TBR Bio Book 2 - Some questions, doubts.....

[sps27]

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Some question that I have doubts with, in TBR, Bio.

1) Take a look at Passage 5 based on Calvin cycle, page 237 in TBR book 2, question 25 in particular. The ans for this question is given as B. Is that correct? The water molecules are not balanced in choice B. Ans C, which I choose has the water molecules balanced but ATP molecules are not balanced. But the book choose B, based on ATP units, not sure why. I apologize to those who don't have TBR. This particular passage has diagrams and big equations.

2) Q: 36 on page 240, TBR Book 2 Bio. Where is the enzyme lactase secreted during digestion, in lactose intolerant individuals. A) The mouth, B) The Stomach C) The Small Intestine D) The Colon. Ans given is C. --- Is it not true that if a person is Lactose intolerant, they lack Lactase and Lactose gets broken by Bacteria in the colon. In that case, should not the ans be D ?

3) Q: 10 on page 232. TBR Book 2 Bio.

Delta G = - 👎(F)(Delta E)
Fumurate + 2h + 2e ---------> Succinate Delta E = +0.03
FAD + 2h + 2e ---------> FADH2 Delta E = -0.22

We can conclude that reaction involving conversion of "Succinate to Fumurate"
A) Delta G = -0.5(F)
B) Delta G = +0.5(F)
C) Delta G = +0.1(F)
D) Delta G = -0.1(F)

The ans given is B. I think the ans should be A, not B. At least from the equations above, that is what I can think of. If you reverse the first eqn, multiply both eqn by 2 and then add them together, you should get Succinate to Fumarate. And if you do all of that, you get -0.5.

 

[MTHFR]

Some question that I have doubts with, in TBR, Bio.

1) Take a look at Passage 5 based on Calvin cycle, page 237 in TBR book 2, question 25 in particular. The ans for this question is given as B. Is that correct? The water molecules are not balanced in choice B. Ans C, which I choose has the water molecules balanced but ATP molecules are not balanced. But the book choose B, based on ATP units, not sure why. I apologize to those who don't have TBR. This particular passage has diagrams and big equations.

2) Q: 36 on page 240, TBR Book 2 Bio. Where is the enzyme lactase secreted during digestion, in lactose intolerant individuals. A) The mouth, B) The Stomach C) The Small Intestine D) The Colon. Ans given is C. --- Is it not true that if a person is Lactose intolerant, they lack Lactase and Lactose gets broken by Bacteria in the colon. In that case, should not the ans be D ?

3) Q: 10 on page 232. TBR Book 2 Bio.

Delta G = - 👎(F)(Delta E)
Fumurate + 2h + 2e ---------> Succinate Delta E = +0.03
FAD + 2h + 2e ---------> FADH2 Delta E = -0.22

We can conclude that reaction involving conversion of "Succinate to Fumurate"
A) Delta G = -0.5(F)
B) Delta G = +0.5(F)
C) Delta G = +0.1(F)
D) Delta G = -0.1(F)

The ans given is B. I think the ans should be A, not B. At least from the equations above, that is what I can think of. If you reverse the first eqn, multiply both eqn by 2 and then add them together, you should get Succinate to Fumarate. And if you do all of that, you get -0.5.

Lactose intolerance doesn't necessarily mean complete lack of lactase, it could also be due to deficiency in lactase or a defective, albeit still present and secreted form of lactase, but in any case the only possible answer is C. Digestive enzymes, for the most part (aside from amylase which is secreted both in the mouth and again in the small intestine since it is broken down in the stomach, and probably a few other obscure, not-relevant-for-MCAT enzymes as well) are secreted in the small intestine. They are not secreted in the colon, a site of water reabsorption and subsequent poopie consolidation, and lactase isn't secreted in the mouth or stomach.

For #3, you were right to switch the equation around. Next, add them together (-0.03 + -0.22 = -0.25). Finally, double that (due to the two electrons, n, involved and plug it into the answer choices (-(2)(F)(-0.25) = +0.5F). I think you simply forgot a step in your arithmetic.

 

[sps27]

For #3, you were right to switch the equation around. Next, add them together (-0.03 + -0.22 = -0.25). Finally, double that (due to the two electrons, n, involved and plug it into the answer choices (-(2)(F)(-0.25) = +0.5F). I think you simply forgot a step in your arithmetic.

Now that you have spelled it out, it all makes so much sense and looks easy. Mental math has screwed me before. I can't afford to make such mistakes......and you are right about Lactose as well. 'Intolerance' does not mean they are deficient. I have to remember that........