Deck 33: Metabolic Integration and Organ Specialization

Question 1

Which of these actions does the brain do during fasting or starvation?

A)It converts endogenous fatty acids into b-hydroxybutyrate.
B)It utilizes b-hydroxybutyrate from the blood stream.
C)It utilizes amino acids for fuel from degradation of brain protein.
D)It utilizes its glycogen stores as a first responding source of fuel.

Answer 1

B

Question 2

What process is coupled to metabolism reactions and determines overall thermodynamic efficiency?

A)NADH oxidation
B)CO₂ release
C)ATP hydrolysis and synthesis
D)reduction of O₂

Answer 2

C

Question 3

What is the term for the constant availability of fuels in the blood,and what is the order of preference for fuel usage?

A)phosphorylation potential;glycogen > triacylglycerols > protein
B)fuel dynamics;triacylglycerols > glycogen > protein
C)metabolic regulation;triacylglycerols > glycogen > protein
D)caloric homeostasis;glycogen > triacylglycerols > protein

Answer 3

D

Question 4

Which of the following is NOT a characteristic of the energy charge (E.C.)of a cell?

A)It is rapidly changed by adenylate kinase.
B)E.C.has a range of 0-1.0.
C)It is a ratio of adenylate phosphoric anhydride bonds to total adenylate concentration.
D)It is 1.0 when all the adenylate is ATP.

Question 5

Muscle contractions occur when a motor nerve impulse causes Ca²⁺ release from specialized compartments.To which regulatory protein does Ca²⁺ bind to initiate events that result in sliding of myosin thick filaments along actin thin filaments?

A)myoglobin
B)calmodulin
C)troponin C
D)Na+/K⁺ ATPase

Question 6

What are the 2 metabolic roles served by ATP?

A)promoting increased reaction speed and dephosphorylation
B)changing both K_m and V_max
C)allosteric regulation and stoichiometric involvement
D)preventing futile cycles and changing K_m

Question 7

An energy charge (E.C.)of 0.9 is roughly 80% ATP,17% ADP,and 3% AMP.At this E.C.,which enzyme activities are low and which enzyme activities higher,respectively?

A)R;U
B)R;S
C)U;R
D)U;S

Question 8

Which of the following is NOT a characteristic of brain tissue?

A)Brain tissue is 20% or so of body mass.
B)Twenty percent of oxygen is consumed by the brain.
C)Oxygen consumption is independent of mental activity.
D)Brain tissue has no significant fuel reserves.

Question 9

Which of these enzymes is activated upon phosphorylation by AMP-activated protein kinase?

A)acetyl-CoA carboxylase
B)phosphofructokinase-2
C)glycogen synthase
D)3-hydroxy-3-methylglutaryl-CoA reductase

Question 10

Which 2 molecules are unique in that they are the only compounds whose purpose is to couple the energy-yielding processes of catabolism to the energy-consuming reactions of anabolism?

A)NADH and ATP
B)ATP and [FADH₂]
C)[FADH₂] and NADH
D)ATP and NADPH

Question 11

Which of these enzymes catalyzes the reaction ATP + AMP à 2 ADP?

A)adenylate phosphorylase
B)AMP-phosphotransferase
C)ADP mutase
D)adenylate kinase

Question 12

Which molecules are fed into catabolism to generate the metabolic intermediates needed to supply anabolism in photoautotrophs?

A)lipids
B)proteins
C)carbohydrates
D)nucleic acids

Question 13

Which of the following is NOT paired with their preferred substrate?

A)brain: glucose
B)heart: fatty acids
C)resting skeletal muscle: glucose
D)adipose tissue: fatty acids

Question 14

Which of the following is a feature of ATP stoichiometry in metabolic pathways?

A)It is not a consequence of evolution.
B)A singular number is not required.
C)It results from biological adaptation.
D)It cannot be predicted from any chemical considerations.

Question 15

What is the approximate energy charge of healthy living cells?

A)0.85-0.88
B)0.75-0.85
C)0.65-0.75
D)0.60-0.65

Question 16

Which regulatory enzyme shows greater activity at low energy charge in an energy-producing pathway?

A)hemoglobin
B)phospholipase C
C)PKA
D)PFK-1

Question 17

Which nucleotides are the principal energy source for protein,phospholipid,and polysaccharide synthesis,respectively?

A)UTP;GTP;CTP
B)GTP;CTP;UTP
C)CTP;UTP;GTP
D)UTP;CTP;GTP

Question 18

The brain prefers to use glucose as fuel.What does it use as it adapts to prolonged fasting or starvation?

A)glucose
B)b-hydroxybutyrate
C)fatty acids
D)amino acids

Question 19

Which of the following metabolic pathways is strictly anabolic?

A)glycolysis
B)gluconeogenesis
C)citric acid cycle
D)pentose phosphate cycle

Question 20

Which of the following is NOT a major component of anabolic pathways?

A)NADH
B)glycolysis and citric acid cycle intermediates
C)ATP,GTP,CTP,UTP
D)NADPH

Question 21

Which of the following is NOT a difference between heart and skeletal muscle?

A)Heart muscle is completely aerobic.
B)Heart muscle prefers fatty acids as fuel.
C)Heart muscle has more phosphocreatine than skeletal muscle.
D)Heart muscle has limited quantities of glycogen.

Question 22

Which of the following is NOT a purpose for the liver?

A)production of insulin to regulate metabolism
B)conversion of amino acids into metabolic fuel
C)production of ketone bodies
D)detoxification of poisons and drugs

Question 23

Which of the following is NOT a fuel for contracting muscles during strictly anaerobic metabolism?

A)palmitic acid
B)creatine phosphate
C)glycogen
D)glucose

Question 24

Which of the following is NOT a use of glucose-6-phosphate in liver?

A)catabolism to acetyl-CoA for fatty acid biosynthesis
B)generation of NADH and hexoses
C)release as glucose to blood stream
D)conversion to glycogen

Question 25

Which of the following is NOT a characteristic of ethanol metabolism in liver?

A)decreased pH levels due to lactic acidosis
B)2 oxidation steps to convert ethanol to acetate;both reactions produce NADH
C)increased acetaldehyde-protein adducts impairing protein function
D)decreased NADH/NAD⁺ ratio in the cell

Question 26

Which enzyme do adipocytes lack so that the futile cycle of triacylglycerol hydrolysis and synthesis is prevented?

A)DHAP reductase
B)glycerol kinase
C)acetyl-CoA carboxylase
D)carnitine acyl transferase

Question 27

Which of the following is NOT a characteristic associated with "brown fat"?

A)high levels of mitochondria rich in cytochromes
B)absence of uncoupler protein-1,thermogenin,in the mitochondrial inner membrane
C)energy from oxidation converted to heat
D)found in newborns and hibernating animals

Question 28

Which process do muscle cells preferentially use during anaerobic exercise?

A)carboxylation of pyruvate to oxaloacetate
B)oxidization of pyruvate to acetyl-CoA
C)decarboxylation of pyruvate to acetaldehyde
D)reduction of pyruvate to lactate

Question 29

Which of the following is NOT a characteristic of leptin?

A)It binds to hypothalamus,inhibits release of neuropeptide-Y,and is thus an anorexic agent.
B)It is a signal molecule that limits food intake and increases energy expenditure.
C)It communicates the status of triacylglycerol levels in the adipocytes to the central nervous system.
D)At low levels,appetite is suppressed;at high levels,appetite is increased.

Question 30

Which of the following is NOT a characteristic of energy metabolism in the heart?

A)The preferred fuel is fatty acids.
B)The range of activity is much less than that in muscle (200-fold).
C)It is unusually rich in mitochondria.
D)The heart consumes over 90% of the total oxygen supply during maximal physical exertion.

Question 31

Which of the following is NOT correct regarding hormones that govern eating behaviour?

A)insulin: stimulates adipocyte leptin production
B)leptin: suppresses appetite when levels are high
C)ghrelin: released from stomach in response to food to further stimulate appetite
D)cholecystokinin: released from the intestines during eating to signal satiety

Question 32

Which of the following is NOT a characteristic of resveratrol?

A)produced in plants,particularly in grape skins,in response to stress
B)activates SIRT1 NAD⁺-dependent deacetylase activity
C)inhibits AMPK in the brain
D)has many of the same effects as caloric restriction

Question 33

Under which of the following conditions are fatty acids released from adipocytes?

A)Insulin levels are high.
B)Glycerol-3-phosphate levels are high.
C)Adipose ATP levels are high.
D)Blood glucose levels are low.

Question 34

What is the general order of available energy sources in muscles during strenuous exertion?

A)glycogen > ATP > glucose > fatty acids > phosphocreatine
B)ATP > phosphocreatine > glycogen >glucose > fatty acids
C)phosphocreatine > glucose > ATP > fatty acids > glycogen
D)fatty acids > phosphocreatine > ATP > glucose > glycogen

Question 35

In which area is glucose NOT pivotal to adipocyte metabolism?

A)formation of DHAP for reduction and esterification of fatty acids
B)provision of glucose-6-phosphate for generating NADPH from the pentose phosphate pathway
C)synthesis of ketone bodies
D)conversion of glucose to fatty acids for storage and export