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Errata

10th Edition Complete Study Guides

LAST UPDATED 05/23/18

BIOLOGY 1: MOLECULES

PAGE # 13
Lecture 1
The three letter abbreviation for Cysteine should be Cys not Cyc.

BIOLOGY 2: SYSTEMS

PAGE # 248
Lecture 1
In Class Exams
Answer Explanations
The answer listed in the table for question 13 should be C, not B.

PAGE # 250
Lecture 1
In Class Exams
Answer Explanations
The answer explanation for Question 13 should read:
C is the best answer. As described by the fluid mosaic model, all proteins inserted into the membrane must have a hydrophobic portion that can interact with the hydrophobic lipids that make up the cell membrane. Choice A is not the best answer because K+ channels are not synthesized in the nucleus. They are made at the rough endoplasmic reticulum like other membrane-bound or secreted proteins. Choice B is not the best answer because the K+ channels do not 'create' the gradient. They play one part, allowing K+ ions to help set up resting potential. Choice D is not a true statement; the K+ channels do not create energy for the cell.

CHEMISTRY

PAGE # 12
Lecture 1
The first sentence of the first paragraph should read,
“Since noble gases tend not to make bonds, electronegativity values are undefined for the first three noble gases.”

PAGE # 53
Lecture 2
In Lecture Question
In Question 33, the diagram should have the following labels:
Atom 1 is the N in the 5 membered ring.
Atom 2 is the F.
Atom 3 is the O that only has a single bond to C.
Atom 4 is the O with a single bond to the C and a single bond to the H in the top right corner.

PAGE # 59
Lecture 2
In Figure 2.19, the bottom molecule in step 1 should be identical to the bottom molecule in step 2, without the circular arrow.

PAGE # 94
Lecture 3
The last two sentences of the first paragraph should read: "Enamines are not stable due to the electron donating nitrogen off of the pi bond. Because nitrogens are less electronegative and more electron donating than oxygen, enamines are better nucleophiles than enols."

PAGE # 103
Lecture 3
In the last Salty text in the margin, at the bottom of the page it should say ‘beta anomer’, not 'beta linkage'.

PAGE # 140
Lecture 4
In Lecture Question
For Question 79, this is the question that was supposed to be printed and it matches the existing answer table and answer explanation.
Question 79
All of the following may be true concerning catalysts and the
reactions which they catalyze EXCEPT:
○ A. Catalysts are not used up by the reaction.
○ B. Catalysts lower the energy of activation.
○ C. Catalysts increase the rate of the reverse reaction.
○ D. Catalysts shift the reaction equilibrium to the right.

PAGE # 285
Lecture 4
In Class Exam
In the formula in the passage, RTln(K) should be negative. There should be a minus sign before the RT: ∆G°= - RTln(K) = ∆H – T∆S

PAGE # 290
Lecture 5
In Class Exam
In passage 1, the equation should read: (P + an2/v 2)(V – nb) = nRT, eliminating the first equal sign.

PAGE # 325
Lecture 3
In Class Exam
Answer Explanations
The answer explanation for question 63 should begin “The melting point of fatty acids increases as the number of double bonds decreases.” not "The melting point of fatty acids decreases…”

PAGE # 335
Lecture 5
In Class Exam
Answer Explanation
For Question 113, the last two lines of the equations should say:
9 × 16 = 144 g/mol
And 3 × MWN = 3 × 14 = 52 g/mol

PAGE # 346
In Lecture Question
Answer Explanation
Question 20 should list D, not C.
Question 79 should list A, not D.

PAGE # 351
Lecture 2
In Class Exam
Answer Explanation
For Question 29, the second sentence should say “3” sigma bonds, not “2”.

PAGE # 358
Lecture 4
In Lecture Question
Answer Explanation
The answer explanation for Question 79 should read:
A is correct. Like macroscopic energy, microscopic energy can be divided into kinetic and potential energy. Kinetic energy is a result of motion, such as vibrational energy, making choice A the correct answer. Electronic, rest mass, and intermolecular energy are examples of potential energy, energy that is stored in some form, at the microscopic scale. Therefore choices B, C, and D are incorrect.

PHYSICS

PAGE # 3
Lecture 1
The hypotenuse of the ramp should be labeled “4m”, not the horizontal base.

PAGE #147
Lecture 5
In the third paragraph, in the 3rd line 'i2' should be 'i1'.
In the last line of the third paragraph, 'i3' should be 'i2'.

PAGE # 153
Lecture 5
In Lecture Question
The diagram with question 110 belongs with question 109.

PAGE # 156
Lecture 5
If a lens has two focal points, how can I determine which sign to ise for the focal length? The rule for both lenses and mirrors is to use a positive sign if light actually travels to that focal point, and negative if light does not actually travel there. For this reason, convergers have positive focal points and divergers have negative focal points. If a diverging lens problem refers to a focal point that lies between the observer and the lens, that focal length should be negative because the photons travel through lens, refract, and never travel through focal point.

PAGE # 163
Lecture 5
Rule #1 should read "Converging mirrors and lenses..."

PAGE # 169
Lecture 5
In Lecture Question
In Question 117, the first sentence of the question stem should say: “An inverted image is created by an object 5 m in front of a mirror.”

PAGE # 214, 231
Lecture 5
In Class Exams
Answer Explanation
On p. 214, Question 107 in the answer table should list A as the best answer.
On p. 231, the first and last six lines of the answer explanation for question107 should be replaced. It should read, “A is the best answer. This question sets up a double-slit diffraction scenario. The light used has a wavelength of 0.35 nm based on the information in the passage. Next, the distance between the slits is 1 nm. Double-slit diffraction is governed by the equation: d sin θ = mλ, where d is the distance between the two slits, θ is the angle between the 0th and mth order maxima, m is the order, and λ is the wavelength of light used. For all double-slit diffraction, there is a maximum called the 0th order maximum directly across from the middle of the two slits. This makes option I likely to be included in the best answer. Choices B and D can be eliminated. The zeroth order maximum is directly across on the screen, so those light rays are basically traveling horizontally to the screen. For the angle to be perpendicular, the second order maximum would have to be on the side with the slits, which is not the case. All maxima form on the screen across from the light source and the slits. This means option II is unlikely. This eliminates choice C, likely making choice A the best answer. However, confirm by reviewing option III. As double-slit diffraction results in a series of alternating bright bands, or maxima, and dark bands, or minima, both maxima and minima appear. Additionally, there is some destructive interference that occurs between the maximum and the minimum for each order as the light rays from each slit sum. Thus, option III is not a component of the best answer. Choice A is the best answer.

PAGE # 236
Lecture 1
In Lecture Question
Answer Explanation
Answer explanation for Question 14 should read:
Horizontal speed has no effect on the length of time that a projectile is in the air, so the 30 m/s of initial horizontal speed can be ignored while solving this problem. Because the initial vertical speed is zero, use the equation x = ½gt2 to solve for time with x = 40 m and g = 10 m/s2 . Another quick approach is to reason that the rock will gain 10 m/s of vertical velocity every second. In this case, the rock goes from 0 m/s to 30 m/s of vertical velocity over 3 seconds. This gives an average vertical velocity of 15 m/s over 3 s, meaning it travels about 45 m downward. This is closest to 40 m, making answer choice A the best answer. Choices B, C, and D would all give huge overestimations using this quick method.

PAGE # 238
Lecture 2
In Lecture Question
Answer Explanation
Answer explanation for Question 29 should read:
In the fourth line of the answer explanation it should say “counterclockwise” not “clockwise”.

REASONING SKILLS

PAGE #16
Lecture i
Table i.3
Please see new, improved table with MCAT® exponent rules:
Old table:
Please do not use this table. The first line, “Addition Rule”, after the = should say (cannot be further simplified). The second line, “Subtraction Rule”, after the = should say (x + y)(x – y). But neither of these rules as given are needed for the MCAT®. They have been replaced in the new table. Please see new, improved table with MCAT® exponent rules:

PAGE # 21
Lecture i
The last sentence of the second to last paragraph should say “inversely proportional to Q”, not “indirectly proportional to Q”.

PAGE # 23
Lecture i
On page 23, there are five graphs, but the side note references the four graphs directly above the side note, not the larger one to the left that is a parabola.
The note should read:
Note: n is greater than zero for the graph of y = nx. If n were equal to zero, the graph would simply be a straight line at y = 0. Also note that n is greater than one for the graphs of y = xn and y = 1/(xn). This is because x1 is simply equal to x. For the graph of y = nlogx, n must be greater than zero, because, if n were equal to zero, the graph would also be a straight line at y = 0.

PAGE # 133
Lecture ii
In Class Exam
For Question 7, choice A should say “I and II”. It currently says “I and III” which is the same as answer choice B.

101 Passages Workbooks

LAST UPDATED 11/03/17

101 Passages: BIOLOGY 1 MOLECULES

PAGE # First page of each test.
Lecture: All
The directions should read:
DIRECTIONS: Most of the questions in this test section are grouped with a passage. Read the passage, then select the best answer to each question. Some questions are independent of any passage and of one another. Select the best answer to each of these questions. If you are unsure of an answer, rule out incorrect choices and select from the remaining options. Indicate your selection beside the option you choose. A periodic table can be found on the last page of this book for you to use at any point during this test section.

Page # 7
Test 1A
In question 2, choice D should read "increased cell death due to decreased plasma membrane fluidity." For question 3, add "at low temperature" to the end of the question stem.

Page # 93, 111,141
First page of tests 3A, 3B and 4A.
The time should say:
Time: 95 minutes.

Page # 39, 83, 131, 175
First page of tests 1C, 2C, 3C, and 4C
The title of these tests should be:
Mini-Test 1C, Mini-Test 2C, Mini-Test 3C, Mini-Test 4C

Page # 102
Test 3A
In question 32 choice B should be 22.

Page # 182
Test 4C
For question 20, the images for choices B and C should be switched. In addition, the x-axis should read ATIP1, ATIP2, ATIP3. The “I” is missing from the label.

Page # 189
Test 1A
In the answer explanation for question 2, the sentence starting from: "Decreased plasma..." should instead say “At physiologic temperature, cholesterol reduces fluidity, so a reduction in cholesterol leads to increased fluidity, eliminating choice D.”

Page # 256, 262
Test 3A
On page 256, the answer to question 32 should be B.
On page 262, the answer explanation for question 32, should read as follows B is the best answer. According to paragraph three, bacteria that have an incomplete TCA cycle use the glyoxylate shunt to bypass steps that release carbon dioxide in the TCA cycle. Remember that one NADH molecule is generated during each of these decarboxylation steps and that two steps of the TCA cycle have carbon dioxide elimination. Thus, bacteria with incomplete TCA cycles generate 2 fewer NADH, 1 fewer FADH 2 , and 1 fewer GTP per acetyl-CoA. This can be doubled to represent losses for a glucose molecule. The sum comes out to 10 ATP from NADH + 3 ATP from FADH 2 + 2 ATP from
GTP loss. The total loss of ATP is 15 ATP, so the final amount generated will be around 21-23 ATP. Choice B is the best answer.

Page # 291
Test 4A
The answer explanation for question 7 should read:
A is the best answer. When interpreting the results of mass spectrometry, if there is molecular ion, it will be the ion with the largest mass. Not all mass spectrometry results will contain a molecular ion, but most of the time, the largest ion is the result of charging the original molecule. The molecular ion is the size of the original molecule but contains one less electron. If D-arabinose were the sample, the molecular ion would be D-arabinose+. It is important to note that the molecular ion, if present in a sample, is not always the one with the highest peak in a mass spectrogram, but rather the ion with the greatest mass. The peak with the largest mass is the one with an m/z of 150, likely indicating that this is the molecular ion, D-arabinose+. Choice A is a strong answer. The other three peaks are all smaller in mass than the one at 150 m/z and are the result of the fracture of the original molecule after being bombarded with electrons. Choices B, C, and D can be eliminated.

101 Passages: BIOLOGY 2 SYSTEMS

Page # 37
Test 2A
Test 2A, question 4 choices C and D should say “depolarization”, not “repolarization”.

Page # 215
Test 2A
The answer explanation for question 4 in Test 2A, should say “black curve” not “red curve”.
On page 262, the answer to question 22 should be C.

Page # 262, 267
Test 4A
On page 267, the answer explanation for question 22 should read:
Choice C is the best answer… [The last two sentences should read:] …"Choice C represents a right shift, which would allow for greater oxygen unloading in the tissues, making it the best answer. Choice D can be ruled out as it represents greater oxygen affinity and reduced unloading."

101 Passages: CHEMISTRY

Page # 29, 216, 237
TEST 1B

The answer choices to question 26 should be changed to:
A. 5 g
B. 12 g
C. 13 g
D. 24 g
In the table on p. 216, the answer to question 26 should be B.
On p. 237, the answer explanation to question 26 should be:
B is the best answer. As discussed previously, there were 0.06 moles of Ta used in the experiment. The final product is Ta2O5 which has a molecular weight of roughly 442 g/mol (181 + 181 + 16 + 16 + 16 + 16 + 16). It takes two Ta atoms to make tantalum pentaoxide, so the final yield is 0.03 moles of Ta2O5 from 0.06 moles of Ta. 0.03 moles × 442 g/mol ≈ 13 g. That is the theoretical yield. The experimental yield will be 90% of 13 g which is 11.7 g. This is closest to choice B, which is the best answer. Choice A is a miscalculation using the atomic weight for Ta rather than the molecular weight for Ta2O5. Choice C results from forgetting to convert from theoretical to experimental yield. Choice D is a result of forgetting to use a mole ratio to convert the number of moles of Ta in the starting materials to the number of moles of Ta in Ta2O5.

Page # 35
Test 1B
In question 6, figure for choice D should show arrow explicitly pointing to the
O−H bond, not the C−O bond.

Page # 43
Test 2A
For question 32, in choice A, there are two bonds shown between N and Pt, one N above and one below the central Pt atom. These should be single bonds not double bonds. Also, in choice A, change to two dots in the same orientation as the bonds between N and H.

Page # 129
Test 4B
In question 29 on p. 129 the equals signs in the denominators of choices C and C. D should be removed.

Page #160
Test 6A
In Figure 2, the calcium oxalate and mg ammonium phosphate H lines switched.

Page # 186
Test 7A
Question 3 should say “MOST”, not “LEAST”.

Page # 178, 353
Test 6B
On page 178, for question 6, choice C, the exponent at the choice should be 3 rather than 2.
On p. 353, in the answer explanation for question 6, the exponent in Ksp = 4[Pb2+ anode] should be 3 rather than 2. The exponent in the second to last line Ksp = 4(...)2 should be 3 rather than 2.

Page # 187, 362
Test 7A
For question 5 on page 187, choice D should be 3.3 × 10−2 M.
For the question 5 answer explantion on page 362, the center equation should read “(0.1 mols HCl/L” not “0.01 mols HCl/L)”.
The last two parts of the equation should read “0.33 × 10−2 mols of triglycerides = 3.3 × 10−3 mols of triglycerides.”
The start of the last paragraph should read: 3.3 × 10−3 moles triglycerides/0.1 L = 3.3 × 10−2 M, so choice D is the best answer.

Page # 257
Test 2B
For the molecule pictured in the answer explanation to question 19, the central N should have 4 bonds, a single bond to H above, a single bond to the carbon on the right, and a double bond on the carbon to the left. The bond from C to O should be a single bond not a double bond. In other words, the double bond should be from C to N, rather than from C to O.

Page # 334, 348
Test 6A
On page 334, the answer for question 57 should be changed from C to D.
The answer explanation for question 57 should read,
“D is the best answer. In order to find the reduction potential of the four DNA bases, the sign of the voltage for the oxidation potential needs to be reversed, making the four values negative, as shown below.

[In the chart, the right label should say ‘Reduction potential (V)’, not‘oxidation’.]
The base with the lowest or most negative reduction potential is LEAST likely to be reduced. The most negative reduction potential belongs to thymine, making choice D the best answer. Remember that the free energy of a reaction can be calculated if the potential of the cell is known, by the equation ΔG = − nFE cell, where n is the number of moles of electrons that are transferred in the balanced reaction, F is the charge on one mole of electrons (96,486 C/mol−1), and E is the potential of the chemical cell.”

101 Passages: PHYSICS

Page # 2, 186
Warm Up
Question 2 should say “1 ng of bacteria” instead of “10−3 ng bacterium”.
In the question stem and answer explanation, all instances of “bacterium” and “flagellum” should be changed to the plural: “bacteria” and “flagella

Page # 22
Test 1B
Information is missing from the table in the passage. Please see the new table here.

Page # 30
Test 1B
The graph is missing a label. Please see the new graph here.

Page # 43, 216
Test 2A
On p. 43, in Question 15, in choices A, B and C, move π from the denominator to the numerator.
On p. 216, in the answer explanation to question 15, the final answer on line 3 should be 200π N. All instances of 200/π should be 200 π. On the second to last line 400/π should be 400π.

Page # 90, 254
Test 3A
On p. 90, question 47 should say “1000 g” not “1000 mg”.
On p. 254, the answer explanation for question 47 should say m = ρV = (1 kg/L)(1 L) (1000 g/kg) = 1000 g

Page # 114
Test 4A
Passage 1
The Key for Figure 2 has the labels/lines switched i.e. Trial 1 should actually be the data points/line that is currently labeled as Trial 2, and vice versa). This change corrects the current issue with questions 4 and 5.

Page # 143, 274, 294
Test 4B
In question 39 on p. 143 it should say “decrease” not “increase”.
In the answer key on p. 274, the answer to question 39 should be C.
On p. 294, the last sentence of the answer explanation to question 39 should say, "Finally, option III would increase the resistance since resistivity is directly proportional to resistance."

Page # 300, 302
Test 5A
On p. 300, the answer to question 15 should be C.
On page 302, the answer explanation to question 15 should read: C is the best answer. According to the question, the part to consider is the portion of the wave that passes through the interface, meaning reflection in choices A and B are out. Reflected waves do not pass through the interface of two mediums. The wave speeds up because sound travels faster through solids like bone, compared to air. When any wave speeds up at the interface, as is the case with sound going from air into bone, the wave bends away from the normal and choice C is the best answer.

101 Passages: PSYCHOLOGY & SOCIOLOGY

Page # 270, 271
Test 5A
In the Answer Table for question 5, the answer should be D, not A.The answer explanation for question 5 should begin, “D is the best answer…”, not A.

9th Edition Complete Study Guides

LAST UPDATED 06/02/17
The most current reprint of the 9th edition Examkrackers MCAT® Manuals is now available and Examkrackers has corrected most errata.

This document contains the only remaining errata in the Spring 2015 Reprint of the 9th edition Manuals.
The Errata Forum no longer applies to this reprint.

This document will be updated as any further errata are posted. Please note the document date above.

How to know that you have the most recent (Spring 2015) Reprint of the manuals:

If your Manuals reflect the following indicators, then you do have the Spring 2015 reprint and can rely only on this
document for any errata.

(Note: If you purchased the Complete Study Package with all 6 Manuals included, verify only one Manual as follows. If you purchased your manuals individually, please verify each Manual as follows.)

Biology 1: Molecules, 9th edition Reprint
page 50, question 36, choice A says "eukaryotic ribosomes are smaller."

Biology 2: Systems, 9th edition Reprint
No changes were made at this reprint. All known errata are included in this document.

Physics 9th edition Reprint
page 196, chart heading reads “Answers to the 30 Minute In Class Exams”

Chemistry 9th edition Reprint
page 141, question 81 includes a chart above the formula

Reasoning Skills 9th edition Reprint
page 160, question 55 the answer should be listed as D not B

Psychology & Sociology 9th edition Rep rint
page 159, question 16 Answer Explanation should say “the encouragement of healthy behaviors” not “unhealthy”.

ERRATA LISTED BY BOOK

BIOLOGY I

Lecture 1, page 25:
Figure 1.17, see figure to the side, where the Km of non-competitive inhibition corresponds to ½ V1max.

Lecture 2, page 47:
In the middle of the last paragraph, it should say "DNA polymerase" not "RNA polymerase" as follows: "As is
shown in Figure 2.15, at each replication fork, one of the separated strands is able to be read continuously in the 3´ → 5´ direction while DNA polymerase continuously synthesizes a complementary strand in the 5´ → 3´ direction".

Lecture 2, page 52, figure 2.19:
The middle image on the left should have the following caption:
"Addition/ deletion - continuing protein
The addition (or deletion) of a nucleotide causes a frameshift. From that point forward, codons are translated on a different reading frame, resulting in different amino acids. If an early stop codon is not introduced, a whole protein is translated. This type of mutation usually results in non-functional proteins."

The image on the bottom left corner of the page should have the following caption:
"Deletion/addition - truncated protein (nonsense) The deletion (or addition) of a nucleotide causes a frameshift. From that point forward, codons are translated on a different reading frame, resulting in different amino acids. If an early stop codon is introduced, the protein is truncated. This type of mutation usually results in non-functional proteins."

Lecture 3, page 87, question 72:
Answer choice B. should say "34" not "32".

In Class Exams, Lecture 3, pages 138 & 155, question 65:
On page 138, question 65 answer choice A. should say "glycogenesis" instead of "glucogenesis".
On page 155, the last sentence of the answer explanation for question 65 should say, " It is insulin that promotes glycogenesis and glycolysis." "glycogenesis"not "glucogenesis".

In Class Exams, Lecture 1, page 148, question 10:
In the answer explanation for question 10, the second sentence should read "If the turnover number (the numerator) decreases..." instead of "(denominator)".

In Class Exams, Lecture 3, page 153, question 57:
The answer explanation to question 57 should read: "As shown in Figure 2..." not "Figure 1."

Lecture 3, page 169, question 72:
The answer explanation to question 72 should say, "The net product of glycolysis for one glucose molecule is 2 ATP and 2 NADH. The additional steps of aerobic respiration produce 30 ATP, based on a total of 2 ATP from the Krebs cycle, 3 ATP/NADH and 8 total NADH, and 2 ATP per FADH 2 and 2 FADH 2 . The 2 ATP from glycolysis can be added to arrive at 32 total ATP. Finally, the NADH from glycolysis must be accounted for. They produce 3 ATP each in the electron transport chain, but also require 2 ATP to enter to mitochondrial matrix based on the question stem. This results in an additional 2 ATP to arrive at the final answer of 34 ATP."

Lecture 4, page 172, question 94:
In the second line, the answer explanation for question 94 should read "whereas a gene that is downregulated will appear red."

BIOLOGY II

Lecture 3, page 85:
In the second paragraph under "Posterier Pituitary" it should say "When water is absorbed from the collecting tubule, the osmolarity of the blood plasma decreases" not increases.

Lecture 3, page 91:
In the second paragraph, the end of the first sentence should say that aldosterone is secreted "from the adrenal cortex", not from the adrenal medulla.

Lecture 4, page 121:
In the middle of the page it should say, "This equation demonstrates the directly proportionate relationship between pressure and resistance." not "indirectly". The signpost should be to "Fluids".

Lecture 4, page 130:
The second paragraph on the page should be titled "B-cell Immunity" in large print, not "T-cell Immunity".

Lecture 6, page 183:
Near the bottom of the first paragraph, it should say, "By contrast to skeletal muscle, which connects bone to bone via ligaments," not 'tendons'.

In Class Exams, Lecture 5, page 227:
Figure 1 of In-Class Exam Passage III. See figure below which shows the macula densa and juxtaglomerular cells. The caption is correct. The glycolysis reaction should not be here.

In Class Exams, Lecture 6, page 233, question 123:
Question 123, answer choice B should say, "CASQ1 null mice are larger than wild-type mice."

In Class Exams, Lecture 5, page 240 & 257, question 112:
The answer explanation should read "A is correct. Again, aldosterone increases the activity of the Na+ -K+ ATPase pump, thereby increasing both Na+ reabsorption and K+ excretion in the distal tubule and collecting duct. Increased K+ excretion, however, does not lead to increased blood pressure. Instead, increased Na+ reabsorption leads to increased thirst and increased blood volume. When Na+ is reabsorbed, water follows. In this way, aldosterone indirectly increases blood pressure. Secretion of vasopressin, the hypothalamic hormone that regulates water reabsorption in the distal tubule and collecting duct is stimulated by Ang II, not aldosterone."

In Class Exams, Lecture 1, page 243, question 20
The answer explanation should read "C is the best answer. As described by the fluid mosaic model, all proteins inserted into the membrane must have a hydrophobic portion that can interact with the hydrophobic lipids that make up the cell membrane. Choice A is not the best answer because K+ channels are not synthesized in the nucleus They are made at the rough endoplasmic reticulum like other membrane-bound or secreted proteins. Choice B is not the best answer because the K+ channels do not 'create' the gradient. They play one part, allowing K+ ions to help set up resting potential. Choice D is not a true statement; the K+ channels do not create energy for the cell."

PHYSICS

Lecture 1, page 3:
The last equation in the cluster of 4 under the figure should read:
dbase = 4 m, not d ramp = 4 m.

Lecture 2, page 50:
In the section, "The Ramp", in the sentence at the end of the 7th line, should say "Thus the force has been reduced by the machine." not "the work".

Lecture 3, page 62:
The fifth sentence under hydraulic lift should read "Since piston 2 has a greater area than piston 1, and force and area are directly proportional when pressure is constant...." -- 'directly' not 'indirectly' proportional.

Lecture 3, page 64:
See new visual below for Figure 3.6. A for area needs to be added to each of the three formulas for force. It should say FB = ρfluidgAΔy. Buoyant force is ρVg. Here that would be ρfluidg AΔy, as AΔy = V.

Lecture 3, page 67:
The text at the bottom of figure 3.9 should read "Object weight = Apparent weight + Weight lost." The second part should read "Fraction of weight lost = ρfluid/ρobject = m fluid/mobject."

Lecture 3, page 76:
In the third paragraph, the equation for area should be A = 2πrd

Lecture 3, page 79, question 69:
Answer choices C and D should both say “because flow speed is lower” as follows:
“C. The pressure is higher in the aneurysm because flow speed is lower in the normal blood vessel.”
“D. The pressure is lower in the aneurysm because flow speed is lower in the normal blood vessel.”

Lecture 4, page 102, question 86:
The following parenthetical should be included at the end of the question stem before the colon. (The equation for power is P = IV).

In Class Exams, Lecture 4, pages 103 & 214 & 225, question 87:
On p. 103, answer choice A to question 87 should say "5.5 x 10 6 ions".
On p. 214, the answer to question 87 should be A.
On p. 225, the answer to question 87 should be A and the answer explanation should read:
"Choice A is correct. The total charge that can be stored across a capacitor, like the cell, can be calculated
by Q = CV. Next, the surface area of the spherical cell = 4πr2 = 4π × (10 -3cm)2 = 1.26 x 10 -5 cm 2 . To find
the total capacitance of the cell membrane, multiply capacitance/area by area: C = 1.26 x 10 -5 × 10 -6 =
1.26 × 10 -11 F. The total charge can be found by multiplying capacitance by the voltage given in the text:
Q = CV = 1.26 x 10 -11 × 70 x 10 -3 = 8.82 × 10 -13 C. Divide the total charge required by the charge per
ion (for potassium, a singly charged ion): 8.82 × 10 -13 / (1.6 x 10 -19) = 5.5 × 10 6 ions. Choice A is the best
answer."

Lecture 4, page 106, question 90:
The following parenthetical should be included at the end of the question stem before the colon (Power = IV = I2R = V2/R).

Lecture 4, page 106, question 91:
The following should be included at the beginning of the question stem: “Voltage sources for alternating current are characterized by their average voltage, Vrms • (Vrms = Vmax/square root of 2)."

Lecture 5, page 155:
See new visual. (Table 5.4, under Divergers d o = f should be included in the smaller block. “No image” refers only to d o = f for Convergers.)

Lecture 5, page 159:
The sentence starting 2/3 of the way down in the last paragraph on p. 159 should read: "Because the
image formed by the objective falls inside the focal length of the eyepiece, the eyepiece forms a virtual,
upright image. Since the first image was inverted, this means that the image viewed by the observer
appears inverted. For both microscopes and telescopes, even though the object of the second lens is the
image of the first one, the object is still "where it belongs" (on the other side of the lens from the observer
and is thus designated positive)."

In Class Exams, Lecture 2, page 173, question 29:
Question 29 should read: "Which position has the greatest torque due to the muscle?"

In Class Exams, Lecture 2, page 174:
The y-axis of Figure 1 should be relabeled "Muscle power (kW)".

In Class Exams, Lecture 3, page 180, question 62:
The question stem should read “pulmonary vein” not “vena cavae”.

In Class Exams, Lecture 4, pages 196 & 208, question 81:
The correct answer is choice C. Both instances of “sin” in the answer explanation should be changed to “cos.” The last two sentences should read:
“In this case, that would be x cos(30°). The work done then is qEx cos(30°).”

In Class Exams, Lecture 5, page 210, question 100:
See new visual for the equation in the answer explanation for question 100. The f1 at the start of the right side of the equation should be removed, and /4πr2 should be added to the end of the equation.

In Class Exams, Lecture 5, page 211, question 105:
In the answer explanation to q. 105, starting with the sentence on the 5th line, should say: "Therefore, the wavelengths of waves at the proximal end would be shorter than those at the distal end. Because wavelength is inversely proportional to frequency, the frequency of waves at the proximal end should be higher. Choice C can be eliminated and choice A is the best answer."

Lecture 1, page 216, question 14:
The answer explanation to q. 14 should say: "Horizontal speed has no effect on the length of time that a projectile is in the air, so the 30 m/s of initial horizontal speed can be ignored while solving this problem. Because the initial vertical speed is zero, use the equation x = ½ gt2 to solve for time with x = 40 m and g = 10 m/s2 . Another quick approach is to reason that the rock will gain 10 m/s of vertical velocity every second. In this case, the rock goes from 0 m/s to 30 m/s of vertical velocity over 3 seconds. This gives an average vertical velocity of 15 m/s over 3 s, meaning it travels about 45 m downward. This is closest to 40m, making answer choice A the best answer. Choices B, C, and D would all give huge overestimations
using this quick method."

Lecture 2, page 218, question 29:
The second sentence of the answer explanation should begin "If the tensions in lines A and B were the only forces acting on the pole,…" not "lines A and C". Also, in the fourth line it should say "counterclockwise" not "clockwise".

CHEMISTRY

Lecture 1, page 14:
The last sentence of the third paragraph should read: "Since there are two electrons in each orbital, the number of electrons in the periods of the periodic table is 2, 8, 18, and 32." It should say "electrons" not "elements".

Lecture 1, page 36:
In the MCAT Think, Reaction 1 should read:
C4H9Cl + OCH 3 - ? C5H12O + Cl
Rate Law under reaction 1:
Rate = kf [C4H9Cl][OCH 3 -]
Reaction 2 should read:
C4H9Cl ? C4H9+ + Cl- (slow step) C4H9+ = intermediate
C4H9+ + OCH 3 - ? C5H12O (fast step)
Rate Law under reaction 2 should read:
Rate = kf [C4H9Cl]α

Lecture 1, page 38:
The last line of "Salty" text at the bottom of the page should say, "If B is tripled and the rate stays the same, 3? = 1; ? = 0." not "? = 1". "If B is tripled and the rate stays the same, 3? = 1, ? = 0."

Lecture 2, page 57, question 29:
Choice A should say "sp3, sp2, sp2, sp3"

Lecture 2, page 59:
The beginning of the last paragraph on the page beneath the two molecules should read "Cyclohexanol and ethanol…" not "Phenol and ethanol…".

Lecture 2, page 63, question 37:
In the reactant, there should be a hydroxyl coming off of the alpha carbon directly to the left of the carbonyl carbon. In the product, the C=O carbonyl on the bottom of the ring and the O on the bottom of the ring need to be swapped in position.

Lecture 3, page 80:
The last sentence of the second paragraph should say: "Across a row in the periodic table, nucleophilicity decreases…" not 'increases'.

Lecture 3, page 94:
In Figure 3.25, on the reactant side, remove the bottom hydrogen and the bond which attaches it to the carbonyl carbon.

Lecture 3, page 100:
The last two sentences of the first paragraph should read: "Enamines are not stable due to the electron donating nitrogen off of the pi bond. Because nitrogens are less electronegative and more electron donating than oxygen, enamines are better nucleophiles than enols."

Lecture 3, page 110:
The last sentence of the first paragraph in the Proteins and Amino Acids subsection should read: “The reaction is a typical nucleophilic substitution reaction, with -OH as the leaving group.” with -OH in place of "alcohol".

Lecture 3, page 113:
The first sentence in the second paragraph should say “The carbon adjacent to the carbonyl carbon is called the …” adding "carbon adjacent to the"

Lecture 4, page 137:
The equation should say delta S rxn = ∆S products - ∆S reactants (Replace the second equal sign with a minus sign).

Lecture 4, page 149, questions 94, 95, & 96:
Questions 94, 95 and 96 should read:

Question 94
During the formation of sulfur trioxide, an increase in temperature would result in:
○ A. a decrease in the equilibrium concentration of oxygen.
○ B. an increase in the equilibrium concentrations of products.
○ C. no change in equilibrium concentrations.
○ D. a decrease in the equilibrium concentration of sulfurtrioxide.

Question 95
For the above reaction, which of the following will most increase the production of heat?
○ A. high pressure and high temperature.
○ B. high pressure and low temperature.
○ C. low pressure and high temperature.
○ D. low pressure and low temperature.

Question 96
If the above reaction was at equilibrium inside a closed
container, decreasing the volume of the container would cause
which of the following?
○A. An increase in the formation of sulfur trioxide
○ B. A decrease in the formation of sulfur trioxide
○ C. No effect on the formation of sulfur trioxide
○ D. The effect cannot be determined with the information provided.

Lecture 5, page 159:
The answer in the middle of the page should read: “P = 5 atm” not P = 5L.

Lecture 5, page 165, question 102:
The second sentence of the question stem should read "The initial temperature is 0°C and pressure remains constant."

Lecture 6, page 181:
In the fourth line of the first paragraph under Solution Concentration, this sentence should be removed. "Molarity depends only on the amount of solvent, not the total volume of solution."

Lecture 6, page 200:
In the subsection “The Nernst Equation,” in the second equation it should say “ln” not “log”.

Lecture 6, page 201:
In the Nernst equation it should say “log” not “ln”.

Lecture 6, page 204:
The first line of Raoult's Law should not have a plus sign, but instead should have nothing between the
mole fraction χa and partial pressure terms Pa, indicating multiplication. Please see updated visual below.
Raoult's Law
Pv = χa Pa

Lecture 7, page 210:
In the figure at the top left of the page containing two amino acids, at the bottom of the structure of Arginine there should be a double bond between the C & NH 2+.

Lecture 7, page 224:
In the fourth paragraph, within the parentheses, the word 'strong' should be changed to 'weak'. It should say "...For a diprotic acid whose conjugate base is a weak acid..."

Lecture 7, page 231:
In the paragraph right above the table, the second to last sentence, "acidic" and "basic" should be switched. The sentence should read:  “The isoelectric point is the average of the first two pK a values for acidic amino acids, and the average of the second and third pK a values for basic amino acids.”

Lecture 7, page 232:
The last sentence, just above the image with many powders, should read: "Thus, x is approximately 5.3 × 10 -6, which is also the concentration of OH-. The pOH is therefore 5.3, and the pH = 14 - 5.3 = 8.7."

In Class Exams, Lecture 4, page 261:
The lightest bars in Figure 2 should be labeled as "T∆S," not "-T∆S."

In Class Exams, Lecture 6, page 273, question 125:
Change the word “solution” at the end of the question to “the sample”. Additionally, the 0.001 on the first line should have an M after it to indicate units of concentration.

In Class Exams, Lecture 1, page 284 and 288, question 26:
On page 284, change the answer for question 26 from B to A. On p. 288, the answer explanation for q.26 should read:
"A is correct. Consider the second second step in the illustrated reactions (the salts, not the separated enantiomers). The salts are stereoisomers because they have the same bond-to-bond connectivity, and they must be diastereomers because they can be separated by physical means (crystallization). Notice from the diagram that they are NOT mirror images of each other, and therefore cannot be enantiomers, eliminating choice B. The salts are not structural isomers because they have the same bond-to-bond connectivity, eliminating choice C. There is no plane of symmetry, eliminating choice D."

In Class Exams, Lecture 1, page 285, question 4:
The last sentence of the answer explanation for question 4 should say "Therefore Ne has a smaller atomic radius than Ar."

In Class Exams, Lecture 1, page 286, question 16:
The Answer Explanation for question 16 should reference "Chamber 2" and "Chamber 3", in place of "Chamber 1" and "Chamber 2" respectively.

In Class Exams, Lecture 4, page 299, question 87:
The 5th sentence of the answer explanation to question 87 should read “Figure 1 shows that lower efflux rates are found in knockout mice, so choices B and C can be eliminated. Figure 1 says nothing about lactate influx, and it also shows that lactate flow is actually decreased in a high pH environment.” The 6th sentence “Choice D must be wrong…” needs no change.

Lecture 3, pages 312 & 322, question 62:
On page 312, change the answer for question 62 from A to C. On page 322, question 62 should read "C is correct." Toward the end of the second line it should say “Choices A and B contain ketones… Choice D contains an ester… Only choice C contains two alcohols.”

Lecture 4, pages 312 & 326, questions 94-96:
On page 312, answers 95 and 96 should be B & A respectively.
On page 326, the answer explanations for questions 94, 95, and 96 should read:
94. D is the best answer. D is the best answer. An exothermic reaction releases heat, which is considered a product. Increasing the temperature disturbs equilibrium by increasing the amount of heat on the product side, resulting in a shift toward the reactants. As a result, the concentration of reactants (SO2 and O2) will increase while the concentration of the product will decrease (SO3). Choices A, B, and C are not strong answers.
95. B is the best answer. B is the best answer. In order to increase the production of heat, the reaction must shift towards the right and generate products. Increasing the temperature will cause a leftward shift, which is opposite the desired effect, eliminating choices A and C. The effects of pressure change are dependent on the moles of gas of the reactants vs. products. Looking only at gases (which are all the compounds in this reaction), 3 moles of reactants generates 2 moles of products. A decrease in pressure shifts the reaction toward the side with more moles of gas, in this case, the reactants. Therefore, a high pressure and low temperature will increase the production of heat, eliminating choice D and leaving choice B as the best answer.
96. A is the best answer. Decreasing the volume causes an increase in pressure (PV = nRT). An increase
in pressure favors a shift towards the side with less moles of gas, which are the products in this
reaction. As a result, the formation of sulfur trioxide will increase.

Lecture 2, page 317, question 29:
In the answer explanation for question 29, the sentence beginning with “Atom 3” should read “Atom 3 has 3 σ bonds and a lone pair that is conjugated with the π bond in the carbonyl. This results in a nitrogen with sp 2 hybridization. Atom 4…” Additionally, the caption pointing to the nitrogen should change to say “sp 2 trigonal planar”.

Lecture 3, page 322, question 102:
The first sentence of the Answer Explanation for question 61 should read “Amines typically act as bases or nucleophiles." Remove the word "weak".

Lecture 5, page 327, question 102:
The equations in the answer explanation should now read:
50 J = P(Vf – Vi) = P[nRTf/P – nRTi/P] = nR(Tf – Ti) = (1 mol)(8.314 J/mol K)(273 K – Tf) Tf = 273 – 50 J/(8.314 J/K) = 267 K = –6o C

Lecture 6, page 330, question 125:
The Answer Explanation for In Lecture question 125 should have the last sentence as follows: “Finally, adding a non-volatile solute decreases the vapor pressure of the whole solution.”

Lecture 6, page 332, question 139:
The answer explanation for question 139 should read: “An electrolytic cell has a negative potential while a galvanic cell has a positive potential. Thus, choice D is the best answer.”

Lecture 7, page 333, question 150:
The Answer Explanation for In Lecture question 150 should read: "... and a concentration of 1.0 × 10 -6 mole/L would result in a pH of 6."

REASONING SKILLS

Lecture i, page 3:
In the fifth paragraph it should say "20% of the questions", not "50%".

Lecture i, page 8:
In the 5th paragraph it should say, "Thus 2.22" not "Thus 2.22".

Lecture i, page 11:
In the second paragraph, it should say "0.00000000000000000000000000199".

Lecture i, page 18:
In the last line, it should say "What if you made the hose larger by increasing the radius?"

Lecture i, page 21:
On page 21, there are five graphs, but the side note references the four graphs directly above the side
note, not the larger one to the left that is a parabola. The note should read:
Note: n is greater than zero for the graph of y = nx. If n were equal to zero, the graph would simply be
a straight line at y = 0. Also note that n is greater than one for the graphs of y = xn and y = 1/(xn). This
is because x1 is simply equal to x. For the graph of y = nlogx, n must be greater than zero, because, if n
were equal to zero, the graph would also be a straight line at y = 0.

Lecture i, page 25:
In the second paragraph, it should say, "Likewise, 1 meter/100 centimeters is the same thing as 1.", not "1
centimeter".

Lecture i, page 26:
The equation for Joules in the middle of the page has a missing equal sign. See new visual below.

Lecture ii, page 29:
In the first sentence on the page it should say "About twenty percent of questions", not "fifty percent".

Lecture ii, page 37:
In the last sentence of the second to last paragraph, it should say "the incidence" not "prevalence" as follows:
"Thus, in this example, the negative control experiment strengthens the argument that any change in the
incidence of cancer in the coffee group is due to the coffee and not to other factors."

Lecture ii, page 39:
Figure ii.4.C should have the x-axis labeled "Score" and the y-axis labeled "Frequency".

In Class Exams, page 156, question 98:
In question 98, the question stem should reference paragraph 7, not paragraph 6.

In Class Exams, page 160:
The column headings should be ii, 1, 2, 3, 4.

PSYCHOLOGY & SOCIOLOGY

Lecture 5, page 109:
The first Salty text in the margin should read "You should also review sections 2.9 and 2.10 in the Biology 2 Systems Nervous System Lecture, which discuss visual processing in the eye and nervous system."

Lecture 5, page 110:
In the middle of the second to last paragraph, the two sentences following the bold, red terms should say, "REM sleep is named for the characteristic eye movements associated with it, but more importantly, it is a separate sleep stage of high brain activity. REM sleep does not occur in the first sleep cycle of the night, but makes up a significant portion of sleep in later cycles."

Lecture 5, page 114, question 112:
The question stem should read: "Which of the following would most likely be found in the blood of a sleep-deprived individual at night?"

In Class Exams, Lecture 1, page 159, question 20:
"The last sentence of the answer explanation should read "The passage states that undocumented immigrants seeking treatment generally have lower CD4 counts than documented immigrants, making choice A the best answer..." not "higher".

In Class Exams, Lecture 5, page 172, question 101:
The following sentence can be cut from the answer explanation as the figure is neither given nor necessary to answer the question. "D is also incorrect because Figure 2 shows a DECREASE in active fear response after fear induction among people with the SS genotype."

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