Term
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Definition
| derived from common ancestor |
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Term
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Definition
| homologs present within one species--often differ in their detailed biochemical functions |
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Term
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Definition
| homologs present within different species with similar biochemical functions |
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Term
| How to calculate alignment score? |
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Definition
+10 points for each identity between aligned sequences
-25 points for gaps (regardless of size) |
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Term
| Which protein structure is most conserved evolutionarily? |
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Definition
| Tertiary is more conserved than primary |
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Term
| Common example of convergent evolution? |
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Definition
| Chymotrypsin and subtilisin (the serine proteases) |
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Term
| Oxygen carrying efficiency of hemoglobin vs. myoglobin? |
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Definition
Hemoglobin: 90%
Myoglobin: 7% |
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Term
| Structural differences between hemoglobin and myoglobin? |
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Definition
Hemo = four polypeptide chains
Myo = single polypeptide |
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Term
| Hemoglobin binds oxygen _____, which means... |
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Definition
| cooperatively, binding of oxygen to a site in one chain increases likelihood that other chains will bind oxygen |
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Term
| Which state of iron in heme is capable of binding oxygen? What is it bound to? |
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Definition
Fe2+
lies in center of protoporphyrin, bound to four pyrrole nitrogen atoms |
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Term
| In myoglobin, the fifth coordination site is occupied by... This is referred to as the... |
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Definition
the imidazole ring of a histidine residue
proximal histidine |
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Term
| Oxygen binding occurs at the ___ coordination site. |
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Definition
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Term
| Oxygen binds with high affinity to... |
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Definition
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Term
| The cooperative binding and release of oxygen by hemoglobin enables it to deliver nearly __ times as much oxygen as myoglobin |
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Definition
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Term
| Deoxyhemoglobin is in the (T/R) state |
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Definition
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Term
| Oxhemoglobin is in the (T/R) state |
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Definition
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Term
| 2,3-BPG binds tightly to the __ state of hemoglobin, lowering the oxygen affinity of hemoglobin |
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Definition
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Term
| Fetal hemoglobin binds oxygen ___ tightly than adult hemoglobin, owing to... |
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Definition
more
weaker 2,3-BPG binding |
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Term
| Bohr effect: decreased pH leads to... |
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Definition
| decreased oxygen affinity |
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Term
| Bohr effect: increased CO2 leads to... |
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Definition
| decreased oxygen affinity |
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Term
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Definition
| reaction rate when enzyme is fully saturated with substrate |
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Term
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Definition
| Michaelis constant, substrate concentration at which reaction rate is half maximal |
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Term
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Definition
| kcat X total concentration of enzyme |
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Term
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Definition
| turnover number, the number of substrate molecules converted into product per unit time at a single catalytic site when the enzyme is fully saturated |
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Term
| Do allosteric enzymes conform to Michaelis-Menten kinetics? |
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Definition
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Term
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Definition
| inhibitor covalently linked to enzyme or bound so tightly that dissociation is very slow |
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Term
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Definition
| Characterized by more rapid equilibrium between enzyme and inhibitor |
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Term
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Definition
| Prevents substrate from binding to active site |
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Term
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Definition
| inhibitor combines only with the enzyme-substrate complex |
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Term
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Definition
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Term
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Definition
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Term
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Definition
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Term
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Definition
| addition or removal of groups to form double bonds |
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Term
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Definition
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Term
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Definition
| ligation of two substrates at the expense of ATP hydrolysis |
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Term
| Five basic strategies of enzymes to form and stabilize the transition state: |
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Definition
1) Use of binding energy
2) Covalent catalysis
3) General acid-base catalysis
4) Metal ion catalysis
5) Catalysis by approximation |
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Term
| What is the crucial component of active sites of carbonic anhydrases? |
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Definition
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Term
| Myosins are examples of ____. Their function is to... |
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Definition
P-loop NTPase enzymes
catalyze hydrolysis of ATP to form ADP and Pi |
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