2nd Sem - 5th Evals Batch 2018 Flashcards by Kristine Veneracion

Which organ plays a central role in metabolism?
a. Liver
• considered to be the “mother” of all organs involved in metabolism accdg.
to Doc Uy, since the integration of different metabolic pathways happens
here.
b. Brain
• not involved in metabolic integration
c. Lungs
• not involved in metabolic integration
d. Kidney
• has a minor role in metabolic integration

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The end product of glycolysis in the liver and kidneys is
a. Pyruvate
• major end product of glycolysis
b. Lactate
• only happens when O2 is not present
c. Oxaloacetate
• an intermediate of TCA
d. Glycerol
• involved in Fatty Acid Metabolism

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The following metabolic pathways are active in the liver of a patient with diabetic ketoacidosis, EXCEPT which one?
• remember: diabetic patients particulary type 1 DM, lack insulin to uptake and utilize glucose leading to -> increased gluconeogenesis from amino acids and ketogenesis from increased FFA
b. Lipolysis
• lack of insulin increased the activity of Lipolysis in adipose tissues
c. TCA cycle
• Low insulin, low TCA. Since no glucose was utilized from Glycosis ->
decreased Acetyl-Coa for TCA
d. Glycogenolysis
• Increased Glycogenolysis since the body has to get more energy from the
lack of glucose uptake e. Gluconeogenesis
• increased gluconeogenesis from AA’s for more energy needs

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Carbohydrates can be converted to proteins or amino acids via which of the following pathways?
a. Through intermediates of the TCA cycle
b. From non–essential amino acids
c. Through transamination of keto acids
d. All of the above

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The preferred fuel of the brain is
a. Glucose
b. Ketones
c. Fatty acid
d. Pyruvate

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Which hormone stimulates protein kinase A by increasing cyclic AMP levels? a. Insulin
b. Thyroxine
c. Glucagon
d. Calcitonin

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Ketoacidosis occurs usually in type 1 DM due to
a. Oversecretion of insulin by the pancreas
b. Increased insulin/glucagon ratio
c. Continuous hepatic glycogenesis
d. Accumulation of ketone bodies

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Ammonia toxicity is most likely associated with advancing disease in
a. Liver
b. Brain
c. Kidney d. Pancreas

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The diet in patients with renal disease should be high in which of the following basic nutrients?
a. Protein
b. Carbohydrates
c. Fats
d. All of the above

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A type 1 DM patient is biochemically in a state of “exaggerated starvation”. Which of the
following statement is TRUE when comparing the metabolic milieu that is occurring in untreated type 1 DM and that of a starving patient?
a. During starvation, brain utilizes ketones in the absence of glucose
b. Ketoacidosis occurs both in type 1 DM and starving patiens
c. Glycogen is absent in type 1 DM because of the absence of insulin
d. Muscle proteis are conserved both in type 1 diabetic and starving patient

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Insulin and glucagon are the main hormones that control the metabolism of the major foodstuffs. These two hormones play an important role in the pathophysiology of type 1 diabetes mellitus. The following reactions are occurring biochemically in an uncontrolled type 1 diabetic patient, EXCEPT which one?
a. The liver is always in gluconeogenic and ketogenic state because the insulin/glucagon ratio cannot increase
b. There is increased protein synthesis in the muscle because of increased GLUT 4 activity.
c. Ketoacidosis develops due to accumulation of ketone bodies and hydrogen ions.
d. There is complete absence of insulin production from the pancreas.

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Branched-chain amino acids are widely used as ergogenic supplements. These are
believed to increase time to exhaustion and protect the body against excessive muscle damage. Which of the following are proteinogenic branched-chain amino acids?
a. Phenylalanine, tryptophan, tyrosine
b. Asparagine, glutamine, methionine
c. Valine, leucine, isoleucine
d. Serine, threonine, tyrosine

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13. The conversion of amino acids to carbohydrates is possible through which of the
following processes?
a. Gluconeogenesis
b. Intermediates of TCA cycle
c. Via oxaloacetic acid
d. All of the above

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Most cancers have exceptional capacity for generation of ATP because of the presence of which of the following:
a. Hypoxia-inducible factor 1α
b. Tumor necrosis factor alpha
c. Interleukin I
d. Interleukin 6

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The only known adipocyte secreting factor that increases tissue sensitivity to insulin:
a. Tumor necrosis factor alpha
b. Adiponectin
c. Interleukin I
d. Interleukin 6

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Visceral obesity or the so-called “apple-type” obesity is almost always associated with
insulin resistance. Which of the following plays the major role in the occurrence of insulin resistance?
a. Increased glucose output by the liver
b. Absence of insulin secretion by the pancreas
c. Increased free fatty acids in the circulation
d. Diminished glucose uptake by the muscle

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During prolonged fasting, insulin secretion is low and glucagon secretion is high, resulting in increased cAMP levels in the liver. The net effect is greater degree of phosphorylation of the regulatory enzymes, namely, which of the following?
a. Glycogen phosphorylase
b. Phosphorylase kinase
c. F–2,6–BPase
d. All of the above

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Which of the following statements is true regarding allosteric effectors regulating key enzymes of metabolism?
a. Glucose activates glycogen phosphorylase and inactivates glycogen synthase
b. Fructose 2,6-bisphosphate inhibits PFK-1 and stimulates fructose 1,6-BPase
c. Citrate activates acetyl-CoA carboxylase, thereby stimulating FA synthesis
d. Malonyl CoA activates carnitine palmitoyltransferase I, thereby activating FA
oxidation

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The preferred fuel of the resting skeletal muscle is:
a. Glucose
b. Ketones
c. Fatty acid
d. Pyruvate

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The following amino acids are both glucogenic and ketogenic, EXCEPT which one? a. Isoleucine
b. Lysine
• Lysine & Leucine are ketogenic only
c. Methionine
d. Phenylalanine

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The following statements regarding generalities of hormones are correct, EXCEPT
a. Extensive cross-talk exists between signaling pathways triggered by a particular hormone–cell membrane-associated receptor complex
b. Excessive, deficient, or inappropriate production and release of hormones are major causes of disease
c. Activated steroid hormone–nuclear receptor complexes generally act as transcription factors that either enhance or repress basal gene expression
d. As one goes down the hypothalamus–pituitary–end organ axis, the half-life and concentration of hormones released per level decreases
e. Larger hydrophilic hormones generally bind and activate cell membrane receptors while smaller hydrophobic bind with intracellular receptors

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Select the correct mode of inactivation/degradation – hormone example pair
a. Cystine disulfide bone breakage – antidiuretic hormone
b. N-terminal cyclic glutamate ring removal – oxytocin
c. Degradation by proteases – adrenocorticotropic hormone
d. Uptake via hepatic asialoglycoprotein receptors – thyrotropin

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This molecule is a hormone derived from tyrosine
a. Thyrotropin-releasing hormone
b. Thyroglobulin
c. Triiodothyronine
d. Thyroid-stimulating hormone

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The following statements regarding steroid hormones and their synthesis are correct,
EXCEPT
a. Propanoyl-CoA acyltransferases are responsible for shuttling steroid hormone parent compounds present in the cytoplasm to the mitochondria
b. Diversity in function is afforded by alternations of the parent compound ring substituents rather than the ring structure itself
c. The parent compound of steroid hormones is pregnenolone while the immediate precursor required for synthesis is cholesterol
• The parent compound of steroid hormones is cholesterol while the immediate precursor required for synthesis is pregnenolone.
d. Even intermediate compounds that are formed during steroid hormone synthesis can freely move in/out the mitochondria and exert biological effects
e. While the hormone-receptor complexes act as transcription factors, steroid hormones can also trigger stimulatory effects initiating at the plasma membrane

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25. Which of the following nuclear receptor type – statement pairs is CORRECT? a. Type II – heterodimerize with retinoid X receptors in the nucleus b. Type I – TH receptors, RARs, Vitamin D receptors, PPARγ • Type I - ER, PR, AR, GR (Steroid receptors) c. Type II – present in both cytoplasm and nucleus, and are able to homodimerize • Type II - present in the nucleus and are able to heterodimerize d. Type I – associated with corepressors/HDACs that dissociate on ligand binding • Type I - associated with heat shock proteins (Hsp 90, Hsp 56) e. Type II – closely related to heat shock proteins Hsp 90 and Hsp 56 • Type I - associated with corepressors/HDACs that dissociate on ligand binding

26. This nuclear receptor domain contains the highly-conserved CI and CII zinc fingers a. DNA-binding domain b. Ligand-binding domain • Contains dimerization surface, ligand-binding pocket (LBP), coregulator binding surface, activation function helix (AF-2) c. A/B region • Contains activation function-1 (AF-1) d. Hinge region • Contains nuclear localization signals/sequences (NLS) e. F region

27. This distinct membrane receptor that recognizes estrogen (and aldosterone) as ligand, allowing it to exert its nongenomic effects, is implicated in resistance to estrogen blockers such as tamoxifene and raloxifene a. GPER b. mPR • decreases cAMP levels (via MAPK pathway) in human breast cancer cells c. CatSper • mediates progesterone-dependent rapit Ca2+ influx in human sperm (impaired Ca 2+ influx is associated with infertility d. RXR

28. Identify the INCORRECTLY-matched domain – description pair a. DBD – contains aa sequences that recognize and bind HREs b. F region – contains the activation function-2 (AF-2) machinery • Ligand-binding domain (LBD) - contains the activation function 2 (AF 2) machinery c. LBD – contains aa sequences that recognize the steroid hormone A-ring d. A/B region – contains the activation function-1 (AF-1) machinery e. Hinge region – has nuclear localization signals needed for intracellular trafficking

29. The following statements regarding thyroid-stimulating hormone (TSH) are true, EXCEPT a. Co- and posttranslational glycosylation is needed for subunit association b. The α-subunit structure is common to that of FSH, LH, and hCG c. Clearance rates depend on the oligosaccharide added during glycosylation d. Its pyroglutamate residue has to be cleaved off in order to inactivate it

30. The following statements regarding thyroid hormone are true, EXCEPT a. They bind to cell membrane GPCRs located on multiple end target organs b. They are degraded via deiodination, conjugation, deamination, and decarboxylation c. T4 must first be deiodinated to T3 in order for it to enter the nucleus d. In plasma, they are protein-bound mainly to thyroxine-binding globulin

A * Thyroid hormones use intracellular receptors (TRα1, TRβ1, TRβ2) * TRH binds to GPCRs found on thyrotopes, lactotropes * TSH binds to GPCRs found on thyroid gland

``` 31. Oligosaccharide side chains that afford higher metabolic clearance rates for TSH are glycoforms that contain these terminal moieties, EXCEPT a. GalNAc sulfate b. Mannose • sugar moiety c. Sialic acid • lower metabolic clearance d. Fucose • sugar moiety ```

32. You are working up a patient who presents with long-standing fatigue, cold intolerance, weight gain, and weak hand grip strength. So far, TSH was the only lab test that was performed; the value is 105 mU/L (normal range: 0.4 – 6.0 mU/L). Taking the situation as a whole, what is the most likely clinical scenario? a. Primary hyperthyroidism • Thyroid is hyperfunctioning, therefore thyroid hormones are high, TSH levels are low b. Secondary hyperthyroidism • Pituitary is hyperfunctioning, therefore both thyroid hormones and TSH levels are high. However, patients with secondary hyperthyroidism should have heat intolerance and weight loss instead. c. Primary hypothyroidism • Thyroid is under-functioning, therefore thyroid hormones are low, TSH levels are high. Moreover, the clinical manifestations indicate hypothyroidism. d. Secondary hypothyroidism • Pituitary is under-functioning, therefore both thyroid hormones and TSH levels are low.

33. The rate-limiting step/enzyme in adrenal steroid hormone synthesis is a. Cholesterol desmolase • cholesterol → pregnenolone (See slide 68 Hormones 1 PPT) b. 17α-Hydroxylase • converts pregnenolone to 17α-hydroxypregnenolone • converts progesterone to 17α-hydroxyprogesterone c. 11β-Hydroxylase • converts deoxycorticosterone to corticosterone • converts deoxycortisol to cortisol d. 18-Hydroxysteroid dehydrogenase • converts 18-hydroxycorticosterone to aldosterone

34. Regarding metabolism/degradation of the adrenal steroid hormones that were discussed, which enzyme system mostly uses cortisol as substrate? a. A-ring reductase system b. Aromatase system c. 11β-Hydroxysteroid dehydrogenase system d. All of the above e. A and B only

35. Which adrenal steroid hormone is present in the plasma mostly in the unbound form, since it has no specific carrier protein? a. Cortisol • bound to corticosteroid-binding globulin (CBG; transcortin) b. Pregnenolone • a precursor of steroid hormones c. Aldosterone d. Dihydrotestosterone • bound tightly to sex-hormone binding globulin (SHBG) in plasma

36. A deficiency or absence of 21β-OHlase or 11β-OHlase activity is the underlying pathology of this disease entity a. Conn syndrome • a.k.a aldosterone-producing adenoma is caused by excess mineralocorticoids b. Cushing disease • caused by a tumor c. Cushing syndrome • d/t excess androgens d. Congenital adrenal hyperplasia

37. Which of the following statements regarding the hypothalamic-pituitary-prolactin axis is INCORRECT? a. Pituitary release of prolactin is stimulated by a particular hypothalamic hormone • TRH stimulates PRL synthesis & release • Estrogen (not a hypothalamic hormone) also stimulates PRL synthesis (direct) b. Prolactin receptors are ubiquitous, and not just on mammary and pituitary tissue c. Prolactin’s structure contains 3 disulfide bonds, and is similar to growth hormone d. Prolactin deficiency more often occurs with deficiency of other anterior pituitary hormones

38. Which of the following can cause a state of growth hormone deficiency? a. Failure to synthesize or secrete IGF-1 b. Low number of GH receptors c. Anterior pituitary or hypothalamic dysfunction d. All of the above can result in a GH-deficient state e. None of the above results in a GH-deficient state

A B C

39. The following statements about acromegaly are true, EXCEPT a. It is GH excess after puberty b. There is increased linear bone growth • There should be increased lateral bone growth c. Patients develop course facial features and organomegaly d. It is associated with hyperglycemia and heart failure

40. Which of the following statements justifies the measurement of serum IGF-1 levels as screening for growth hormone excess? a. Unlike GH, its levels do not fluctuate widely because it is highly protein-bound b. Its rate of synthesis and secretion increases in response to high GH levels c. With 3 S–S bridges in its structure, it is similar to the anabolic hormone insulin d. Recombinant preparation of IGF-1 can be used to treat childhood GH deficiency

41. Which of the following anterior pituitary hormones is derived from the macromolecule pre- proopiomelanocortin (pre-POMC)? a. Somatotropin b. Corticotropin c. Thyrotropin d. Follitropin

``` 42. The GPR54 receptor on GnRH neurons is triggered by this peptide, thus initiating puberty a. γ–Amino butyric acid b. Dopamine c. Somatostatin d. Kisspeptin ```

43. Clearance of gonadotropins occurs in the same fashion as that of which anterior pituitary hormone? a. Somatotropin b. Corticotropin c. Thyrotropin d. Prolactin

44. In the testes, testosterone (synthesized from progesterone) is converted to this active form of the androgen by this enzyme a. DHT... 5α-reductase b. DHEA... 5α-reductase c. Androstenedione... aromatase d. DHT... 21β-hydroxylase

45. The following statements regarding ovarian estrogens estrone and estradiol are true, EXCEPT a. Its A-ring contains 3 double bonds, and it lacks a methyl group on carbon 19 b. Its synthesis requires progesterone to be directly acted upon by aromatases • testosterone is the one acted upon by aromatases c. As with testosterone synthesis, cholesterol is needed as parent compound d. They are eventually converted into at least 40 metabolites that are conjugated

46. This carrier protein transports vasopressin and oxytocin from the paraventricular and supraoptic nuclei of the hypothalamus to the posterior pituitary a. Pre-POMC • precursor of ACTH, Endorphin, MSH b. Neurophysin • carrier proteins c. γ–Amino butyric acid d. Kisspeptin • initiates GnRH secretion at puberty

47. The following are what vasopressin and oxytocin have in common, EXCEPT a. A tocin ring formed by a disulfide bridge between Cys-1 and Cys-6 b. The same set of stimuli that influence their secretion from the posterior pituitary • Secretion of vasopressin is influenced by plasma hyperosmolality (osmoreceptors) and depletion of effective intravascular volume (volume receptors) while secretion of oxytocin is influenced by labor and lactation. c. Proteins (neurophysins) that carry them down axons coming from the hypothalamus d. The same number of amino acids in their structures e. Similar type of degrading enzymes that break their defining structures

48. This GPCR binds Ca2+ downstream production of 12- and 15-HETE arachidonic acid to inhibit PTH synthesis and release a. Calcitonin receptors b. RANK c. CaSR • High serum Calcium binds to calcium sensing receptor (CaSR) on chief cells that ultimately generate intracellular signals inhibit PTH synthesis and release. d. Osteoprotegerin • a decoy receptor that is decreased in the MAPK (p38 pathway)

49. Through the action of Ca2+ [your answer in #48], which enzymes are stimulated in turn to produce these downstream molecules that inhibit PTH secretion? a. Proteinases b. Phospholipases c. Protein kinases d. Phosphodiesterases

50. When a. 1α-hydroxylase activity is enhanced, increasing 1,25-dihydroxycholecalciferol PTH binds and activates its receptor, the following events happen, EXCEPT levels b. Via the MAPK pathway, osteoprotegerin levels drop, causing RANK-L levels to rise c. Ca2+ transporters expression on renal tubular cells increases, increasing Ca2+ absorption d. RANK-L levels drop, inhibiting NFATc1 expression needed for osteoclast differentiation • RANKL activates amplification of NFATc1→ osteoclast differentiation

51. Which of the following statements regarding calcitonin is TRUE? a. Produced by thyroid gland C-cells, it strongly antagonizes the physiologic effects of PTH • weakly antagonizes the physiologic effects of PTH b. Its receptors, when stimulated, interfere with and prevent osteoblast differentiation • interfere with and prevent osteoclast differentiation c. Between calcitonin and Ca2+, concentration of the latter has more influence on PTH levels d. Calcitonin preparations have no role in treatment of disorders of calcium metabolism • used as (part of) treatment for osteoporosis, metastatic bone disease, Paget’s disease

52. Angiotensin II increases the activity of this enzyme, which converts 18- hydroxycorticosterone to aldosterone a. 18-hydroxysteroid dehydrogenase b. 17β-hydroxysteroid dehydrogenase • converts dehydroepiandrosterone to 5-androstenediol • converts androstenedione to testosterone c. 11β-hydroxylase • converts deoxycorticosterone to corticosterone • converts deoxycortisol to cortisol d. 21β-hydroxylase • converts progesterone to deoxycorticosterone • converts 17α-hydroxyprogesterone to deoxycortisol

53. These cardiovascular hormones make use of receptor guanylyl cyclases to exert their biologic effects a. Natriuretic peptides b. Nitric oxide c. Endothelin • uses G-protein coupled receptors (GPCR) d. All of the above e. A and B only

A | B

54. Which of the following statements about renin are CORRECT? a. It is an enzyme that has aspartyl protease activity b. It serves as the rate-limiting step in the RAA cascade c. It converts angiotensinogen to angiotensin I d. All of the above statements are correct e. Only A and C are correct

A B C

55. During pathologic states such as high blood pressure and diabetes mellitus, this/these cardiovascular hormone(s) can also increase oxidative stress and inflammation, leading to significantly increased risk of developing atherosclerosis a. Aldosterone b. Renin c. Angiotensin II d. Nitric oxide • vasodilator, anti-inflammatory, inhibits platelet aggregation e. A through C only

A B C

56. A patient comes in the emergency room unconscious; her capillary blood glucose was very low at 20 mg/dl. After administering 50% intravenous dextrose solution, she started coming to. After gathering this patient’s history, you decided to check a C-peptide level. C-peptide level was later reported to you as “undetectable.” What could be the most likely cause of this patient’s dangerously low blood glucose level? a. Exaggerated secretion of insulin after oral glucose intake b. Administration of an exogenous source of insulin c. Excessive amounts of insulin coming from a neuroendocrine tumor d. None of the above can result in this kind of clinical picture e. Only A and C are correct

``` 57. The proglucagon molecule synthesized in small intestinal L cells yields which of the following? a. Glucagon • from pancreatic α-cells b. GLP-1 c. GLP-2 d. All of the above e. B and C only ```

B | C

58. Currently, only this/these glucose-regulating hormone/s qualify as incretins a. GIP b. GLP-1 c. GLP-2 d. A and B only e. B and C only

A | B

59. This enzyme, a serine protease, degrades and deactivates incretins a. 5α-Reductase • converts testosterone to dihydrotestosterone (DHT) b. Dipeptidyl peptidase-4 c. Pyroglutamyl peptidase d. Cystine aminopeptidase • metabolizes oxytocin

60. The insulin receptor is a prototype of this group of receptors a. Receptor tyrosine kinases b. Receptor guanylyl cyclases • Nitric oxide, natriuretic peptides c. G-protein couple receptors • Angiotensin II, Endothelin-1, somatostatin, d. Receptor serine-threonine kinases

61. Hormones assignment question. This factor promotes erythropoiesis through coordinated cell type-specific hypoxia responses, generally coming from the lung. a. HIF b. TNF c. VEGF d. EGF

62. Hormones assignment question. This is an isoprenoid compound or structure upon which a complex oligosaccharide chain is made prior to transfer to a target protein during the process of posttranslational modification. a. Dolichol phosphate b. Phosphatidic acid c. Phosphatidylcholine d. Sphingomyelin

63. Hormones assignment question. This gastrointestinal hormone has a special O-acyl group which it uses to anchor itself to cell membranes a. Ghrelin b. Cholecystokinin c. Gastrin d. Secretin