Deck 19: Metabolic Integration

Question 1

Which of the following would show increased activity levels in a liver cell after exposure to insulin?

A) phosphorylase kinase
B) phosphofructokinase-1
C) glycogen phosphorylase
D) fructose-1,6-bisphosphatase

Answer 1

phosphofructokinase-1

Question 2

The synthesis of dihydroxyacetone phosphate from amino acid backbones and lactate is carried out by the pathway.

A) triacylglycerol
B) lactate
C) triphosphate
D) glyceroneogenesis

Answer 2

glyceroneogenesis

Question 3

The expected outcome in adipose tissue after exposure to glucagon would be an increased

A) glucose uptake through GLUT4.
B) glycerol synthesis.
C) fatty acid uptake from lipoprotein particles.
D) triacylglycerol hydrolysis.

Answer 3

triacylglycerol hydrolysis.

Question 4

Which of the following activates triacylglycerol hydrolysis and fatty acid export in adipose tissue?

A) insulin
B) glucagon
C) somatostatin
D) LpL

Question 5

Glucagon-like peptide-1 (GLP-1) is a hormone peptide secreted by intestinal L cells. It is secreted in response to the nutrient detection in the small intestine. The resulting physiological response is the lowering of blood glucose levels. Which of the following is a potential mechanism for how GLP-1 causes this physiological response?

A) stimulation of glucagon release
B) stimulation of insulin release by pancreatic $\beta$ cells
C) increase in the apoptosis rate of pancreatic $\beta$ cells
D) downregulation of GLUT4

Question 6

Which tissue participates in the Cori cycle in order to maintain metabolic homeostasis?

A) skeletal muscle
B) adipose tissue
C) kidney
D) brain

Question 7

The blood-brain barrier results from , which allow glucose and to enter the brain.

A) astrocytes; ketone bodies
B) astrocytes; triacylglycerols
C) hepatocytes; ketone bodies
D) hepatocytes; triacylglycerols

Question 8

Which of the following is secreted by visceral fat?

A) glucagon
B) adipokines
C) somatostatin
D) phosphocreatine

Question 9

Which organ is responsible for regulating physiological levels of glucose?

A) liver
B) muscle
C) adipose tissue
D) brain

Question 10

Glucagon stimulates glucose export by increasing metabolic flux through gluconeogenesis in the

A) liver.
B) skeletal muscle.
C) adipose.
D) brain.

Question 11

On exposure to insulin, the liver responds by upregulating , which in turn causes the upregulation of _.

A) protein phosphatase 2A; acetyl-CoA carboxylase
B) protein phosphatase 2A; glycogen synthase
C) protein phosphatase 1; phosphorylase kinase
D) protein phosphatase 1; glycogen phosphorylase

Question 12

The pancreatic cell type that is responsible for the production of somatostatin is the cells.

A) "acinar"
B) " $\alpha$ "
C) " $\beta$ "
D) " $\gamma$ "

Question 13

A comparison of kidney and liver would show that both

A) accept blood through the portal vein.
B) express glucokinase.
C) express phosphoenolpyruvate carboxykinase.
D) express adipokines.

Question 14

Which of the following is unlikely to affect metabolic homeostasis?

A) physical activity
B) tissue dysfunction
C) psychological stress
D) telomere duplication

Question 15

Metabolic homeostasis relies on maintaining

A) maximum ATP synthase activity.
B) optimal metabolite concentrations.
C) maximum flux through the citric acid cycle.
D) minimal inhibition of gluconeogenesis.

Question 16

Predict the metabolic outcome of a partial inhibition of lipoprotein lipase.

A) Neurons in the brain would no longer use free fatty acids as a fuel source.
B) Rates of glycogen breakdown in heart muscle would increase.
C) Levels of ketone bodies in the blood would decrease.
D) Liver lactate dehydrogenase activity levels would decrease.

Question 17

Analysis of various cell types after exposure to insulin would show an increase in triacylglycerol synthesis in which of the following?

A) brain
B) skeletal muscle
C) liver
D) pancreas

Question 18

Skeletal muscle can use all of the following as metabolic fuel EXCEPT

A) glucose.
B) free fatty acids.
C) chylomicrons.
D) ketone bodies.

Question 19

What is the expected outcome in a liver cell after exposure to insulin?

A) activation of fructose-1,6-bisphosphatase
B) allosteric inhibition of protein phosphatase 1
C) phosphorylation of phosphofructokinase-2/fructose-2,5-bisphosphatase
D) increased cytoplasmic concentration of fructose-2,6-bisphosphate

Question 20

Which tissue participates in the triacylglycerol cycle in order to maintain metabolic homeostasis?

A) skeletal muscle
B) liver
C) kidney
D) brain

Question 21

The net effect of leptin signaling in humans includes

A) decreased appetite.
B) decreased basal metabolic rates.
C) increased set point.
D) decreased thrifty gene expression.

Question 22

PPARs have a variety of functions in lipid metabolism that include all EXCEPT

A) regulation of lipid transport.
B) mobilization of fatty acid oxidation.
C) mobilization of lipid synthesis.
D) decreasing insulin sensitivity.

Question 23

Leptin is a

A) mutated form of insulin.
B) hormone receptor expressed in adipocytes.
C) adipocyte peptide hormone.
D) recessive gene that causes obesity.

Question 24

A lack of energy balance may lead to

A) type 1 diabetes.
B) a BMI value of less than 30, indicating obesity.
C) type 2 diabetes.
D) increased skeletal muscle breakdown.

Question 25

Thrifty genes are __________ during times of starvation and __________ when physical activity is low.

A) beneficial; beneficial
B) beneficial; detrimental
C) detrimental; detrimental
D) detrimental; beneficial

Question 26

Analysis of enzyme activity in both liver and muscle cells on insulin exposure would show a decrease in the activity of

A) glycogen phosphorylase.
B) fructose-1,6-bisphosphatase.
C) pyruvate dehydrogenase complex.
D) phosphofructokinase-1.

Question 27

Human gene variants favoring individuals with a capacity to store extra fat during times of feast are known as

A) Neel variants.
B) thrifty genes.
C) leptos genes.
D) Pima variants.

Question 28

Which of the following changes in metabolic flux would be expected to occur during long periods without food?

A) decreased release of fatty acids from adipose tissue
B) decreased gluconeogenesis in liver and kidney cells
C) decreased ketogenesis in liver cells
D) protein degradation in skeletal muscle

Question 29

The set point can be increased as a result of

A) a sedentary lifestyle.
B) starvation.
C) negative energy imbalance.
D) weight loss.

Question 30

During periods of starvation, gluconeogenesis increases in the liver. Which of the following is a major substrate for glucose biosynthesis under these conditions?

A) glutamate
B) alanine
C) urea
D) fatty acids

Question 31

The average amount of adipose tissue the body maintains at physiological homeostasis is known as the

A) energy balance.
B) adipose energy balance.
C) BMI.
D) set point.

Question 32

Neuronal samples from wild-type mice were monitored in the absence and presence of leptin via Western blotting. The data are shown below. Choose the answer that correctly identifies the NPY/AGRP neuronal samples obtained in the absence and then the presence of leptin.

A) B; C
B) D; B
C) A; C
D) C; A

Question 33

The graph below shows the relative changes in concentration of glucose, fatty acids, and ketone bodies during 40 days of starvation. Choose the answer that correctly labels the data on the graph.

A) X = fatty acids; Y = glucose; Z = ketone bodies
B) X = glucose; Y = fatty acids; Z = ketone bodies
C) X = ketone bodies; Y = glucose; Z = fatty acids
D) X = ketone bodies; Y = fatty acids; Z = glucose

Question 34

What might occur if a mutation in the leptin receptor causes it to be always activated, even in the absence of leptin?

A) "JAK2 will be activated."
B) " $\alpha$ -MSH secretion will be low."
C) "NPY secretion will be high."
D) "AGRP secretion will be high."

Question 35

Which of the following neurons is a second-order neuron and therefore does NOT respond directly to leptin?

A) POMC
B) orexigenic
C) NPY
D) AGRP

Question 36

Which of the following is NOT one of the three peroxisome proliferator-activated receptor nuclear receptor proteins that function in metabolic homeostasis?

A) PPAR $\alpha$
B) PPAR $\beta$
C) PPAR $\delta$
D) PPAR $\gamma$

Question 37

Enzyme activities after PPAR signaling were monitored in both liver and skeletal muscle. When compared with activities before PPAR signaling, which of the following would have been found to increase in liver but NOT in skeletal muscle?

A) acyl CoA dehydrogenase
B) enoyl-CoA hydratase
C) transketolase
D) acetyl-CoA acetyltransferase

Question 38

When basal metabolic rates are decreased and appetite is increased, which type of neurons are likely activated?

A) anorexigenic
B) orexigenic
C) POMC
D) ghrelin

Question 39

DB mice display the __________ phenotype and express leptin levels when compared with OB mice.

A) same; higher
B) same; lower
C) different; higher
D) different; lower

Question 40

Analysis of enzyme activity in both liver and muscle cells on insulin exposure would show an increase in the activity of which of the following?

A) glucokinase
B) protein phosphatase 2A
C) glycogen phosphorylase
D) pyruvate dehydrogenase complex

Question 41

Compared with a normal patient, a person with type 1 diabetes would display during a glucose tolerance test.

A) lower starting blood glucose level
B) more rapid rise in blood glucose levels after drinking the glucose solution
C) more rapid recovery to normal blood glucose levels after drinking the glucose solution
D) reduction in blood glucose levels after drinking the glucose solution

Question 42

Orlistat and olestra can both lead to undigested lipids in the colon, yet they do so by contrasting mechanisms. Orlistat __________, whereas olestra _.

A) inhibits pancreatic lipase; activates PPAR $\gamma$
B) inhibits pancreatic lipase; is a fat substitute that is not a substrate for pancreatic lipase
C) is a fat substitute that is not a substrate for pancreatic lipase; inhibits pancreatic lipase
D) activates PPAR $\gamma$ ; inhibits pancreatic lipase

Question 43

Analysis of a patient with metabolic syndrome would indicate low

A) HDL levels.
B) LDL levels.
C) blood pressure.
D) visceral fat.

Question 44

Which of the following would be expected to be degraded by the proteasome in a cell that has been exposed to TNF- $\alpha$ ?

A) IRS1
B) phosphorylated IRS1
C) phosphorylated IF $\kappa$ B $\alpha$
D) NF $\kappa$ B

Question 45

Serum levels of high-molecular-weight adiponectin are in obese individuals, in part because of __________ suppression of adiponectin expression.

A) decreased; TNA- $\alpha$
B) decreased; insulin
C) increased; TNA- $\alpha$
D) increased; insulin

Question 46

Thiazolidinedione activates PPAR $\gamma$ in adipose tissue. This results in the upregulation of

A) TNF- $\alpha$ .
B) plasminogen activator inhibitor 1.
C) interleukin-6.
D) phosphoenolpyruvate carboxykinase.

Question 47

Modify the schematic below by properly labeling the four neurons (W, X, Y, and Z).

A) W = orexigenic; X = anorexigenic; Y = POMC; Z = NPY/AGRP
B) W = anorexigenic; X = orexigenic; Y = NPY/AGRP; Z = POMC
C) W = anorexigenic; X = orexigenic; Y = POMC; Z = NPY/AGRP
D) W = anorexigenic; X = orexigenic; Y = NPY/AGRP; Z = POMc

Question 48

TNF- $\alpha$ causes the __________ of insulin signaling in _.

A) inhibition; muscle cells
B) activation; liver cells
C) activation; adipocytes
D) activation; kidney cells

Question 49

Activation of __________ in __________ leads to downregulation of adiponectin.

A) IKK; adipocytes
B) p38 MAP kinase; adipocytes
C) p38 MAP kinase; liver cells
D) JNK; adipocytes

Question 50

Monitoring fatty acid metabolism in a patient before and after administration of metformin would show a decrease of fatty acid synthesis in and an increase in fatty acid oxidation in .

A) liver; heart
B) liver; adipose tissue
C) adipose tissue; liver
D) skeletal muscle; heart

Question 51

What might be the outcome of a mutation that causes the adiponectin receptor to be constitutively activated?

A) very low levels of GLUT4 in muscle cell membranes
B) high levels of acetyl-CoA carboxylase activity
C) insulin resistance
D) highly activated AMPK

Question 52

Metformin is a(n)

A) " $\alpha$ -glucosidase inhibitor."
B) "sulfonylurea inhibitor of pancreatic ATP-dependent K+ channels."
C) "AMPK stimulator."
D) "PPAR $\gamma$ agonist."

Question 53

Which protein will be phosphorylated in a muscle cell in an obese individual with elevated serum levels of free fatty acids?

A) protein kinase C
B) insulin receptor
C) IRS1
D) GLUT1

Question 54

A patient has been diagnosed with metabolic syndrome. To establish the diagnosis, the doctor likely performed several tests. A test that the doctor was UNLIKELY to perform would be

A) an assessment of abdominal obesity.
B) fasting followed by glucose tolerance test to establish insulin sensitivity.
C) monitoring of blood pressure.
D) a blood test for lipid levels.

Question 55

Muscle cells from normal and obese type 2 diabetic patients were analyzed for plasma membrane lipid content. Which of the following would likely be elevated in the diabetic patient?

A) IR
B) IRS1
C) IP3
D) DAG

Question 56

After a meal is consumed by an individual with chronically elevated levels of free fatty acids, __________ is expected to occur.

A) increased glucose uptake
B) increased activation of protein kinase C
C) increased glycogen synthesis
D) activation of the phosphoinoside-3 kinase pathway

Question 57

Which of the following drugs stimulate adrenergic receptor signaling?

A) ephedrine
B) lorcaserin
C) orlistat
D) thiazolidinedione

Question 58

Anorexigenic neurons express the receptor.

A) MC4
B) Y1/Y5
C) Y2
D) NPY

Question 59

Adiponectin is

A) a lipid hexamer.
B) a multimeric protein.
C) produced by the pancreas.
D) produced at high levels in obese people.

Question 60

Whipple surgery, sometimes carried out on patients battling pancreatic cancer, is one of the most demanding surgeries to perform. It involves removing parts of the pancreas and rerouting aspects of the digestive track. Which of the following side effects may result from Whipple surgery?

A) "type 1 diabetes"
B) "type 2 diabetes"
C) "leptin insensitivity"
D) " $\alpha$ -MSH overproduction"

Question 61

The exchange of fatty acids and triacylglycerols between the liver and adipose tissue is an ongoing process that helps maintain metabolic homeostasis. What is the name of this process?

Question 62

The numerical value of a food that indicates how quickly glucose is released into the blood is called the

A) calorie.
B) GRP (glucose-release point).
C) set point.
D) glycemic index.

Question 63

What is the fuel source for ATP production that is used in a 200-meter sprint?

A) muscle phosphocreatine
B) liver glycogen
C) muscle glycogen
D) adipose tissue fatty acids

Question 64

Analysis of phosphorylated proteins in a cell with a fully active AMPK would reveal that is phosphorylated.

A) cytochrome oxidase
B) cytochrome c
C) phosphofructokinase-2
D) PPAR $\alpha$

Question 65

AMPK can be activated by

A) high-fat diet.
B) exercise.
C) fasting.
D) PPAR $\alpha$ .

Question 66

Fad diets may lead to biochemical outcomes that are unfavorable. Which diet may lead to ketoacidosis?

A) Atkins diet
B) Ornish diet
C) Weight Watchers
D) olestra-rich diet

Question 67

When AMPK is bound by AMP and is phosphorylated at Thr172, activity will .

A) glycogen synthase; increase
B) phosphofructokinase-2; decrease
C) acetyl-CoA carboxylase; increase
D) hormone-sensitive lipase; decrease

Question 68

How can hormone(s) cause the upregulation of the glucose transporter type 4 protein in liver and adipose cells?

Question 69

Which list correctly places the foods in order of lowest to highest glycemic index?

A) corn chips < soda < cherries
B) peanuts < donut < skim milk
C) broccoli < soda < corn chips
D) donut < broccoli < pretzel

Question 70

A steep drop in blood glucose concentration occurs after consumption of high glycemic index foods because of a(n)

A) insulin spike.
B) glucagon spike.
C) insulin drop.
D) catecholamine spike.

Question 71

Most fad diets do not work because

A) they cost too much.
B) 40% of people do not "stick to it."
C) they increase caloric intake.
D) they slow metabolism because of a lack of micronutrient consumption.

Question 72

What are the two aspects of energy within an organism that must be considered to determine the energy balance?

Question 73

What fuel source will last the longest before being depleted during intense exercise?

A) liver glycogen
B) muscle phosphocreatine
C) muscle ATP
D) adipose tissue fatty acids

Question 74

What are the concentrations of glucose that would be expected of a healthy individual after an 8-hour fast and after consuming a large soft pretzel?

A) 80 mg/dL; 130 mg/dL
B) 130 mg/dL; 180 mg/dL
C) 75 mg/dL; 100 mg/dL
D) 125 mg/dL; 75 mg/dL

Question 75

What is the process of maintaining optimal metabolic concentrations and managing chemical energy reserves in tissues? Describe the three primary factors that influence this process.

Question 76

During intense exercise, muscle ATP stores will be depleted in about

A) 3 minutes.
B) 5 minutes.
C) 30 seconds.
D) 3 seconds.

Question 77

Distinguish between the main energy sources of brain versus cardiac muscle.

Question 78

Fully active AMPK results in an increase in all pathways listed EXCEPT

A) glycolytic flux.
B) fatty acid oxidation.
C) oxidative phosphorylation.
D) fatty acid synthesis.

Question 79

Which of the following functions by specifically targeting neuronal control of food consumption?

A) ephedrine
B) olestra
C) lorcaserin
D) orlistat

Question 80

Reduced levels of molecular-weight serum adiponectin in obese individuals results in activation of AMPK signaling in muscle cells.

A) low; decreased
B) low; increased
C) high; decreased
D) high; increased