Biochemistry- AAMC FLASH CARDS fully solved 2023

Biochemistry- AAMC FLASH CARDS fully solved 2023The Michaelis-Menten Kinetic equation - correct answer Which combination of lipid type and temperature results in the most disordered membrane? - correct answer Lipid with unsaturated acyl at high tempearture Because unsaturated acyl chains do not pack well well together. They are a mess. When you add high temperature they become a hot mess. Because they is more movement in high temps. The side chain of which amino acid is most likey to form a hydrogen bond with the side chain of glutamate? a. Asp b. Ala c. Gln d. Val - correct answer C. Gln-Glutamine-Polar In order to hydrogen bond with glutamate and amino acid side chain must contain a hydrogen bond donor group to match with the glutamate acceptor. First thing to look for is the basic amino acids, then after you look for the polar. What is the dependent variable in an experiment that determines the Michaelis-Menten kinetic parameters of an enzyme? a. Initial velocity b. Initial substrate concentration c. Enzyme concentration d. Fraction of substrate bound - correct answer A. Initial Velocity Dependent variable is the variable that it's value is dependent on the independent variable. In the Michaelis-Menten the substrate is constantly changed being the independent variable and the dependent variable is the velocity. Consider the four DNA strands, which one will have the highest melting temperature? a. Strand 1 ATTGCATT b. Strand 2 GATTAATT c. Strand 3 GATCGTTC d. Strand 4 ATGTATTG - correct answer C. Strand 3 GATCGTTC Why: Because the melting temperature of a double stranded DNA is a fuction of how many GC base pairs it contains. There is also a postive effect if the GC pairs occur at the end. Protein Separation Technique Isoelectric focusing Native PAGE SDS-PAGE under nonreducing conditions SDS-PAGE under reducing conditions - correct answer Isoelectric focusing- Cause a seperation in their pI. Native PAGE- Cause a seperation in the molecular Mass. (structural description-size, kDA) SDS-PAGE under nonreducing conditions-In a non-reducing SDS-PAGE, you still denature the protein - you just leave the disulfide bridges intact. So the protein will be mostly denatured and if it has disulfides. SDS-PAGE under reducing conditions- reducing agent (beta-mercaptoethanol/BME), which further denatures the proteins by reducing disulfide linkages, thus overcoming some forms of tertiary protein folding Cyanogen bromide cleaves peptide bonds first by undergoing a nucleophilic attack by the side chain of a methionine residue. Which atom is the nucleophile in this reaction? a. sulfur b. carbon c. oxygen d. nitrogen - correct answer A. Sulfur For a nucleophilc attack you need an atom with lone pairs. And sulfur is the only atom in methionine that has lone pairs. The transition of which amino acid from the interior of a soluble globular protein to the surface is associated with the largest positive delta G? a. Asp (Asparatic Acid -D) b. Phe (Phenylalanine - F) c. Glu (Glutamic Acid-E) d. Ser (Serine- S) - correct answer B. Phenylalanine To answer this question you need to know that positive delta G, means it requires a lot of effort and energy. Also know that it will only be a hydrophobic amino acid that it will take that much energy to move it from the interior to the outer.