BIOL 100 DISCUSSION PRACTICE QUIZ #2
1.  Which statement is not true about Griffithês experiments?  a) mice injected 
with S (smooth) pneumococci die  b) mice injected with heat-killed S 
pneumococci die  c) mice injected with heat-killed S pneumococci and live R 
(rough) pneumococci die  d) mice injected with the R strain live

2.  From the above experiemnts what principle did Griffith 
discover?____________________. Breifly explain this principal in 
relation to his observations.


What did the experiments of Avery, MacLeod, and McCarty add to Griffithês 
work?_______________
3.  What evidence do we have that in the helical form of the DNA molecule 
that the base pairs are composed of one purine and one pyrimidine?

4.  A nucleotide may contain: a) a purine  b) a pentose  c) a phosphate group  
d) a pyrimidine e)a-->d
5.  The double-helix model of DNA, as suggested 
by__________and_____________, was based on what three main lines 
of evidence gathered by other researchers?



6.  Adenine and guanine are:  a) double-ringed purines  b) single-ringed 
purines  c) double-ringed pyrimidines  d) single-ringed pyrimidines  e) none 
of the above
7. In DNA and RNA, which carbon atoms of the sugar molecule are 
connected by a phosphodiester bond?
8.  What would you need to do in order to change a DNA molecule into an 
RNA molecule?

9.  How do nucleotides and nucleosides differ?

10.  What chemical group is found at the 5ê end of a DNA 
chain?_________At the 3ê end?________
11.  From the x-ray diffraction data by Wilkens and Franklin, which of the 
following pieces(s)  of information was determined about DNA?  a) it had a 
uniform diameter  b) it was long and narrow  c) its shape could be spiral   
d) all of the above 
12.  Is an A-T or C-G pair harder to break?explain

13.  The percent of cytosine in a DNA molecule=17%.  What is the % of 
adenine in that DNA?_____
14.  Watson and Crick:  a) established the double-stranded nature of DNA
  b) established the principle of base-pairing (complementarity)  c) explained 
how DNAês structure permitted it to be replicated  d) the 2 DNA strands are 
antiparallel  e) a----->d
15.  Each DNA strand has a backbone that consists of alternating:  a) purines 
and pyrimidines  b) nitrogen-containing bases  c) hydrogen bonds  d) sugar 
and phosphate molecules
16.  Name the mechanism by which DNA is 
replicated?_________________
In terms of new DNA and old DNA, what will the DNA of the: parent 
have?_____________the first generation of daughter cells 
have?_______________the second generation?________________
17.  Lets suppose you want to make DNA in a test tube.  You were given 
nucleotides.  Name three other things you need to add in order to make 
DNA?

18.  In terms of origins of replication, how does DNA replication in 
Prokaryotes differ from that found in Eukaryotes?
19.  DNA synthesis:  a) proceedes 3ê-->5ê  b) requires a DNA primer  c) is 
bidirectional  d)  is continuous on both newly synthesizing DNA strands
20.  If synthesis is moving in this direction (---->), which strand below (top or 
bottom) is the template for the lagging strand (Okazaki fragments) during 
DNA replication?_____________Which strand would serve as a template 
for RNA synthesis?___________                        5ê----------------------3ê
                                                                                        3ê----------------------5ê
21.  One of the strands of a DNA molecule has the following sequence
 5ê-AGCGGT-3ê
What will the sequence of the mRNA (codons) be? 
 5ê-_________________-3ê
What will be the sequence of the anticodons on the tRNA? 
 3ê-_______________-5ê
22.  The process of converting DNA into RNA is 
called________________. This process  is catalyzed by the 
enzyme______________________, and occurs in 
the_____________of the cell.
23.  __________sequences, which bind________________ and 
__________________determine where transcription starts.  
___________ sequences determine where transcription stops.
24.  List three different types of RNA molecules, and breifly describe the main 
functions of each.
25.  Which of the following is not found on mRNAs:  a) promoter  b) poly A 
tail  c)  5ê untranslated leader sequence  d) 3ê untranslated region  e) AUG 
f) stop codon  g) protein coding sequence 
26.  The process of converting RNA into protein is 
called___________________, and occurs in the 
_________________of the cell.
27.  What is the difference between a charged and uncharged tRNA?

28.  During translation, an individual tRNA floats into the _______ site of 
the large ribosomal subunit, where its___________ base pairs with 
complementary ________sequences on the mRNA.
29.  Compare and contrast the following two events in terms of what their 
consequences would be.  Event #1: an incorrect nucleotide is inserted into the 
new DNA strand during replication, and not corrected by the proofreading or 
repair systems before the next replication.  
Event #2: an incorrect nucleotide is inserted into a mRNA during 
transcription.








30.  List the three types of rRNAs found in Prokaryotic 
cells:_______,_________,___________  
and in Eukaryotic cells___________,_____________,_____________.
31.  A typical Prokaryotic ribosome has two subunits:  A small subunit, which 
binds___________, and is composed of _______ and ___________; A 
large subunit, which has two sites that can bind________, and is composed 
of ________, __________, and _________________.
32.  Which site on the large ribosomal subunit contains a tRNA bound to a 
newly synthesized polypeptide_____________
33.  Determine whether the following statements concerning the 
characteristics of the genetic code are True or False. For those which are false, 
state why.
a) Each mRNA codon that specifies an amino acid in a polypeptide chain 
consists of 2 nucleotides__
b) In general the code is universal.  All organisms share the same 
language_________
c) More than one codon occurs for each amino acid_____
d) All 64 codons specify for amino acids________
e) In some cases the same amino acid will be specified by several codons 
whose second and third positions are identical, but the base at the first 
position may be A, U, C, or G______
f) The genetic code in mRNA is read without gaps and in successive, 
nonoverlapping codons_____
g)  Wobble occurs in the anticodon. This feature allows for less exact base 
pairing so that the base at the 5ê end of the anticodon can potentially pair with 
one of three different bases at the 3ê end of the codon______
h) Protein synthesis is typically initiated by codon AUG (N-formyl 
methionine), and is terminated by three codons (UAU, UAA, UGA) which do 
not code for any amino acid__________
i) Each tRNA can only recognize one codon_______
k) Every protein begins with the same amino acid______
34.  The step in translation when a peptide bond forms between the amino 
acid attatched to the tRNA in the_____site of the ribosome and the growing 
polypeptide attatched to the tRNA in the____ site is 
called_______________.  During this time the now-uncharged tRNA in 
the____site is released from the ribosome and the ribosome moves one 
codon down the mRNA in a process called________________. Does this 
process require energy?
35.  Define polyribosome:

36.  Draw a rough skematic of the translation initiation complex . In your 
diagram include: ribosome (ssu and lsu), mRNA, AUG, special methionine 
tRNA (fMET-tRNA), A and P sites.