Monday, October 22, 2012

Multiple Choice Questions- Lipid Metabolism

1-  All except one are true about gastric lipase-
a)   Main preduodenal lipase
b)   Hydrolyzes triglycerides containing short and medium chain fatty acids
c)   Primary site of hydrolysis is sn-3ester linkage
d)   Optimum pH is 6.0-7.0                                                  
2-  Pancreatic juice does not contain which of the followings-
a)   Bile salts
b)   Phospholipase A2
c)   Lipase and colipase
d)   Lipoprotein lipase                                                            
3-  The dietary fats are transported as –
a)   Micelles
b)   Chylomicons
c)   Fatty acid – Albumin complex
d)   Liposomes
4-  One and the only energy requiring step in fatty acid oxidation is catalyzed by which of the following enzymes-
a)   Thiolase
b)   Acyl co A dehydrogenase
c)   Thiokinase
d)   Beta-OH Acyl co A dehydrogenase                                              
5-  A fatty acid with 14 carbon atoms will undergo how many cycles of beta oxidation
a)   7
b)   4
c)   6
d)   5                                                                                                  
6-  Which statement best describes the oxidation of odd chain fatty acids?
a)   Additional specific enzymes are needed for the oxidative process
b)   One carbon is removed in one cycle
c)   End product is propionyl co A
d)   Hydroxy fatty acids are produced
7-  Which statement out of the followings is incorrect about Zellwegar syndrome?
a)   Results from the absence of functional peroxisomes
b)   Characterized  by hypoglycemia and ketosis
c)   Caused by a defect in the import of enzymes into the peroxisomes
d)   Death occurs within 6 years of life.
8-   What is the molecular basis of the  statement “fats burn in the flame of carbohydrates”-
a)   Fats are hydrolyzed in the presence of carbohydrates
b)   Fatty acids and glucose are simultaneously oxidized
c)   Acetyl co A is the common product of fattyacid  and glucose oxidation
d)   Acetyl co A is oxidized completely in the presence of oxaloacetate in TCA cycle
9-  Which of the following statements correctly describes the enzyme Thiolase?
a)   It yields Acetoacetyl co A as a product
b)   It yields Malonyl co A as a product
c)   Forms Co A ester as a product
d)   Requires beta keto acyl co A as a substrate
10-NADPH required for the fatty acid synthesis can be generated from-
a)   HMP pathway
b)   Glycolysis
c)   TCA cycle
d)   All of the above                                                                      
11-Which of the followings is not used for fatty acid synthesis?
a)   Cobalamine
b)   NADPH
c)   Biotin
d)   Bicarbonate
12-The key regulatory enzyme of fatty acid synthesis is-
a)   Acyl co A synthetase
b)   Acetyl co A carboxylase
c)   Keto acyl synthase
d)   Thioesterase
 13-  Malonyl co A is a direct inhibitor of which enzyme of fatty acid oxidation?
a)   Carnitine Acyl Transferase –I
b)   Carnitine Acyl Transferase –II
c)   Thiokinase
d)   None of the above
14-When the liver is  actively synthesizing fatty acids, a concomitant decrease in beta oxidation of fatty acids is due to-
a)   Inhibition by end product
b)   Decrease in adipolysis
c)    Inactivation of  specific enzymes of  fatty acid oxidation
d)   Inhibition of translocation between cellular compartments
15-  Which out of the followings is the primary ketone body?
a)   Acetone
b)   Acetoacetate
c)   Beta-hydroxy butyrate
d)   Hydroxy Methyl glutarate
16-All are conditions of ketosis except one -
a)   Starvation
b)   Uncontrolled diabetes mellitus
c)   High carbohydrate  diet
d)   Von Gierke’s disease
17-The key enzyme for the utilization of ketone bodies is-
a)   Thiolase
b)   Thiophorase
c)   Thiokinase
d)   Thioesterase
18-The key regulatory enzyme of cholesterol synthesis is-
a)   HMG- Co A synthase
b)   HMG Co A lyase
c)   HMG Co A reductase
d)   Mevalonate kinase
19-Choose the incorrect statement about cholesterol synthesis
a)   All the carbon atoms are derived fromAcetyl CoA
b)   Process is cytoplasmic
c)   NADPH is the main coenzyme
d)   Highly expensive energetically
20-  The process by which bile acid sequestrants lower serum cholesterol  level  is-
a)   Direct Inhibition of cholesterol synthesis
b)   Promote cholesterol catabolism
c)   Promote cholesterol excretion
d)   Divert cholesterol metabolism towards bile acid formation

------------------------------------------ Best Wishes: Dr.Ehab Aboueladab, Tel:01007834123, ------------------------------------------
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