TBR BIO Section 8 questions 45 and 50

[anomedic]

---

Members don't see this ad.

View attachment figure 1.docx

Please see attachment for figure and questions.

My concerns are:

I don't really understand the figure, what does Net de novo oxidation mean? does it indicated Net de novo lipogenesis (DNL) ?

For Question 45, choice B, how can you tell based on the chart that glycogen stores are filling before DNL begins?
For Question 45, choice D, what indicator in the figure leads to the conclusion that DNL is used to disposed of excess carbohydrates consumed during days 5-10?
And since C is the correct answer choice for this question, how can you tell that glycogen stores are eventually saturated?


For Question 50 the explanation says A is correct because the first few days of CHO feeding mainly increase the glycogen stores and not the fat stores. How can this be inferred from the figure? How can you read fat stores from this figure?

All help would be greatly appreciated.

 

[osprey099]

View attachment 20501

Please see attachment for figure and questions.

My concerns are:

I don't really understand the figure, what does Net de novo oxidation mean? does it indicated Net de novo lipogenesis (DNL) ?

For Question 45, choice B, how can you tell based on the chart that glycogen stores are filling before DNL begins?
For Question 45, choice D, what indicator in the figure leads to the conclusion that DNL is used to disposed of excess carbohydrates consumed during days 5-10?
And since C is the correct answer choice for this question, how can you tell that glycogen stores are eventually saturated?


For Question 50 the explanation says A is correct because the first few days of CHO feeding mainly increase the glycogen stores and not the fat stores. How can this be inferred from the figure? How can you read fat stores from this figure?

All help would be greatly appreciated.

For question 50, I can't see the figure but the answer is A because when you are on a low carb diet, you cannot increase fat stores because fat stores increase when you are eating a lot of carbs and all the carb stores are filled up so your body makes your fat stores load up. C is incorrect because you want glycogen stores to increase during an athletic event so you have more energy and obviously D is incorrect because increased endurance is beneficial.

For question 45, I do not know what de novo lipogenesis means but it must be referring to some sort of lipid (fat) production because it has the word "lipogenesis" in it. Therefore, B is true without even needing to refer to the diagram because glycogen stores fill first before fat stores. D is true for the above reasoning as well and obviously A is true because more carbs = more carb oxidation. By POE, you can arrive at choice C but if you use the graph, then I'm guessing it's choice C because the dashed line indicating glycogen storage potential is not shaded..

 

[anomedic]

Thanks Osprey009! I understand the logic behind your explanations, and it has cleared things up. However, I'm still somehwat frustrated I can't interpret the graph in the areas I highlighted in my first post to arrive at those same results. For question 50, the diagram is the same as that for question 45.

 

[circulus vitios]

Question 45: Glyocogen storage saturation can be seen on days 9 & 10 -- the little sliver that extends beyond the dotted line.

The graph made absolutely no sense until I read the explanations. Maybe this is why people recommend against using TBR Biology.

 

[Singhp03]

Question 45: Glyocogen storage saturation can be seen on days 9 & 10 -- the little sliver that extends beyond the dotted line.

The graph made absolutely no sense until I read the explanations. Maybe this is why people recommend against using TBR Biology.

I encountered the same thing, the graph was confusing until I started reading the questions, and C seemed clearly invalid since day 9-10 clearly show saturation. If it was not saturated by day 9-10, you would see an Exponential upward increase. good quesiton👍

 

[anomedic]

Thanks for your response guys! I'm still not entirely satisfied with the invalidity of choice C (question 45), simply because I don't know what they mean by net de novo oxidation. I can see that net de novo oxidation extends beyond carbohydrate intake during days 9-10, but WHY does this mean that glycogen stores are saturated?
Furthermore, I don't see anything in this figure that would allow me to read fat stores. Yet, the explanation to answer 50 says "the first few days of CHO feeding mainly increase the glycogen stores and not the fat stores". Does anyone know how you can tell this from the figure? or is it just a rule of thumb that fat stores can start increasing only after glycogen stores have been fully saturated.