Chapter 24 Nutrition, Metabolism, and Body Temperature Regulation
Using Figure 24.1, match the following:
Using Figure 24.1, match the following:
1) Ten-step enzymatically driven process that converts glucose into pyruvic acid.
2) Occurs via substrate-level phosphorylation.
3) Produces the CO2 involved during glucose oxidation.
4) Where the hydrogens removed during the oxidation of food fuels are combined with O2.
5) Contains ATP synthases, small rotary motors.
6) ATP formed by oxidative phosphorylation.
7) Involves sugar activation, sugar cleavage, and oxidation and ATP formation.
Match the following:
B) Krebs cycle and electron transport chain
8) Glucose serves as the initial reactant.
9) Involves the removal of hydrogen electrons and CO2 from the substrate molecule.
10) Occurs in the cytosol of a cell.
11) Produces the most ATP.
12) Involves the use of oxygen to pick up excess hydrogen and electrons.
Match the following:
13) Breakdown of glycogen to release glucose.
14) Formation of glucose from proteins or fats.
15) Storage of glucose in the form of glycogen.
16) Breakdown of glucose to pyruvic acid.
Match the following:
B) beta oxidation
17) Synthesis of lipids from glucose or amino acids.
18) Splitting of triglycerides into glycerol and fatty acids.
19) Conversion of fatty acids into acetyl groups.
20) Formation of ketone bodies.
1) Beta oxidation is the initial phase of fatty acid oxidation, and it occurs in the cytoplasm.
2) The increased use of noncarbohydrate molecules for energy to conserve glucose is called glucose sparing.
3) Except for lactose and some glycogen, the carbohydrates we ingest are mainly from animals.
4) The term essential nutrient refers to the chemicals that can be interconverted in the liver so that the body can maintain life and good health.
5) The most abundant dietary lipids in the diets of most Americans are triglycerides.
6) There are no complete proteins. All animal products should be
eaten with plant material to make a complete
7) The body is considered to be in nitrogen balance when the amount of nitrogen ingested in lipids equals the amount excreted in urine.
8) The amount of protein needed by each person is determined by the age, size, and metabolic rate of the person.
9) Vitamins are inorganic compounds that are essential for growth and good health.
10) Cellular respiration is an anabolic process.
11) Glycolysis is a series of six chemical steps, most of which take place in the mitochondria.
12) Glycogenesis begins when ATP levels are high, and glucose entering cells is phosphorylated to glucose-6-phosphate and converted to its isomer, glucose-1-phosphate.
13) All athletes require diets high in protein and calories in order to perform and to maintain their muscle mass.
14) In order for amino acids to be oxidized for energy, the amine group (NH2) must be removed.
15) Including the ATP from glycolysis, the cell gains 34 ATP
molecules from aerobic metabolism of one glucose
16) The body requires adequate supplies of only three minerals
(calcium, sodium, chloride) and trace amounts of all
17) Processes that break down complex molecules into simpler ones are anabolic.
18) For use as fuel, all food carbohydrates are eventually transformed to glucose.
19) Triglycerides and cholesterol do not circulate freely in the bloodstream.
20) Normal body temperature range is 98.6-100°F, regardless of external temperature.
21) A deficit of potassium can cause rickets.
22) It would not be healthy to eliminate all fats from your diet because they serve a useful purpose in maintaining the body.
23) The body's thermoregulatory centers are located in the thalamus.
24) Carbohydrate and fat pools are oxidized directly to produce cellular energy, but amino acid pools must first beconverted to a carbohydrate intermediate before being sent through cellular respiration pathways.
25) High levels of HDLs are considered good.
26) Diets high in cholesterol and saturated fats tend to produce high HDL concentrations.
27) Ghrelin, produced by the stomach, is a powerful appetite stimulant.
28) Peptides called NPY and AgRP are powerful appetite enhancers.
29) The primary function of carbohydrates is energy production within cells.
Fill-in-the-Blank/Short Answer Questions
1) The Krebs cycle produces ________ ATP molecules per glucose molecule by substrate-level phosphorylation.
2) Which nutritional state constitutes the period during and shortly after eating when nutrients are flushing into the bloodstream from the GI tract?
3) Fat burning causes an accumulation of acetyl CoA, which the liver converts to ________.
4) ________ is controlled hyperthermia.
5) The enzymes that catalyze oxidation-reduction reactions by removing hydrogen are specifically called ________.
6) The process of splitting glucose through a series of steps that
produces two pyruvic acid molecules is called
7) In the Krebs cycle, citric acid is followed by ________ acid.
In PKU, the tissue cells are unable to use the amino acid
phenylalanine present in all protein foods. The defect involves a
deficiency of the enzyme phenylalanine hydroxylase that converts
phenylalanine to tyrosine. Galactosemia results from an abnormality or
lack of liver enzymes needed to transform galactose to glucose. Both
can lead to brain damage.
8) Compare and contrast PKU and galactosemia.
The metabolic rate of the elderly declines steadily with age as skeletal muscles begin to atrophy and activity usually declines. Even eating enough to maintain proper nutrition, the metabolic rate is so slow that not all of the food is used for energy.
9) Explain why the elderly more easily gain weight, even though they may actually eat very little.
(1) Radiation is the loss of heat as thermal energy.
(2) Conduction is the transfer of heat between objects that are in direct contact with each other.
(3) Convection is the process of replacing the warm air around the body with cooler air and thus removing body heat.
(4) Evaporation cools by removing large amounts of heat as water changes state from liquid to gas.
10) What are the four mechanisms of heat exchange and how are they defined?
The amino acid pool consists of the body's total supply of free amino acids needed to resynthesize body proteins. Even though a small amount of amino acids and proteins is lost daily in urine, these are replaced through diet. If they are not replaced, the amino acids resulting from tissue breakdown become a part of the pool.
11) Define amino acid pool and explain how the pool is maintained even though we excrete amino acids daily.
Fat-soluble vitamins are most likely involved in hypervitaminosis, because they are stored in the body and excesses are not removed.
12) Hypervitaminosis may have serious consequences. Which vitamin group, water or fat soluble, is most likely to be involved in such cases and why?
Obesity is a BMI (body mass index) greater than 30. Health problems accompanying or following obesity include a higher incidence of arteriosclerosis, hypertension, coronary artery disease, and diabetes mellitus.
13) What is obesity, and what health problems accompany or follow its onset?
The postabsorptive state is controlled by the interaction of the
sympathetic nervous system and several hormones, especially glucagon.
The trigger for initiating postabsorptive events is damping of insulin
release, which occurs as blood glucose levels begin to drop. Insulin
levels decline, and the insulin-induced cellular responses are
14) How is the postabsorptive state controlled and initiated?
Monosaccharides are phosphorylated immediately upon entry into cells
so that entry into metabolic
pathways is possible. Additionally, phosphorylation, to change the structure of glucose, allows the maintenance of a diffusion gradient for simple glucose. Phosphorylation also prevents glucose from leaving the cell.
15) What is the significance of the fact that monosaccharides are phosphorylated immediately upon entry into cells?
When oxygen is not present in sufficient amounts, the NADH + H+
produced during glycolysis begins to
unload its hydrogen "baggage" back onto pyruvic acid, reducing it. This addition of hydrogen atoms to pyruvic acid results in the production of lactic acid.
16) Explain what happens to pyruvic acid if oxygen is not present in sufficient quantities to support the electron transport system.
Nitrogen balance is a state when the amount of nitrogen ingested in
proteins equals the amount of
nitrogen excreted in urine and feces. Factors leading to negative nitrogen balance, when protein breakdown exceeds the use of protein for building structural or functional molecules, include physical and emotional stress, poor-quality dietary protein, and starvation. Factors leading to positive nitrogen balance, when the rate of protein synthesis is higher than the rate of its breakdown and loss, include the normal condition in growing children and pregnant women, periods of rebuilding or repair following illness, and site-specific regeneration following injury.
17) Define nitrogen balance. List three factors that might lead to negative nitrogen balance and three that might result in positive nitrogen balance.
John was suffering from heat exhaustion due to excessive loss of body fluids (indicated by his wet Tshirt); his low blood pressure; and cool, clammy skin. To help his recovery, he should be given fluid and electrolyte replacement therapy and should be cooled down.
Clinical Questions / Essay Questions
1) After chopping wood for about 2 hours, on a hot but breezy afternoon, John stumbled into the house and immediately fainted. His T-shirt was wringing wet with perspiration, and his pulse was faint and rapid. Was he suffering from heat stroke or heat exhaustion?
Explain your reasoning and note what you should do to help John's recovery.
Harry's symptoms indicate a fever caused by his bacterial pneumonia.
The white cells battling the
pneumonia release pyrogens that act directly on the hypothalamus, causing its neurons to release prostaglandins. The prostaglandins reset the hypothalamic thermostat to a higher temperature, causing the body to initiate heatpromoting mechanisms. Vasoconstriction causes a decline of heat loss from the body surface, cooling of the skin, and shivering.
2) Harry is hospitalized with bacterial pneumonia. When you visit
him, his teeth are chattering, his skin is cool and clammy to the
touch, and he complains of feeling cold, even though the room is quite
Explain his symptoms.
Hank suffered from a genetic disorder known as "familial hypercholesterolemia," a condition in which the LDL receptors are absent or abnormal, the uptake of cholesterol by tissue cells is blocked, and the total concentration of cholesterol and LDLs in the blood is enormously elevated. Victims of the disease usually die in adolescence of coronary artery disease.
3) Hank, a 17-year-old high school student, suffered a heart attack
during a recreational swim. An autopsy revealed that he had had
atherosclerosis and that his death had been caused by coronary artery
What might have been the cause of this disease that usually strikes a person much older than Hank?
When asked what he had been taking, the athlete confessed that he was
taking megadoses of vitamins to"help his body get stronger."
Overdoses of vitamins A, D, E, C, B6, and niacin can be toxic.
4) A young athlete is admitted to the hospital with diarrhea,
vomiting, bone and joint pain, hyperglycemia, and tingling sensations.
What is the problem?
The deep, rapid respirations were the body's attempt to compensate for the extremely low pH.
5) The patient is a 28-year-old female with insulin-dependent
diabetes. She developed viral gastroenteritis with nausea and
vomiting. She did not take her insulin and she became increasingly
nonresponsive. Her husband called 911 and she was taken to the
emergency room. Her pulse rate was 128 and her respiratory rate was
28, deep, and
smelled fruity (Kussmaul breathing). Her urinary glucose and ketone levels were both 4+. Her pH was dangerously low.
Explain how the body attempted to compensate for the low serum pH.
Many fad diets are nutritionally unhealthy, particularly if they limit certain groups of nutrients. Some of the liquid high-protein diets contain poor-quality protein and are actually dangerous.
6) The patient is 45 years old and is obese. He states he has been on
the Atkins diet and has lost 20 pounds.
What are the dangers inherent in following fad diets for quick weight loss?
The obese have a higher incidence of arteriosclerosis, hypertension, coronary artery disease, and diabetes mellitus.
7) What are the possible complications of obesity from a medical standpoint?
The omega-3 fatty acids in cold-water fish have a powerful antiarrhythmic effect on the heart and also make blood platelets less sticky, thus helping to prevent spontaneous clotting that can block blood vessels and lower blood pressure.
8) The patient is 52 years old and has a history of hypertension. His
cholesterol level is 245. He states his job is very stressful and he
is recently going through a divorce. He admits to being overweight and
has an inactive lifestyle. His father died of a stroke at age 60. He
is worried about having a heart attack and/or stroke and wishes to
change his lifestyle. The nurse encourages the patient to eat more
Explain why eating more fish would be of benefit for this patient.
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