Cerebral Blood Flow, Cerebrospinal Fluid, and Brain Metabolism

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Questions

Question 1

What is the amount of free energy liberated by the complete oxidation of one mole (180 grams) of glucose?

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Question 2

Under the usual physiological conditions of temperature and reactant concentrations, how much energy is liberated by the removal of each of the last two phosphate radicals from an ATP molecule?

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Question 3

What are the three chemical components that combine to form adenosine triphosphate (ATP)?

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Question 4

Glucose represents, on average, what percentage of the final products of carbohydrate digestion in the alimentary tract?

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Question 5

Which enzyme, present in large amounts in liver cells, allows glucose-6-phosphate to be converted back to glucose and released into the blood?

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Question 6

What is the primary mechanism for glucose transport through the membranes of most tissue cells, such as muscle and adipose cells?

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Question 7

With the exception of liver and brain cells, the amount of glucose that can diffuse into most body cells in the absence of insulin is sufficient for what?

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Question 8

What percentage of their weight can muscle cells store as glycogen?

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Question 9

What is the name of the process that breaks down the cell's stored glycogen to re-form glucose in the cells?

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Question 10

Which two hormones can activate the enzyme phosphorylase to cause rapid glycogenolysis?

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Question 11

What is the net gain in ATP molecules from the entire glycolytic process for each molecule of glucose utilized?

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Question 12

What is the overall efficiency of ATP formation during glycolysis, representing the percentage of energy from the original glucose that is captured in ATP?

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Question 13

In which part of the cell does the Citric Acid Cycle (Krebs Cycle) take place?

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Question 14

For each molecule of glucose that is metabolized, how many molecules of ATP are formed directly within the Citric Acid Cycle itself?

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Question 15

Approximately what percentage of the total ATP created through glucose metabolism is formed during the process of oxidative phosphorylation?

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Question 16

What is the total number of hydrogen atoms released for each original molecule of glucose during glycolysis, formation of acetyl-CoA, and the citric acid cycle?

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Question 17

The chemiosmotic mechanism for forming ATP occurs entirely within which cellular organelle?

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Question 18

What is the maximum number of ATP molecules that can be formed from the complete degradation of one molecule of glucose to carbon dioxide and water?

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Question 19

What is the overall maximum efficiency of energy transfer when converting the energy from one molecule of glucose into ATP?

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Question 20

Excess cellular ATP controls energy metabolism by inhibiting which key enzyme in the glycolytic pathway?

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Question 21

In addition to ATP, what ion formed in the citric acid cycle also strongly inhibits the enzyme phosphofructokinase?

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Question 22

Anaerobic glycolysis is described as being extremely wasteful of glucose because it only uses about what percentage of the total energy in the glucose molecule to form ATP?

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Question 23

Under anaerobic conditions, the major portion of pyruvic acid is converted into what substance to allow glycolysis to continue?

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Question 24

Which tissue in the body is especially capable of converting lactic acid back to pyruvic acid and using it for energy, particularly during heavy exercise?

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Question 25

What is the name of the second important mechanism for the breakdown and oxidation of glucose, which is responsible for as much as 30 percent of glucose breakdown in the liver?

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Question 26

The hydrogen released during the pentose phosphate pathway combines with which molecule, which is significant for its role in fat synthesis?

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Question 27

When the body's carbohydrate stores decrease below normal, what is the process of forming glucose from amino acids and the glycerol portion of fat called?

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Question 28

Approximately what percentage of the amino acids in the body proteins can be easily converted into carbohydrates?

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Question 29

During fasting, approximately what percentage of the liver's glucose production comes from gluconeogenesis?

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Question 30

Which hormone, secreted by the adrenal cortex, is especially important for promoting gluconeogenesis by mobilizing proteins from body cells?

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Question 31

What is considered the normal blood glucose concentration in a person who has not eaten a meal within the past 3 to 4 hours?

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Question 32

After a meal containing large amounts of carbohydrates, the blood glucose level in a person without diabetes mellitus seldom rises above what concentration?

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Question 33

What is the term for the process where chemical reactions in cells are linked with physiological systems to provide energy for functions like muscle activity and glandular secretion?

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Question 34

What happens to fructose and galactose after they are absorbed from the intestinal tract?

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Question 35

What is the reason that storing large quantities of carbohydrates as glycogen does not significantly alter the osmotic pressure of intracellular fluids?

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Question 36

What is the initial effect of both epinephrine and glucagon that leads to the activation of phosphorylase?

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Question 37

During glycolysis, glucose is first converted into fructose-1,6-diphosphate and then split into two molecules of what three-carbon compound?

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Question 38

The conversion of two pyruvic acid molecules into two molecules of acetyl-CoA releases how many hydrogen atoms?

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Question 39

What is the principal function of the early stages of glucose degradation, such as glycolysis and the citric acid cycle?

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Question 40

In the chemiosmotic mechanism, the energy from the electron transport chain is used to do what?

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Question 41

The enzyme ATP synthase uses the energy from what process to convert ADP into ATP?

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Question 42

How many ATP molecules are produced for every two hydrogen atoms that are released by their dehydrogenase beyond the first stage of the chemiosmotic oxidative schema?

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Question 43

What happens to the excess pyruvic acid and hydrogen atoms when their quantities build up during anaerobic glycolysis?

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Question 44

The pentose phosphate pathway is especially important because it can provide energy independently of all the enzymes of which other pathway?

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Question 45

Glucose is preferentially stored as glycogen until the cells have stored an amount sufficient to supply the energy needs of the body for how long?

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Question 46

After the glycogen-storing cells are saturated, what happens to additional excess glucose?

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Question 47

What are the basic stimuli that increase the rate of gluconeogenesis?

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Question 48

By how much can insulin increase the rate of glucose transport into most cells compared to when no insulin is secreted?

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Question 49

During the conversion of pyruvic acid to acetyl-CoA, what vitamin derivative is required to form the coenzyme A portion?

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Question 50

What is the net reaction for the entire glycolytic process per molecule of glucose?

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Other chapters

Functional Organization of the Human Body and Control of the “Internal Environment”The Cell and Its FunctionsGenetic Control of Protein Synthesis, Cell Function, and Cell ReproductionTransport of Substances Through Cell MembranesMembrane Potentials and Action PotentialsContraction of Skeletal MuscleExcitation of Skeletal Muscle: Neuromuscular Transmission and Excitation-Contraction CouplingExcitation and Contraction of Smooth MuscleCardiac Muscle; The Heart as a Pump and Function of the Heart ValvesRhythmical Excitation of the HeartThe Normal ElectrocardiogramCardiac Arrhythmias and Their Electrocardiographic InterpretationThe Circulation: Overview of the Circulation; Medical Physics of Pressure, Flow, and ResistanceVascular Distensibility and Functions of the Arterial and Venous SystemsThe Microcirculation and the Lymphatic System: Capillary Fluid Exchange, Interstitial Fluid, and Lymph FlowLocal and Humoral Control of Tissue Blood FlowNervous Regulation of the Circulation and Rapid Control of Arterial PressureCardiac Output, Venous Return, and Their RegulationMuscle Blood Flow and Cardiac Output During Exercise; the Coronary Circulation and Ischemic Heart DiseaseCardiac FailureCirculatory Shock and Its TreatmentThe Body Fluid Compartments: Extracellular and Intracellular Fluids; Interstitial Fluid and EdemaUrine Formation by the Kidneys: I. Glomerular Filtration, Renal Blood Flow, and Their ControlUrine Formation by the Kidneys: II. Tubular Reabsorption and SecretionRenal Regulation of Potassium, Calcium, Phosphate, and Magnesium; Integration of Renal Mechanisms for Control of Blood Volume and Extracellular Fluid VolumeRegulation of Acid-Base BalanceKidney Diseases and DiureticsRed Blood Cells, Anemia, and PolycythemiaResistance of the Body to Infection: I. Leukocytes, Granulocytes, the Monocyte-Macrophage System, and InflammationResistance of the Body to Infection: II. Immunity and AllergyBlood Types; Transfusion; Tissue and Organ TransplantationHemostasis and Blood CoagulationPulmonary VentilationPrinciples of Gas Exchange; Diffusion of Oxygen and Carbon Dioxide Through the Respiratory MembraneTransport of Oxygen and Carbon Dioxide in Blood and Tissue FluidsRespiratory Insufficiency—Pathophysiology, Diagnosis, Oxygen TherapyPhysiology of Deep-Sea Diving and Other Hyperbaric ConditionsOrganization of the Nervous System, Basic Functions of Synapses, and NeurotransmittersSensory Receptors, Neuronal Circuits for Processing InformationThe Eye: I. Optics of VisionThe Eye: II. Receptor and Neural Function of the RetinaCortical and Brain Stem Control of Motor FunctionContributions of the Cerebellum and Basal Ganglia to Overall Motor ControlCerebral Cortex, Intellectual Functions of the Brain, Learning, and MemoryBehavioral and Motivational Mechanisms of the Brain—The Limbic System and the HypothalamusStates of Brain Activity—Sleep, Brain Waves, Epilepsy, PsychosesThe Autonomic Nervous System and the Adrenal MedullaGeneral Principles of Gastrointestinal Function—Motility, Nervous Control, and Blood CirculationPropulsion and Mixing of Food in the Alimentary TractSecretory Functions of the Alimentary TractMetabolism of Carbohydrates and Formation of Adenosine TriphosphateLipid MetabolismProtein MetabolismThe Liver as an OrganDietary Balances; Regulation of Feeding; Obesity and Starvation; Vitamins and MineralsEnergetics and Metabolic RateBody Temperature Regulation and FeverIntroduction to EndocrinologyPituitary Hormones and Their Control by the HypothalamusThyroid Metabolic HormonesAdrenocortical HormonesInsulin, Glucagon, and Diabetes MellitusParathyroid Hormone, Calcitonin, Calcium and Phosphate Metabolism, Vitamin D, Bone, and Teeth