Solution to Multiple Choice Questions- Lipid Metabolism (Set-1)

23 Nov
1-  All except one are true about gastriclipase-
a)   Main preduodenal lipase
b)   Hydrolyzes triglycerides containing shortand medium chain fatty acids
c)   Primary site of hydrolysis is sn-3ester linkage
d)   Optimum pH is 6.0-7.0                        (d)
2-  Pancreatic juice does not contain which ofthe followings-
a)   Bile salts
b)   Phospholipase A2
c)   Lipase and colipase
d)   Lipoprotein lipase                                (d)
3-  The dietary fats are transported as –
a)   Micelles
b)   Chylomicons
c)   Fatty acid – Albumin complex
d)   Liposomes
(b)
4-  One and the only energy requiring step infatty 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
(c)
5-  A fatty acid with 14 carbon atoms willundergo how many cycles of beta oxidation
a)   7
b)   4
c)   6
d)   5                                                        (c)
6-  Which statement best describes theoxidation 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
(c)
7-  Which statement out of the followings isincorrect about Zellwegar syndrome?
a)   Resultsfrom the absence of functional peroxisomes
b)   Characterized  by hypoglycemia and ketosis
c)   Causedby a defect in the import of enzymes into the peroxisomes
d)   Death occurs within 6 years of life.
(b)
8-   Whatis the molecular basis of the  statement “fats burn in the flame of carbohydrates”-
a)   Fats are hydrolyzed in the presence ofcarbohydrates
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 presenceof oxaloacetate in TCA cycle
(d)- see the comment also
9-  Which of the following statements correctlydescribes 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
(d)
10- NADPHrequired for the fatty acid synthesis can be generated from-
a)   HMP pathway
b)   Glycolysis
c)   TCA cycle
d)   All of the above                                   (a)
11- Which of the followings is not used for fattyacid synthesis?
a)   Cobalamine
b)   NADPH
c)   Biotin
d)   Bicarbonate
(a)
12- Thekey regulatory enzyme of fatty acid synthesis is-
a)   Acyl co A synthetase
b)   Acetyl co A carboxylase
c)   Keto acyl synthase
d)   Thioesterase
(b)
13-  Malonyl co A is a direct inhibitor of whichenzyme of fatty acid oxidation?
a)   Carnitine Acyl Transferase –I
b)   Carnitine Acyl Transferase –II
c)   Thiokinase
d)   None of the above
(a)
14- Whenthe liver is actively synthesizing fatty acids, a concomitant decrease in betaoxidation 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 betweencellular compartments
                                                          (d)
15-  Which out of the followings is the primaryketone body?
a)   Acetone
b)   Acetoacetate
c)   Beta-hydroxy butyrate
d)   Hydroxy Methyl glutarate
                                                          (b)
16- All are conditions of ketosis except one -
a)   Starvation
b)   Uncontrolled diabetes mellitus
c)   High carbohydrate  diet
d)   Von Gierke’s disease
                                                          (c)
17-The key enzyme for the utilization ofketone bodies is-
a)   Thiolase
b)   Thiophorase
c)   Thiokinase
d)   Thioesterase
                                                          (b)
18-The key regulatory enzyme of cholesterolsynthesis is-
a)   HMG- Co A synthase
b)   HMG Co A lyase
c)   HMG Co A reductase
d)   Mevalonate kinase
                                                          (c)
19- Choose the incorrect statement aboutcholesterol synthesis
a)   All the carbon atoms are derived fromAcetyl CoA
b)   Process is cytoplasmic
c)   NADPH is the main coenzyme
d)   Highly expensive energetically
                                                          (b)
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 bileacid formation
                                                              (d)

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One Response to “Solution to Multiple Choice Questions- Lipid Metabolism (Set-1)”

  1. Dr Namrata Chhabra November 23, 2011 at 3:52 pm #

    Dear students,
    For question no.8- The molecular basis of fats are burnt in the fire of carbohydrates- The answer can be explained as-
    Fats- lets say fatty acids upon oxidation produce Acetylco A,which is completely oxidized in TCA cycle. The functioning of TCA cycle depends upon the availability of oxaloacetate, which is considered to be mainly a product of carboxylation of pyruvate (Although there are other sources of oxaloacetate but this is considered to be the main source)
    Pyruvate is the end product of glycolysis(Though there are alternative sources of pyruvate but glucose oxidation is the main source). Glucose represents carbohydrate group. In other words carbohydrates form glucose, which forms pyruvate and that forms oxaloacetate. Thus oxaloacetate is a representative of carbohydrates.
    Thus to conclude, acetyl co A (Product of fatty acid oxidation) can be completely burnt(oxidized) only under the fire( in the prsence) of carbohydrates(oxaloacetate- in TCA cycle).

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