KEY

NTR 150: Exam 1

General Comments: Because this is a take home exam you have plenty of time to provide thorough (but concise) answers expressed in complete, grammatically correct sentences, so please do so. If I ask you to compare or differentiate between two things, then please explain the characteristics of BOTH things; don’t just explain one thing and assume that I know that the other is the opposite.

  1. What organ systems of our bodies rely primarily on Carbohydrates for Energy? Theoretically, why would it be dangerous to consistently consume a diet low in carbohydrates? If I stop eating all carbohydrates, what macromolecule will my bodyburn for energy, after it exhausts all its carbohydrate reserves? (3)

Nervous system/RBC. It would starve cells that depend on carbs for nutrients. Body will burn fats, then proteins.

  1. In what units do we typically measure the energy content of foods? Which of the three macronutrients that we consume contains the most energy per gram? What is its energy content? (3)

Kcals. Fat. 9 kcal/gram

  1. Name the three classes of macromolecules that we eat. Name the building blocks (monomers) of each one. Is absorption of each of these monomers passive (no energy required) or active (requires energy input), and why? (12)

Carbsmonosaccharides /glucoseActive/cotrasportmoving against its conc. gradient

Fatsglycerol and fatty acidspassivemoving down its conc. gradient

ProteinsAmino AcidsActive/cotransportmoving against its conc. gradient

  1. What types of physical activity (low intensity or high intensity) would you suggest to someone who is trying to lose weight and why? Give an example of an activity you would suggest. (4)

Low intensity, because it focuses calorie burning on stored triglycerides. Smimming, walking, leisure biking. These also do less damage to joints, which are more susceptible to damage due to high resistance or high impact.

  1. Modify your DietAnalysis Plus profile (if need be) to reflect a desire to hold your weight constant. What is your DRI of calories now? Now change your profile to reflect a desire to lose 2 pounds per week. What is your DRI now? How many fewer calories must you consume to lose 2 pounds per week? Does the program suggest that you reduce your intake of each macronutrient by the samerelativeamount, or by different amounts? What percentage of each macronutrient should you eat now? (5)

If you answered all these questions, you got points

  1. Go to the pantry and pick two packaged foods with nutrition labels. List each food item, and the number of calories contained in TWO servings of each one. What percentage of the total calories comes from fats? How many gramsof carbohydrate are in each serving and what percentage of those come from sugars? (8)

If you answered all these and your numbers made sense, you got points.

  1. List three general guidelines that MyPyramid suggests for improving your diet. Which one of these do you personally need to improve on most? (4)
  1. List three signals (hormonal or otherwise) that prompt us to want to eat? Is each one of these physiological or psychological? Does each of these signals originate inside the body or outside? Name two parts of the body that influence our feelings of hunger and satiety. (11)

Sight or smell of food.Initially a physiological signalOriginates outside body

The feel of foodPhysiologicalOutside stimulus

Thoughts of foodPsychological;Inside stimulus

Can interact with any of the above

Low blood glucose levelsPhysiologicalInside

High blood solute conc.PhysiologicalInside

Many other possibilities

Hypothalamus, baroreceptors in stomach, Chemoreceptors in duodenum and stomach, Cerebral cortex, etc…

  1. What would you say to someone who insists that fats are completely useless to us and should be eliminated from our diets, and why? Give specific examples of why you agree or disagree with them? (3)

Fats are necessary, to make phospholipid bilayers of all cells, as a source of energy, as a means of padding joints and organs, as raw material for making hormomes, as a layer of insulation.

  1. Where does mechanical digestion begin? Where does chemical digestion begin? What molecules are digested there, and what enzymes are doing the digesting? (4)

Both mechanical and chemical begin in the mouth. Salivary amylase chemically digests carbs, but all molecules are mechanically digested.

  1. Name two accessory organs that aid in digestion and tell me what hormones or enzymes each produces? What effects does each of those molecules have? (6)

Liver - produces and stores bile - emulsifies fats

Pancreas - sectretes pancreatic amylase, proteases, lipases - digests carbs, proteins, lipids, respectively

Gall bladder - stores bile - emulsifies fats

  1. The stomach is a very acidic environment. Name two functions of that acid. What type(s) of macromolecules are mainly digested in the stomach? Where, in our bodies, do we use those macromolecules? Why are cells of the stomach not immediately digested by the Hydrochloric acid (HCl) that they secrete? (5)

Acid denatures proteins and kill bacteria as well as activating pepsinogen for protein digestion. Proteins digested in stomach. Use them in bloodstream for clotting, fighting infection, maintaining pH; in cell membrane for sensing and responding to environment and as structural support (cytoskeleton); Protein makes up most mass of our muscles; Use it to make bone. Stomach cells are covered by a think, protective layer of mucus.

  1. Differentiate between Type 1 and Type 2 diabetes. Why might someone who eats foods with lots of added and simple sugars have a higher risk of developing Type 2 diabetes than someone who is eats more complex carbohydrates? Discuss a treatment for type 2 diabetes that does not involve medication. (7)

Type I: Pancreatic cells do not produce insulin; it's a genetic disorder

Type II: Body cells are deaf to presence of insulin…eventually, pancreatic cells wear out and do not produce insulin; induced by poor diet choices. Simple sugars have a high glycemic index, which causes blood sugar spikes and crashes, causing pancreas to work harder to produce insulin. A diet low in refined carbs and sugars and daily exercise will improve symptoms of type II diabetes.

  1. Explaintwo reasons why we have sphincters separating each tube (or sack) in our digestive tract. (4)

Need to specialize different parts of the tube for different digestive functions, need to regulate speed of digestion/release of food into each bag.

  1. Differentiate between nutrient dense foods and calorie dense foods and give an example of each. (4)

Nutrient dense foods have a high nutrient:calorie ratio. Calorie dense foods have a low nutrient:calorie ratio. A bowl of fruit or vegetables is an example of nutrient dense food and a bowl of twix bars is an example of a calorie dense food.