Examkrackers Errors

[tco]

I'm pretty frustrated with EK as of right now. They charge you to see the errors in the books that you've already purchased.

I've searched this topic and have seen a few threads complaining about the errors but none doing anything about it.

I'm suggesting that we start a floating or sticky thread for all of the errors that we think we find in the products. This applies to the 1001 questions, study guide, AO series, and anything else that EK makes. It's not to hurt EK's reputation, but rather to be critical of every bit of information that we come across. Face it, every prep company has mistakes in their products, but I think it's a little ridiculous to charge your customers to see your mistakes.

To avoid copyright infringement (I don't know what the rules are exactly for this kind of thing), I'm just going to ask general questions and list the question number or page number after it. Any help would be great.

Bio 1001, page 35:

Question 194

I was always lead to believe (via my Cell book) that carbohydrate attachment to protein was limited to the Golgi. Is this not correct?

I also thought that question 184 was pathetically worded.

Question 202

Maybe I'm just reading too much into it, but I thought that all digestion (mechanical) began in the mouth. Chemical digestion of carbohydrates begins in the mouth and chemical digestion of proteins begins in the stomach. Lipid and nucleotide digestion begins in the small intestine.

Is there anything wrong with what I just said?

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[minhaj]

I dont have the EK 1001 bio book and I dont know the question but I know from my cell bio class that glycosylation occurs in ER as well. If I am not mistaken, the sugars that are added are usually oligosaccharides.

As for 202, again I dont have the book but there is nothing wrong with what you said.
EK 1001 bio book has many errors in it from what I have read on these forums, so dont completely trust what the book says.

 

[HawkeyePostOp]

I've noticed mistakes in these books, but #'s 184, 194, and 202 seem to be passable.
184 - weird but correct
194 - glycosylation of proteins in the ER is common, so the book is right
202 - ehh i guess it's technically wrong. The process of digestion begins with mastication, but they hardly ever mention mastication on MCAT. Salivary amylase in the mouth only breaks starch into sugar, and can't handle protein. I would still put "C. stomach" because the question is emphatic about the protein.

 

[tco]

I have problems with those types of questions.

It seems like if I would put "stomach, because HCl and mechanical grinding," it would be wrong because, "all digestion begins with mechanical digestion in the mouth."

If this type of question were on the MCAT, would it be less ambiguous than that?

Edited because I'm an idiot.

 

[cornpops21]

I have problems with those types of questions.

It seems like if I would put "stomach, because HCl and mechanical grinding," it would be wrong because, "all digestion begins with mechanical digestion in the mouth."

If this type of question were on the MCAT, would it be less ambiguous than that?

Edited because I'm an idiot.

Where are you reading this?

Only carbohydrate digestion occurs in the mouth from salivary amylase. There actually is some lipid digestion that occurs in the mouth but the lipase activity is nowhere near the efficacy of pancreatic lipase. Either way, the question is asking about protein, and protein digestion does not occur in the mouth. It starts in the stomach and is finished and reabsorbed in the small intestine.

This question doesn't seem ambiguous to me.

 

[Quantum Chem]

According to Wiki (yes, I know, its Wiki): http://en.wikipedia.org/wiki/Digestive_system mechanical digestion starts in the mouth. Also, if I remember the EK Audio Osmosis also states that digestion begins in the mouth by breaking food into smaller pieces, although its been a while since I've listened to it so I could be wrong on that one.

 

[cornpops21]

According to Wiki (yes, I know, its Wiki): http://en.wikipedia.org/wiki/Digestive_system mechanical digestion starts in the mouth. Also, if I remember the EK Audio Osmosis also states that digestion begins in the mouth by breaking food into smaller pieces, although its been a while since I've listened to it so I could be wrong on that one.

According to Wiki,

"Mechanical and chemical digestion begin in the mouth where food is chewed, and mixed with saliva to break down starches".

So, as I said before, the only thing being broken down in the mouth is carbohydrates. This is the 'mechanical' and 'chemical' digestion that starts in the mouth. Breakdown of all other macromolecules occurs elsewhere.

 

[tco]

Not exactly correct, corn pops. Mechanical digestion begins in the mouth with any type of molecule. Without mechanical digestion, chemical digestion would work, it would just take much, much longer. Enzymes provide specific chemical digestion. That's where the amylases, trypsins, nucleases, and lipases come into play.

To put it this way, I'm confident enough in the previous statement, and confident enough that the book is wrong, that if a similar question were asked on the real MCAT, I would put that the digestion begins in the mouth.

Yes, QuantamChem, that phrase is on the EK Audio Osmosis CD.

 

[tco]

Okay...on page 88 of the 1001 Physics book, the graph that you use for questions 826-841...

When A is opened and B is closed, why does no current flow through the circuit containing resistor e?

 

[futuredoctor10]

Cornpops21/ TCO: Yeah the question (which I don't have in front of me) is testing a very subtle nuance.

Mechanical digestion begins in the mouth, with any type of molecule. This includes proteins, starches, and other molecules. Mechanical digestion refers to the breaking down of food into smaller particles which occurs as you masticate/chew. By increasing the surface area of the food, it makes it easier for enzymes to subsequently (chemically) digest the food.

However, where chemical digestion begins depends on the substance. Chemical digestion of STARCHES begins in the mouth when food is chewed, as salivary amylase can digest the starch into sugar. However chemical digestion of PROTEINS occurs in the stomach where pepsin can exert its enzymatic effects.

if a similar question were asked on the real MCAT, I would put that the digestion begins in the mouth.

I think on the MCAT, they would have to specify. If they said where does mechanical digestion begin, the mouth is correct for ANY type of molecule - protein, starch, etc. If they asked where chemical digestion begins, they would have to specify the molecule as it depends.

Please clarify anything wrong in the above post, and hope this helps!

 

[Excelsius]

I'm pretty frustrated with EK as of right now. They charge you to see the errors in the books that you've already purchased.

I've searched this topic and have seen a few threads complaining about the errors but none doing anything about it.

I'm suggesting that we start a floating or sticky thread for all of the errors that we think we find in the products. This applies to the 1001 questions, study guide, AO series, and anything else that EK makes. It's not to hurt EK's reputation, but rather to be critical of every bit of information that we come across. Face it, every prep company has mistakes in their products, but I think it's a little ridiculous to charge your customers to see your mistakes.

To avoid copyright infringement (I don't know what the rules are exactly for this kind of thing), I'm just going to ask general questions and list the question number or page number after it. Any help would be great.

Bio 1001, page 35:

Question 194

I was always lead to believe (via my Cell book) that carbohydrate attachment to protein was limited to the Golgi. Is this not correct?

I also thought that question 184 was pathetically worded.

Question 202

Maybe I'm just reading too much into it, but I thought that all digestion (mechanical) began in the mouth. Chemical digestion of carbohydrates begins in the mouth and chemical digestion of proteins begins in the stomach. Lipid and nucleotide digestion begins in the small intestine.

Is there anything wrong with what I just said?

Based on the information here, there will be no copyright infringement for you to post the errata for EK. The errata for Audio Osmosis have already been posted on SDN.

Does anyone have access to the errata? In that other thread they say that the website provides no more than 1-2 errata per book. Is that still the case? If so, then it's worthless.

 

[PlatinumPenny]

Hello all,
I'm just starting to go through this books so I'll continue to post errors/questions/request for better answer explainations as I find them:

1st error: pg 12 q#138 the quantum number that specifies the shell level is th azimuthal number, therefore the answer should be B not A (the answer in the back says A)

Also if anyone could explain the answer to #156 that would be great!

Thanks!!

 

[futuredoctor10]

Based on the information here, there will be no copyright infringement for you to post the errata for EK. The errata for Audio Osmosis have already been posted on SDN.

Does anyone have access to the errata? In that other thread they say that the website provides no more than 1-2 errata per book. Is that still the case? If so, then it's worthless.

Bump- anyone have access to the errata? How many errors/bk, particularly in EK Biology (7th ed)? I haven't come across anything blatantly wrong yet just wondering thanks!

 

[tory70]

Paying them to tell us what inaccuracies they sold us is ludicrous.

Why doesn't someone with access to the EK errata forum just dump all those threads here, or throw them out on the net in a torrent or on eDonkey? I'm sure it would be seeded forever. PM me a user/pass and I'll have someone from a country with more lenient copyright restrictions do it legally for us all.

The audio osmosis errata are all over the place here, why not the paper errata too?

 

[robbinblue458]

did anyone ever get the examkrackers books erratas?

 

[ericflem4286]

If you send EK a receipt they will give you a free month access to the errata...unfortunately they do not have alot of errata posted.


I have been disappointed that they did not proofread the books. I have alot of blanks where sqrts should be and random question marks on a diagram printed UNDER a symbol...and sometimes they have the greek letter and sometimes they put just the regular letter....

 

[cartersam]

1st error: pg 12 q#138 the quantum number that specifies the shell level is th azimuthal number, therefore the answer should be B not A (the answer in the back says A)

As I understand it, the azimuthal number is l, which specifies the subshell. The principle quantum number, n, specifies the shell level. I don't seem to have the same edition as you, so maybe I am misunderstanding you or the concept. Can someone else verify or dismiss?

 

[TriagePreMed]

Based on the information here, there will be no copyright infringement for you to post the errata for EK. The errata for Audio Osmosis have already been posted on SDN.

Does anyone have access to the errata? In that other thread they say that the website provides no more than 1-2 errata per book. Is that still the case? If so, then it's worthless.

This is old, but yes, that is the case. Sometimes that 1 or 2 errata is "It should read chromatid, not chromtid." To say their errata is a joke is a severe understatement.

 

[ElliottB]

Granted, I'm using 6th edition of EK books, I have found TONS of mistakes in my books. Several spelling mistakes but more importantly some blatantly wrong "answers" to the practice questions. I'll see if I can compile all of the ones I've found.

 

[cdnwpg]

anyone update on the errata present in the EK 1001 series? Anyone have a comprehensive list?

 

[UofT9919]

MCAT BIOLOGY Errata
Lecture 2
Page #25, Question #2

Posted: Tue Oct 23, 2007 1:57 pm Post subject:

Page #25, Question #2

The final sentence on page 25 should read, "Each nucleotide is bound to the next by a phosphodiester bond between the third carbon of one deoxyribose and the fifth carbon of another deoxyribose."

Page #41, Question #2
Transition and transversion should be defined as follows:

Transition: purine→purine (A↔G) OR pyrimidine→pyrimidine(C↔T)
Transversion: purine→pyrimidine OR pyrimidine→purine (A,G↔C,T)
Page #47, Question #2
"chromtids" should read "chromatids."

LECTURE 9
Page #177

Posts: 459
Posted: Tue May 25, 2010 5:22 pm Post subject:

Page #177

On page 177 of biology, the statement "ontogeny recapitulates phylogeny" is misleading, and is actually the way that Haeckel's refuted recapitulation theory is often stated.

"Haeckel's recapitulation theory claims that the development of advanced species passes through stages represented by adult organisms of more primitive species."

Reference:
Wikipedia contributors. "Recapitulation theory." Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, 21 May. 2010. Web. 25 May. 2010.

Instead, the statement should be as follows: "The early embryonic stage of an organism is often similar to the same embryonic stage of related species, but is not necessarily similar to the adult stages of these species. In other words, species which have an evolutionary relationship typically share the early stages of embryonal development and differ in later stages."


MCAT ORGO
Lecture 1
Page #141, Question #2
The book's explanation should read "B is the only amide with benzene." Since the nitrogen is attached to a carbonyl carbon, the functional group is an amide, not just an amine.
Lecture 4
Page #136, Question #74
In the explanation to Question 74, "enantiomers" should be replaced by "epimers." The products cannot be enantiomers because the original chiral center's configuration is retained. Since they differ at only one chiral carbon, they are epimers.
Verbal Reasoning Test 10 Answer Key Should Read:

Question 9 - pg 375 reads "A", should read "D"
Question 33 - pg 375 reads "A", should read "B"
Question 34 - pg 375 reads "D", should read "A"

 

[UofT9919]

anyone update on the errata present in the EK 1001 series? Anyone have a comprehensive list?

On the website it has no errors for all the 1001 books.

 

[cdnwpg]

On the website it has no errors for all the 1001 books.

Thanks for the list you posted.

So just to be clear: are you saying every question in every 1001 book has a correct answer?

 

[ort77]

The problem states the following

A particle moving from position 1 to position 2 moves along path C ( which is a half circle ). It travels at a constant speed of 5 π m/s. At exactly half way through the trip (1/4 of a circle) its average vertical velocity is:

Diagram shows path C with radius of 5 m.

Ok the answer given of 10 m/s is the final vertical velocity not the average vertical velocity which is given by kinematic equation V avg= Vi + Vf/2.

The correct answer is 5 m/s which is not even provided as an answer choice.

To solve substituted Vf=x/t in the kinematic equation which simplifies to V avg = x/2t.
I then used equation ( speed = d/t ) solved for time and substituted into the simplified kinematic equation to solve for average velocity which is 5 m/s.

 

[Rabolisk]

The problem states the following

A particle moving from position 1 to position 2 moves along path C ( which is a half circle ). It travels at a constant speed of 5 π m/s. At exactly half way through the trip (1/4 of a circle) its average vertical velocity is:

Diagram shows path C with radius of 5 m.

Ok the answer given of 10 m/s is the final vertical velocity not the average vertical velocity which is given by kinematic equation V avg= Vi + Vf/2.

The correct answer is 5 m/s which is not even provided as an answer choice.

To solve substituted Vf=x/t in the kinematic equation which simplifies to V avg = x/2t.
I then used equation ( speed = d/t ) solved for time and substituted into the simplified kinematic equation to solve for average velocity which is 5 m/s.

You are wrong. The correct answer is 10 m/s. Vy avg = deltaY/deltat = 5m/0.5 s = 10 m/2.

I'm afraid I am not exactly sure I follow what you did. This isn't exactly an easy problem, but if you post what you did more clearly, I can probably show where you went wrong.

 

[tartrate]

You are wrong. The correct answer is 10 m/s. Vy avg = deltaY/deltat = 5m/0.5 s = 10 m/2.

I'm afraid I am not exactly sure I follow what you did. This isn't exactly an easy problem, but if you post what you did more clearly, I can probably show where you went wrong.

Hmm...this is an interesting question.

What is wrong with this logic?

Vyi=0m/s (y component of velocity at the top of circle)
Vyf=5m/s (y component of velocity at side of circle)

Vavg=(Vyi+Vyf)/2=2.5m/s

An answer of Vavg=10m/s sounds a bit off. To obtain such an average, we can imagine several scenarios, such as Vyi and Vyf both being 10m/s, or Vyi=0 and Vyf=20m/s. Both sound unreasonable, since speed=5m/s, so the max possible component vector should be 5m/s.

 

[Rabolisk]

Vavg = (Vyi + Vyf)/2 only works when there is constant acceleration. There is constant acceleration in this problem, but not in the y or -y direction. Also, speed is 5π m/s.

 

[tartrate]

Also, speed is 5π m/s.

Haha, this clears things up. On my screen the pi looks like an N, so I thought it was just a typo.

 

[epsilonprodigy]

I think I found another one: EK Physics 1001 #407:

Ball A and ball B are suspended from strings. Ball A swings down in a semi-circle from height h, and hits ball B.
If ball A has a mass that is "much" larger than ball B, and hits a stationary ball B at velocity v, what is the maximum velocity ball B can attain, assuming a perfectly elastic collision?

• In other words, mass of A is approaching infinity, and mass of B is approaching zero.
• Kinetic energy will be fully transferred and conserved, because it is an elastic collision.
• If "all" of ball A's kinetic energy is transferred to ball B, ball A will then come to a stop.
• Ball B will then assume all of the kinetic energy that ball A had, most of which will be accounted for by its velocity, since mass of ball B is approaching zero and is insignificant in comparison to mass of ball A.

I did this with momentum and energy equations both, and got that technically in this case, the velocity of ball B would then also be approaching infinity. But the book says that the limit of ball B's velocity is 2v, or twice the velocity of ball A. I did it accounting for and ignoring gravity (by first equating ball A's potential energy with its kinetic energy and plugging sqrt 2gh in as velocity.) I always get that ball B's velocity would be approaching infinity since the momentum and KE of ball A were approaching infinity. I am going to bring it to a physics professor on Monday, but does anyone see anything wrong with my argument?

 

[Rabolisk]

Don't bring it to your professor, EK is correct. You went wrong by assuming that ball A will stop after the collision, which is not possible for an elastic collision. Check out the thread wikipremed physics for further info.

 

[dougkaye]

I agree w/ original poster re EK. pretty frustrating at times. I have had much better results w/ BR material, but I'm not buying it for bio b/c I already have EK 1001. It's pretty good (at least passage-based), but is in need of some edits by a committee of PhD's.

I wouldn't worry too much about questions like Q. 202 -- you're not missing anything conceptually it's just a badly worded question. I don't think the real MCAT will have such ambiguous questions (at least I hope not!).

 

[Renaissance Man]

I have also been frustrated with EK material. The EK 101 VR passages is great practice but has quite a few errors. Be careful to not just check your answers according to the lists at the beginning of each answer section. Often the list of answers do no match the answers given in the explanation section. For one of the questions, the explanation has all 4 answer choices labeled as "WRONG"

 

[TheMDEmcee]

#268 in the Physics 1001 EK Book. How can it be slowing down if tension is less than the weight. Nevermind...I see that it was moving upwards at first.

 

[NycTm]

I was doing problem 982 on EC 1001 Physics and the answer was POSITIVE 0.44 however I calculated the magnification on lens 2 and it was NEGATIVE 0.33 and according to problem 976 if x is < f 1 and L > f 2 then the final image must be real and inverted so the image is a postive value for lens 2. If the image is positive value and plugging in magnification formula m= - i/o then magnification must be a negative value and the explanation said it suppose to be positive 0.33 which I don't understand.... the lens problems making me go nuts plz help