodies bind to antigens and trigger phagocytosis by macrophages</p> Signup and view all the answers

Which assay allows the rapid screen and quantification of an antigen in a complex sample?

<p>Enzyme-linked immunosorbent assay (ELISA)</p> Signup and view all the answers

What is the impact of sickle cell anemia on human health and resistance to malaria?

<p>It worsens human health and decreases resistance to malaria</p> Signup and view all the answers

Which globin protein is responsible for binding oxygen in the muscles?

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

What is the equation for the fraction of binding sites occupied by a ligand?

<p>q = [PL] / ([PL] + [P])</p> Signup and view all the answers

What is the equation for the dissociation constant Kd?

<p>Kd = 1 / Ka</p> Signup and view all the answers

What is the significance of the partial pressure of O2 at which 50% of the available binding sites are occupied?

<p>It represents the concentration of O2 at which half of the binding sites are occupied</p> Signup and view all the answers

What is the equation for the fraction of binding sites occupied by a ligand when the ligand is a gas expressed in terms of partial pressures?

<p>q = p50 + pO2</p> Signup and view all the answers

What is the dissociation constant Kd for the interaction between avidin and biotin?

<p>1 x 10^-15 M</p> Signup and view all the answers

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