Final Study Material

Question 0

A 45yo woman w/BMI 35 reports polydipsia, polyuria, and frequent nightly calls to the bathroom which interfere with sleep. Exam reveals BP= 150/90; HR= 90/min; Resp= 21/min; Urinanlysis= glucose 2+; albumin and ketones negative. Blood: Triglycerides= 170mg/dL, HDL= 30mg/dL, random blood glucose= 220mg/dL, HbA1c= 9%. Diagnosed as having insulin-resistant diabetes. Abnormal response of which intracellular messaging pathways would be expected in the muscle tissue of this patient?

Answer 0

MAPK phosphorylation

Question 1

How do cells get signals inside the cell from outside?

Answer 1

transduction

Question 2

Patient presents with hyperflexible joints and more than normal elasticity of skin. Possibly Ehlers Danlos Syndrome. Which region is the procollagen triple-helix formed?

Answer 2

Within the RER

Question 3

Pt X brought to ER w/watery diarrhea and severe dehydration. Pt ingested toxin caused by Vibrio cholera. Which GPCR does the toxin act upon?

Answer 3

cAMP

Question 4

Group of scientists recently discovered new drug for treating CHF. In vitro studies of cardiomyocyte cell line reveal drug inhibits activity of membrane protein that brings sodium into cells and calcium out of cells. What is the mechanism by which this drug is acting on cardiomyocytes?

Answer 4

inhibition of a voltage-gated ion channel

Question 5

What is the signaling pathway of Trimeric G-proteins?

Answer 5

Ligand binds receptor > receptor activated > Ga releases GDP > Ga binds GTP > Ga binds adneylyl cyclase

Question 6

Pt has aggressive tumor that is growing rapidly. Cancer cells are undergoing autocrine signaling by releasing fibroblast growth factor (FGF). What effect is occurring?

Answer 6

Activation of ERK

Question 7

Dr. Scientist is treating his cells in culture with an abundant amount of platelet derived growth factor. He has performed the appropriate assays to conclude that the PDGF has complete tyrosine phosphorylation, yet does not see phosphorylated ERK. What is the most likely cause for his observations?

Answer 7

A mutation in the SH2 domain of Grb

Question 8

Pt has very soft, thin, stretchy skin and joint hypermobility. Concern pt is at increased risk of having aortic aneurism. Genetic test reveals pt has a mutation in the gene for lysyl oxidase. Reduced activity for this enzyme causes impaired processing of which molecule?

Answer 8

Collage

Question 9

Which protein component of the ECM allows for the expansion and contraction of tissues by undergoing a state of decreased entropy during expansion and increased entropy during contraction?

Answer 9

Elastin

Question 11

Occurence of retinoblastoma disease and complete inactivation of the Rb tumor suppressor involves…?

Answer 11

a second mutation of Rb gene in hereditary retinoblastoma

Question 12

In a membrane, which of the following is most likely to be found in the interior of the bilayer, away from water?
A. Carbon chains of fatty acids
B. Glutamic acid-containing portion of intrinsic proteins
C. Phosphate portions of intrinsic proteins
D. The portion of a hormone receptor that binds the hormone
E. The sugar moiety of a glycolipid

Answer 12

A

Question 13

The thyroid is stimulated by TSH produced by the pituitary and transported by the bloodstream. What kind of hormonal signaling is this?

Answer 13

Endocrine

Question 14

Where do steroid hormones generally bind?

Answer 14

Intracellular receptors

Question 15

Acetylcholine binding to M1 muscarinic receptor in the brain results mainly in
A. synthesis of cAMP
B. formation of DAG/IP3
C. opening of ion channels
D. sequestering of Ca2 to intracellular stores
E. stimulation of MAPK pathway

Answer 15

B

Question 16

Histamine H2 receptors stimulate GI motility and secretion of digestive juices. H2 receptor antagonists such as cimetidine and ranitidine are used to treat peptic ulcers. They lead to.
A. reduced hydrolysis of PIP2 into IP3 and DAG
B. increased hydrolysis of PIP2 into IP3 and DAG
C. decreased production of cAMP
D. increased production of cAMP
E. increased production of cGMP

Answer 16

C

Question 17

You are working with a disaster relief organization in an area where unusually heavy monsoon rainfalls caused widespread flooding in a shanty town. There is a lack of clean water, so people are forced to use floodwater for consumption, washing and other needs. You patients are suffering from serve rice-water-like diarrhea, resulting in dehydration and weakness. Which describes the underlying pathomechanism?
A. ADP-ribosylation of EF-2, so that protein synthesis is prevented
B. ADP-ribosylation of alpha-subunit of Gs by bacterial toxic, so that this protein can no longer stimulate the production of cAMP by adenylate cyclase
C. ADP-ribosylation of alpha subunit of Gi by a bacterial toxin, so that this protein can no longer stimulate the production of cAMP by adenylate cyclase
D. ADP-ribosylation of the alpha subunit of Gi by a bacterial toxin, so that this protein constantly prevents the production of cAMP by adenylate cyclase
E. ADP-ribosylation of the alpha subunit of Gs by a bacterial toxin, so that this protein constantly stimulates the production of cAMP by adenylate cyclase

Answer 17

E

Question 18

Apart from short-term regulation of glucose and amino acid uptake and cellular metabolism, insulin also regulates gene expression in target cells. Which protein modification is involved?

Answer 18

Binding of GTP in exchange for GDP to RAS stimulated by GEF

Question 19

A 47yo man is delivered to hospital for malaise, jaundice, edema, and ascites. On exam had 2cm hepatomegaly and 5 to 6 cm splenomegaly. Bloodwork revealed acanthocytosis (spur cells) and severe liver disease. Liver ultrasound showed nodular hepatomegaly, and biopsy showed advanced cirrhosis with iron accumulation. His bone marrow was hyper cellular. While waiting for a liver transplant, the pt was treated with diuretics but progressed to grade IV hepatic encephalopathy and died. If you analyzed the lipid composition of the pt’s RBCs you would find increased concentration of…?

Answer 19

cholesterol

Question 20

6mo female pt scheduled for surgery to correct pulmonary stenosis and hypoplasia of pulmonary arteries. Her wt was 16.3lbs, results of preoperative laboratory tests were as expected, and her blood type was O Rh+. For the cardiopulmonary bypass, the priming solution consisted of 1 unit of packed erythrocytes, 1 unit whole blood, and 200mL of Ringer solution with appropriate medications. The pt was cooled to a core temp of 84.2F for the operation. 5 min after bypass started perfusionist realized that machine prepared for pt had been switched with that for another patient with group A+. Pt immediately infused w/glucocorticoids, antihistamines, and diuretics. Urin was alkalized w/Bicarb. In addition, the pt received ultrafiltration to remove inflammatory cytokines and plasmapheresis w/frozen plasma. Surgery was completed successfully, and pt was transferred to ICU. During the following day, lab values indicated the formation of immune complexes and minor hemolysis but no change in liver and kidney function. Further recovery was uneventful. To remove isohemagglutinines in the pt blood by plasmapheresis, plasma from a donor of which of the following blood groups should be used?

Answer 20

A

Question 21

54yo 2 pack/day smoker is on isosorbide denigrate (long-acting NO precursor for angina pectoris). BMI 31. Extensive extraneous info about trip Took viagra. Got light-headed and irregular pulse. Near syncope, reported to ER. Most of symptoms had resolved. BP 15mmHg below norm, and there were isolated ventricular premature beats on his EKG. Pt given fluids, 24-hr Holter monitor, and referral to cardiologist. Side effects originate from what?

Answer 21

Increased cGMP levels due to nitrate and increased cGMP levels due to the effects of the inhibitor of type 5 phophodiesterase

Question 22

In effort to get mouse model for retinitis pigments, Sakamoto, and coworkers induced mutation in the germ line of mice with ethyl nitrosourea and then screened the descendants. One line had a V685M missense mutation in PDE6A, the mouse gene for the alpha subunits of phosphodiesterase 6. In homozygous mice, phosphodiesterase activity was non detectable, and photoreceptors are destroyed by day 14 after birth, even when the animals were reared in the dark. Heterozygous animals were not affected. How would you expect measurements of [cGMP] and [Ca2+] in vertical cone cells of homozygous mutated mice to compare with those of normal mice? (Note: cGMP bones to the TRP-M1 ion channels and allows Na and Ca to flow into the cell) Assume normal ambient light.

Answer 22

both are increased

Question 23

Which of the following will prevent the biosynthesis of prostaglandins, even when the appropriate substrate and purified biosynthetic enzyme are incubated together?
A. Absence of ATP in incubation buffer
B. Absence of Ca2+ and glucose in buffer
C. Presence of NAD/NADP in the incubation buffer
D. Incubation of substrate with biosynthetic enzyme under strict, anaerobic conditions.
E. Incubation of substrate with a biosynthetic enzyme containing iron

Answer 23

D. COX transforms AA to PGH2 by insertion of 2 oxygen molecules

Question 24

Protein X participates in prostaglandin biosynthesis. Protein X is undetectable in normal tissue and detectable in skin with inflammation. What is the most valid conclusion about info provided?

Answer 24

Protein X is COX2-isoenzyme.

Question 25

What is the medical molecular and medical rationale for eating a diet/supplement rich in omega-3 PUFA as nutritional approach to improve health?

Answer 25

to replace omega-6 PUFA AA in phospholipids of cell membrane bilayers, EPA