MCAT Practice Exam Questions and Answers 100% Pass

MCAT Practice Exam Questions and Answers 100% Pass Thin layer chromatography can use silica plates which are very polar. Will polar or non polar substances have lower Rf values on this plate? ✔✔Polar substances - they ...

MCAT Practice Exam Questions and Answers 100% Pass Thin layer chromatography can use silica plates which are very polar. Will polar or non polar substances have lower Rf values on this plate? ✔✔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? ✔✔7 What type of bond is usually disrupted during denaturation of proteins? ✔✔H bond Is uracil a purine or pyrimidine? ✔✔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? ✔✔NO, they are very stable (T/F): Bomb calorimetery is a good way to determine bond enthalpies within a compound. ✔✔FALSE - would need a ton of info What is the approximate pKa of COOH, NH3+? ✔✔2; 9 What would happen if dideoxynucleotides were omitted from a replication mixture? ✔✔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 = __ + __ ✔✔Atmospheric pressure + gauge pressure Conditions of extreme starvation result in a high level of __. ✔✔Cortisol As non-polar protein groups cluster in water, water has a (increase/decrease) in entropy. ✔✔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 __. ✔✔Operator - to prevent RNA polymerase from binding What charge do basic amino acids have at pH 7.4? ✔✔+ What makes group I and II introns different from non-grouped introns? ✔✔They are SELFSPLICING i.e. they do not have splicing proteins to help them When an action potential induces a muscle contraction, Ca2+ is released into the __. ✔✔Cytosol (not the sarcoplasmic reticulum) Are the particles released by gamma decay charged? What does this mean for their movement in electric fields and magnetic fields? ✔✔No - gamma decay releases photons which are uncharged; uncharged molecules do not move in electric fields or magnetic fields How do beta particles behave in electric and magnetic fields? ✔✔Beta decay releases electrons - negatively charged particles are deflected by electric and magnetic fields Does blood flow faster through capillaries or arteries? Why? ✔✔Blood flows faster through arteries - capillaries have a greater NET cross-sectional area Which has higher BP: systemic or pulmonary circulation? Explain why. ✔✔Systemic has a higher BP - pulmonary circulation is shorter than systemic, which means it has less resistance (formula), and the right ventricle generates less force (to pulmonary circulation) than the left ventricle does (to systemic circulation). Since P = F/A and pulmonary has lower force and area, pressure in pulmonary must be lower than systemic. Which has a higher blood flow rate (BFR): pulmonary or systemic circulation? ✔✔They are equal because they are connected in series How does inhalation facilitate venous flow into the right atrium? ✔✔Because during inhalation, thoracic pressure decreases (diaphragm pushes down and expands thoracic cavity), which causes blood to flow from high to low pressure (from veins into right atrium) - this is negative pressure breathing Which way do positive charges migrate towards in an electric field: towards the anode or cathode? ✔✔Cathode What are anomers? ✔✔Diastereomers of cyclic sugars (the SAME sugar, i.e. dif forms of (ex) glucose) - differ configurations at the anomeric carbon (alpha (down) or beta (up) position of the OH group) Switching from one anomer to another is called (rotamutation/mutarotation). ✔✔Mutarotation (rotamutation does not exist) Counterclockwise is (R/S) absolute configuration. ✔✔S configuration What is the difference between d-/l- and D-/L- notation? What about +/- notation? ✔✔Lowercase letters are for optical activity (as are + and -; + is the same as d, - is the same as l); uppercase letters are just for configuration One enantiomer is d- or D-, the other enantiomer must be l- or L- (same with R and S) Dextroamphetamine is also known as __-amphetamine. ✔✔+ or d- (because name is DEXTROamphetamine, meaning it rotates light to the right, and + and d- represent the same thing)