Which of the following reactions would liberate the most energy?
A)complete oxidation of a molecule of sucrose to CO2 and water
B)conversion of a molecule of ADP to ATP
C)respiration of a molecule of glucose to lactic acid
D)conversion of a molecule of glucose to carbon dioxide and water
A)complete oxidation of a molecule of sucrose to CO2 and water
The formation of glucose from glycogen is
A)gluconeogenesis
B)glycogenesis
C)glycogenolysis
D)glycolysis
C)glycogenolysis
The net gain of ATP from the complete metabolism (aerobic) of glucose is closest to
A)2
B)30
C)36
D)4
B)30
Which of the following best defines cellular respiration?
A)intake of carbon dioxide and output of oxygen by cells
B)excretion of waste products
C)inhalation of oxygen and exhalation of carbon dioxide
D)oxidation of substances by which energy is released in usable form to the cells
D)oxidation of substances by which energy is released in usable form to the cells
what is formed during aerobic respiration when electrons are passed down the electron transport chain.
A)oxygen
B)water
C)glucose
D)NADH + H+
B)water
Metabolic rate is relatively low in
A)Youth
B)Physical exercise
C)Old age
D)Fever
C)Old age
In a temperate climate under ordinary conditions, the greatest loss of body heat occure through
A)radiation
B)conduction
C)evaporation
D)none of the above
radiation
Which of the following is not a function of the liver?
A)glycogenolysis and gluconeogenesis
B)synthesis of cholesterol
C)detoxification of alcohol and drugs
D)synthesis of glucagon
E)deamination of amino acids
D)synthesis of glucagon
Amino acids are essential (and important) to the body for all the following except
A)production of some hormones
B)production of antibodies
C)formation of most structural materials
D)as a source of quick energy
D)as a source of quick energy
A person has been on a hunger strike for seven days, compared to normal he has
A)Increased release of fatty acids from adipose tissue and ketosis
B)Elevated glucose concentration in the blood
C)Increased plasma insulin concentrations
D)Increased glycogen synthase (enzyme) activity in the liver
A)Increased release of fatty acids from adipose tissue and ketosis
Transamination is a chemical process by which
A)protein is synthesized
B)an amine group is transferred from an amino acid to a keto acid
C)an amine group is cleaved from the amino acid
D)amino acids are broken down for energy
B)an amine group is transferred from an amino acid to a keto acid
Three days after removing the pancreas from an animal, the researchers find a persistent increases in
A)Acetoacetic
B)Urine volume
C)Blood glucose
D)All of the above
D)All of the above
Hunger apetite, obsesity, and physical activity are interrelated thus
A)Hunger sensations arise primarily from the stimulation of receptors in the stomach and intestine in response to the absence of food in these organs.
B)Obesity, in most cases, is a result of the abnormally high emzymatic activity of the fat-synthesizing enzymes in adipose tissue
C)In all cases of obesity, the energy content in digested food has exceeded the energy expenditure of the body
D)In a normal individual, increasing blood glucose concentration increases hunger sensation
C)In all cases of obesity, the energy content in digested food has exceeded the energy expenditure of the body
Body temperature regulation is
A)Influenced by temperature receptor in the skin
B)Influenced by temperature of the blood profusing the heat regulation centers of the brain
C)Subject to both neural and hormonal control
D)All of the above.
D)All of the above.
Which of the following yields the greatest caloric value per gram?
A)fats
B)proteins
C)carbohydrates
D)all are equal in caloric value
A)fats
What is cellular respiration? What is the common role of FAD and NAD+ in cellular respiration?
Cellular respiration is a group of reactions that break down (oxidize) glucose, fatty acids, and amino acids in the cell. Some of the energy released is used to synthesize ATP. FAD and NAD+ function as reversible hydrogen acceptors that deliver the accepted hydrogen to the electron transport chain.
Describe the site major events and outcomes of glycolysis.
Glycolysis occurs in the cytoplasm of cells. It may be separated into three major events: (1) sugar activation, (2) sugar cleavage, and (3) oxidation and ATP formation. During sugar activation, glucose is phosphorylated, converted to fructose, and phosphorylated again to yield fructose-1,6-biphosphate, consuming two molecules of ATP. These reactions provide the activation energy for the later events of glycolysis. During sugar cleavage, fructose-1,6-biphosphate is split into two 3-carbon fragments: glyceraldehyde-3-phosphate or dihydroxyacetone phosphate. During oxidation and ATP formation, the 3-carbon molecules are oxidized by the removal of hydrogen (which is picked up by NAD). Inorganic phosphate groups that are attached to each oxidized fragment by high-energy bonds are cleaved off, capturing enough energy to form four ATP molecules. The final products of glycolysis are two molecules of pyruvic acid, two molecules of reduced NAD, and a net gain of two ATP molecules per glucose molecule.
Pyruvic acid is a product of glycolysis, but it is not the substance that joins the pick-up molecules to enter the krebs cycle. What is that substance?
Pyruvic acid is converted to acetyl CoA, which enters the Krebs cycle. For pyruvic acid to be converted to acetyl CoA, the following must take place: decarboxylation to remove a carbon, oxidation to remove hydrogen atoms, and combination of the resulting acetic acid with coenzyme A to produce acetyl CoA.
Define Glycogenesis, glycogenolysis, gluconeogenesis, and lipogenesis. Which is (are) likely to be occurring
Glycogenesis is the process by which glucose molecules are combined in long chains to form glycogen. Gluconeogenesis is the formation of new sugar from noncarbohydrate molecules. Lipogenesis is the term for triglyceride synthesis.
Glycogenesis (and perhaps lipogenesis) is likely to occur after a carbohydrate-rich meal.
Gluconeogenesis is likely to occur just before waking up in the morning.
What is the harmful result when excessive amounts of fats are burned for energy? Name two conditions that might lead to this result
Metabolic acidosis due to ketosis is the result of excessive amounts of fats being burned for energy. Starvation, unwise dieting, and diabetes mellitus can result in ketosis.
Make a flow chart that indicates the pivotal intermediates through which glucose can be converted to fat.
Distinguish between the role HDLs and that of LDLs
HDLs function to transport cholesterol from the peripheral tissues to the liver. LDLs transport cholesterol to the peripheral tissues.
List some factors that influence plasma cholesterol levels. Also list the source and fates of cholesterol in the body
Factors influencing plasma cholesterol levels include diet (through intake of cholesterol and/or saturated fatty acids), smoking, drinking, and stress. Sources of cholesterol in the body include the intake of animal foods and production from acetyl coenzyme A in the liver (and intestinal cells). Cholesterol is lost from the body when it is catabolized and secreted in bile salts that are eventually excreted in feces. It is used by body cells in plasma membranes and in synthesizing vitamin D and steroid hormones.
What is meant by “body energy balance” and what happens if the balance is precise.
“Body energy balance” refers to the balance between energy intake and total energy output. If energy intake exceeds energy output, weight is gained. Weight is lost if energy output is greater than energy intake.
Explain the effect of the following on metabolic rate: thyroxine levels, eating, body surface area, muscular exercise, emotional stress, starvation
Metabolic rate is increased with increased production of thyroxine. Eating increases metabolic rate, an effect called chemical thermogenesis. A higher ratio of body surface area to body volume requires a higher metabolic rate because heat exchange surface area is greater. Muscular exercise and emotional stress increase metabolic rate. Starvation decreases metabolic rate.
Explain the terms “core” and “shell” relative to body temperature balance. What serves as the heat-transfer agent from one to the other?
The body’s core includes organs within the skull and the thoracic and abdominal cavities. The core has the highest temperature. The shell, or skin, has the lowest temperature. Blood serves as the heat transfer agent between the core and shell.
Compare and contrast mechanisms of heat loss with mechanisms of heat promotion, and explain how these mechanisms determine body temperature.
Heat-promoting mechanisms to maintain or increase body temperature include vasoconstriction in the shell, which inhibits heat loss via radiation; conduction and convection; increase in metabolic rate due to epinephrine release; and shivering. Heat-loss mechanisms include vasodilation of blood vessels in the skin and sweating (which enhances heat transfer via evaporation).
Whenever core temperature increases above or decreases below normal, peripheral and central thermoreceptors send input to the hypothalamus. Much like a thermostat, the hypothalamus responds to the input by initiating the appropriate heat-promoting or heat-loss reflex mechanisms via autonomic effector pathways.
Critical Thinking
Calculate the number of ATP molecules that can be harvested during the complete oxidation of an 18-carbon fatty acid. (Take a deep breath and think about it…you can do it.)
The number of ATP molecules resulting from the complete oxidation of a particular fatty acid can be calculated easily by counting the number of carbon atoms in the fatty acid and dividing by two to determine the number of acetyl CoA molecules produced. For our example, an 18-carbon fatty acid yields 9 acetyl CoA molecules. Because each of these yields 12 ATP molecules per turn of the Krebs cycle, a total of 108 ATP molecules is provided from the oxidative pathways: 9 from electron transport oxidation of 3 NADH + H+, 2 from the oxidation of 1 FADH2, and a net yield of 1 ATP during the Krebs cycle. Also, for every acetyl CoA released during beta oxidation, an additional molecule each of NADH + H+ and FADH2 is produced which, when reoxidized, yield a total of 5 ATP molecules more. In an 18-carbon fatty acid, this would occur 8 times, yielding 40 more ATP molecules. After subtracting the ATP needed to get the process going, this adds up to a grand total of 147 ATP molecules from that single 18-carbon fatty acid!
Critical Thinking
Every year dozens of elderly people are found dead in their unheated apartments and listed as victims of hypothermia. What is hypothermia and how does it kill? Why are the elderly more susceptible to hypothermia than the young?
Hypothermia is low body temperature from prolonged uncontrolled exposure to cold. Uncorrected, the situation progresses to a coma and finally death by cardiac arrest, once the body temperature approaches 21C (pg. 953 in Marieb). The elderly are more susceptible to hypothermia than the young because, older people have a lower metabolism rate than young people therefore; it is more difficult for them to maintain normal body temperatures like younger adults
Critical Thinking
Frank Moro has been diagnosed as having severe atherosclerosis and high blood cholesterol levels. He is told he is at risk for a stroke or heart attack. What foods would you suggest he avoid like the plague? What foods would you suggest he add or substitute in his diet program? What activities would you recommend?
I would suggest that Mr. Moro avoid foods such as eggs, red meats and organ meats like liver Foods Containing LDL Cholesterol. I would suggest that he add lots of Vitamin E such as dark green vegetables, nuts, and seeds to his diet (pg. 916 in Marieb). And I would recommend that Mr. Moro should do more moderate to vigorous activities for 30 minutes per day like walking, jogging, biking, or even gardening to help lower his cholesterol
Critical Thinking
In the 1940s some physicians prescribed low doses of a chemical called dinitrophenol(DNP) to help patients lose weight. This drug therapy was band after a few patients died. DNP uncouples the chemiosmotic machinery. Explain how this causes weight loss.
The chemiosmotic machinery concerns the operation of the electron transport chain and generation of the proton gradient during which most ATP is harvested in the mitochondria. If uncoupled, cells will use more and more nutrients in an effort to generate needed ATP, leaving fewer “calories” for protein synthesis and tissue maintenance.
Critical Thinking
While attempting to sail solo from Los Angeles to Tahiti, Simon encountered a storm that marooned him on an uninhabited island. He was able using his ingenuity and a pocket knife, to obtain plenty of fish to eat, and roots were plentiful. However, the island was barren of fruits and soon his gums began to bleed and he started to develop several infections. Analyze his problem.
Since there isn't any fruit for Simon to eat on the island, his body is being deprived of Vitamin C which is used in collagen synthesis, causing his teeth and gums to degenerate
Critical Thinking
Gregor, a large beefy man, came home from the doctor's office and complained to his wife that his blood tests “were bad.” He told her that the doctor said he would have to give up some of his steaks and butter. He went on to mourn the fact that he would have to start eating more cottage cheese and olive oil instead. What kind of problem was revealed by his “bad” blood tests? How should his wife respond to his choice of food substitutes and why? What foods should she suggest?
The problem that was revealed is he has high cholesterol. His wife should be supportive of the choice of substitutes because they will help to reduce his cholesterol levels, but she should also be concerned because the trans-fat in cottage cheese and olive oil, sparks a greater increase in LDLs, and a greater reduction in HDLs, producing the unhealthiest ratio of total cholesterol to HDL . She should suggest more green leafy vegetables, nuts, seeds, apples and other citrus fruits