Session 6 - Cholesterol

1. 1Which of the following is NOT true regarding sources of cholesterol?

   1. A75% of all cholesterol arises from de novo synthesis
   2. B25% of all cholesterol comes from diet
   3. CVirtually all nucleated cells can synthesize cholesterol
   4. DThe liver and intestine account for approximately 30% each of total synthesis
2. 2Which of the following are functions of cholesterol? (Select all that apply)

   1. AIt is a structural component of the cell membranes.
   2. BIt is a building block for peptide hormones.
   3. CIt is a precursor for bile acids.
   4. DIt is important for the production of vitamin D.
3. 3Which of the following is the rate-limiting and key regulated step in cholesterol synthesis?

   1. ASynthesis of mevalonate by HMG-CoA reductase
   2. BSynthesis of mevalonate by mevalonate kinase
   3. CSynthesis of HMG-CoA by HMG-CoA synthase
   4. DSynthesis of phosphomevalonate by mevalonate kinase
4. 4Which of the following enzymes is responsible for the terminal reaction in cholesterol synthesis?

   1. A7-dehydrocholesterol reductase
   2. BHMG-CoA reductase
   3. CMevalonate kinase
   4. DHMG-CoA synthase
5. 5Defects in brain cholesterol metabolism can potentially cause which of the following? (Select all that apply)

   1. AAlzheimer's disease
   2. BHuntington's disease
   3. CParkinson's disease
   4. DMultiple sclerosis
6. 6Which of the following does not contribute to the regulation of the rate-limiting step of cholesterol synthesis?

   1. AHormonal regulation
   2. BFeedback inhibition
   3. CATP regulation
   4. DRate of enzyme degradation
7. 7You have a patient with hypercholesterolemia who is responding well to lovastatin therapy. Which of the following is NOT true about this medication?

   1. AIt is decreasing cholesterol synthesis.
   2. BIt is increasing the degradation of LDL receptors.
   3. CIt is inhibiting HMG-CoA reductase.
   4. DIt is a reversible competitive inhibitor.
8. 8Which of the following are true regarding lipoproteins? (Select all that apply)

   1. AThey transport triglycerides to peripheral tissues.
   2. BThey are comprised of a central hydrophilic core and a hydrophobic membrane.
   3. CTheir membranes consist of only phospholipids and protein.
   4. DThey transport cholesterol to peripheral tissues.
9. 9Apoproteins are essential integral and peripheral components of lipoproteins. Which of the following is NOT one of their functions?

   1. AProvide structural integrity
   2. BServe as activators or cofactors for enzymes involved in lipoprotein metabolism
   3. CServe as ligands for various receptors
   4. DRequired for the degradation of the lipoprotein when structure is compromised
10. 10Which of the following is the correct order of density (low to high) of lipoproteins?

    1. AChylomicron - VLDL - LDL - HDL
    2. BHDL - LDL - chylomicron - VLDL
    3. CHDL - LDL - VLDL - chylomicron
    4. DVLDL - LDL - chylomicron - HDL

11. 11Which of the following are sources of HDL? (Select all that apply)

    1. ALiver
    2. BIntestine
    3. CVLDL
    4. DChylomicrons
12. 12Which of the following is NOT true regarding lipoprotein composition?

    1. AChylomicrons are the only lipoprotein with apoprotein B48.
    2. BVLDL, LDL, and HDL all have apoprotein B100.
    3. CChylomicrons, VLDL, and HDL all have apoprotein E.
    4. DLDL has only apoprotein B100.
13. 13Which of the following must occur for lipoproteins to transport cholesterol?

    1. ANothing is required, lipoproteins transport free cholesterol.
    2. BCholesteryl ester must be hydrolyzed into fatty acid and free cholesterol.
    3. CCholesterol must be converted to cholesteryl ester by acyl CoA-cholesterol acyl transferase
    4. DCholesterol must be converted to cholesteryl ester by cholesteryl ester hydrolase
14. 14Apo B48, Apo A, Apo C, and Apo E are the main apoproteins of which lipoprotein?

    1. AChylomicrons
    2. BLDL
    3. CHDL
    4. DVLDL
15. 15Clearance of chylomicron remnants is mediated by _________ as it is recognized by the LDL and LRP receptors.

    1. AApo A
    2. BApo C
    3. CApo E
    4. DB48
16. 16Regarding chylomicron metabolism, __________ activates lipoprotein lipase, which breaks down triglycerides to fatty acids and glycerol.

    1. AApo A
    2. BApo E
    3. CApo C
    4. DB48
17. 17An individual has low levels of triglycerides and a reduced risk of cardiovascular disease. They have been identified to have a rare loss-of-function mutation. Which gene is most likely affected?

    1. AApo C-III
    2. BApo C-I
    3. CApo C-II
    4. DApo E
18. 18You have a patient with very high circulating levels of chylomicrons and triglycerides with pancreatitis. This could be caused by a mutation in which of the following genes? (Select all that apply)

    1. ALipoprotein lipase
    2. BApo C-II
    3. CApo C-III
    4. DApo C-I
19. 19Which of the following are clinical manifestations of chylomicronemia? (Select all that apply)

    1. APalmar crease xanthomas
    2. BLipemic plasma
    3. CTuberous xanthomas
    4. DAutosplenectomy
20. 20The MTTP gene encodes for a protein essential for the assembly of Apo-B lipoproteins. Someone with a mutation of this gene could expect all of the following EXCEPT?

    1. AMalabsorption of nutrients from fat-soluble vitamins
    2. BConstipation and weight gain
    3. CAnemia
    4. DMuscle weakness
21. 21A defect in apoprotein E would most likely result in?

    1. AAccumulation of chylomicron remnants in plasma
    2. BLow levels of triglycerides
    3. CDeficiency of lipoprotein lipase
    4. DVitamin malabsorption
22. 22VLDL mainly transports __________ to extra-hepatic tissues, while LDL mainly delivers __________ to cells in the body.

    1. Atriglycerides, cholesterol
    2. Bcholesterol, triglycerides
    3. Ccholesterol, cholesterol
    4. Dtriglycerides, triglycerides
23. 23A VLDL molecule has acquired Apo C and Apo E and activated lipoprotein lipase. Fatty acid and glycerol have been released from the VLDL. Which is the next logical step in this metabolism sequence?

    1. AIDL is taken up by Apo E receptors and LDL receptors.
    2. BVLDL is secreted by the liver.
    3. CLDL is recognized by LDL receptors.
    4. DApo E is returned to HDL.
24. 24Which apoprotein is responsible for the binding interaction that internalizes VLDL by the cells?

    1. AApo E
    2. BApo A
    3. CApo C
    4. DB100
25. 25Which apoprotein is responsible for mediating the binding of LDL (ligand) and LDL (receptor) during internalization?

    1. AApo B100
    2. BApo C
    3. CApo E
    4. DApo 48
26. 26You have a patient with an Apo E mutation. Which of the following would you NOT expect to see?

    1. AHypertriglyceridemia
    2. BHypercholesterolemia
    3. CNormal LDL clearance
    4. DImpaired LDL clearance
27. 27Which of the following would you NOT expect to see with an LDL receptor mutation?

    1. AHypercholesterolemia
    2. BPredisposition to coronary artery disease
    3. CHigh triglycerides
    4. DReduced clearance of LDL
28. 28Which of the following is responsible for reverse cholesterol transport?

    1. AHDL
    2. BChylomicron
    3. CVLDL
    4. DLDL
29. 29Synthesis of nascent HDL starts with synthesis and secretion of apolipoprotein ___________.

    1. AApoA-I
    2. BPLTP
    3. CCETP
    4. DApo E
30. 30Which of the following does NOT contribute to the maturation of nascent HDL?

    1. AProgressive accumulation of cholesteryl esters.
    2. BExcess cholesterol in peripheral tissues being pumped out with ATP-binding cassette transporter 1.
    3. CLCAT converting cholesterol to cholesteryl ester.
    4. DSecretion of ApoA-I.
31. 31Low cholesteryl ester transfer protein activity promotes which of the following? (Select all that apply)

    1. AHDL formation
    2. BHDL reduction
    3. CDevelopment of atherosclerosis
    4. DReduced risk of atherosclerosis
32. 32HDL unloads triglycerides, phospholipids, and cholesterol esters via the ___________ receptor.

    1. ASR-B1
    2. BCETP
    3. CABCA-1
    4. DApoA-1
33. 33Which of the following could result in a defect in HDL metabolism? (Select all that apply)

    1. ADefect in ApoA-1
    2. BDefect in LCAT
    3. CDefect in CETP
    4. DDefect in SR-B1
34. 34A mutation in the ABCA1 gene could cause all of the following EXCEPT?

    1. APrevention of the release of cholesterol and phospholipids from cells.
    2. BInability to transport cholesterol and phospholipids out of cells.
    3. CHigh HDL levels
    4. DIncreased risk of cardiovascular disease
35. 35You have a patient with a partial LCAT deficiency. Which of the following is NOT true regarding their condition?

    1. AThey will have progressive corneal opacification and vision impairment.
    2. BTreatment includes a low fat diet and dialysis.
    3. CBoth HDL and LDL levels are affected.
    4. DThis condition is also called "fish eye disease"
36. 36A CETP deficiency could result in which of the following? (Select all that apply)

    1. AIncreased HDL
    2. BLow CETP level
    3. CDecreased HDL size
    4. DHigh levels of ApoA-1
37. 37You have a female patient with a total cholesterol of 260 and an HDL of 40. Which of the following is NOT true?

    1. AThey are at an increased risk of coronary artery disease.
    2. BTheir HDL is an acceptable level.
    3. CTheir LDL is high.
    4. DThey are at an increased risk of atherosclerosis.
38. 38Which of the following is an example of a non-modifiable risk factor for atherosclerosis?

    1. AFamily history
    2. BDiabetes
    3. CHypertension
    4. DDiet
39. 39Select the correct sequence of atherosclerosis pathogenesis.

    1. ALesion initiation - fibrous plaque formation - fatty streak formation - thrombus formation
    2. BThrombus formation - fibrous plaque formation - fatty streak formation - lesion initiation
    3. CLesion initiation - fatty streak formation - fibrous plaque formation - thrombus formation
    4. DFatty streak formation - fibrous plaque formation - lesion initiation - thrombus formation
40. 40PCSK9 inhibitors have shown great promise in lowering lipid levels and reducing atherosclerosis risk. How does it accomplish this?

    1. AReduces triglycerides
    2. BLowers blood sugar levels
    3. CReduces degradation of LDL receptors
    4. DPrevents blood clots

Description

Biochemistry Quiz on Session 6 - Cholesterol, created by Kathleen Lonergan on 20/06/2019.

Author

Kathleen Lonergan

Language

English

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History

Created on 20 Jun 2019 · updated on 20 Jun 2019

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biochemistry

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