Deck 18: Interorgan and Intracellular Coordination of Energy Metabolism in Vertebrates

Question 1

Which of the following is commonly stored as an energy reserve by the heart?

A)glycogen
B)creatine phosphate
C)triacylglycerols
D)ketone bodies
E)lactate

Answer 1

B

Question 2

Which of the following hormones is correctly described?

A)ghrelin: produced in pancreas,stimulates appetite
B)adiponectin: produced in adipose tissue,stimulates appetite
C)insulin: produced in pancreas,stimulates appetite
D)leptin: produced in intestines,suppresses appetite
E)none of the above

Answer 2

B

Question 3

For each of the following biochemical pathways,give the effect of each hormone as either activated ( $\uarr$ ),inhibited ( $\downarrow$ )or no effect (NE).

Answer 3

Question 4

Which of the following types of tissue can use glucose,but not fatty acids,as a source of fuel?

A)skeletal muscle
B)cardiac muscle
C)liver
D)brain
E)adipose

Question 5

Which of the following pathways would be active between meal when blood glucose is low but inactive after several days of starvation?

A)glycogenolysis
B)lipolysis
C) $\beta$ -oxidation
D)ketogenesis
E)gluconeogenesis

Question 6

Which of the following is true of glucagon?

A)it is released from the pancreatic $\beta$ -cells when glucose levels are low
B)its synthesis and release are exclusively under the control of epinephrine
C)the primary targets of glucagon are liver,adipose and muscle tissue
D)major pathways promoted by glucagon include glycogenolysis and glycolysis
E)none of the above

Question 7

What process in the brain consumes most of the ATP that is produced?

A)movement of actin/myosin
B)maintenance of membrane potentials
C)active transport of glucose and amino acids
D)cellular growth
E)none of the above

Question 8

Which of the following molecules is made in the liver solely for export?

A)ketone bodies
B)triacylglycerols
C)glucose-6-phosphate
D)glycogen
E)none of the above

Question 9

For skeletal muscle,which of the following correctly pairs the activity state with the source of energy?

A)resting: glucose
B)resting: amino acids
C)exertion: glucose
D)exertion: fatty acids
E)none of the above

Question 10

Which of the following transporters is only present on the surface of muscle cells following insulin binding?

A)GLUT1
B)GLUT2
C)GLUT3
D)GLUT4
E)GLUT5

Question 11

Although AMPK and mTOR generally play opposing roles in metabolic control,which of the following pathways is activated by both of these molecules?

A)glucose transport
B)glycolysis
C)gluconeogenesis
D)cholesterol synthesis
E)none of the above

Question 12

Under starvation conditions,which of the following shows an increase in activity in the first few days,followed by a large decrease in activity after a week?

A)use of ketone bodies by the brain
B)lipolysis
C)glycolysis
D)muscle protein mobilization
E)none of the above

Question 13

Which of the following is the ultimate action that causes release of insulin from pancreatic $\beta$ -cells?

A)opening of ATP-gated K⁺ channels
B)closing of ATP-gated K⁺ channels
C)catabolism of glucose resulting in increased ATP
D)opening of voltage gated Ca²⁺ channels leading to decreased cytosolic Ca²⁺
E)opening of voltage gated Ca²⁺ channels leading to increased cytosolic Ca²⁺

Question 14

Which of the following pathways is activated in response to phosphorylation of key enzymes by AMPK?

A)glycogenolysis in the heart
B)glycolysis in the heart
C)gluconeogenesis in the liver
D)fatty acid synthesis in the liver
E)triacylglycerol synthesis in the liver

Question 15

Which of the following hormones affects the arcuate nucleus of the hypothalamus and ultimately results in an inhibition of nutrient intake?

A)adiponectin
B)leptin
C)ghrelin
D)glucagon
E)none of the above

Question 16

If a group of transgenic mice that overexpress SIRT1 was fed as much food as the mice desired to eat,what would be the consequences?

A)shortened lifespan with increased incidence of age-related diseases such as diabetes and cardiovascular disease
B)normal lifespan with increased incidence of age-related diseases
C)normal lifespan with no increased incidence of age-related diseases
D)lengthened lifespan with increased incidence of age-related diseases
E)lengthened lifespan with no increased incidence of age-related diseases

Question 17

The two hypotheses for insulin resistance are the lipid overload and the inflammation hypotheses.The lipid overload hypothesis primarily involves fat accumulation in __________ tissue while the inflammation hypothesis primarily involves secretion of inflammatory molecules from ___________ tissue.

A)adipose;liver
B)muscle;adipose
C)adipose;adipose
D)muscle;liver
E)adipose;muscle

Question 18

For each of the following tissue types,list the fuel(s)stored,preferred fuel(s)and exported fuel(s)under normal conditions.

Question 19

The transcription factor PGC-1 $\alpha$ is controlled by two forms of covalent modification.Which of the following correctly identifies a mechanism of control?

A)phosphorylation by AMPK inhibits PGC-1 $\alpha$
B)dephosphorylation by AMPK activates PGC-1 $\alpha$
C)acetylation by SIRT1 activates PGC-1 $\alpha$
D)deacetylation by SIRT1 activates PGC-1 $\alpha$
E)dephosphorylation by AMPK and deacetylation by SIRT1 activates PGC-1 $\alpha$

Question 20

What is the general reaction type catalyzed by most of the sirtuins?

A)deadenylation
B)deacetylation
C)dehydrogenation
D)deamination
E)dehydration

Question 21

For each of the following liver enzymes,indicate what happens to the enzyme (i.e. ,phosphorylated/dephosphorylated…)when the cell is under the influence of glucagon.Indicate whether the enzyme is activated or inhibited and how that contributes to the overall role of glucagon.

PFK-2:

Pyruvate kinase:

Fruc-1,6-BPase:

Glycogen phosphorylase: