Chapter 8 pt 2

Question 1

Some Bases of DNA Are ______________

Answer 1

Methylated

Question 2

____________ & ____________ e are methylated more often

Answer 2

Adenine and cytosine

Question 3

_____________ Carry Chemical Energy in Cells

Answer 3

Nucleotides

Question 4

________________ are Components of Many Enzyme Cofactors

Answer 4

Adenine Nucleotides

Question 5

________________ (cyclic AMP, or cAMP), formed from ATP in a reaction catalyzed by adenylyl cyclase, an enzyme associated with the inner face of the plasma membrane.

Answer 5

Adenosine 3′,5′-cyclic monophosphate

Question 6

Cytosine pKa at N3 is

Answer 6

4.5

Question 7

Thymine pKa at N3 is

Answer 7

9.5

Question 8

Molecules are neutral molecules at pH 7
but can undergo ______________ from keto to enol form Lactam» lactim > double lactim

Answer 8

tautomerism

Question 9

Adenine pKa at N1 is

Answer 9

3.8

Question 10

Guanine pKa at N7 is

Answer 10

2.4

Question 11

______________ Bond attaches the pentose ring to a nucleobase to form a nucleoside

Answer 11

Beta-N-Glycosidic

Question 12

Anomeric carbon in _______________ is bonded to N1 or N-9 of base

Answer 12

B configuration (stable toward hydrolysis but cleavage is catalyzed
by acid
– Nearly free rotation around glycosidic bond in
free nucleotides
– Anti conformation is found in normal B-DNA)

Question 13

Nucleotides are ________ & ________

Answer 13

nucleoside + one or more phosphates (have many cellular roles)

Question 14

What are the best known nucleotides?

Answer 14

ADP & ATP

Question 15

Nucleotide deriviate

Answer 15

ADP-Glucose

Question 16

5-Methylcytosine

Answer 16

common in eukaryotes and found in bacteria

Question 17

N6-Methyladenosine

Answer 17

is common in bacteria but not in eukaryotes

Question 18

Epigenetic markers

Answer 18

Differentiate self DNA from
foreign DNA (prokaryotes) or
active genes (eukaryotes)

Question 19

Epigenetic markers (Minor Nucleosides in DNA: Modification after DNA synthesis)

Answer 19

Differentiate self DNA from
foreign DNA (prokaryotes) or
active genes (eukaryotes) (Environmental conditions affect
gene activation/ deactivation
* Pattern can be inheritable)

Question 20

Inosine (Minor Nucleosides in RNA)

Answer 20

May occur in the “wobble position” of anticodons in tRNA (De-aminated adenosine; Provides richer genetic code)

Question 21

Pseudouridine

Answer 21

Found widely in tRNA and rRNA of eukaryotes Made
from uridine by enzymatic isomerization after RNA synthesis

Question 22

Deamination

Answer 22

100 C  U events /day in a mammalian celL

Question 23

Depurination

Answer 23

10,000 purines lost/day in a mammalian cel

Question 24

________________, Chemical Mutagenesis, and Radiation Damage of DNA causes aging (No detail discussed)

Answer 24

Accumulated Oxidative

Question 25

______________ Hydroxylguanine especially in mitochondrial DNA

Answer 25

Oxidative damage

Question 26

_______________ Methylation of guanine

Answer 26

Chemical alkylation

Question 27

_____________ induces dimerization of pyrimidines; this may be the main
mechanism for skin cancers.

Answer 27

UV light

Question 28

_______________ (X-rays and -rays) causes ring opening and strand
breaking which must be repair by complex recombinatio

Answer 28

Ionizing radiation

Question 29

Nucleic Acid Structure: Polynucleotides are nucleotide “residues” linked by _________________

Answer 29

phosphodiester (3’ –OH of nucleotide-1 linked to 5’ P of
nucleotide-2)

Question 30

_____________ RNA Hydrolysis under alkaline conditions

Answer 30

Base-catalyzed

Question 31

______________ Carries the code for the Amino Acid Sequence of Proteins

Answer 31

Messenger RNA

Question 32

DNA template —–> mRNA —–> single stranded with ribose instead of
deoxyribose and uracil instead of __________

Answer 32

thymine (One mRNA may code for more than one protein
* Transfer RNA (tRNA) transfers genetic information from DNA to
proteins  tRNA codon specifies a specific am)