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TLS Online TPP Program

#Question id: 18835

Polymerase chain reaction (PCR) utilizes a heat-stable polymerase (Taq polymerase) to amplify DNA strand. Which of the statement best describes why thermo-stable polymerases are required for PCR?

#Unit 13. Methods in Biology
  1. PCR needs thermal cycling, and the Taq polymerases can be inactivated since they are not needed during the low-temperature steps. 
  2. Heat stable (Taq) polymerase do not break the dsDNA unless the temperature is very high. Therefore a heat-stable (Taq) polymerase is required.
  3. PCR needs thermal cycling, and the heat-stable (Taq) polymerases will not denature to lose efficacy in DNA polymerization during the high temperature (95oC) step. 
  4. The interaction between divalent cations and DNA polymerase is much efficient during high-temperature steps. Thus PCR requires heat-stable DNA polymerase.
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TLS Online TPP Program

#Question id: 2152

#Unit 2. Cellular Organization

Precursors of membrane phospholipids are

a. soluble in the cytosol.                    

b. incorporated into biosynthetic intermediates.

c. sometimes complexed with fatty-acid-binding proteins.

d. stored in glycerolosomes.

e. sometimes activated by conjugation with CDP.
TLS Online TPP Program

#Question id: 2153

#Unit 2. Cellular Organization

Membrane phospholipids include

a. cholesterol.            

b. plasmologens.        

c. sphingolipids.         

d. triglycerides.                      

e. bile acids.
TLS Online TPP Program

#Question id: 2154

#Unit 2. Cellular Organization

Membrane lipids are distributed appropriately between the two leaflets of a given membrane by

a. dockases.    

b. trumpases.              

c. fatty acid desaturases.        

d. flippases.    

e. transmembrane tunnelases.
TLS Online TPP Program

#Question id: 2155

#Unit 2. Cellular Organization

Cholesterol is

a. unrelated to any plant lipids.                     

b. not found in chloroplast membranes.

c. encoded by an intron-containing gene on chromosome 23.

d. relatively abundant in the plasma membrane and endocytic membranes.

e. synthesized in the ER.
TLS Online TPP Program

#Question id: 2156

#Unit 2. Cellular Organization

Proteins known to be involved in Golgi apparatus independent transport of lipids include

a. StAR protein.                                 

b. Neimann-Pick C1 (NPC1) protein.

c. HMG CoA reductase.                    

d. acyl:cholesterol acyl transferase (ACAT).

e. cholesterol 7α-hydroxylase.  
TLS Online TPP Program

#Question id: 2157

#Unit 2. Cellular Organization

Which of the following is not a metabolic derivative of cholesterol?

a. dolichol                  

b. vitamin D               

c. bile acids    

d. v-SNARE molecules                     

e. NSF