DNA L14 Flashcards
I. DNA is the Genetic Material - SEQ, CC DNA experiments II. DNA structure - CC, HD DNA structure III. SEQ, HD DNA replication
1
Q
chromosomes
A
- DNA + proteins
2
Q
DNA structure
A
- nucleotides – phosphate group, sugar, nitrogenous base
3
Q
2 types of nitrogenous bases
A
- purines (2 rings) – A,G
- pyrimidines (1 ring) – C,T
4
Q
Erwin Chargaff
A
- total purine (A+G) = total pyrimidine (C+T)
- amount A = amount T
- amount C = amount G
- but A+T not equal to C+G
5
Q
Rosalind Franklin
A
- DNA is double helix
- bases on inside
- diameter consistant
6
Q
sugar phosphate backbone (found on each strand of DNA)
A
- alternating sugar and phosphate group
- outside of helix
- not variable
7
Q
nitrogenous bases (found on each strand of DNA)
A
- covalently attached to backbone
- variable (4 bases)
- information in sequence
8
Q
H bonds
A
- strands held together with H bonds
- A+T (2 H bonds)
- C+G (3 H bonds)
9
Q
base pairing rules
A
- purine + pyrimidine
10
Q
strands are antiparallel
A
- run in opposite directions
- carbons in sugar numbered 1-5
- 5’C - phosphate
- 3’C - hydroxyl
11
Q
semi conservative replication
A
- each new double helix contains “old” strand and “new strand”
12
Q
initiation
A
- DNA must be unwound
- proteins required:
- DNA helicases - unzip/open
- single-stranded binding proteins - keep open
- topoisomerases - break and reform bonds - slightly change shape
13
Q
elongation
A
- nucleotides always added 5’ to 3’ direction
- 5’ phosphate group attached to previous 3’ hydroxyl
14
Q
nucleoside triphosphate
A
- monomers of nucleic acids
- nucleoside (sugar + base) and 3 phosphate groups
- release pyrophosphate when added to DNA strand
- forms new phosphodiester bond
15
Q
DNA polymerases
A
- enzymes - add nucleotides to growing DNA molecule
- adds to 3’OH
- requires RNA primer
