1. Nucleotides, Nucleic Acids, & DNA

Question 0

different “codes”

Answer 0

single letter code for DNA, transcripted to single letter code for RNA, tranlsated to triple letter codon for amino acids (and ultimately proteins)

Question 1

central dogma

Answer 1

DNA—RNA—> protein

via transcription, then translation

Question 2

base

Answer 2

fundamental unit of nucleic acid

planar, stack together in a double helix

Question 3

purines

Answer 3

A, G

larger

Question 4

pyrimidines

Answer 4

C, U, T

smaller

Question 5

nucleoside

Answer 5

based attached to a ribose sugar

Question 6

nucleotide

Answer 6

nucleoside attached to a phosphate

Question 7

adenine example

Answer 7

adenine= base
adenosine=nucleoside
adenylate=nucleotide

Question 8

ribose

Answer 8

aldose, exists in cyclic form

attaches molecules via 5’ hydroxyl

Question 9

DNA v. RNA

Answer 9

DNA: H at position 2, thymine
RNA: OH at position 2, uracil

Question 10

DNA is aways written

Answer 10

5’ to 3’

if not labeled on exam, assume 5’ to 3’

Question 11

AT v. GC linkages

Answer 11

AT: 2 H bonds
GC: 3 H bonds

Question 12

How many base pairs per turn in DNA double helix?

Answer 12

10.5

bases hydrogen bond on the interior, phosphate bonds on the outside

Question 13

DNA complementarity

Answer 13

allows each strand to serve as a template during replication

Question 14

DNA undergoes?

Answer 14

HEMIconservative replication

each new strand produced consists of 1 parent strand & 1 daughter strand

Question 15

forms of DNA?

Answer 15

A form: right handed double helix w/11 bp turns
B form: MOST COMMON, right handed double helix w/10.5 bp turns
Z form: least common, left-handed double helix with 12 bp turns

Question 16

palindrome

Answer 16

2 sequences that are identical when read 5’ to 3’

Question 17

mirror repeat

Answer 17

symmetry occurs on the same strand

Question 18

DNA secondary structure: hairpin

Answer 18

formed from a palindrome sequence, with each base binding with its complement on the other side of the palindrome

Question 19

RNA structure

Answer 19

single stranded (can be double stranded)
double stranded RNA is more stable than double stranded DNA
more relaxed helix than DNA
can form hairpins, secondary structure is protein-like

Question 20

complementarity (2 things)

Answer 20

1. aspect for both double stranded DNA & double stranded RNA

2. basis for anti-parallel stability in the nucleic acid

Question 21

what stabilizes nucleic acids?

Answer 21

weak, non-covalent bonds & the exclusion of water

Question 22

what destabilizes nucleic acids?

Answer 22

heat & salt

Question 23

melting (denaturing) curve for nucleic acids

Answer 23

melting temperature (Tm) = temperature at which 50% of the strands are separated

as melting temp goes up, GC content goes up

Question 24

“DNA” breathing

Answer 24

in AT rich regions of DNA, we observe transient strand separation occurring even at physiological temperatures