Question 1

The compound that consists of ribose linked by an N-glycosidic bond to N-9 of adenine is

Accepted Answer

adenosine

Question 2

A major component of RNA but not of DNA is:

Accepted Answer

uracil

Question 3

The difference between a ribonucleotide and a deoxyribonucleotide is:

Accepted Answer

a deoxyribonucleotide has an —H instead of an —OH at C-2.

Question 4

Which one of the following is TRUE of the pentoses found in nucleic acids?

Accepted Answer

The pentoses are always in the β-furanose forms.

Question 5

The phosphodiester bonds that link adjacent nucleotides in both RNA and DNA:

Accepted Answer

join the 3' hydroxyl of one nucleotide to the 5' hydroxyl of the next.

Question 6

The phosphodiester bond that joins adjacent nucleotides in DNA:

Accepted Answer

associates ionically with metal ions, polyamines, and proteins.

Question 7

The alkaline hydrolysis of RNA does NOT produce:

Accepted Answer

3',5'-cAMP

Question 8

The alkaline hydrolysis of RNA DOES produce:

Accepted Answer

A) 2'- AMP
B) 2',3'-cGMP
C) 2'-CMP
D) 3'-UMP

Question 9

The DNA oligonucleotide abbreviated pATCGAC:

Accepted Answer

has a hydroxyl at its 3' end.

Question 10

For the oligoRIBOnucleotide pACGUAC:

Accepted Answer

the nucleotide at the 5' end has a phosphate on its 5' hydroxyl.

Question 11

The nucleic acid bases:

Accepted Answer

are roughly planar.

Question 12

Which of the following statements concerning the tautomeric forms of bases such as uracil is correct?

Accepted Answer

The lactam form predominates at neutral pH.

Question 13

In a double-stranded nucleic acid, cytosine typically base-pairs with:

Accepted Answer

guanine

Question 14

In the Watson-Crick model for the DNA double helix (B form) the A–T and G–C base pairs share
which one of the following properties?

Accepted Answer

The distance between the two glycosidic (base-sugar) bonds is the same in both base pairs,
within a few tenths of an angstrom.

Question 15

The experiment of Avery, MacLeod, and McCarty in which nonvirulent bacteria were made virulent
by transformation was significant because it showed that:

Accepted Answer

genes are composed of DNA only.

Question 16

Chargaff's rules state that in typical DNA:

Accepted Answer

A + G = T + C.

Question 17

In the Watson-Crick structure of DNA, the:

Accepted Answer

absence of 2'-hydroxyl groups allows bases to lie perpendicular to the helical axis.

Question 18

In the Watson-Crick model of DNA structure:

Accepted Answer

the distance between two adjacent bases in one strand is about 3.4 Å.

Question 19

Which of the following is NOT true of all naturally occurring DNA?

Accepted Answer

The ratio A+T/G+C is constant for all natural DNAs.

Question 20

Which of the following is TRUEof all naturally occurring DNA?

Accepted Answer

A) Deoxyribose units are connected by 3',5'-phosphodiester bonds.
B) The amount of A always equals the amount of T.
C) The two complementary strands are antiparallel.
D) Two hydrogen bonds form between A and T.

Question 21

In the Watson-Crick model of DNA structure (now called B-form DNA):

Accepted Answer

the bases occupy the interior of the helix.

Question 22

The double helix of DNA in the B-form is stabilized by:

Accepted Answer

nonspecific base-stacking interaction between two adjacent bases in the same strand.

Question 23

In nucleotides and nucleic acids, syn and anti conformations relate to:

Accepted Answer

rotation around the sugar-base bond.

Question 24

B-form DNA in vivo is a ________-handed helix, _____ Å in diameter, with a rise of ____ Å per
base pair.

Accepted Answer

right; 20; 3.4

Question 25

In double-stranded DNA:

Accepted Answer

the two strands have complementary sequences.

Question 26

Which of the following is a palindromic sequence?

Accepted Answer

GGATCC
CCTAGG

Question 27

Triple-helical DNA structures can result from Hoogsteen (non Watson-Crick) interactions. These
interactions are primarily:

Accepted Answer

hydrogen bonds involving the bases.

Question 28

Double-stranded regions of RNA:

Accepted Answer

can form between two self-complementary regions of the same single strand of RNA.

Question 29

When double-stranded DNA is heated at neutral pH, which change does not occur?

Accepted Answer

The covalent N-glycosidic bond between the base and the pentose breaks.

Question 30

Which of the following deoxyoligonucleotides will hybridize with a DNA containing the sequence
(5')AGACTGGTC(3')?

Accepted Answer

(5')GACCAGTCT(3')

Question 31

The ribonucleotide polymer (5')GTGATCAAGC(3') could only form a double-stranded structure with:

Accepted Answer

(5')GCTTGATCAC(3').

Question 32

In comparison with DNA-DNA double helices, the stability of DNA-RNA and RNA-RNA helices is:

Accepted Answer

RNA-RNA > DNA-RNA > DNA-DNA.

Question 33

In the laboratory, several factors are known to cause alteration of the chemical structure of DNA. The
factor(s) likely to be important in a living cell is (are):

Accepted Answer

A) oxygen.
B) UV light.

Question 34

Compounds that generate nitrous acid (such as nitrites, nitrates, and nitrosamines) change DNA
molecules by:

Accepted Answer

deamination of bases.

Question 35

In DNA sequencing by the Sanger (dideoxy) method:

Accepted Answer

the role of the dideoxy CTP is to occasionally terminate enzymatic synthesis of DNA where Gs
occur in the template strands.

Question 36

In the chemical synthesis of DNA:

Accepted Answer

the nucleotide initially attached to the silica gel support will become the 3' end of the finished
product.

Question 37

In living cells, nucleotides and their derivatives can serve as:

Accepted Answer

A) carriers of metabolic energy.
B) enzyme cofactors.
C) intracellular signals.
D) precursors for nucleic acid synthesis.

Question

Question

Question

Chp 8 MC

Nucleotides and Nucleic Acids

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