Unit XIII (68-74) - Metabolism and Temperature Regulation

Question 1

ATP is present in all cells.

True or False

Answer 1

True

Guyton Pg 853

Question 2

Which of the following constitutes 80% of the products of carbohydrate digestion in the GIT?

A. Glucose
B. Fructose
C. Galactose
D. Xylose

Answer 2

A. Glucose

Guyton Pg 854

Question 3

Which of the following enzymes breaks up glucose-6-phosphate into glucose and phosphate?

A. Phosphorylase
B. Glucose phosphatase
C. Glucokinase
D. Hexokinase

Answer 3

B. Glucose phosphatase

Guyton Pg 854

Question 4

By what mechanism does glucose get transported into the cytoplasm of the cell?

A. Pores
B. Endocytosis
C. Facilitated diffusion
D. Pinocytosis

Answer 4

C. Facilitated diffusion by binding properties of membrane glucose carrier protein

Guyton Pg 854

Question 5

Which of the following hormones has the greatest effect on promoting facilitated diffusion of glucose?

A. Glucagon
B. Insulin
C. Estrogen
D. Thyroxine (T4)

Answer 5

B. Insulin

Guyton Pg 855

Question 6

In the liver, which of the following enzymes catalyzes the phosphorylation of glucose to glucose-6-phosphate?

A. Glucose phosphatase
B. Hexokinase
C. Glucokinase
D. Phosphorylase

Answer 6

C. Glucokinase; Hexokinase catalyzes the same reaction but in most OTHER cells vs the liver.

Guyton Pg 855

Question 7

Where is glycogen stored in the largest quantities?

A. Liver and kidneys
B. Liver and lung
C. Muscle and kidneys
D. Liver and muscle

Answer 7

D. Liver and muscle

Guyton Pg 855

Question 8

The phosphorylation of glucose is reversible in which of the following cells (SELECT ALL THAT APPLY)?

A. Hepatocytes
B. Renal tubular epithelial cells
C. Intestinal epithelial cells
D. Cardiac myocytes

Answer 8

A, B, and C. Hepatocytes, renal tubular epithelial cells, and intestinal epithelial cells. Glucose phosphatase is available and when activated can reverse the reaction.

Guyton Pg 855

Question 9

Which of the following is the correct pathway of glycogenesis?

A. Glucose-6-phosphate –> Glucose-1-phosphate –> Uridine diphosphate glucose –> Glycogen
B. Glucose-6-phosphate –> Uridine diphosphate glucose –> Glucose-1-phosphate –> Glycogen
C. Glucose-1-phosphate –> Glucose-6-phosphate –> Uridine diphosphate glucose –> Glycogen
D. Glucose-1-phosphate –> Uridine diphosphate glucose –> Glucose-6-phosphate –> Glycogen

Answer 9

A. Glucose-6-phosphate –> Glucose-1-phosphate –> Uridine diphosphate glucose –> Glycogen

Guyton Pg 855

Question 10

During rest, the enzyme phosphorylase is

A. Active
B. Inactive

Answer 10

B. Inactive because phosphorylase phosphorylates glycogen to break it down into glucose for energy (energy is not needed during rest, this promotes storage of glycogen).

Guyton Pg 856

Question 11

Which of the following pyrogens acts directly on the hypothalamus?
A.	LPS from bacterial wall
B.	IL – 1
C.	Bacterial endotoxins
D.	Prostaglandin E2

Answer 11

Answer: B
Ref: Guyton P. 920

Question 12

Which of the following can cause a decrease in basal metabolic rate? 
A.	Fever
B.	Malnutrition
C.	Growth hormone
D.	Testosterone

Answer 12

Answer: B
Ref: Guyton P. 908

Question 13

Which one of the following tissues primarily has GLUT 4?

a. Erythrocytes
b. Skeletal muscle
c. Endothelial cells of the blood-brian-barrer
d. Beta-cells of the pancreas

Answer 13

Correct: B Skeletal muscle

Question 14

Which one of the following is insulin dependent?

a. GLUT 1
b. GLUT 2
c. GLUT 3
d. GLUT 4

Answer 14

Correct: D GLUT 4

Question 15

Which of the lipoproteins transports triglycerides mainly to adipose tissue?

a. VLDL
b. HDL
c. LDL
d. VHDL

Answer 15

Correct: A VLDL

Question 16

Which of the following lipoproteins is protective against atherosclerosis?

a. VLDL
b. HDL
c. LDL
d. VHDL

Answer 16

Correct: B HDL

Question 17

Which of the following lipoproteins transports triglycerides from the liver to various tissues in the body?

a. VLDL
b. HDL
c. LDL
d. VHDL

Answer 17

Correct: C LDL

Question 18

Are fatty acids generally found bound to albumin or free in the blood?

a. bound
b. free

Answer 18

Correct: A Bound

Question 19

What is the alternative pathway (to the glycolytic pathway) in the formation of fatty acids?

a. B-oxidation
b. Kreb’s cycle
c. Glycolysis
d. Pentose phosphate pathway

Answer 19

Correct: D Pentose phosphate pathway

Question 20

How many moles of ATP are formed from a triglyceride molecule?

a. 8
b. 18
c. 28
d. 38

Answer 20

Correct: B 18 from fat

Reminder: 38 from carbs

Question 21

Ketoacidosis is a result of a deficiency in which one of the following? (The deficiency limits entry of acetyl-CoA into the citric acid cycle.)

a. Oxaloacetate
b. Citrate
c. Succinate
d. Fumarate

Answer 21

Correct: A Oxaloacetate

Question 22

Name the triglycertide-rich lipoprotein that is synthesized by the liver?

a. VLDL
b. HDL
c. LDL
d. VHDL

Answer 22

Correct: A VLDL

Question 23

Name the rate-limiting enzyme in cholesterol synthesis.

a. HMG-CoA reductase
b. HMG-CoA synthase
c. Famesyl diphosphate synthase
d. Lanosterol synthase

Answer 23

Correct: A HMG-CoA reductase

Question 24

HDL returns cholesterol to the liver in a pathway known as ________?

a. Receptor-mediated endocytosis
b. Exogenous pathway
c. Reverse cholesterol transport
d. Endogenous pathway

Answer 24

Correct: C Reverse cholesterol transport

Question 25

What is the mechanism used by cell to take up LDL cholesterol from the circulation? a. Receptor-mediated endocytosis b. Exogenous pathway c. Reverse cholesterol transport d. Endogenous pathway

Answer 25

Correct: A Receptor-mediated endocytosis

Question 26

What protein is required for receptor-mediated endocytosis that allows LDL uptake from the circulation? a. VLDL receptor b. HDL receptor c. LDL receptor d. VHDL receptor

Answer 26

Correct: C LDL receptor

Question 27

Which one of the following proteins is integral to buffering the blood? a. albumin b. IgG c. hepsidin d. IgM

Answer 27

Correct: A albumin

Question 28

Which of the following organs primarily stores proteins? a. Kidneys b. Liver c. Heart d. Brain

Answer 28

Correct: B Liver

Question 29

Which of the following enzymes initiates deaminiation of proteins? a. Glutamate dehydrogenase b. Aminotransferase c. Dehydrogenase d. Isomerase

Answer 29

Correct: B Aminotransferase

Question 30

Which of the following hormones promotes fat synthesis by stimulating lipoprotein lipase? a. Glucocorticoids b. Insulin c. Glucagon d. Thyroid hormone

Answer 30

Correct: B Insulin

Question 31

Which of the following hormones decreases liver glycogenolysis? a. Glucagon b. Epinepherine c. Glucocorticoids d. Growth hormone

Answer 31

Correct: C Glucocorticoids

Question 32

Which one of the following hormones decreases liver gluconeogenesis? a. Insulin b. Glucagon c. Epinephrine d. Glucocorticoids

Answer 32

Correct: A Insulin

Question 33

Which one of the following hormones decreases protein synthesis? a. Insulin b. Glucocorticoids c. Thyroid hormone d. Growth hormone

Answer 33

Correct: B Glucocorticoids

Question 34

What is the most abundant store of high-energy phosphate bonds in the cells a. ATP b. Phosphocreatine c. Glucose-6-Phosphate d. Phosphofructokinase

Answer 34

Answer: B (Guyton Ch 73)

Question 35

Which mechanism of heat loss is the most important at high temperatures? a. Conduction b. Convection c. Evaporation d. Radiation

Answer 35

Answer: C (Guyton Ch 74)

Question 36

Which tissue is especially susceptible to damage by hyperpyrexia ? a) liver b) brain c) kidneys d) red blood cells

Answer 36

Answer : b; Guyton (12th edition), p. 876-877

Question 37

Which of the following best describes nonshivering thermogenesis in response to cold stress ? a) Sympathetic stimulation of muscle → production of a large amounts of heat and ATP b) Sympathetic stimulation of brown fat → production of a large amounts of heat and ATP c) Sympathetic stimulation of white fat → production of a large amount of heat but almost no ATP d) Sympathetic stimulation of brown fat → production of a large amount of heat but almost no ATP

Answer 37

Answer : d; Guyton (12th edition), p. 865

Question 38

What is the rate limiting factor of energy release in resting conditions? a. ADP b. ATP c. GDP d. GTP

Answer 38

Answer: A

Question 39

Which of the following does not increase metabolic rate? a. Fever b. Thyroid hormone c. Sleep d. Growth hormone e. Appropriate nutrition

Answer 39

Answer: C

Question 40

When ambient temperature becomes greater than the temperature of skin, what type of cooling is utilized and effective? a. Convection b. Conduction c. Radiation d. Evaporation

Answer 40

Answer: D

Question 41

Where is the panting center in dogs that becomes activated when they overheat? a. Temperature regulating centers in the hypothalamus b. Pneumotaxic center in the pons c. Somatosensory neurons d. Primary motor center in the posterior hypothalamus

Answer 41

Answer: B

Question 42

When a mammal is cold, the hypothalamus causes all of the following except which mechanism for maintaining body temperature? a. Non-shivering thermoregulation b. Shivering c. Vasoconstriction d. All of these are methods of maintaining core body temperature

Answer 42

Answer: D

Question 43

What factors contribute to heat stroke in dogs? a. As body heat rises, the metabolic rate decreases b. Evaporation does not remain an effective method of heat loss c. Since cell function continues appropriately, there is continued heat production from metabolism d. Humidity levels remain static despite panting

Answer 43

Answer: B

Question 44

Which of the following correctly describes the biologic function of phosphocreatinine? a. A backup energy source that can be used instead of ATP to power cellular metabolism b. A transfer molecule carrying high energy electrons to the electron transport chain c. An energy buffer allowing quick restoration of intracellular ATP pools d. An alternative energy source used for energetically demanding reactions only due to the presence of a phosphate bond that can release more energy than ATP

Answer 44

Answer c (Guyton 904)

Question 45

Which of the following are pyrogenic? a. IL-1 b. IL-2 c. IL-10 d. TGFB

Answer 45

Answer a (Guyton 920)

Question 46

By which method is heat transferred from deep tissues to the skin? a. Convection b. Radiation c. Conduction d. evaporation

Answer 46

Answer: Convection

Question 47

An increase in this endogenous product results in an increase in the hypothalamic temperature set point in the face of a fever a. Prostaglandin E2 b. IL-6 c. IL-1 d. TNFa

Answer 47

Answer: PGE2

Question 48

Which of the following species does not have a carotid rete for thermoregulation? a. Dogs b. Cats c. Horses d. Cattle

Answer 48

Answer: C Horses; Cunningham pg 562

Question 49

In most species sweating is under the control of A] Sympathetic adrenergic nerve fibers B] Sympathetic cholinergic nerve fibers C] Parasympathetic adrenergic nerve fibers D] Adrenal medulla

Answer 49

Answer: B Cunningham Chapter 53, pg 563

Question 50

When substrate concentrations become low, the rate of metabolic reactions depend upon A] Substrate concentration B] Enzyme concentration C] Both of the above D] None of the above

Answer 50

Answer: C Guyton and Hall Chapter 73

Question 51

Which of the following correctly describes the carotid rete found in sheep and other ungulates? A. The carotid artery takes a tortuous path to the brain and thus heat dissipates as it travels. By the time the blood reaches the brain, it has cooled sufficiently. B. The carotid rete is a countercurrent mechanism between the jugular vein and carotid artery. The artery loses heat to the vein as blood flows in opposite directions. C. The carotid artery forms a complex network of vessels that is bathed in a sinus of arterial blood that supplies the nasal cavity. The arterial blood is therefore colder due to exposure to the environment of the nasal cavities, thus the arterial blood transfers and loses heat to the cooler sinuses and the blood delivered to the brain is cooled prior to entering the brain. D. The carotid artery forms a complex network of vessels that is bathed in a sinus of venous blood that has drained the nasal cavity. The venous blood is therefore colder than the arterial blood, thus the arterial blood transfers and loses heat to the cooler veins and the blood delivered to the brain is cooled prior to entering the brain.

Answer 51

Correct Answer: D | Ref: Cunningham, pg. 561-562

Question 52

Which molecule is considered a reserve of energy and forms when excess ATP is present in the body? a. Creatine Kinase b. Phosphocreatine c. Guanine Triphosphate d. Adenosine Monophosphate

Answer 52

Correct Answer: B | Ref: Guyton pg. #904

Question 53

Which of the following cytokines is considered most important in the development of fever? a. IL-1 b. IL-2 c. IL-6 d. IL-13

Answer 53

Answer: A

Question 54

In most species (except horses), sweating is controlled by which type of nerve fibers? a. sympathetic adrenergic b. sympathetic cholinergic c. parasympathetic adrenergic d. parasympathetic cholinergic

Answer 54

Answer: B

Question 55

The most abundant store of high-energy phosphate bonds in the body is normally: A. Adenosine triphosphate (ATP) B. Phosphocreatine C. Phosphofructokinase D. Glycogen

Answer 55

ANSWER: B (Guyton Ch 73)

Question 56

``` The following hormone plays a crucial role in acclimization to heat: A. Thyroid hormone B. Antidiuretic hormone C. Angiotensin II D. Aldosterone ```

Answer 56

ANSWER: D (Guyton Ch 74)

Question 57

Which of the following will decrease the body’s metabolic rate? a. Increased temperature b. Increased thyroid hormone c. Prolonged malnutrition d. Increased growth hormone

Answer 57

Answer: C. Reference: Guyton Ch. 73 Pg. 908

Question 58

What is the only means by which the body can rid itself of heat when the temperature of the surroundings is greater than the skin temperature itself? a. Radiation b. Convection c. Conduction d. Evaporation

Answer 58

Answer: D. Reference: Guyton Ch. 74 Pg. 913

Question 59

Which of the following is mainly a PHYSIOLOGIC mechanism to increase body temperature? a) Decreased thyroid releasing hormone secretion from the hypothalamus b) Increased neural release of norepinephrine c) Release of IL-1 from macrophages d) Increased ATP production from oxidative phosphorylation

Answer 59

Answer: B (Chu). C) this is a pathologic cause that is usually induced by bacteria. Source: Guyton Ch. 73 p. 909 and Ch. 74 p. 911

Question 60

Which of the following is the most important mechanism to decrease core body temperature when the ambient temperature is higher than body temperature? a) Radiation b) Convection c) Conduction d) Evaporation

Answer 60

Answer: D (Chu); Source: Guyton Ch. 74 p. 913

Question 61

``` Which of the following decreases metabolic rate? A. Male sex hormone B. Thyroid hormone C. Growth hormone D. Fever E. Sleep ```

Answer 61

Correct answer: E. | Ref: Guyton, Ch.73 pg. 908

Question 62

``` Which of the following constitutes the primary mechanism of heat loss from the body? A. Conduction to air B. Conduction to objects C. Convection D. Evaporation E. Radiation of heat waves ```

Answer 62

Correct answer: E. | Ref: Guyton, Ch. 74 pg. 913 (Figure 74-4)

Question 63

``` Which of the following do not increase the metabolic rate? A. Growth Hormone B. Testosterone C. Thyroid Hormone D. Malnutrition ```

Answer 63

Answer: D

Question 64

``` Which of the following neurotransmitters is not stimulatory to sweat glands? A. Epinephrine B. Norepinephrine C. Dopamine D. Acetylcholine ```

Answer 64

Answer: C

Question 65

``` Which anatomical area has more heat-sensitive neurons than cold-sensitive neurons? A. Anterior hypothalamic-preoptic area B. The skin C. Abdominal viscera D. The spinal cord ```

Answer 65

Answer: A