Term
Diameter of double helix?
Length of one complete turn of helix?
Distance between base pairs (rungs)? |
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Definition
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Term
| What does negative delta G mean? |
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Definition
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Term
| In differential centrifugation of a cell culture homogenate, what is the order of pelleting you would expect? |
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Definition
500x g for 10 minutes = nuclear fraction
10,000x g for 20 minutes = mitochondrial fraction
100,000x g for an hour = microsomal fraction (supernatant contains cytoplasm/soluble proteins) |
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Term
| Describe gel filtration chromatography |
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Definition
-Discriminates based on size
-Also called molecular exclusion
-Porous beads made of agarose or polyacrylamide
-Small molecules can get stuck in beads
-Large molecules exit first |
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Term
| Describe ion exchange chromatography |
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Definition
-Separated on basis of charge
-Negatively charged beads (cation exchange)
-Proteins with low density of positive charge emerge first because they don't get stuck to the beads |
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Term
| Describe affinity chromatography |
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Definition
-Can be used to isolate transcription factors
-General affinity chromatography uses His tags and metal ions
-Proteins with His tags bind tightly to metal ions while other proteins flow through
-Elute His tagged proteins with imidazole |
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Term
| Describe high pressure liquid chromatography (HPLC) |
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Definition
-Column materials very finely divided which results in more resolving power
-Requires high pressure to ensure adequate flow rate
-High resolution and rapid separation
-Detector monitoring absorbance of elutate at particular wavelength placed immediately after column |
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Term
| What does B-Mercaptoethanol do (SDS PAGE) |
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Definition
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Term
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Definition
| pH at which the protein's net charge is zero |
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Term
| Describe isoelectric focusing |
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Definition
Left side = low pH (+)
Right side = high pH (-)
Current applied and proteins migrate to pI |
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Term
| Describe two-dimensional gel electrophoresis |
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Definition
| Isoelectric focusing, then separation by size with SDS PAGE |
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Term
Define these elements of protein purification quantification:
Total protein
Total Activity
Specific Activity
Yield
Purification level |
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Definition
Total protein: Protein concentration in each fraction X fraction's total volume
Total activity = enzyme activity in fraction X fraction's total volume
Specific activity = Total activity/Total protein
Yield = Measure of activity retained after each purification as a percentage of the activity in the crude extract
Purification level = measure of increase in purity... Specific activity after each step/Specific activity of initial extract |
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Term
| What is ultracentrifugation useful for? |
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Definition
| Separating biomolecules and determining their masses |
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Term
| How can you determine peptide sequences? |
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Definition
| automated Edman degradation (label, release, label, release) |
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Term
| Where does cyanogen bromide cleave? |
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Definition
| Carboxyl side of methionine residues |
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Term
| Where does O-Iodosobenzoate cleave? |
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Definition
| Carboxyl side of tryptophan residues |
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Term
| Where does hydroxylamine cleave? |
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Definition
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Term
| Where does 2-nitro-5-thiocyanobenzoate cleave? |
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Definition
| Amino side of cysteine residues |
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Term
| Where does trypsin cleave? |
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Definition
| carboxyl side of lysine and arginine residues |
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Term
| Where does clostripain cleave? |
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Definition
| carboxyl side of arginine residues |
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Term
| Where does staphylococcal protease cleave? |
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Definition
| carboxyl side of aspartate and glutamate residues (glutamate only under certain conditions) |
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Term
| Where does thrombin cleave? |
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Definition
| Carboxyl side of arginine |
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Term
| Where does chymotrypsin cleave? |
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Definition
| Carboxyl side of tyr, trp, phe, leu, and met |
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Term
| Where does carboxypeptidase A cleave? |
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Definition
| amino side of C terminal residue (NOT arg, lys, or pro) |
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Term
| Difference between monoclonal and polyclonal antibodies? |
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Definition
Monoclonal are all identical, produced by clones of a single antibody-producing cell. They recognize one specific epitope.
Polyclonal antibodies are heterogenous mixtures of antibodies, each specific for one of the various epitopes on an antigen |
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Term
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Definition
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Term
| Describe nuclear magnetic resonance spectroscopy (NMR) |
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Definition
Energy separation from magnetic field
Different spins: alpha and beta
Transition between spin states (from alpha to beta as a result of irradiation) gives NMR line |
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Term
| The classic Watson/Crick helix is _-DNA |
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Definition
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Term
| A and B DNA are ___ handed helices while Z DNA is a __ handed helix |
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Definition
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Term
| Most DNA in the cell is in what form? |
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Definition
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