AAMC B/BC Section Bank-done Flashcards
The stereochemical designators α and β distinguish between:
epimers at an anomeric carbon
The answer to this item is C since the α versus β designation distinguishes between molecules with multiple chiral centers, but differ only in the configuration of the site known as the anomeric carbon atom.
Which ideal solution exhibits the greatest osmotic pressure?
- 1 M MgCl2
- 2 M NaCl
- 2 M CaCl2
- 5 M glucose
The answer to this question is C because the solution listed has the greatest concentration of solute particles. CaCl2 dissociates into three ions, making the solution listed 0.6 M in solute particles.
Which event is directly mediated by a ligand-gated ion channel?
Influx of Na+ across the motor end plate resulting in the depolarization of the muscle fiber membrane
The answer to this question is C because the influx of Na+ across the motor end plate occurs when Na+ ion channels bind the ligand acetylcholine.
A single point mutation in a gene results in a nonfunctional protein. Individuals heterozygous for this mutation were identified using a Southern blot. Which pair of wild-type (WT) and mutant alleles most likely contains the mutation?
The answer to this question is A because a Southern blot uses a restriction digest to differentiate between mutant and wild-type alleles. In order for a Southern blot to be useful, the mutation should either create or eliminate a restriction site, most of which are palindromes and 4 to 6 base pairs long. The mutation shown in this option is the only one that disrupts a palindromic sequence, AAGCTT. This sequence is the recognition sequence for HindIII.
One amino acid is ____ daltons.
110Da (g/mol)
Nativs, non-reducing, reducing
Native-page: everything in-tact, separated by size and charge or shape like you said. ie. If we had a heterotrimer, we only would see one band.
SDS-page non-reducing(w/o B-ME): S-S are intact but protein is denatured ie. If we had a heterotrimer, we would only see one band.
SDS-page reducing (w/ B-ME): S-S become reduced protein is still dentured. ie. If we had a heterotrimer, we would see 3 separate bands.
Native, non-reducing, reducing
Native-page: everything in-tact, separated by size and charge or shape like you said. ie. If we had a heterotrimer, we only would see one band.
SDS-page non-reducing(w/o B-ME): S-S are intact but protein is denatured ie. If we had a heterotrimer, we would only see one band.
SDS-page reducing (w/ B-ME): S-S become reduced protein is still dentured. ie. If we had a heterotrimer, we would see 3 separate bands.
Small Kd means
Small Kd = high affinity because smaller concentration of substrate required to saturate 50% of the enzyme available
Small Kd means
Small Kd = high affinity because smaller concentration of substrate required to saturate 50% of the enzyme available
cDNA has no ____
introns
A characteristic of noncompetitive inhibitors is that they bind the enzyme and the enzyme–substrate complex with the ___ affinity; Vmax is affected, but KM does not change.
same
For isoelectric focusing, which separates proteins based on isoelectric point, a stable _____ must be established in the gel.
pH gradient
Ovarian cells are _____ cells, and osteoclasts are ______ cells
epithelial, connective tissue
Peptide hormones are ____ and _____ in blood. Hormones that must bind transport proteins are steroid proteins, which are lipophilic.
hydrophilic and soluble
uncompetitive inhibitors bind their target enzymes only when ___________________
the substrate is first bound to the enzyme
cytochrom c is associated with the mitochondrial inner membrane, where it functions in the _____ _____ ______.
electron transport chain
_________ is one of the mitochondrial proteins that is released into the cytosol when the cell is activated by an apoptotic stimulus.
Cytochrome c
methods of separating proteins
isoelectric focusing separates proteins based on their isoelectric point (the pH at which the net charge of the protein is zero) and ion exchange chromatography separates proteins based on their net charge. In contrast SDS-PAGE separates proteins based on their mass and affinity chromatography separates proteins based on their interactions with specific ligands.
methods of separating proteins
isoelectric focusing separates proteins based on their isoelectric point (the pH at which the net charge of the protein is zero) and ion exchange chromatography separates proteins based on their net charge. In contrast SDS-PAGE separates proteins based on their mass and affinity chromatography separates proteins based on their interactions with specific ligands.
know citric acid cycle and glycolysis
know like how many reduced electron carriers between steps of citric acid cycle and know which enzymes are different between glycolysis and gluconeogenesis
___________ is not used in cDNA cloning, while ________ are used
RNA polymerase
while DNA polymerase (in DNA amplification), DNA ligase (in ligation of the cDNA to DNA vector) and reverse transcriptase (in reverse transcription of RNA to cDNA) are used during cDNA cloning
____, _____, and _____ are used as starting materials in gluconeogenesis
lactate, oxaloacetate, and α-ketoglutarate
______ is the enzyme that catalyzes the rate-limiting step in glycogen breakdown (glycogenolysis)
Glycogen phosphorylase
-know glycogenolysis
______ is the enzyme that catalyzes the rate-limiting step in glycogen breakdown (glycogenolysis)
Glycogen phosphorylase
-know glycogenolysis
