MCAT Practice Exam Questions And Answers 2022/2023

Thin layer chromatography can use silica plates which are very polar. Will polar or non polar substances have lower Rf values on this plate? - Answer - Polar substances - they will have a higher affinity for the silica and thus will not travel as far as the non polar substances A titration of a strong acid with a strong base or vice versa has an equivalence point around what pH? - Answer - 7 What type of bond is usually disrupted during denaturation of proteins? - Answer - H bond Is uracil a purine or pyrimidine? - Answer - Pyrimidine (A is a purine, so must be paired with a pyrimidine, also U replaces T, and T is a pyrimidine) Are peptide bonds highly reactive? - Answer - NO, they are very stable (T/F): Bomb calorimetery is a good way to determine bond enthalpies within a compound. - Answer - FALSE - would need a ton of info What is the approximate pKa of COOH, NH3+? - Answer - 2; 9 What would happen if dideoxynucleotides were omitted from a replication mixture? - Answer - DNA polymerase would replicate the entire copy of DNA and produce copies of all the same length - gel electrophoresis would reveal one large band Total pressure = __ + __ - Answer - Atmospheric pressure + gauge pressure Conditions of extreme starvation result in a high level of __. - Answer - Cortisol As non-polar protein groups cluster in water, water has a (increase/decrease) in entropy. - Answer - Increase - more water molecules are free now that they don't have to solvate each individual molecule of protein On the lac operon, the repressor binds to the __. - Answer - Operator - to prevent RNA polymerase from binding What charge do basic amino acids have at pH 7.4? - Answer - + What makes group I and II introns different from non-grouped introns? - Answer - They are SELF-SPLICING i.e. they do not have splicing proteins to help them When an action potential induces a muscle contraction, Ca2+ is released into the __. - Answer - Cytosol (not the sarcoplasmic reticulum)