Biochemistry Session 2 - Protein Structure and Function

There are thousands of protein possibilities within the human body, but their functions tend to fall under broad categories. For example, enzymes are catalysts. What is an example of a protein that would fall under the regulation-signaling-communication category?

A protein that normally contains one serine was incorrectly translated from a mutated mRNA strand and now it contains one alanine in its place. No other amino acids in the chain were affected. What could we expect to result?

Which of the following are true regarding peptide bonds? (Select all that apply)

Which of the following successfully describes the primary structure of a polypeptide chain?

Bovine insulin consists of a primary structure of an A polypeptide chain and a B polypeptide chain. The total structure is being structurally stabilized by cysteines forming reversible covalent linkages. What is the term for this bond?

The alpha helix is one of the most common secondary structures. All peptide bonds in the helical domain are engaged in _____________, contributing to an overall very stable structure.

A beta sheet is a super secondary structure consisting of multiple beta-strands lined up next to one another in flat, planar arrays. Which bond listed below is responsible for the for this structure's conformation and stability?

Myoglobin is a product of combined inter-helix interactions between 7 alpha-helix domains. This is an example of _________ structure.

Which of the following inter-subunit interactions are responsible for precisely stabilizing the quaternary structure? (Select all that apply)

Generally, protein structure orients hydrophobic amino acids to the interior of the protein and hydrophilic amino acids to the exterior. However, exceptions do exist, and hydrophilic amino acids can be found in the interior. What could happen to the protein if water came into contact with the interior hydrophilic amino acids?

Where are "the instructions" for folding a protein into its native functional structure?

Which of the following is NOT true regarding chaperone assisted protein folding?

A stable protein, RNaseA, is very stable. It is denatured by exposing it to a chaotrophic agent, a disulfide bond reducing agent, and then subjected to elevated heat. At this point, it was no longer functional. However, function returned when environmental conditions were returned to normal. Which of the following is true about the aforementioned reaction? (Select all that apply)

You have been asked to quickly denature a fairly stable protein. You have tried heating it up, dissolving it in an organic solvent, and shaking it. What is another method you could try? (Select all that apply)

A modified protein with an added acetyl group is denatured. What could we expect to see in terms of functionality?

You have two febrile patients in your clinic. Patient A has had a sustained fever of 104 degrees Fahrenheit for three days. Patient B has had a sustained fever of 101 degrees Fahrenheit for one day. Which of the following statements are correct? (Select all that apply)

Many serious diseases can arise from the accumulation of plaques as a direct result of protein folding missteps. Which of the following is NOT a step that could ultimately lead to the accumulation of aggregates?

The ubiquitinylation system is analagous to what scenario?

If a protein is entering the S26 proteosome, what can you correctly assume? (Select all that apply)

Glycosylation of cell surface proteins helps to coordinate a layer of water molecules to act as an external lubricant for the cell. Which of the following examples accurately utilizes this mechanism?

Which of the following is NOT true regarding the Na+/K+ ATPase pump?

The Na+/K+ ATPase pump is an active transport system, meaning energy is expended to support its function. Which of the following steps involves the phosphorylation of ATP?

You have a heart failure patient that has clinically improved after being prescribed digoxin, a digitalis derivative. Which of the following could explain the mechanism of this improvement?

The lung airway of a healthy human has a balance of sodium and chloride ion transport through the CFTR channel. A cystic fibrosis patient has an absent or defective CFTR channel, leading to what implications? (Select all that apply)

There are two major CFTR mutations found in cystic fibrosis. Which of the following mechanisms could explain the impaired ion transport process?

What is the main function of collagen?

Which of the following is NOT true regarding the structure of collagen?

Scurvy is a deficiency of vitamin C, resulting in a destabilization of collagen at normal body temperature. Which of the following is the mostly likely reason for this denaturation?

Which step directly leads to the formation of a pervasive collagen cross-linked matrix (fibril)?

In osteogenesis imperfecta, point mutations to the COL1A1 and COL1A2 genes can result in unstable collagen fibers. Which of the following could be an explanation for this instability? (Select all that apply)

Myoglobin primarily stores oxygen, whereas hemoglobin allows for oxygen transport and delivery. What is the main explanation for this variance in function?

Each hemoglobin subunit can bind to one oxygen molecule. What happens after the first oxygen molecule binds to the first deoxyhemoglobin subunit?

As oxygen tension drops in peripheral tissues, hemoglobin tends to switch to which conformation?

Hemoglobin subunits have two primary histidines, a proximal and a distal. What are the functions of the distal histidine? (Select all that apply)

Which of the following scenarios would heme exhibit the lowest affinity for oxygen?

Which of the following promotes oxygen ejection from hemoglobin? (Select all that apply)

Which of the following is NOT true regarding fetal hemoglobin?

At what age would we expect to see a baby's gamma hemoglobin have a higher percentage than beta hemoglobin?

Which of the following accurately describes Hb-S sickle cell anemia? (Select all that apply)

A peptide bond:

Which of the following statements about protein structure is correct?

An 80-year old man present with impairment of higher intellectual function and alterations in mood and behavior. His family reported progressive disorientation and memory loss over the last 6 months. There is no family history of dementia. The patient was tentatively diagnosed with Alzheimer disease. Which one of the following best describes the disease?

Which of the following statements concerning the binding of oxygen by hemoglobin is correct?