The correct answer is D

Respiration begins in the cytoplasm but is completed in the mitochondria. The first step of respiration is glycolysis, which occurs in the cytoplasm. Pyruvate from this reaction is converted to acetyl CoA, which enters the Krebs cycle in the mitochondria. NADH and FADH₂ from the Krebs cycle enter the electron transport chain in the cristae, the inner membrane of the mitochondria.

(A) Opposite. The process is begun in the cytoplasm.

(B) Distortion. Glycolysis is not associated with being in the area of the cell membrane.

(C) Distortion. No part of glycolysis occurs in the nucleus.

(E) Distortion. Proteins are created by ribosomes. Glycolysis has nothing to do with ribosomes.

The correct answer is C

A cell that is involved in active transport, such as the epithelial cells of the intestine, will require large amounts of ATP. If a cell utilizes large amounts of ATP, it must produce it in many mitochondria.

(A) Distortion. High levels of adenylate cyclase are found in cells that rely heavily on a second messenger system.

(B) Distortion. Many polyribosomes are found in molecules that synthesize high levels of protein.

(D) Distortion. High levels of DNA synthesis occur in cells that are rapidly dividing.

(E) Distortion. High amounts of lysozomes are found in phagocytic cells such as macrophages.

The correct answer is D

People with the blood type AB are known as the universal recipients. They have both A and B blood group antigens on the surface of their red blood cells. Therefore, their blood will have no antibodies to any of the blood antigens and they can receive blood from type A, B, and O donors.

(A) Distortion. Yes this is true but it is not the only type of blood that the individual can receive.

(B) Distortion. Yes this is true but it is not the only type of blood that the individual can receive.

(C) Distortion. Yes this is true but it is not the only type of blood that the individual can receive.

(E) Distortion. The AB individual is a universal recipient and can receive any type of blood.

The correct answer is D

A trivalent carbon with an unpaired electron does not possess an octet and can hence be considered electron deficient. The free radical, then, just like carbocations, is stabilized by the presence of groups which can share electrons inductively (alkyl groups) or defuse the electron deficiency through resonance (conjugated systems). The order of free radical stability goes 3°>2°>1°>methyl. Allylic and benzylic radicals are similar to tertiary radicals in terms of stability because of resonance delocalization. The free radicals shown in choice A (benzylic), choice B (tertiary), and choice E (allylic) are all relatively stable, and therefore these three choices are incorrect. The radicals offered in choices C and D are both relatively unstable, but the methyl radical depicted in choice D is more unstable than the primary radical in choice C. Thus choice D, as the most unstable free radical, is the credited choice.

(A) Distortion. Benzylic free radicals are relatively stable due to resonance with the benzene ring.

(B) Distortion. Tertiary free radicals are relatively stable.

(C) Distortion. Primary free radicals are among the least stable free radicals. However, it is not the least stable of all the answer choices.

(E) Distortion. Allylic free radicals are relatively stable due to resonance with the double bond.

The correct answer is A

Qualitative thermodynamics questions can be answered by applying the definitions of the various state functions. This question asks about entropy, which can be defined as the energetic equivalent of randomness, or disorder. The question thus translates into “Which of the following will have an increase in disorder as the reaction proceeds from left to right?” Recall that the general order of increasing entropy goes: solid < liquid < ions in solution < gas. Choice A is thus correct since it shows one mole of a highly ordered, crystalline solid, metallic sodium, and one mole of a somewhat well-ordered, hydrogen-bonding liquid, water, transforming into two moles of aqueous ions, Na⁺ and OH^-, and one mole of gas, H₂. The relatively well-ordered reactants are replaced by highly disordered products as the reaction proceeds, and a net increase in disorder, or entropy, is the result.

(B) Opposite. Choice B shows the deposition of gaseous iodine. This represents a large decrease in entropy as the random motion of the gas phase molecules is replaced by the highly ordered crystal structure of the solid phase. Therefore, this reaction is accompanied by a decrease in entropy.

(C) Opposite. Choice C shows a reaction between aqueous sulfuric acid and aqueous barium hydroxide; this reaction is simultaneously a precipitation, as the barium ions combine with the sulfate ions to form the ionic solid, barium sulfate, and a neutralization, as the aqueous acid reacts with the aqueous base to form water. Precipitation takes aqueous ions to ionic solid and thus represents a decrease in entropy. Neutralization takes aqueous ions to molecules of liquid and is accompanied by a net decrease in disorder; therefore C is accompanied by a decrease in entropy.

(D) Opposite. Choice D shows the formation of liquid water or, alternatively, the combustion of gaseous hydrogen. By either description, this reaction proceeds with a large decrease in entropy as the mole and a half of mixed gas phase molecules transform into one mole of pure liquid.

(E) Distortion. Choice A is the credited answer choice.

The correct answer is E

This question combines some basic stoichiometry with thermodynamic values for a reaction. We are given the ΔH_comb per mole of ammonia and the mass of ammonia in grams. Applying dimensional analysis, we must convert the mass of ammonia into moles, and then multiply by kcal/mol to find the total number of kcal. Ammonia has a formula weight of 14 + 3(1) = 17 g/mol, therefore:

(34 g)/(17 g/mol) = 2 mol

(2 mol)(81 kcal/mol) = 162 kcal.

Note that it is not necessary to come up with a balanced equation for the combustion reaction to do this problem.

(A) Miscalculation. Random calculation error.

(B) Miscalculation. Random calculation error.

(C) Miscalculation. Random calculation error.

(D) Miscalculation. Failed to multiply ΔH_comb of NH₃(g) by the number of moles of NH₃(g)

The correct answer is E

We can translate the choices into the elements to which the given electron configurations correspond simply by counting up the total number of electrons in each and setting this number of electrons equal to the atomic number of the neutral element:

A. 11 electrons atomic number 11 sodium, Na

B. 12 electrons atomic number 12 magnesium, Mg

C. 13 electrons atomic number 13 aluminum, Al

D. 14 electrons atomic number 14 silicon, Si

E. 15 electrons atomic number 15 phosphorus, P

Recalling that metals form basic anhydrides while nonmetals form acid anhydrides, it follows that the least metallic element will have the most acidic anhydride. Metallic character decreases from left to right across the Periodic Table, and therefore phosphorus will be the least metallic of these elements and will have the most acidic anhydride. Listed below are the balanced hydration reactions for each of the most common anhydrides of the elements in the choices above, and the usual acid/base classification of the hydrate formed:

A. Na₂O + H₂O 2 NaOH, strong base

B. MgO + H₂O Mg(OH)₂, base/amphoteric

C. Al₂O₃ + 3 H₂O 2 Al(OH)₃, amphoteric

D. SiO₂ + 2 H₂O Si(OH)₄, amphoteric

E. P₂O₅ + 3 H₂O 2 H₃PO₄, weak acid

(A) Distortion. This anhydride is a very strong base.

(B) Distortion. This anhydride is a base.

(C) Distortion. This anhydride is acidic or basic depending on the situation.

(D) Distortion. This anhydride is acidic or basic depending on the situation.

The correct answer is D

The first step in solving the problem is to determine the likelihood of each slot’s occurrence. Say, then, that the likelihood of each of the 36 regular slots is x. Then the likelihood of each of the two special slots (0 and 00) is 3x. To solve for x, we note that the sum of the probabilities for all 38 slots is 1, so: and . This means that the probability for each special slot is (or , but we won’t reduce the fraction here because we’re going to add it to another in a moment). The probability that (a) a red even number, will occur is , or . The probability that (b) a red 23, will occur is . The probability that (c) 00, will occur is . So the probability that (a) or (b) or (c) will occur is the sum of these probabilities, .

All of the other answers are designed to catch you if you make various simple mistakes. For example, answer choice C is designed to catch you if you decide that the denominator for each probability is going to be 38. The discussion above shows that this is not the case: there are 38 slots, but because they are differently weighted, none of them has a chance of occurring.

The correct answer is B

Forty percent is the same as , so the total portion of the student body that are women is exactly two-fifths of the freshmen plus three-fifths of the rest. Since one-fifth of the student body is freshmen, the fraction of all the students that are female is . Fraction multiplication gives us , i.e. . This is the fraction of the whole student body that is female. We will assume that everyone who isn’t female is male, so the portion of the student body that is male is , which is . To turn this fraction into the number of students, multiply it by the total number of students: the number of male students is . Dividing 600 by 25 yields 24, and multiplying 24 by 11 yields 264, our total.

The trickiest of the wrong answers is D, which is the total number of female students. Although all of the figures are given in terms of female students, the question is in fact about the male students. The other answers are reasonable results if you make a couple of simple mistakes.

The correct answer is D

With 12 games played and 6 remaining, the season is 18 games long. In order to average 2.0 goals per game, the forward must score goals in the season. He’s scored 20 so far, so he needs to score 16 more. With 6 games to go, that’s an average of goals per game. Simplifying this expression we get or goals per game.

The correct answer is E

To get the most out of her money, Susan wants to buy as many apples as she can at the 6 for 89¢ rate, since at less than 15¢ per apple it is a better deal than buying by-the-apple. To see how many sets of 6 she can buy, divide $10 by $0.89, or more to the point, divide 1,000¢ by 89¢ with remainder. The correct answer is 11 with remainder 21¢, that is, , and . So after buying 11 sets of six apples for 89¢ per set, she has 21¢ left over, with which she can buy one more apple at the 20¢-per-apple rate, with 1¢ left in her pocket, which will not afford her any more apples. Her change is therefore $0.01.

The correct answer is D

This Keyhole question requires identifying which opening will exactly fit the 3D object on the left. The object can be inserted through the Keyhole in any orientation, but once it begins, it cannot be rotated. The shape is a cylinder with a piece taken out of the top that rests on a rounded base. Although the piece removed from the top of the cylinder is not visible in choice D, it is the correct answer since the removal of that piece does not change the need to have space for the rest of the cylinder to pass through.

The correct answer is A

The task here is to rank the angles from smallest to largest. Try comparing the given angles to 90° and 45°. Doing so shows that the correct answer is A.

The correct answer is E

For Hole Punching questions, you must determine where the punched holes will be when the paper is unfolded. To help narrow down, count the total number of holes that will be created. The top-right punch goes through four layers, and the bottom-left punch goes through two layers. That means the correct answer will have six holes, eliminating A, C, and D. From there, only E correctly shows the top hole unfolding to both the first and second rows, so E is correct.

The correct answer is C

This Top-Front-End question requires identifying the missing top view. The solid lines represents edges that can be seen from that view, whereas the dashed lines represent hidden edges that are not visible from the given perspective. Since the C shape in the front view curves to the right, the right interior edge cannot be seen from the top and should be represented by a dashed line. In contrast, the left interior edge is visible from the top so should be a solid line. Only choice C shows the correct pattern of solid line to the left of center and dashed line to the right of center, so C is correct.