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54 Cards in this Set
- Front
- Back
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What is a disulfide bond? |
When the SH groups of two amino acids join to form an S-S link |
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If the R group for the amino acid lysine is —CH2–CH2–CH2–CH2–NH3+, then how many dissociable groups does lysine have in an acid–base titration? |
3 of the CH2, it needs one for its self! |
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The chirality of amino acids is the result of what? |
The alpha carbon being bonded to four different chemical groups. |
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What two amino acids contain SH (sulfide) groups? |
Methionine and Cystine |
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What active group do all amino acids, except proline, contain? |
the amino group (NH) |
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What is true about peptide bonds? |
Created by linking the alpha amino group of one ammino acid with the alpha carboxyl group of another.
This reaction is a dehydration reaction.
The peptide bond may be refered to as a an amide bond. |
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What did Pauling and Corey learn about the structure of peptide bonds? |
Peptide bonds are planar, and do no rotate around the C-N axis |
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Where are the 'R' groups of amino acids found in the alpha helix? |
On the outside of the helix. |
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What intermoleculer force stabalizes beta sheets? |
H-bonds |
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How dose urea disrupt protein structure? |
It disrupts H-bonds |
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How dose Guanidinium Chloride disrupt protein structure? |
It disrupts H-bonds and electrostatic forces |
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Why do proteins absorb UV light at 280nm? |
Do to Tyr and Trp chromophores |
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What is the basis for the Fluroescamine protein assay? |
The formation of fluorescent upon uptake of fluorescamine and its reaction with primary amino acids |
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What is Edman degredation used for? |
Determing the N-terminal amino acids sequence of peptides and proteins. |
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What happens to a protein at a pH above its isoelectric point? |
It will be neagtively charged and deprotenated, also it will move twordes the anode. |
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What happens to a protein at a pH below its isoelectric point? |
It will become positivley charged, protonated and move to the cathode. |
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What is true about the the relationship between Ka and Kd with protein ligand binding? |
A larger Ka means a smaller Kd (dissasociation constant) |
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What is the prosthetic group in conjugated proteins? |
A non-protein permanently attatched to a protein that grants it a unique function or reactivity |
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What is Delta-G 0? |
The change in Gibb's free energy under standard conditions (1M, 298K) |
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How dose a catalys accelerate a chemical reaction? |
By decreasing Gibb's free energy of activation |
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What are the two main peramiters that describe the functionality of an enzyme catalyst? |
Michaelis consant (Km) and Vmax |
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5,5’-dithiobis-2-nitrobenzoic acid (DTNB; a.k.a. Ellman reagent) will react with? |
Thiol(SH) group of Cys |
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What is true about the cis configuration when dealing with peptide bonds? |
Rarely occurs with polypeptides |
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What part of an antigen binds to an antibody? |
The epetope |
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What part of an immunoglobuling dose not bind the antigen? |
The Fc domain |
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What distinguishes hemoglobin and myoglobin? |
Myoglobin has no quatinary structure |
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In myoglobin, how can its oxygen affinity be described? |
Hyperbolic |
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How can the the affinity for O2 with hemoglobin be described? |
Sigmoidale (S-shaped) |
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What is the name for increased O2 affinity in partialy saturated hemoglobin? |
Positive cooperativity |
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What is the Bohr effect? |
Decreased hemoglobin O2 affinity during periods of low pH, and in increase in Blood CO2 |
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What protein changes shape when ATP is hydrolised? |
Conformation of myosin |
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What is true about the transition state between the reactent and the product? |
The transition intermediate always have higher energy (less favorable) than either the reactents or the product. |
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What is the Michaelis–Menten equation? |
Vi = Vmax[S]/(Km + [S]) |
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With a Michaelis Menten plot of Vi as a dependent on [S] what results? |
the initial velocity approaches the maximum velocity as the substrate concentration approaches infinity |
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What is the reciprical plot of the Michaelie Menten? |
Lineweaver-Burk plot (double resipricle) |
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What enzimes catalyse reaction where the substrate changes oxidation states? |
Oxidoreductase |
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What enzymes move a chemical group from one substrate to another? |
Transferase |
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What is the the fatty acid, 18:2 (delta9,12)? |
Linoleic Acid |
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What is the fatty acid 18:1 (delta 9)? |
Oleic Acid |
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Esterfication of one molecule of glycerol with three fatty acids, produsces what? |
Triacylglycerol |
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What is the precusros to prostoglandins? |
A fatty acid |
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Why do trans fatty acids occur in food? |
chemical reduction (hydrogenation) used in the production of margarine generates both cis and trans isomers |
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What is true about the chrolesterol in mammal cells versus it in bacterial cells? |
Mammal cells have a lot of cholesterol, bacteria rarley have any |
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What type of phospholipid movement is least common in memebranes? |
A lipid flipping from one leaflet to the other |
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What drives faciliated diffusion? |
Diffrences in solute concentrations |
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What causes interactions between alkyl chains in molecuels (Ex: fatty acids)? |
Priamrily vander-walls forcers, longer chains mean stronger interactions |
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What happens to the nitrogenous bases of DNA at physiological pH? |
They are positively charged and hydrophobic |
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What is the name for the DNA strand which is continulously synthiszied in the 5' to 3' direction? |
The leading strand |
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What dose DNA ligation mean? |
Joining two DNA segements |
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What can the sticky ends created by the cleaving of DNA with restriction enzymes do? |
Make ends that can bind with cohesive ends made by other restriction enzymes |
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What enzyme attatches tRNA to its amino acid? |
aminoacyl-tRNA synthetases |
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What sequence in mRNA for prokaryotes positions the mRNA on the 30 ribosome? |
The Shine-Dalgarno segement |
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What unit is used to measure the size of a ribosome? |
Svedberg unit |
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What are some posttrasnlational changes to protein? |
Deformylation of the leading formyl-Met residue
Hydrolysis of one or more amino acids from the N terminus of the protein
Phosphorylation of Tyr, Ser, or Thr residues
Oxidation of thiol groups in Cys residues to form disulfide bonds |
