Psl Exam 1: Gi And Stem Cells

Front 1

If hematopoietic stem cells were transplanted into a host and it could be shown that
descendents of the transplanted stem cells became neurons, that would be an example of

A. apoptosis.

B. canalization.

C. trans-differentiation.

D. embryonic stem cell therapy.

E. normal hematopoiesis.

Back 1

C. trans-differentiation.

Front 2

Which of the following is FALSE of telomeres?

A. They are replicated by DNA polymerase.

B. They are highly repetitious sequences of DNA base pairs.

C. They are found at the ends of chromosomes.

D. They determine the life span of somatic cells.

E. They shorten as most cells age.

Back 2

A. They are replicated by DNA polymerase.

Front 3

Embryonic stem cells differ from adult stem cells in that only embryonic stem cells

A. are 'immortal' with respect to cell division.

B. can self-renew indefinitely.

C. can produce descendents that are differentiated.

D. can be safely transplanted directly into a host.

E. are derived from cells cultured from a blastocyst

Back 3

E. are derived from cells cultured from a blastocyst.

Front 4

Based on the assigned reading and lecture notes on apoptosis, which of the following
correctly pairs a protein molecule with its role in apoptosis?

A. Caspase--controls the permeability barrier of mitochondria

B. p53--directly degrades proteins during apoptosis

C. Fas--receptor protein that inhibits apoptosis when activated

D. Bcl-2--protects cells against apoptosis

E. ICE-like proteases--involved in necrosis, not apoptosis

Back 4

D. Bcl-2--protects cells against apoptosis

Front 5

Which of the following statements is TRUE?

A. The majority of cells in the bone marrow are hematopoietic stem cells.

B. Stem cells are identified by marker proteins expressed on their surface.@

C. Red blood cells (erythrocytes) are the only blood cell not derived from
hematopoietic stem cells.

D. Intestinal stem cells are found in the intestinal villi.

E. Hematopoietic stem cells are embryonic stem cells.

Back 5

B. Stem cells areidentified by marker proteins expressed on their surface.

Front 6

In the Wnt signaling pathway, Wnt is a(n) ______ that activates a ________ called Frizzled, which in turn allows __________ to enter the nucleus and alter transcription.

A. adhesion protein, protein kinase, APC

B. caspase, telomerase, actin

C. protein kinase, substrate, a second messenger

D. signal molecule, GPCR, beta-catenin

E. GPCR, adenylyl cyclase, cAMP

Back 6

D. signal molecule, GPCR, beta-catenin

Front 7

For the production of embryonic stem cells, which of the following correctly describes
an advantage of the somatic cell nuclear transfer (SCNT) method compared to the in vitro
fertilization method?

A. SCNT does not give rise to a blastocyst.

B. The embryonic stem cells from SCNT need not be differentiated before
transplanation.

C. The cells from SCNT do not require growth in cell culture before
transplantation.

D. The blastocyst from SCNT cannot develop into an individual organism.

E. SCNT can overcome problems of immune rejection that is a serious obstacle
to IVF strategy

Back 7

E. SCNT can overcome problems of immune rejection that is a serious obstacle
to IVF strategy.

Front 8

Which of the following correctly describes the concept of a cancer stem cell?

A. A cell capable of unlimited self-renewal and differentiation.

B. A tumor cell resistant to cancer chemotherapy.

C. A tumor cell capable of producing a new tumor when transplanted.

D. A tumor cell with mutations affecting proliferation and apoptosis.

E. A normal tissue stem cell with mutations.

Back 8

C. A tumor cell capable of producing a new tumor when transplanted.

Front 9

The specialized environment within a tissue in which a stem cell is maintained as a stem
cell is called its

A. trophoblast.

B. niche.

C. crypt.

D. marrow.

E. marker.

Back 9

B. niche.

Front 10

Which of the following hormones inhibits the migrating motor complex?

A. Motolin

B. Acetylcholine

C. Insulin

D. Norepinephrine

E. Gastrin

Back 10

E. Gastrin

Front 11

Entry of food into the stomach

A. inhibits gastric motility.

B. stimulates relaxation of the ileocecal sphincter.

C. pushes food into the duodenum.

D. increases pressure within the stomach lumen.

E. promotes gastroparesis.

Back 11

B. stimulates relaxation of the ileocecal sphincter.

Front 12

Histamine stimulates hydrochloric acid (HCl) release from parietal cells by

A. activating H1 histamine receptors.

B. increasing cAMP levels.

C. increasing intracellular Ca2+ levels.

D. activating protein kinase C (PKC).

E. All of the above are correct.

Back 12

B. increasing cAMP levels.

Front 13

The cephalic phase of gastric acid secretion is regulated by

A. entry of food into the stomach.

B. the acid-buffering capacity of gastric chyme.

C. activation of sympathetic nerves.

D. M3 muscarinic receptors.

E. CCKA receptors.

Back 13

D. M3 muscarinic receptors.

Front 14

Gastrin

A. is released from duodenal I-cells.

B. inhibits pancreatic enzyme secretion.

C. binds and activates the CCKB receptor.

D. inhibits gastric motility.

E. Both ‘A’ and ‘C’ are correct.

Back 14

C. binds and activates the CCKB receptor.

Front 15

Mobilferrin

A. transports intracellular ferrous iron (Fe2+) in duodenal enterocytes.

B. binds ferrous iron (Fe2+) in the lumen of the duodenum.

C. regulates endocytosis of the transferrin receptor.

D. is the storage form of iron in hepatocytes.

E. mobilizes ferric iron (Fe3+) from heme iron.

Back 15

A. transports intracellular ferrous iron (Fe2+) in duodenal enterocytes.

Front 16

Vitamin B12

A. complexed with trans-cobalamin II is transported across the apical plasma membrane
of duodenal enterocytes.

B. binds to haptocorrin in low pH environments.

C. is synthesized in mammalian cells.

D. is released from the lysosome in response to increased pH.

E. binds to intrinsic factor within the stomach lumen.

Back 16

B. binds to haptocorrin in low pH environments.

Front 17

Which of the following hormones is secreted by adipose tissue and regulates food
consumption?

A. Orexin

B. PYY3-36

C. Insulin

D. Leptin

E. Neuropeptide Y

Back 17

D. Leptin

Front 18

Ghrelin

A. is released from gastric endocrine cells during interdigestive periods.

B. stimulates melanocortin containing neurons in the arcuate nucleus.

C. stimulates neuropeptide Y containing neurons in the arcuate nucleus.

D. suppresses food intake after a meal.

E. Both ‘A’ and ‘C’ are correct.

Back 18

E. Both ‘A’ and ‘C’ are correct.

Front 19

A human subject complains that she is always gassy and suffers from chronic
diarrhea. Samples from her proximal large intestine contain elevated -limited dextrin oligosaccharide. Her physical condition is most like due to a deficiency in which of the following enzymes?

A. Sucrase

B. Lactase

C. Amylase

D. Isomaltase

E. Maltase

Back 19

D. Isomaltase

Front 20

Smooth muscle electrical activity and contraction was measured in the ileum of a
laboratory animal. The basic electrical rhythm (BER) of the laboratory animal is identical to that of a human. Administration of drug A causes the frequency of the BER in the ileum to increase to 12 times per minute. Administration of drug B allows the depolarization phase of the ileum BER to reach a spike (action) potential. Administration of

A. drug A will cause the ileum to contract 12 times per minute.

B. drug B will cause the ileum to contract 12 times per minute.

C. drug A will cause the ileum to contract 9 times per minute.

D. drug B will cause the ileum to contract 9 times per minute.

E. drug A and B will cause the ileum to contract 9 times per minute.

Back 20

D. drug B will cause the ileum to contract 9 times per minute.

Front 21

Increased circulatory concentrations of secretin inhibits secretion of

A. pancreatic bicarbonate ion (HCO3_).

B. gastric acid (HCl)

C. biliary bicarbonate ion (HCO3_).

D. somatostatin.

E. Both ‘A’ and ‘B’ are correct.

Back 21

B. gastric acid (HCl).

Front 22

Which of the following xymogens are directly activated by brush border enterokinase?

A. Trypsinogen@

B. Chymotrypsinogen

C. Proelastase

D. Procarboxypeptidase

E. All of the above are correct.

Back 22

A. Trypsinogen@

Front 23

The secretin potentiates cholecystokinin (CCK)-stimulated xymogen release from
pancreatic acinar cell by

A. increasing intracellular cAMP levels.

B. activating protein kinase C (PKC).

C. binding to the CCKB receptor.

D. stimulating parasympathetic activity.

E. inhibiting sympathetic activity.

Back 23

A. increasing intracellular cAMP levels.

Front 24

Gallbladder contraction is regulated by the

A. CCKA receptor.

B. somatostatin receptor.

C. ß-adrenergic receptor.

D. FGF-15 receptor.

E. secretin receptor.

Back 24

A. CCKA receptor.

Front 25

Fibroblast growth factor-15 (FGF-15) expression in the ileum is induced by bile acids
activating the

A. farnesoid X receptor (FXR).

B. bile acid receptor.

C. plasma transferrin receptor.

D. CCKA receptor.

E. fatty acid binding protein.

Back 25

A. farnesoid X receptor (FXR).

Front 26

Prior to absorption, proteins must be digested to

A. amino acids.

B. polypeptides.

C. pentapeptides.

D. oligopeptides.

E. amino acids, dipeptides, and tripeptides

Back 26

amino acids, dipeptides, and tripeptides.

Front 27

A nerve ending that secretes acetylcholine onto an absorptive enterocyte is injected
with a dye that spreads throughout the nerve. The nerve cell body labeled by the dye will most likely be located in the

A. brain stem.

B. pelvic region of the spinal cord.

C. arcuate nucleus.

D. paravertebral ganglion.

E. submucosal plexus

Back 27

E. submucosal plexus

Front 28

Activation of parasympathetic nerves increase blood flow to the gastrointestinal tract
by

A. releasing acetylcholine on vascular smooth muscle cells.

B. stimulating nitric oxide release from vascular endothelial cells.

C. decreasing mucosal cell metabolic activity.

D. blocking vasoconstriction induced by adenosine.

E. decreasing the release of secretin from duodenal enterocytes.

Back 28

B. stimulating nitric oxide release from vascular endothelial cells.

Front 29

The portal circulatory system delivers blood from the gastrointestinal tract to the liver,
for following reasons. Which is the exception?

A. Conversion of glucose to triacylglyceride.

B. Storage of glucose as glycogen.

C. Detoxification of pesticides and herbicides.

D. Elimination of bile salts.

E. Conversion of lactate to glucose.

Back 29

D. Elimination of bile salts.

Front 30

Chylomicrons

A. enter the circulatory system via lacteals.

B. diffuse across the unstirred layer and are absorbed the duodenal enterocyte.

C. will reform in the lumen of the duodenum in the absence of bile.

D. are digested by pancreatic lipase.

E. All of the above are correct.

Back 30

A. enter the circulatory system via lacteals.

Front 31

Absorption of galactose into the duodenal enterocyte is dependent upon which of the
following.

A. Sodium-dependent glucose transporter 1

B. Sodium-dependent galactose transporter

C. Na+-K+-ATPase

D. GLUT2

E. Both ‘A’ and ‘C’ are correct.

Back 31

E. Both ‘A’ and ‘C’ are correct.

Front 32

Which of the following therapeutics inhibits the proton pump in parietal cells?
Parenthesis indicates active ingredient.

A. Tums (calcium carbonate)

B. Rolaids (calcium carbonate, magnesium hydroxide)

C. Gelusil (aluminum hydroxide, magnesium hydroxide, simethicone)

D. Zantac (ranitidine)

E. Nexium (esomeprazole)

Back 32

E. Nexium (esomeprazole)

Front 33

Entry of gastric acid into the duodenum slows gastric emptying by

A. activating short reflexes in the enteric nervous system.

B. stimulating gatrin release from duodenal G-cells.

C. stimulating cholecystokinin release from duodenal I-cells.

D. stimulating parasympathetic activity.

E. All of the above are correct.

Back 33

A. activating short reflexes in the enteric nervous system.