Chapter 8: Nucleotides and Nucleic Acids Flashcards
What is a “Nucleotide”
Nitrogeneous base
Pentose
Phosphate
What is a “Nucleoside”
Nitrogeneous base
Pentose
What is a “Base”
Nitrogeneous base
What are 7 functions of Nucleotides?
Energy for metabolism (ATP) – Enzyme cofactors (NAD+) – Signal transduction (cAMP) – Storage of genetic info (DNA) – Transmission of genetic info (mRNA) – Catalysis (ribozymes) – Protein synthesis (tRNA and rRNA)
At what pH is a Phosphate group charged?
Negatively charged at neutral pH
Where is the phosphate group typically attached?
At the 5’ position (but may also be attached to other positions)
What’s the difference between a ribonucleoside and a dexoyribonucleoside? What are there abbreviations?
ribonucleoside (ex: AMP, ADP, ATP) has a 2’OH group and dexoyribonucleoside (dAMP, dADP, dATP) has a 2’ H group.
Derivatives of pyrimidine or purine Nitrogen-containing heteroaromatic molecules Planar or almost planar structures Absorb UV light around 250-270 nm
Nucleobases
In pyrimidine bases, where are both DNA and RNA found?
Cytosine
In pyrimidine bases, where are DNA only found?
Thymine
In pyrimidine bases, where are RNA only found?
Uracil
Pyrimidine Bases (Cytosine, Thymine, Uracil) are neutral molecules at pH 7 and are good what?
H-bond donors and acceptors
In purine bases, where are Adenine and Guanine found?
both DNA and RNA
Good H-bond donors and acceptors
Neutral molecules at pH 7
Purine Bases
In nucleosides and nucleotides, the pentose ring is attached to the base via an ___ and formed how?
N-glycosidic bond. Bond is formed to the anomeric carbon of the sugar in Beta-configuration
Beta N-glycosidic bond is formed to what position in pyrimidines?
in purines
N1
Beta N-glycosidic bond is formed to what position in purines?
N9
Is Deoxyadenylate (deoxyadenosine 5’-monophosphate) a nucleotide or nucleoside nomenclature?
nucleotide
Is Deoxyadenosine a nucleotide or nucleoside nomenclature?
nucleoside
What are the SYMBOLS for “Deoxyadenylate” (deoxyadenosine 5’-monophosphate) and “Deoxyguanylate” (deoxyguanosine 5’-monophosphate)?
A, dA, dAMP; G, dG, dGMP
What kind of rotation can occur around the N-glycosidic
bond in free nucleotides?
free
What conformations occur in N-Glycosidic Bond?
syn or anti
What’s the nucleic acid for Purine?
None
What’s the nucleic acid for Adenine?
RNA and DNA
What’s the nucleic acid for Guanine?
RNA and DNA
What’s the nucleic acid for Pyrimidines?
None
What’s the nucleic acid for Cytosine?
RNA and DNA
What’s the nucleic acid for Thymine?
DNA
What’s the nucleic acid for Uracil?
RNA
Is Adenylate a nucleotide or nucleoside nomenclature?
Nucleotide
What are the SYMBOLS for “Adenylate” (adenosine 5’-monophosphate)
A, AMP
TRUE/FALSE:
Modification of nucleotides is done after DNA synthesis
True
Where is 5-Methyldeoxycytidylate commonly found?
Eukaryotes (also found in bacteria)
Where is N6-Methyldeoxyadenylate commonly found?
Bacteria (not found in bacteria)
In prokaryotes, what is the epigenetic marker?
Mark own DNA so that cells can degrade foreign DNA
In eukaryotes, what is the epigenetic marker?
Mark which genes should be active (negative
regulation)
What are some minor nucleotides in RNA?
Inosine and Pseudouridine
Where is Inosine found?
in the “wobble position” of the anticodon in
tRNA
Where is Pseudouridine found?
widely in tRNA and rRNA
How is Inosine made?
deaminating adenosine
How does pseudouridine assist tRNA?
stabilize the structure of tRNA
How does pseudouridine assist rRNA?
folding of rRNA
DNA backbone is fairly stable or unstable?
fairly stable
RNA backbone is fairly stable or unstable?
unstable
We read polynucleotides in what direction?
read the sequence from 5’ to 3’
Polynucleotides have linear polymers which means?
no branching or cross-links
TRUE/FALSE:
Polynucleotides, with a negatively charged backbone, are covalent bonds formed via phosphodiester linkages
True
Hydrolysis of DNA is catalyzed by what enzyme?
DNAse
Hydrolysis of RNA is catalyzed by what enzyme?
RNAse
Watson-Crick base pairs predominate in double-stranded
DNA. What are the pairs for A, T, C, G, Purine, Pyrimidine?
A pairs with T
C pairs with G
Purine pairs with pyrimidine
In Hydrogen bonding interactions,
Two bases can hydrogen bond to form a base pair
TRUE/FALSE:
For monomers, large number of base pairs is
possible.
In polynucleotide, only few possibilities exist
True
What are required for complementarity of DNA?
Two chains differ in sequence(read from 5’ to 3’)
Two chains are complementary
Two chains run antiparallel
TRUE/FALSE:
A-T and C-G pairs are favorable?
True
First, strand separation.
Each strand serves as a template for the synthesis of a new strand.
Synthesis is catalyzed by enzymes known as DNA polymerases.
Newly made DNA molecule has one daughter strand and one parent strand.
Replication flow of Genetic Code
Code Carrier for the Sequence of Proteins
Messenger RNA (mRNA)
Instead of deoxyribose and thymine, mRNA contains what?
Contains ribose and uracil
mRNA is single or double stranded?
Single
TRUE/FALSE:
mRNA is synthesized using DNA template?
True
One mRNA may code for how many proteins?
more than one protein (polycistronic)
Matching Amino Acids with the mRNA Code
Transfer RNA (tRNA)
TRUE/FALSE:
tRNA molecules have quite complex structures,
this is an actively studied field
True