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19 Cards in this Set
- Front
- Back
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______ are the principal agents for expression of the information contained in the genome.
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Proteins
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Conjugated proteins with prosthetic group of ________ are called....
1) Lipids 2) Carbohydrates 3) Phosphate groups |
1) Lipoproteins
2) Glycoproteins 3) Phosphoproteins |
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Which level of protein structure describes the covalent (peptide bonds) bonded amino acid sequence?
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Primary
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Which level of protein structure describes the non-covalent interactions between residues close to each other in the primary sequence?
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Secondary
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Which level of protein structure describes the non-covalent or covalent interactions between secondary structural elements?
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Tertiary
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Which level of protein structure describes the non-covalent or covalent interactions between different polypeptide chains?
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Quaternary
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Amino acid residues represent the __________ structure of protein structure.
a) primary b) secondary c) tertiary d) quaternary |
a) primary
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Alpha helices represent the __________ structure of protein structure.
a) primary b) secondary c) tertiary d) quaternary |
b) secondary
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A polypeptide chain represent the __________ structure of protein structure.
a) primary b) secondary c) tertiary d) quaternary |
c) tertiary
remember, alpha helices and beta sheets are secondary and they make up the polypeptide chains |
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Subunits represent the __________ structure of protein structure.
a) primary b) secondary c) tertiary d) quaternary |
c) tertiary
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Assembled subunits are an example of __________ structure of protein structure.
a) primary b) secondary c) tertiary d) quaternary |
d) quaternary
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True or False: A general principle governing protein folding is that folding occurs to achieve the minimal energy structure.
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True. The most stable minimal energy structure is usually what occurs. Proper folding = minimal energy!
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Which of the following is FALSE? In a properly folded (minimal energy) protein,
a) hydrophobic residues will occur in the hydrophobic core b) all ionic and polar groups will occur on the surface of the molecule c) no overlap in van der Waal's radii will occur d) none of the above |
b) is false. MOST ionic and polar groups will be on surface but polar groups can also occur inside. They'll just interact with each other or there may be a little water inside that they'll interact with.
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Which of the following is false about the formation of secondary structures?
a) the most stable and common forms are are alpha-helix and beta-sheet structures b) maximize hydrogen bonds between alpha-aminos and alpha-carbonyls of peptide bonds c) minimize electrostatic interactions between R-groups d) minimize steric clashes between R-groups |
c) is false! MAXIMIZING electrostatic interactions between R-groups is favorable.
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The single bonds between the alpha-carbons and carbon and nitrogen of the peptide bond remain free to rotate. However, ___________ limits that rotation to certain angles phi and psi.
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steric hinderance
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Why does basic and acidic residues 3 residues apart indicate the possibility of an alpha helix?
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The stabalizing effect on the alpha helix of electrostatic interaction occurs between acidic and basic amino acids 3 residues apart.
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In an alpha helix, what properties of R groups /amino acids confer
a) stabilization b) destabilization |
a) stabilization: electrostatic interaction btwn acidic and basic a.a.s 3 residues apart
b) destabilization: bulky R groups in close proximity |
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Charge distribution on the alpha helix induces a partial _________ charge at the amino terminus and a partial ________ charge at the carboxyl terminus.
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positive at amino terminus ; negative at carboxyl terminus .
Thus, acidic residues near the amino terminus stabilize. Basic residues there destabilize. Basic residues near carboxyl terminal stabilize and acidic residues here destabilize. |
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What amino acid residues tend to disrupt helical or sheet structures and facilitate turns?
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Gly - contributes to flexibility bc lacks a bulky R group
Pro - can form a cis peptide bond to effect a 180 degree turn |
