DNA Structure Flashcards
What makes up a nucleotide?
- Nitrogenous base
- Pentose Sugar
- One or more phosphate groups
What is a nucleoside?
Nitrogenous base+sugar (w/o phosphate group)
Where does the phosphate attach to the sugar?
5’C
Where does the nitrogenous base attach to the sugar?
1’C
What are the two groups of nitrogenous bases? Describe each and what makes up each group.
Pyrimidines- single ring C, T
Purines- double-ringed A, G
What is deoxyribose and what does it correspond with?
Missing one O bonded to 2’C (in DNA)
What is ribose and what does it correspond with?
Has OH bonded to 2’C
What reaction makes polynucleotides?
Dehydration reaction
Where does the phosphodiester linkage occur?
Sugar-phosphate backbone
What side of the polynucleotide do you add to?
3’ side
What is Rosalind Franklin known for?
Proposed 2 strands with sugar-phosphate backbone and bases on the interior after using X-ray Crystallography
What is Watson and Crick known for?
Build models of a double helix to conform to the X-rays and chemistry of DNA
What is the shape of DNA?
Double helix
What does it mean to be antiparallel in structure?
Backbone runs opposite 5’->3’
What bond links base pairs?
H-bonding
What is the pairing of the base pairs?
A-T and C-G
What is right handed chirality?
Twist moves helix away
What is the helical pitch?
The height of one full turn which consists of 10 base pairs
How many h-bonds are in A-T bonding?
2
How many h-bonds are in C-G bonding?
3
What does more h-bonds mean?
More stable
The 5’ side of DNA will match with what?
3’ side of complementing pair
What kind of structure does RNA have?
Single stranded
What are the different types of RNA?
mRNA, tRNA, rRNA, sRNA
What is the hydrogen bond of each base pair in RNA?
A-U
C-G
What kind of bond is in the single stranded backbone?
Covalent
What is the role of DNA?
Heredity, traits
What did Fredrick Griffith discover?
Discovered bacterial transformation- transmitted cell to cell and that DNA can confer new traits
What did Alfred Hershey and Martha Chase discover?
Discovered DNA is component of phage that enters cells= genetic material
What did Erwin Chargaff discover?
Discovered DNA composition varies from one species to the next- diversity made DNA more credible candidate for genetic material
What are Chargaff’s rules? 2
- The base composition of DNA varies between species
2. In any species the number of A and T bases equal and the number of G and C bases are equal
What is the difference between RNA and DNA?
RNA has... Single-stranded Uses uracil instead of thymine Not double helix Ribose (OH off 2C)
