Discussion:
Synthesis/RNA/DNA
1.The basic differences between RNA and DNA are:
a.The organic bases only
b.Bases, ribose units, and the phosphodiester linkage
c.Bases, ribose units, and the glycosidic bond type
d.Bases and the ribose units only.
2.The solubility characteristics of the pyrimidine or purine bases and the corresponding nucleosides differ greatly. Which of the following statements is not true?
a.purine bases are quite soluble in water.
b.Nucleosides are much more soluble than the corresponding bases.
c.Nucleosides and nucleotides are quite soluble in water.
d.Ribose units are very soluble in water.
3.Adenosine and guanosine are found predominantly in which tautomeric forms, respectively?
a.Amino & keto, respectively
b.Imino & keto, respectively
c.Amino & enol, respectively
d.Imino & enol, respectively
4.The component(s) of DNA which is (are) responsible for the absorbance band at 250-270 nmis:
a.Bases, pentoses. and phosphates all contribute
b.Only bases
c.Only bases and pentoses
d.Only pentoses and phosphates
5.AMP has three relevant ionizable groups. NI of adenine has pKa 4.0 and the phosphomonoester has pKas at 1.0 and 6.0 the net charge on AMP at pH 7.0 is approximately:
a.-3
b.-2
c.-1
d. 0
6.The thermodynamically most favorable form for pyrimidine nucleotides is:
a.Syn conformation
b.Anti conformation
c.Both are equally favored
d.Cannot be predicted
7.Which molecule contains an acid anhydride bond?
a. DNA
b.ATP
c.AMP
d. CAMP
8.All the NTPs are essential for RNA synthesis but GTP is also essential in:
a.Protein biosynthesis
b.Glycogen biosynthesis
c.Phospholipid biosynthesis
d.Fatty acid biosynthesis
9.The oligonucleotide, AUGGp, has all these properties except
a.Composed of ribonucleotides
b.Contains a 3' phosphate
c.Has a net charge pf -2 at pH 8.5
d.Contains three phosphodiester bonds.
10.To what target sequence on DNA is the oligonucleotide pAATTCCGG complementary?
a.TIAAGGCC
b.CCGGAATT
c.UUAAGGCC
d.CCGGAAUU
11.Which of the following characterizes the DNA in human cells?
a.DNA is located at a mesosome.
b.DNA is complexed with nonhistone proteins to form a nucleosome.
c.DNA is complexed with histone proteins with the DNA residing in the interior of the nucleosome.
d.DNA is complexed with the basic histone proteins and winds around the exterior of the histone protein "core".
12.An individual heterogeneous nuclear RNA (hnRNA):
a.Contains intron sequences not found in the final mature mRNA.
b.Contains exon sequences which are removed prior to translation.
c.Encodes more than one protein.
d.Can be found in the cytoplasm.
13.The RNA molecules which are involved in processing the hnRNA are:
a.mRNA
b.tRNA
c.rRNA
d.snRNA
14.RNA is hydrolyzed in basic solution but DNA is not. This occurs because:
a.Thymine is found in DNA, but uracil is not.
b.DNA is double stranded. while RNA is single stranded.
c.DNA contains a 2'-deoxyribose, while RNA does not.
d.RNA has modified bases, while DNA does not
15. What statement is incorrect about the different RNA molecules?
a.tRNA contain numerous intramolecular hydrogen bonds between bases.
b.There are more distinct tRNA molecules than there are rRNA molecules.
c.rRNA are complexed to proteins in the ribosomes.
d.The most abundant RNA molecule in the cell is mRNA.