Term
| How do hydrogen bonds affect water's heat of vaporization |
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Definition
| H-bonds increase the heat of vaporization |
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Term
| What is the influence of water's dielectric constant on solute solubility? |
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Definition
| Water's high dielectric constant makes it easy for polar molecules to solubilize |
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Term
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Definition
| pH where weak acid is 50% protonated and 50% deprotonated |
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Term
| What is the bicarbonate buffer system? |
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Definition
| Carbonic anhydrase converts carbon dioxide and water into carbonic acid, which dissolves in bloodstream to bicarbonate (HCO3- + H+) |
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Term
| What is the bicarbonate buffer system? |
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Definition
| Carbonic anhydrase converts carbon dioxide and water into carbonic acid, which dissolves in bloodstream to bicarbonate (HCO3- + H+) |
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Term
| Which form of amino acids are found in eukaryotes? |
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Definition
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Term
| What are globular proteins? |
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Definition
| compact proteins stabilized mainly by hydrophobic interactions |
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Term
| What are fibrous proteins? |
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Definition
| geometrically linear and have repeating unit structure |
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Term
| What are transmembrane proteins? |
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Definition
| regions of protein span lipid bilayer |
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Term
| Conformations of peptide bonds |
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Definition
| Peptide bonds always planar and trans to minimize steric i/a's |
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Term
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Definition
| Phi is the angle between N and alpha carbon. Psi is the angle between alpha carbon and carboxyl carbon. |
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Term
| What are the three main types of secondary structure? |
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Definition
| alpha helix, beta sheet, and beta turn (reverse turn) |
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Term
| What are the H-bonds that stabilize alpha helix |
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Definition
| Hydrogen bonding between each carbonyl oxygen and the amide hydrogen of an amino acid 4 residues further down the chain |
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Term
| Where are the R groups in alpha helix? |
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Definition
| Outside of the helix to minimize steric i/a's between the R groups |
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Term
| Main features of beta sheets |
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Definition
| Average length is 6 residues, have three mutually perpendicular features (direction of backbone, direction of H-bonding between strands, and direction of side-chains alternating above and below plane of sheet) |
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Term
| Main difference between H-bonding of alpha helix and beta sheet |
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Definition
| Alpha helix uses intra-strand H-bonding while beta sheet uses inter-strand H-bonding |
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Term
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Definition
| direction of polypeptide chains change by 180 degrees. Most contain 2 residues. |
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Term
| Difference between intramolecular and intermolecular protein-protein interactions |
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Definition
| Intramolecular contact lead to protein folding while intermolecular contact lead to fibrils or aggregation |
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Term
| What stabilizes the native state conformation of a protein |
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Definition
| Balance of forces that favor Folding (hydrophobic collapse, intramolecular hydrogen bonds, van der Waals forces) and Unfolding (conformational entropy and hydrogen bonding to water/solvent) |
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Term
| Why do nonpolar molecules form droplet in water? |
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Definition
| To decrease surface area, which decreases the amount of ice-like water that must organize itself around the nonpolar molecules, increasing the entropy of the water. |
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Term
| What are the two main characteristics of fibrils? |
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Definition
| They are insoluble and precipitate themselves out of the cell. Once you get to fibrils, it is very difficult to get back to the native fold. |
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Term
| How do molecular chaperones work? |
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Definition
| bind to nascent (emerging) polypeptides and stabilize them mostly by binding hydrophobic residues. Otherwise these hydrophobic residues tend to associate with other hydrophobic residues, leading to intra- or inter-molecular associations with other proteins that prevent proper folding |
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Term
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Definition
| (PRoteinaceous Infectious virON); type of infectious agent that does not carry any genetic material |
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Term
| Key event in prion pathogenesis |
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Definition
Proteins with a pathological conformation that infect and propagate the pathological conformation change
Key event in pathogenesis of prion diseases is a conformational change in the prion protein PrP(C) (a-helical) to PrP(Sc) (b-sheet). B-sheet form is insoluble due to formation of amyloid cross-b structure |
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Term
| Simple summary of how prion disease occurs |
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Definition
| A-helical form is more stable, B-sheet form slightly less stable, unfolded form slightly less stable. Equilibrium occurs between all 3 forms. Mutation occurs that slightly favors B-sheet form over unfolded form. When B-sheets reach a certain concentration, the cross-linked structure forms. Eventually cross-linked B-sheet structure increases and begins to precipitate out. |
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