Class 8 of Fall 2018 – Chapter 4 – Finish Carbohydrates; Start Early Portion of Chapter 5 – Protein

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Questions from Students about Exam 1

Question:    Professor Dixon,
I just wanted to confirm based off of your recent announcement, we don’t have to cover chapter 5 protein at all for the exam? It is on the review sheet, so I just wanted to make sure.   Thanks!  R

Answer: Hi,   Thank you for the question.  There will be a small part of Chapter 5 on Exam 1.  Essentially the material up to about slide 40 of the protein Powerpoint will be covered.  The Exam was already made up and I thought I could get to that material.  By far, the most material comes from carbohydrates.    Joe Dixon

Question:   Hello Professor,
I had a question about the first exam. How in depth do you want us to read into your book (Obesity Explosion) for the first exam?  Thanks, A

Answer:  Hi A,    Since I haven’t gotten to the material in the book, no questions will come from that material.   However, the book develops some of the lecture material more completely.  But really, there is not enough time to present lecture material from both sources, so just enjoy the book if you can and wish to.  Thanks for the question!   Joe Dixon

Question:   Hi professor Dixon,   This was just a curious question unrelated to the exam. I wanted to ask you after class but you’ve must be surrounded by people asking questions on the exam. Are diabetes more of a result of hereditary/genetic issue or more of an age issue?  Thanks.   Best, A

Answer:  Dear A,   This is a great question.  Because Type 2 diabetes rates are climbing and highly associated with obesity – there is definitely a weight – genetic susceptibility aspect to it.  After all, humans haven’t changed their genes that much in 50 years or so. And of course, there is an age aspect, too. More Americans are living longer.  As you age, things stop working so well.  So my sister is in her 70s and is not heavy, yet she has type 2 diabetes. It might be that the beta cells in her pancreas don’t work as well as they use to.  Also, there is an indication that immune diseases are increasing.  So I think it is all these things together.  Although thin people do get type 2 diabetes, it is a very small percentage compared to heavy people.    Joe Dixon

Question:  I have a brief question from study guide.
What are the three peptide hormones involved in signaling during digestion that we need to know? Are they Enteric Hormones, Gastrin , secretin, and cholecystokinin?
And how detailed do we have to memorize the system of digestion? Do we focus on gastric or every part in the digestion such as esophagus, large intestine, cecum, appendix, rectum, saliva, salivary amylose etc….
Because I only see you mention some about gastric and villi in PPT, I am not sure what we need to prepare for exam 1.  Sorry for bothering.
Have a good day.  Sincerely Yours, T

Answer:   Hi T,   Thank you for the question.  This year I did not go through digestion in Chapter 3 so thoroughly as some years.  So I did not emphasize it on the exam.  The most important aspects for now are digestion of carbohydrates – pancreatic amylase breaks down the long chains to disaccharides, and then maltase, secreted from the enterocytes, breaks down the maltose to individual glucoses.  Then the glucose is taken into the enterocyte by a transporter that requires sodium.  These transporters are very similar to the protein I highlighted in the first protein lecture on Monday.  The proteins go through the entire membrane and they usually have tunnels built into them.

So really, if your quickly read the text and concentrate on the above, you should be OK. Excellent question! And certainly no bother!  Sincerely,  Joe Dixon

Questions:   Good Afternoon!  I had some questions while I was studying,How many kcal per gram does alcohol have?
I know 4kcal per g of carb and protein
and 9 per g of fat.

What are insulin’s two major effects on target cells?
Im not exactly sure what you mean by target cells

Thank you for clearing this up !!

Answers:   Hi A,    Alcohol has 7 Kcal/gram –  this year I did not emphasize this and it is not on the exam.  But I am always amazed how many Kcal there are in a glass of wine.  Wine, Red Table, Cabernet Sauvignon 5 oz svg. – 122 kcal

Vodka, Distilled, 80 Proof 1.00 fl. oz. – 64 kcal
Vodka, Distilled, 80 Proof 3.01 fl. oz. – 193 kcal

Concerning the two major effects of insulin on target cells.  First target cells are the cells the hormone affects.  For example, secretin secreted by the endocrine cells in the upper intestine, pretty much primarily target the pancreatic acinar cells, the cells that secret digestive enzymes:  “The pancreatic acinar cell is the functional unit of the exocrine pancreas. It synthesizes, stores, and secretes digestive enzymes. Under normal physiological conditions, digestive enzymes are activated only once they have reached the duodenum.

However, insulin probably affects every cells to a certain degree.  But liver cells and muscle cells are especially sensitive to insulin.  In most cells, insulin has 1) a stimulatory effect on protein synthesis; and 2) it sends intracellular signals that affect metabolism.  (In muscle, insulin specifically increase glucose uptake int muscle cells.

Thank you for the good questions.   Joe Dixon

Questions:   Hello Professor,  I had a few questions I was wondering if you could answer or even better explain.  From the study guide I was having difficulty answering the following and was wondering if you could help me so I may be better prepared for the exam.  Chapter 3:  Does the cell use little fires for energy?

Chapter 4:  When did sucrose use become common in the diet of the British?

And then also in Chapter 5 I was wondering how many of the questions you wanted us to direct our focus on as I remember you saying we only needed to know 7 pages or 40 slides I believe.
Answers: Hi A,  Thank you so much for your questions.

The first one is a thought question – what keeps us warm – especially in the winter?  We went over the mechanism of fire and certainly fire can keep us warm if we are close enough.  Most cells are extremely small – the liver hepatocyte is only 20 microns in diameter – not much room for a fire.  This question has deep ramifications – is the obesity explosion due to the fact that we now have central heating and hot water for showers?

In the lecture I mentioned that sugarcane was domesticated in Indonesia about 1 to 2 thousand BC, and it slowly traveled to Europe.  The first mention of sugar in Europe occurred in Venice in the 900s AD.  Certainly the Romans did not have sugar.  The common folk of Great Britain did not have sugar until somewhere between 1650 and 1750.  By 1750, even common folk in Britain used sugar in their tea and coffee.  And soon after Americans did too. So the answer is about 1750 for sure – relatively late in the history of agriculture.

There are a few questions on protein on the exam – and yes – I only went over the first 40 slides in the lecture on Monday.  Remember, you don’t need to know structures of the amino acids.

Thanks for the questions!  Sincerely, Joe Dixon



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