Chapter 3 - Nucleic Acids Flashcards Preview

Biochemistry > Chapter 3 - Nucleic Acids > Flashcards

Flashcards in Chapter 3 - Nucleic Acids Deck (19):
0

Monomeric units with phosphates

Nucleotides

1

What does nucleosides lack?

Phosphates

2

What are the two purine bases?

Adenine & Guanine (in both DNA and RNA)

3

What are the three pyrimidine bases?

Cytosine (in both DNA and RNA),
Thymine (in DNA)
Uracil (in RNA)

4

Where is the glycosidic bond of purines and pyrimidines?

Purines attached at N9 to sugar at C1'
Pyrimidines attached at N1 to sugar at C1'

5

What substrates do DNA and RNA synthesis require?

dNTP & NTP substrates

6

Nucleotides are linked through what kind of bond?

Phosphodiester bonds (between the 3' and 5' hydroxyl groups) to form long polymers

7

Reactive nucleoside triphosphates (dNTP's or NTP's) are added to growing polynucleotide chain at what end?

3' end

8

List the Chargaff's rules

1. All tissues in the same species have the same % of all 4 nucleotides
2. % of purines = % of pyrimidines
3. %A = %T and %G = %C

9

What's the bond between A & T?

2 H bonds

10

What's the bond between C & G?

3 H bonds, which is stronger than the bond between A & T

11

What is double helix stabilized by?

1. Hydrophobic interactions: base stacking
2. H-bonding between bases purinepyrimidine
3. Cations: neutralize the (-) charge on phosphates along the helix of DNA

12

Which kind of DNA forms under dehydrated, non-physiological conditions; right-handed helix

A form DNA (A-DNA)

13

Which kind of DNA forms when fully hydrated and under conditions in vivo; right-handed helix; majority of proteins recognize major groove

B-DNA

14

Found in G-C rich DNA sequences; left-handed helix; may be important in protein recognition & gene regulation

Z-DNA

15

Stability or melting temperature (Tm) is a function of what?

GC content

16

What are the most common structures of RNA?

A-form double helices and hairpins

17

What reads gene information encoded in mRNA copied from DNA?

tRNA

18

What does tRNA do?

Transfers the appropriate amino acid to a growing polypeptide chain during protein synthesis