Protein Structure: Primary and Secondary

Which level of protein structure is determined directly by the sequence of amino acids?

Protein domains are always dependent on other regions of the protein for proper folding.

What type of interaction primarily stabilizes the alpha-helix and beta-sheet structures?

Rigid ______ residues can disrupt alpha helices and beta sheets in secondary structures by introducing kinks in the polypeptide backbone.

Which of the following statements accurately describes the role of R-groups in tertiary structure formation?

Disulfide bonds are covalent bonds that can only form between amino acids that are adjacent to each other in the primary sequence.

Which of the following contributes to a protein achieving its lowest possible energy state during folding?

Proteins known as molecular ______ assist other proteins in achieving their proper 3D conformation, particularly under cellular stress.

What is the fundamental mechanism by which prions cause disease?

A protein domain always spans the entire length of a single polypeptide chain.

Match each level of protein structure with its description:

How does the environment influence the folding of a protein, in conjunction with its primary structure?

In an alpha helix, how many amino acid residues are typically present in each turn?

Beta sheets can only exist in a parallel configuration.

What type of interactions are unstructured loops (aka random coils) primarily involved in?

The stability of a protein is dependent on the free energy change (ΔG) between its folded and unfolded states, with a more stable folded state corresponding to a ______ ΔG.

Which disease is associated with the misfolding and aggregation of prion proteins?

Protein motifs always exhibit enzymatic activity.

Which level of protein structure is characterized by the arrangement of multiple polypeptide chains?

What types of bonds, other than hydrogen bonds, contribute to holding the quaternary structure of a protein together?

If a protein is composed of two identical subunits, what term best describes it?

Adjacent chains in beta sheets MUST run in the same direction.

Which of the following properties of amino acids determine how they will interact to determine the tertiary structure?

If enough time has passed during evoultion, similar ______ appear in many related proteins.

List the four levels used to describe protein structure.

How is protein structure genetically determined, and at how many levels can it be described?

What are protein domains, and what characteristic defines them within a protein sequence?

Explain how the 3D structure of a protein is related to its function.

Describe the primary structure of a protein.

How does the mRNA code relate to the primary structure of a protein?

What factors, in combination with primary structure, determine the higher-order structures of a protein?

What are the two well-known secondary structures in proteins, and what type of bonding stabilizes them?

How are alpha helices formed, and where do the R-groups of the amino acids project?

Describe the difference between parallel and antiparallel beta sheets.

Explain how proline residues can disrupt secondary structures in proteins.

Describe the tertiary structure of a protein, and what types of interactions primarily stabilize it?

What role do unstructured loops (aka random coils) play in protein tertiary structure?

How do covalent disulfide bonds contribute to protein structure, and between which amino acid residues do they form?

Explain how a protein achieves its most stable conformation in terms of energy state.

Outline the overall energy principle that governs protein folding, comparing the unfolded and folded states.

Why is it important to consider the effects on the surrounding water solvent when looking at protein folding?

What are molecular chaperones (chaperonins), and what role do they play in protein folding?

Explain how abnormally folded proteins (prions) can cause disease.

What is a protein domain, and how does it fold relative to other regions of the protein?

How do protein domains contribute to the modular nature of proteins?

In a multi-domain protein, how do the functions of individual domains typically relate to the overall function of the protein?

What are protein motifs, and how do they relate to protein domains?

Describe the quaternary structure of a protein.

What are the differences between protein homomers and heteromers.

What types of bonds or interactions stabilize quaternary structures in proteins?