Chapter 10.3 Flashcards
primary structure of DNA
refers to- the string of nucleotides joined together by phosphodiester linkages
three components of each DNA nucleotide
sugar
phosphate group
nitrogen containing base
what are the two types of nitrogenous bases?
purine
pyrimidine
name the purines
consist of a 5 member ring attached to a 6 member ring
adenine
guanine
name the pyrimidines
consist of a 6 member ring only
cytosine
thymine
uracil
what is the difference between ribose and deoxyribose?
deoxyribose- (DNA’s sugar)
- has a hydrogen atom (-H) attached to the 2’ carbon atom
- has one fewer oxygen atom overall
- less reactive than RNA, more stable for long term genetic coding
ribose- (RNA’s sugar)
- has hydroxyl group (-OH) attached to the 2’ carbon atom
- more reactive than DNA because of additional oxygen atom
nucleoside
a term referring to a deoxyribose/ribose sugar joined with a nitrogenous base
what makes up the phosphate group?
- phosphorous atom bonded to four oxygen atoms
- always bonded to the 5’ carbon atom of the sugar
- usually carry a negative charge = making DNA acidic
what are deoxyribonucleotides?
nucleotides in DNA containing deoxyribose
ribonucleotides
nucleotides in RNA containing ribose
phosphodiester linkages
Phosphodiester bond connecting two nucleotides in a polynucleotide strand.
connect the 3’ carbon atom of one nucleotide to the 5’phosphate group of the next
-always goes 5’ —> 3’
how many hydrogen bonds do C-G pairs have?
3
how many hydrogen bonds to T-A pairs have?
2
secondary structure of DNA
refers to its 3 dimensional configuration
(fundamental helical structure)
-antiparallel double helix
what are the 3 secondary structures of DNA?
A form
B form -
Z form
