BPK 143 Chapter Notes - Chapter 12: Intramuscular Fat, Carbohydrate Metabolism, Myocyte

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tealrabbit156

2 Mar 2013

School

Simon Fraser University

Department

Biomedical Physio & Kines

Course

BPK 143

Professor

Tony Leyland

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Document Summary

Factors governing the selection of fuels for muscular work. Carbohydrates and fats are the major fuels used during exercise. Percentage utilization of fats, carbohydrates, and proteins in energy metabolism during exercise depends on the following factors: intensity of exercise. At rest, about two-thirds of the atp produced in muscle tissue is derived from the breakdown of fatty acids, while the other third is derived from the breakdown of glycogen and glucose. Protein is not used as an energy source unless you are severely deficient in carbohydrate and not adapted to such a diet. Typical muscle glycogen utilization at various exercise intensities: duration of exercise. At exercise intensities between 65% and 85% of. , it commonly takes 80 120 minutes to deplete muscle glycogen stores. For athletes performing long-duration events, there is a real danger that they will deplete too much glycogen before their event is completed. As exercise duration increases, the proportion of energy production from fats begins to increase.

Related Questions

Question 2

The DSM-IV describes an "Eating Disorder Not OtherwiseSpecified" as:

self-starvation that leads to severe nutrient deficiencies

compulsive eating disorder

a variety of atypical eating behaviors used to maintain or lowerbody weight

recurrent episodes of extreme overeating followed byself-induced vomiting

Question 3

The nutrition paradox refers to:

coexistance of underweight and obesity in the same region

too mucn vitamin A in foods rich in vitamin C

poor countries that have excessive rates of obesity

obese children from nonobese parents

Question 4

Which of the following represents a nutrition transition?

decreased reliance on carbohydrates

increased consumption of sugar

increased availibility of maize over corn

lower-fat subsistence crops

Question 5

Which of the following is NOT part of the GOBI initiative?

breast-feeding

obesity control

immunization

growth monitoring

Question 6

Which of the following is a response to the drawbacks of theGreen Revolution?

WIC

high yield varities of grains

sustainable agriculture

biotechnology

Flag this Question

Question 70.5 pts

Worldwide, the major cause of undernutrition is:

unequal distribution of food

diseases (like AIDS)

poor farming practices

overpopulation

Question 8

Which agency monitors all confirmed causes of food-borneillness?

EPA

FDA

CDC

USDA

Question 9

In which of the following environments does Clostridiumbotulinum flourish?

acidic

alkaline

<40 degrees F

> 140 degrees F

Question 10

Which of the following is an example of food intoxication?

Norwalk virus

Salmonella

hepatitis A

Clostridium botulinum

Question 11

All of the following describe characteristics of the femaleathlete triad EXCEPT

menstrual dysfunction

disordered eating

hypertension

osteoporosis

Question 12

Impulsive, low self-esteem, seeks attention, extroverted, anderratic describe personality traits of:

bulemia nervosa

binge-eating disorder

obesity

anorexia nervosa

Question 13

Obsessive-compulsive, perfectionism, socially inhibited,compliant, and emotionally restrained describe personality traiatsof

binge-eating disorder

anorexia nervosa

bulimia nervosa

obesity

Question 14

The Institute of Medicine recommends a minimum of ________minutes of physical activity each day for adults.

Question 15

Regular exercise reduces the risk of type 2 diabetes by all butwhich of the following?

decreases the cellular uptake of blood glucose

delays the onset of complications of type 2 diabetes

increases control of blood glucose

enhances the action of insulin

Question 16

What is meant by the overload principle?

stretching a muscle group beyond the joint's healthy range ofmotion

improving fitness by placing extra physical demand on thebody

complete depletion of the body's glycogen

subjecting the body to inappropriately high stress

Question 17

The acronym FIT stands for:

fatigue, intensity, and training.

flexibility, increase, and training.

fitness, increase, and time.

frequency, intensity, and time.

Question 18

To achieve cardiorespiratory fitness it is recommended thattraining should occur ________.

3-5 days a week

daily

more than 5 days a week

2-3 days a week

Question 19

To achieve and maintain physical fitness, exercise intensityshould be ________ of the maximal heart rate.

35-50%

15-25%

25-30%

50-80%

Question 20

In which of the following types of exercise would CP (creatinephosphate) be an important source of energy?

biking up a mountain

sprinting in the 100-meter race

running a 10-kilometer road race

playing in a football game

Question 21

Which is NOT an advantage of aerobic metabolism over anaerobicmetabolism?

Much more energy is produced for every fuel molecule.

Aerobic metabolism acts more quickly.

Harmful metabolites do not accumulate as quickly.

A greater fuel supply is available.

Question 22

An unwanted effect of an overly vigorous warm-up is:

increased muscle temperature.

glycogen depletion.

increased body temperature.

reduced stress levels.

Question 23

Each day Bill power-walks for 45 minutes. Which fuel source(s)provide(s) energy during this activity?

amino acids

glucose

fatty acids

fatty acids and glucose

Question 24

The main disadvantage of using fat as a fuel is:

the body's limited storage capability.

its low energy density.

its slow metabolic breakdown.

the limitation of anaerobic metabolism.

Question 25

Joseph plays basketball for his high school team and he isconcerned that he is not consuming enough kilocalories to supporthis activity. Which of the following would be the best indicatorthat he is not consuming adequate kilocalories?

His hemoglobin is low.

His blood glucose levels are low.

His performance has been impaired.

He is losing weight.

Question 26

Rachel is a gymnast who trains 2 hours/day on average. Shesupports her daily activity by consuming 2,500 kilocalories perday. How many kilocalories should she be consuming fromcarbohydrate sources?

1,500-1,625 kilocalories

1,125-1,300 kilocalories

1,300-1,500 kilocalories

1,625-1,750 kilocalories

Question 27

The best time to replenish glycogen stores is:

the day after exercising.

a few hours before exercising.

the day before exercising.

right after exercising.

Question 28

In which of the following events would carbohydrate loading bethe most beneficial?

cross country skiing

baseball game

weight lifting

100-yard dash

Question 29

Osteoporosis, eating disorders, dehydration, and heat illnessare all possible consequences of:

the Zone diet.

carbohydrate loading.

inadequate dietary intake.

overtraining.

Question 30

Which of the following is the most potentially harmful?

heat syncope

heatstroke

heat cramps

heat exhaustion

Question 31

Which of the following athletes would be LEAST likely to developiron deficiency anemia?

a female marathon runner

a male basketball player who is a vegan

a female gymnast

a male distance swimmer

Question 32

Amenorrhea, sometimes seen in female athletes, is:

the onset of menstruation.

osteoporosis.

the loss of the menstrual cycle.

frequent diarrhea.

Question 33

Some athletes believe that caffeine can enhance athleticperformance because it has been shown to:

increase the transport of amino acids to exercising muscle.

increase muscle flexibility and strength.

increase the use of fatty acids as a fuel source.

regenerate ATP for energy.

Question 34

Which of the following ergogenic aids has been shown to enhanceshort-term exercise and resistance training?

chromium picolinate

creatine

carnatine

ephedrine

Question 35

Consuming processed foods as opposed to whole foods decreasesthe risk of contracting a food-borne illness.

True

False

Question 36

Regular physical activity can increase HDL-cholesterol.

True

False

Question 37

Nearly 1 in 6 American adults reports getting no physicalactivity at all.

True

False

Question 38

Lactic acid is a by-product of high-intensity exercise.

True

False

Question 39

Training can enhance the ability to store glycogen.

True

False

Question 40

The primary fuel source utilized in both anaerobic and aerobicexercise is protein (amino acids).

True

False

Question 41

Studies suggest that athletes need to consume more than 2grams/kg of protein each day to maintain muscle strength.

True

False

Question 420.5 pts

Refigerating or freezing foods will kill any bacteria present inthe food.

True

False

Question 43

Most athletes do not consume enough protein to support theiradded physical activity.

True

False

Question 44

Thirst is a very reliable indicator of dehydration.

True

False

The people of Malaysia belong to three communities: the local people called Malays, immigrants from South India called Tamils, and immigrants from China. During the early 20th century, the Malays lived mainly in coastal villages, the Tamils worked on rubber estates, and the Chinese worked in tin mines. In general, the people were very poor and they consumed a limited variety of foods.[1] Rice was the staple diet of all three communities and therefore the key source of caloric and nutrient content. Malays typically grew their own rice and dehulled it before consuming it; dehulling partially removes the aleurone layer of the rice seed. Following their South Indian food habits, the Tamils ate parboiled rice, and the Chinese ate polished white rice imported from Thailand. It was found that among the three Malaysian communities, the Chinese community was much more prone to suffer from some degree of sub-optimal thiamin intake. Out of every 1,000 Chinese inhabitants, about 120 had mild thiamin deficiency, about 80 had severe thiamin deficiency, and about 16 people had died of it. Suboptimal intake of thiamin was rare in Malays and was not reported at all in Tamils.[1] Thiamin, also called Vitamin B1, is required for all tissues, and its deficiency causes the disease Beriberi. Less severe deficiency results in non-specific symptoms such as weight loss, malaise, irritability, and confusion. Although the origin of the word Beri-beri is disputed, it is believed to be a Philippine word meaning âI canât, I canâtâ and was probably coined to refer to the lack of neuromotor coordination in people afflicted with this disease.[2] Thiamin is water-soluble and is stable in the acidic medium. It is unstable to heat, oxygen, and UV light in neutral and alkaline medium. The active form of thiamin is thiamin pyrophosphate (TPP). This active form is a cofactor for pyruvate dehydrogenase and transketolase enzymes that are involved in the metabolism of carbohydrates. These enzymes play an important role in the biosynthesis of a number of cell constituents such as neurotransmitters, pentoses, and reduced equivalents, used in oxidant stress. The human body cannot store thiamin and therefore requires a continuous supply of the vitamin. The thiamin in an individual on a thiamin-free diet typically depletes in fewer than two weeks. Thiamin absorption is affected by compounds, called thiamin antagonists or anti-thiamin factors, that alter the structure of thiamin. These compounds include alcohols, polyphenols, flavonoids, and thiaminase, a heat labile enzyme found in certain foods.[2] In affluent countries, where the diet is rich in thiamin, the most common cause of thiamin deficiency is excessive alcohol consumption. Alcohol intake affects thiamin status in two ways. First, alcoholics get a significant percentage of their daily energy intake from alcoholic beverages, which are nutrient deficient. In other words, alcoholics replace their consumption of nutrient dense foods that are part of their normal diet with the consumption of nutrient deficient alcohol. Second, alcohol inhibits the intestinal ATPase involved in the absorption of thiamin.[4] Sub-clinical thiamin insufficiency associated with excessive alcohol consumption produces an encephalopathy called Wernicke-Korsafoff syndrome. Patients with this syndrome have a higher than normal incidence of abnormal transketolase, which has a very low binding affinity to TPP. This problem can be overcome by putting patients on high-dose thiamin therapy. Some patients, however, might have a form of abnormal transketolase that does not bind at all with TPP. Such people do not respond to high-dose thiamin therapy.[4] Thiamin deficiency is observed in individuals who have low thiamin intake and a diet rich in polished rice, especially if their diet also consists of anti-thiamin factors such as tea, coffee, raw fermented fish, and betel nuts. The minimum amount of thiamin needed by the body can increase because of increased physiological or metabolic demands arising from pregnancy and lactation, heavy physical exertion, illnesses like cancer, liver diseases, hyperthyroidism, and surgery. Since TPP is required for carbohydrate metabolism, the recommended dietary allowances for thiamin are based on the assumption that its intake is related to total energy intake. The recommended dietary allowance in the United States is 0.5 mg/1000 Kcal.

Questions
1. Thiamin deficiency was observed only in the Chinese community even though all three
communities had the same staple (rice) diet. Explain.
2. On packages of enriched rice sold in supermarkets, the rice preparation directions state that the
rice should not be washed before cooking. Explain.
3. Severe metabolic acidosis caused by high levels of lactate is often associated with thiamin
deficiency. Explain.
4. Provide two plausible explanations for what might cause above normal levels of pyruvate in blood
and urine. How can one determine which of the two explanations is correct?
5. Why does thiamin utilization increase among cancer patients?
6. A negative correlation exists between the need for thiamin and the amount of fat in the diet.
Explain.

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OOC #3 Due: Monday, March 19, 2018, 5pm CASE: The Runnersâ Experiment, Integration of Metabolism Case Study Overview This case is designed to help students understand the importance of glucogenic substrates in human metabolism and the interconnections between carbohydrate, fat, and protein metabolism in humans. Because the focus of this case is the integration of metabolic pathways, we recommend that students be exposed to the topics through Chapter 23 (Chapters 19 and 20 are not necessarily required); referring to Sections 27.4 and 27.5 of the textbook (Stryer 8E) before beginning this case may also be useful for this out-of-class assignment. You may work individually or in groups to complete this case study, but you must submit your own work in Canvas (âEnter your ooc #3 answers hereâ). You are encouraged to refer to your textbook throughout the case, and internet access is permitted, although it is not necessary for the completion of the case. You will need to iteratively acquire, analyze, and integrate data as you progress through the case and answer assessment questions found throughout the case. You are encouraged to carefully consider investigation options; guessing is discouraged. Your score on this assignment will reflect correct answers. Learning Objectives This case is intended for remediating or extending student capabilities in these difficult topics: 1) The real-world applications of the study of human metabolism. Students will: â¢ Use real biochemical tests to evaluate and âsolveâ a metabolic disorder case. â¢ Consider the importance of factors like personal and family history, diet, medications taken, and symptoms in solving a biochemical case. 2) Critical and interrelated pathways in human central metabolism. Students will: â¢ Review carbohydrate, lipid, and amino acid metabolic pathways. â¢ Review fatty acid metabolism and recognize the distinctions between the oxidation of even- and odd-chain fatty acids. 3) Connections between carbohydrate, fat, and protein metabolism in humans. Students should be able to: â¢ Outline and explain the importance of glucogenic substrates in human metabolism. o Understand why the inability to convert acetyl-CoA to glucogenic substrates in humans leads to protein wasting. o Explain the importance of ketone body formation and ammonia transport/disposal in human metabolism. â¢ Explain the important differences between the metabolic intermediates produced by the oxidation of even- vs. odd-chain fatty acids. 4) Practice critical thinking skills involving data. Students will: â¢ Evaluate data provided by metabolite and enzyme tests. â¢ Integrate multiple pieces of biochemical data. âThe Runnersâ Experimentâ, Integration of Metabolism Case Study Introduction Race day had come. âFinallyâ thought Michael. He was a marathon veteran, but this race was different. He felt terrible: âProbably a coldâ he had told his girlfriend, but nothing was going to stop him today. Today was the day he would finally prove his brother Dave wrong and he had 26.2 miles to do it. The two young men shook hands shortly before the race started. Dave was thin, like Michael, but not âgauntâ. Michaelâs girlfriend Jan, had actually used that word to describe Michael a few days prior. His cheeks had receded recently. âSeriously, you should stop this... you look terrible!â Jan said. âItâs just pre-race training... and of course, the experimentâ he thought. âIâll be fine!â he assured her with a wink before leaving their apartment. âToday is the day we settle this!â he now called to Dave as they took off down the race route. But Dave only smiled and accelerated to leave Michael behind. As Dave disappeared into the crowd, Michael called out: âItâs not about speed! Itâs about endurance dummy!â, but Dave was too far ahead to hear. 1 For weeks they had been talking about their plan, the experiment, and how much money they were going to make. Michael smiled to himself and then put his head down to focus on the run. Dave was long gone but Michael was certain that he would see him again soon enough... that is, until he started to feel dizzy... Juan had worked at several marathon-medical tents before. It was always the same: people try to run the race without training properly, and they end up at the tents. Most are dehydrated and exhausted, others just âhit the wallâ, when their bodies run out of glycogen and some even have heart attacks, mainly due to poor training. This particular day wasnât very hot, but it didnât take much to overwhelm people during a marathon. Working the races was a nice excuse for an ER doctor to get out in the sun for a few hours on the weekend and a chance to help some people... for Juan that was as addicting as running. Two hours in and Juan was bored. The chatter on the radio was the same as always: dehydrated runners at both tents, and one elderly person from the crowd had to be treated for heat exhaustion, just from standing too long... so far it was a slow day. Suddenly the radio chatter picked up. The ambulance from the medical tent at the 10-mile mark was headed in to his direction with a young man who was unresponsive. The incoming call was interrupted by a second voice: the ambulance from the medical tent at the 20-mile mark ALSO had an unresponsive man. âWhat are the odds?â Juan thought. The two ambulances arrived simultaneously. Runner ID tags identified both subjects immediately: Michael and Dave Gard, two brothers! Dave was unconscious, but otherwise looked OK. When Juan saw Michael however, he was startled into action; he would not have guessed that the two men were brothers! You are a biochemistry student who is shadowing an ER doctor who has just admitted two young males. One man, Dave, regained consciousness prior to arrival, while the other, Michael, regained consciousness only after arriving at the hospital and is still delirious. Neither man was particularly dehydrated, having drunk water during the race. Both have been stabilized, but blood and urine samples from before they were treated are available for you to test. It is up to you to discover what might be the problem with the two brothers. Consider that there are two primary questions to answer in this case study: â¢ What caused both brothers to lose consciousness during the race? Here are some potential biochemical hypotheses for you to consider: Ketoacidosis Lactic acidosis Ammonia toxicity Mercury poisoning Acute hyperglycemia due to type II diabetes Hypoglycemia Phenylketonuria Maple-syrup urine disease â¢ What is the biochemical explanation for the differences in the conditions of the two brothers? You may now conduct additional investigations to explore the details of this case and to test hypotheses so that you can eventually answer both of these questions. Note: for this case, you are encouraged to explore ALL possible investigations to gather as much information as possible to explain the brothersâ conditions before finishing the case by continuing to the final assessments. You will be scored on this exercise based on your answers to assessment questions found throughout the case so you are STRONGLY encouraged to use your textbook to complete this exercise; you may also use the internet as necessary. RECOMMENDED INITIAL INVESTIGATIONS: Evaluate the overall physical appearance of the two brothers including insect bites or other injuries Results: The men are identical in height. Dave has a lean, athletic build, but is not unusually thin for a long- distance runner. Michael, on the other hand, appears to be severely emaciated. You note sunken eyes and 2 cheek bones and protruding ribs, indicating a lack of not only body fat but also muscle tone. No injuries or other abnormalities are apparent. Investigate past medical history including current medications Results: Neither man smokes, drinks, or uses illegal drugs. They are not on any medications. Dave reports that Michael had not been feeling well prior to the race, but had thought that he was âjust coming down with a cold or somethingâ. Given that the men were both avid marathoners, no one apart from Michaelâs girlfriend Jan had been concerned about Michaelâs recent and rapid weight-loss. Investigate the relationship between the two brothers in greater detail Dave explains that the two of them are not just brothers, they are best friends and despite their grossly different appearances at the moment, they are identical twins! He says: âBefore we started our experiment just a few weeks ago, most people couldnât tell us apart!â Dave mentioned something about an experiment; you could ask him more about this. The following is now a new investigation option: Ask Dave about âThe Experimentâ Results: Dave tells you that the two brothers had been planning to develop a new dietary supplement company, Gard Nutraceuticals, selling purified fish oil, which they believe is a health panacea. They disagreed on the best fish oil to bring to market however, so the men had been conducting an experiment to settle this disagreement. Both had been taking fish-oil pills along with a multi-vitamin for the past three weeks while they tapered back their training runs dramatically. When you press Dave about what else he and Michael were eating, shockingly he says ânothingâ. They had been eating enough fish oil to consume 3000 Calories per day, which is normal for marathon training (approximately 330 grams of fish oil per day). Each brother had been touting a different product: Michael was taking wild-caught salmon oil, while Dave was eating oil from a flathead (striped) mullet. The bet was to determine whether fish oil was an adequate caloric- replacement supplement for athletes, and whose product was better. To make the decision unambiguous, the pair was going to use the marathon to decide the winner since the boys had nearly identical marathon times in previous races. The details of this fish-oil experiment may merit further investigation. In particular, some fish contain high levels of mercury, which could be toxic if consumed in large quantities. You now have the following two new investigation options available to you: Test hair for common toxins (heavy metals and narcotics) and ask Dave about mercury contamination in the supplements Investigate the composition of the dietary supplements the subjects were eating SECONDARY INVESTIGATIONS: DETERMINE BLOOD SERUM CONCENTRATIONS OF: Common immunoglobins (IgG, IgA, IgM) and ammonium (NH4+) levels Results for Dave: All values for immunoglobin concentrations are at the low end of the normal ranges, which is normal for someone finishing a marathon. (normal ranges: [IgG] = 560â1800 mg/dL; [IgM] = 45â250 mg/dL; [IgA] = 100â400 mg/dL); [NH4+] = 20 mmol/L (normal range: 12- 48 mmol/L) Results for Michael: Severely low levels of IgG, IgM, and IgA. [NH4+] = 67 mmol/L (normal range: 12â48mmol/L)

1. Which of the following might cause the concentration of ammonium ions found in the blood to increase? (Select ALL that apply!) A. An increase in the rate of fatty acid catabolism by Î²-oxidation B. An increase in the rate of protein and amino acid catabolism C. An increase in the rate of glucose oxidation through the pentose phosphate pathway D. An increase in the rate of glucose oxidation through glycolysis and the citric acid cycle E. A defect in the urea cycle F. Galactosemia G. Lactose intolerance

Free fatty acids (FFAs) and triacylglycerides (TAGs) Results for Dave: 500 mg/dL FFAs (normal range: 190â420 mg/dL); 190 mg/dL TAGs (normal range: 40â150 mg/dL) Results for Michael: 660 mg/dL FFAs (normal range: 190â420 mg/dL); 230 mg/dL TAGs (normal range: 40â150 mg/dL) Glucose and Glycosylated Hemoglobin (HbA1c as a marker) Results for Dave: [Glc] = 39 mg/dL (normal range: 70â110 mg/dL) Note: This value indicates severe hypoglycemia; HbA1c = 4.4% (normal range: 4â6.5%) Results for Michael: [Glc] = 31 mg/dL (normal range: 70â110 mg/dL) Note: This value indicates severe hypoglycemia; HbA1c = 3.2% (normal range: 4â6.5%)

2. When a typical person runs a marathon, they do not become severely hypoglycemic to the extent that either Michael or Dave did. Some people consume carbohydrates during the race in the form of foods, gels, or sports drinks that have added sugar. However, even when dietary carbohydrates are not consumed during the race, how does the body of a healthy individual maintain adequate levels of blood glucose during sustained aerobic exercise such as running a marathon? (Select ALL that apply!) Hint: You may wish to review pages 657-661, 698-699, & 814-819 of Stryer 8E before attempting this question! In addition, remember to consider the sources of glucose, not ATP. A. Even numbered fatty acids are catabolized and the carbon is used for gluconeogenesis in the liver. B. Muscles run gluconeogenesis and export glucose into blood. C. Ketone bodies are produced by adipose cells and converted into glucose by the liver. D. Muscles convert lactate back into glucose and export this glucose back out into the blood. E. The exclusively ketogenic amino acids (leucine and lysine) are deaminated and the carbon skeletons used to synthesize glucose. F. Glucogenic amino acids are deaminated and the carbon skeletons used to synthesize glucose. G. Most blood glucose will come from the breakdown of muscle glycogen (glycogenolysis) and the export of this glucose from muscles to the blood. H. Most blood glucose will come from the breakdown of brain glycogen (glycogenolysis) and the export of this glucose from brain to the blood. I. Most blood glucose will come from the breakdown of liver glycogen (glycogenolysis) and the export of this glucose from the liver to the blood.

H3O+ ions: blood pH Results for Dave: pH = 7.31 (normal range: 7.35â7.45) Results for Michael: pH = 7.2 (normal range: 7.35â7.45) The physician you are shadowing tells you that a value of 7.31 indicates acidosis but this value will not normally cause a loss of consciousness. A pH value of 7.2 indicates severe acidosis and could result in neurological problems. 4 Ketone bodies (acetoacetate and acetone) Results for Dave: low but detectable levels (normal range: undetectable) Results for Michael: dangerously high levels of both found.

3. What macromolecules can be catabolized such that the resulting carbon can be used to create ketone bodies? A. Fatty acids B. Amino acids C. Glucose D. Glycogen E. All of the above can be used to produce acetyl-CoA, so they can all be used to make ketone bodies.

4. When are ketone bodies produced in an otherwise healthy human being? A. When fatty acid levels in the blood are low B. When glutamine levels in the blood are low C. When glucose levels in the blood are low D. When lactate levels in the blood are low E.

When blood pH is low Lactate and pyruvate Results for Dave: [lactate] = 2.0 meq/L (normal range: 0.5â2.2 meq/L); [pyruvate] = 0.05 meq/L (normal range: 0â0.11 meq/L) Results for Michael: [lactate] = 0.7 meq/L (normal range: 0.5â2.2 meq/L); [pyruvate] = 0.02 meq/L (normal range: 0â0.11 meq/L) DETERMINE URINE CONCENTRATIONS OF: branched-chain a-keto acids Results for both Dave and Michael: undetectable levels (normal range: undetectable)

5. What would an increased amount of branched-chain a-keto acids in the urine indicate? (Select ALL that apply!) A. A defect in fatty acid catabolism B. A defect in fatty acid transport C. A defect in a citric acid cycle enzyme D. A defect in carbohydrate metabolism E. A defect in amino acid catabolism F. Phenylketonuria G. Lactose intolerance H. Maple-syrup urine disease phenyl-pyruvate (a phenylketone)

Results: Both Dave and Michael: undetectable levels (normal range: undetectable)

6. What would an increased amount of phenyl-pyruvate in the urine indicate? (Select ALL that apply!) A. A defect in fatty acid catabolism B. A defect in fatty acid transport C. A defect in a citric acid cycle enzyme D. A defect in carbohydrate metabolism E. A defect in amino acid catabolism F. Phenylketonuria G. Lactose intolerance H. Maple-syrup urine disease

SPECIFIC ENZYME TESTS: Lactate dehydrogenase (LDH) Results for both Dave and Michael: [LDH] = 150 U/L (normal range: 110â210 U/L) Liver Asp amino-transaminases (AST) and Ala amino-transferase (ALT) Results for Dave: Both enzymes are within normal range (normal range: 7â55 U/L) Results for Michael: Both enzyme expression levels are elevated. Pyruvate dehydrogenase (PDH) Results for both Dave and Michael: PDH complex activity= 2.5 nmol/(minâ¢mg) (normal range: 2â 2.5 nmol/(minâ¢mg) Test cells for Electron Transport Chain enzyme activities Results for both Dave and Michael: ETC enzyme activities were normal. SPECIAL INVESTIGATIONS Test hair for common toxins (heavy metals and narcotics) and ask Dave about mercury contamination in the supplements Results: Dave immediately points out that they worked with a chemist to extensively purify the fish oils to remove any mercury contamination. An independent laboratory verified that there are only trace levels of mercury left in their formulations, and Dave brings up the documentation on his smart-phone, showing that the analysis is good. Mercury toxicity will be negligible regardless of how much oil is consumed. Also, no heavy metals or narcotics were detected in hair samples from either brother. Investigate the composition of the dietary supplements the subjects were eating. Results: Complete hydrolysis followed by esterification of the TAGs in the two fish oil samples allowed fatty acid composition to be analyzed by gas chromatography. The table shows the compositions of oil consumed by Dave (from the striped mullet Mugil cephalus) and Michael (from Atlantic salmon Salmo salar) Dave Michael 16:0 fatty acid 11% 16% 16:1â7 fatty acid 5% 6% 18:1â9 fatty acid 15% 20% 20, 22, or 24 carbon omega-3 or omega-6 fatty acids 36% 45% 15, 17, 19, and 21 carbon fatty acids 25% 4% 12 or 14 carbon fatty acids 6% 7% Unidentified 2% 2% 6

7. What is the most significant difference between these two fish oil samples in terms of their fatty acid compositions? Note: it may be helpful to briefly review fatty acid structure and nomenclature from Section 12.1, pages 342-344, Table 12.1 of Stryer 8E before answering this question. A. The oil that Dave is consuming is much higher in saturated fatty acids than Michaelâs oil. B. The oil that Dave is consuming is much higher in oleic acid than Michaelâs oil. C. The oil that Dave is consuming is much higher in palmitic acid than Michaelâs oil. D. The oil that Michael is consuming is much higher in omega-3 fatty acids than in omega-6 fatty acids. E. The oil that Dave is consuming is much higher in odd-numbered fatty acids than Michaelâs oil. F. The oil that Michael is consuming is much higher in unsaturated fatty acids than Daveâs oil.

8. What is different about the metabolism of odd- vs. even-numbered fatty acids? (Select ALL that apply!) A. Odd-numbered fatty acids are not broken down by Î²-oxidation. B. Odd-numbered fatty acids are primarily broken down by Ï-oxidation. C. Odd-numbered fatty acids cannot be broken down by humans. D. Odd-numbered fatty acids require additional enzymatic steps to fully degrade. E. Odd-numbered fatty acids do not require carnitine in order to be transported into the mitochondria. F. Odd-numbered fatty acid metabolism produces a four-carbon succinyl group attached to CoA.

9. What is an important consequence of producing succinyl-CoA at the end of odd-numbered fatty acid metabolism rather than the normal product by Î²-oxidation of even-numbered fatty acids? A. Acetyl-CoA is a citric acid cycle intermediate but succinyl-CoA is not. B. Acetyl-CoA is glucogenic but succinyl-CoA is strictly ketogenic. C. Succinyl-CoA is glucogenic, but acetyl-CoA is strictly ketogenic. D. None of the above are true.

10. Review again which brother is taking which oil and which oil contains a large percentage of odd- numbered fatty acids. What is a critical physiological consequence of this difference? A. Michael can make ketones from the oil in his diet but Dave cannot. B. Dave can make ketones from the oil in his diet but Michael cannot. C. Michael can make ATP using the oil in his diet but Dave cannot. D. Dave can make ATP using the oil in his diet but Michael cannot. E. Dave can make far more glucose from the oil in his diet than Michael can. F. Michael can make glucose from the oil in his diet but Dave cannot. You have uncovered a critically important aspect of this case. As you continue your investigation, consider what biochemical consequences might occur when someone is not consuming glucose and cannot convert the food that they are eating into glucose. ENDING THE CASE AND THE ASSESSMENT QUESTIONS: The student should be able to fully explain the reason(s) for Dave and Michaelâs incidents in biochemical and physiological terms, including reasons for the significant differences between the two brothersâ conditions and to fully justify and completely explain their reasoning based on the evidence gathered. Criteria to complete the case are the selection of ALL possible investigation options and completion of the associated assessment questions. If all of the criteria are not met: you may be missing vital information to sufficiently explain this incident. Assessment Questions for âThe Runnersâ Experimentâ

11. The citric acid cycle begins with the condensation of acetyl-CoA with oxaloacetate. Possible sources for carbon that may be converted into acetyl-CoA in active muscle include: (Select ALL that apply!) A. Pyruvate B. Î²-oxidation of fatty acids C. Amino acid catabolism D. Conversion of ketone bodies from the blood back to acetyl-CoA E. Stored glycogen in the muscle

12. Though not included in the case, both men had elevated levels of the enzymes carnitine acyltransferase I and II. Why might the men have elevated levels of these enzymes? A. These enzyme levels rise after eating a carbohydrate-rich meal to aid in carbohydrate metabolism (glycolysis). B. Carnitine levels rise after eating and these enzymes are expressed to catabolize the extra carnitine. C. Both men are producing abnormally high levels of these enzymes as a side effect of utilizing amino acids for energy. D. These enzymes are elevated because both men are getting their energy primarily from Î²- oxidation and these enzymes are needed for fatty acids to be transported into the mitochondria. E. Likely both men have high levels of these enzymes because they are identical twins and share a genetic polymorphism.

13. Why is glucose a necessary fuel in the human body and what organs or cell types rely most heavily on glucose? A. Most human tissues cannot use glucose as an energy source. B. Glucose is necessary for the continued function of the Na+/K+ pump, and the brain is the only organ that uses glucose as an energy source. C. During exercise, the brain stops using glucose so that it can be used by the muscles. D. Glucose is necessary because it is used by almost all tissues for energy and biosynthesis, and the brain relies almost entirely on glucose as an energy source. E. Glucose is necessary because it is the only source of energy that can fully be oxidized to produce ATP, and the liver relies heavily on glucose as its sole energy source.

14. During their three-week, pre-marathon self-experiment, both Daveâs and Michaelâs livers had to produce some glucose. Which of the following molecules could be used by the liver to create the glucose that is needed to supply the brain and other tissues in a healthy person on a normal diet? (Select ALL that apply) A. Pyruvate B. Lactate C. Glycerol D. Any citric acid cycle intermediate (this excludes acetyl-CoA!) E. Even-chain fatty acids F. Alanine G. Acetyl-CoA 8

15. Which of the following statements about even-chain fatty acids is/are FALSE? (Select ALL that apply) A. The product of the oxidation of even-numbered fatty acid chains is multiple acetyl groups bound to CoA molecules. B. Humans have all the appropriate enzymes necessary to use even-chain fatty acids as glucogenic precursors through their conversion to acetyl-CoA. C. A difference between even-chain and odd-chain fatty acids is that only odd-chain fatty acids produce propionyl groups bound to CoA. D. The products of the oxidation of an odd-numbered fatty acid chain are multiple 3-carbon propionyl groups bound to CoA. E. The products of the oxidation of an odd-numbered fatty acid chain are acetyl groups and a final propionyl group attached to CoA.

16. What is happening to Dave and Michael in regard to their metabolisms? (Select ALL that apply) A. Because the human body cannot create glucose from even-chain fatty acid oxidation, both runners are starving their bodies of glucose due to their restrictive diets. B. Most of their energy is coming from fatty acid oxidation, so ketone bodies are being produced to free up CoA for continued Î²-oxidation. C. The brothers have compromised immune systems because of a genetic disorder that affects their metabolism. D. Their diet high in fatty acids resulted in a large build-up of glycogen in their livers and muscles. E. Excessive fatty acid oxidation resulted in protein wasting, which led to acidification of the blood.

17. What are the functions of Asp aminotransferase (AST) and Ala aminotransferase (ALT)? And why are they elevated in Michael? A. These enzymes function in glucose catabolism, catalyzing the transfer of an amino group; levels of these enzymes would be elevated due to the excessive protein wasting occurring in Michaelâs body to meet his need to produce glucose in the absence of other dietary gluconeogenic substrates. B. These enzymes function in fatty acid catabolism, catalyzing the transfer of a hydroxyl group; levels of these enzymes would be elevated due to excessive glycogenolysis occurring in Michaelâs body to meet his need to produce glucose in the absence of other dietary gluconeogenic substrates. C. These enzymes function in protein catabolism, catalyzing the transfer of an amino group; levels of these enzymes would be elevated due to the excessive protein wasting occurring in Michaelâs body to meet his need to produce glucose in the absence of other dietary gluconeogenic substrates. D. These enzymes function in protein catabolism, catalyzing the transfer of an amino group; levels of these enzymes would be elevated due to the excessive ketone body production that is occurring in Michaelâs body to meet his need for energy sources in the absence of other dietary gluconeogenic substrates. E. These enzymes function in ketone body catabolism, catalyzing the transfer of an amino group; levels of these enzymes would be elevated due to the excessive ketone body production that is occurring in Michaelâs body to meet his need for energy sources in the absence of other dietary gluconeogenic substrates.

18. Why are Michaelâs blood ammonia levels elevated and why are high levels of ammonia dangerous? A. Ammonia levels in the blood are high due to the rapid degradation of proteins; high levels of ammonia lead to dangerous levels of ketone bodies in muscle. B. Ammonia levels in the blood are high because of burning calories from vigorous exercise; high levels of ammonia lead to dangerous levels of ketone bodies in muscle. C. Michaelâs blood ammonia is high due to the rate of ketone body production in his body; high levels of ammonia are dangerous because ammonia passes easily through the blood-brain barrier and is highly toxic to the brain. D. Ammonia levels are high because it is a byproduct of Î²-oxidation of fatty acids; high levels of ammonia lead to dangerous levels of ketone bodies. E. Michaelâs blood ammonia is high due to the rate of protein wasting (catabolism of non-essential proteins to provide glucogenic carbon skeletons) in his body; high levels of ammonia are dangerous because ammonia passes easily through the blood-brain barrier and is highly toxic to the brain.

19. What is/are the source(s) of the excessively high levels of ketone bodies in Michael but not Dave? (Select ALL that apply) A. Ketone bodies are being formed from catabolism of carbohydrates for energy metabolism. B. Ketone bodies are being formed as a byproduct of excessive glycogenolysis. C. Ketone bodies are being formed from ketogenic amino acids released from protein catabolism. D. Ketone bodies are being formed from the products of Î²-oxidation of fatty acids from both stored triglycerides and the ingested fish oil. E. Ketone bodies are being produced in Michaelâs brain to provide energy for the liver. F. Michael is producing large amounts of ketone bodies because he is severely hypoglycemic and has likely been hypoglycemic for most of the past few weeks.

20. Why are the two twins experiencing such different symptoms? (Select ALL that apply) A. Michael probably has a genetic inborn error in metabolism that Dave does not. B. One brother is in much better shape for the run than the other because of training. C. Michaelâs case is more severe because he relies on glycolysis (by way of lactic acid fermentation) for energy. D. Michaelâs supplement has almost no odd-numbered fatty acids, so his body is undergoing more protein wasting, and producing dangerous levels of ketones. E. Daveâs case is milder because the supplement he is taking contains a significant amount of odd- numbered fatty acids, some of which may be used to produce glucose. F. The twins exhibit minor variations in metabolic adaptation to dietary changes based on their genetics.

21. Which of the following would likely be true if the brothers were NOT identical twins? A. Carnitine levels would be higher in Dave than in Michael. B. Their bodies would have used different sources of energy to respond to a long term run. C. They would not have overexerted their bodies because they would be less competitive if they were not identical twins. D. The brothers would have had the same amount of ketone production. E. It would be more difficult to determine the impact of diet in this case because there would have been a greater chance that their differing symptoms were due to genetic variation in metabolism.

22. What is causing Michaelâs neurological issues and what is the cause of this problem? (Select ALL that apply) A. Michael is exhibiting the first signs of diabetes, trigged by the vigorous run. B. Michael has depleted his main stores of glucose and is therefore experiencing neurological effects from hypoglycemia. C. Michael has severe hypoglycemia and ketoacidosis because of metabolic failures, both which are known to affect mental status. D. As a result of excessive protein and amino acid degradation, Michael is also experiencing mild ammonia toxicity, which is likely exacerbating his neurological issues. E. Michael is experiencing side effects of extreme dehydration.

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BPK 143 Chapter Notes - Chapter 12: Intramuscular Fat, Carbohydrate Metabolism, Myocyte

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