Biochm chpt 5 whole doc MC only

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Which of the following is true about protein-ligand interactions?

Proteins can only bind to other proteins as ligands.

Protein-ligand interactions are critical for an organism to respond rapidly to changing circumstances. (correct)

Protein-ligand interactions are irreversible.

Protein-ligand interactions are not specific, allowing proteins to bind to any molecule.

What determines the specificity of protein-ligand interactions?

The size and shape of the protein.

The size, shape, charge, and hydrophobic or hydrophilic character of the protein. (correct)

The charge and hydrophobic or hydrophilic character of the protein.

The ability of the protein to discriminate among different molecules.

What is true about the conformation of proteins?

Changes in protein conformation can be both subtle and dramatic. (correct)

Proteins have a fixed conformation that does not change.

Conformational changes in proteins are not essential to their function.

Changes in protein conformation are always subtle.

Which of the following statements about dissociation constant (Kd) is correct?

Kd is the reciprocal of Ka Signup and view all the answers

What does Kd represent in the context of ligand-receptor binding?

Kd represents the ligand concentration at which half of the available receptor binding sites are occupied Signup and view all the answers

Which of the following statements about hemoglobin and myoglobin is correct?

Myoglobin binds carbon monoxide (CO) more than 20,000 times better than oxygen (O2) Signup and view all the answers

Which of the following statements about hemoglobin is true?

Hemoglobin undergoes a structural change when binding oxygen. Signup and view all the answers

What is the purpose of hemoglobin binding oxygen cooperatively?

To bind oxygen efficiently in the tissues. Signup and view all the answers

What is the Hill coefficient in the context of ligand binding?

A measure of ligand binding cooperativity. Signup and view all the answers

Which of the following statements about protein-ligand interactions is true?

Protein-ligand interactions are regulated by induced fit Signup and view all the answers

What is the role of heme in myoglobin and hemoglobin?

Heme is a protein-bound prosthetic group in myoglobin and hemoglobin Signup and view all the answers

What is the relationship between the association constant (Ka) and the affinity of a ligand for a protein?

Higher Ka indicates higher affinity Signup and view all the answers

According to the text, what does a Hill coefficient greater than 1 indicate?

Positive cooperativity Signup and view all the answers

According to the text, what does the MWC model suggest about ligand binding in a multisubunit protein?

All subunits are in the same conformation Signup and view all the answers

According to the text, what is the relationship between the binding of H+ and CO2 and the binding of O2 in hemoglobin?

They have an inverse relationship Signup and view all the answers

Which of the following is true about the Bohr effect?

It describes the effect of pH on the binding and release of O2 by hemoglobin Signup and view all the answers

Which of the following statements is true about oxygen binding to hemoglobin?

When [O2] is high, hemoglobin binds O2 and releases H+ Signup and view all the answers

What is the effect of 2,3-bisphosphoglycerate (BPG) on the affinity of hemoglobin for oxygen?

It decreases the affinity of hemoglobin for oxygen Signup and view all the answers

Which type of immune response is directed at bacterial infections and extracellular viruses?

Humoral immune response Signup and view all the answers

What is the major class of antibodies, which is one of the most abundant blood serum proteins?

Immunoglobulin G (IgG) Signup and view all the answers

What is the purpose of vaccines?

To teach the immune system what viral particles look like Signup and view all the answers

Which type of antibody preparation contains a mixture of antibodies that recognize different parts of a protein?

Polyclonal antibodies Signup and view all the answers

What is the basis for a variety of important analytical procedures?

Antigen-antibody interaction Signup and view all the answers

What type of antibodies are synthesized by a population of identical B cells and recognize the same epitope?

Monoclonal antibodies Signup and view all the answers

What are the major proteins of muscle?

Actin and myosin Signup and view all the answers

What is the structure of myosin?

A fibrous tail and a globular head Signup and view all the answers

What are thick filaments made of?

Aggregated myosin Signup and view all the answers

What is the structure of thin filaments?

F-actin along with troponin and tropomyosin Signup and view all the answers

What happens when an actin monomer binds to the head of myosin?

Muscle contraction occurs Signup and view all the answers

What organizes the thin and thick filaments into ordered structures in muscle fibers?

Myofibrils Signup and view all the answers