11.  All of the following pertain to nitrogenous bases except  
A.  Form pairs by hydrogen bonding
B.  Guanine pairs with uracil
C.  Adenine pairs with thymine
D.  Cytosine and thymine are pyrimidines
E.  Allows variation from one nucleotide to another which creates the encoded information

12.  Each nucleotide is composed of  
A.  One phosphate, one nitrogenous base, one sugar
B.  One phosphate, one nitrogenous base, two sugars
C.  Two phosphates, one nitrogenous base, one sugar
D.  Two phosphates, one nitrogenous base, two sugars
E.  One phosphate, two nitrogenous bases, one sugar

13.  Base pairs in DNA are held together by _____ bonds.  
A.  Peptide
B.  Non polar covalent
C.  Polar covalent
D.  Hydrogen
E.  Sulfhydryl

14.  The duplication of a cell’s DNA is called  
A.  Mitosis
B.  Replication
C.  Transcription
D.  Translation
E.  Mutation

15.  Structural genes code for  
A.  Ribosomal RNA molecules
B.  Transfer RNA molecules
C.  Cellular proteins
D.  Gene expression elements
E.  All of the choices are correct

16.  During replication, each parent DNA strand serves as a _____ for synthesis of new DNA strands.  
A.  Copy point
B.  Template
C.  Comparison molecule
D.  Scaffold
E.  Reservoir

17.  Semiconservative replication refers to  
A.  Each base bonding at the 1′ position of the sugar
B.  A purine always bonding to a pyrimidine
C.  One helix strand that runs from the 5′ to 3′ direction and the other strand runs from the 3′ to 5′ direction
D.  An original parent DNA strand and one newly synthesized DNA strand comprising a new DNA molecule
E.  None of the choices are correct

18.  DNA polymerase III  
A.  Is needed for adding nucleotides during mRNA synthesis
B.  Synthesizes new DNA only in the 5′ to 3′ direction
C.  Cannot add nucleotides to the lagging strand
D.  Synthesizes an RNA primer
E.  All of the choices are correct

19.  Okazaki fragments are attached to the growing end of the lagging strand by  
A.  DNA ligase
B.  DNA polymerase
C.  DNA helicase
D.  DNA gyrase
E.  Primase

20. The enzyme that helps pack DNA into the cell by coiling the DNA into a tight bundle is: 
A. DNA ligase
B. DNA polymerase
C. DNA helicase
D. DNA gyrase
E. Primase