DNA Structure Flashcards
1
Q
what is chargaff’s discovery
A
- there is significant DNA variation between species, thus DNA could be the genetic material
2
Q
what is chargaff’s rules
A
a = t
g= c
the composition of DNA varies between species
3
Q
what does the DNA structure look like
A
- a double stranded molecule with particular features
4
Q
what are the components of DNA
A
- bases
- phosphates
- deoxyribose sugar
- the single unit building blocks of the macromolecule DNA are nucleotides
5
Q
how are polynucleotides formed
A
- nucleotide monomers are joined together with PHOSPHODIESTER BONDS tp form polynucleotide = nucleic acid
6
Q
which direction does the DNA (and RNA) strands synthesis in
A
5’ –> 3’
7
Q
how are phosphodiester bonds formed
A
the hydroxyl group on the 3rd carbon of one nucleotide reacts with the phosphate group attached to the 5th carbon on another nucleotide
8
Q
are the 2 strands antiparallel or parallel
A
antiparallel
9
Q
what do 2 antiparallel DNA strands form
A
- a double stranded helix
10
Q
what is the Watson-cricks model of the DNA structure
A
- DNA has a double-stranded helical structure
- the sugar phosphate backbone is on the outside
- the base are on the inside
- stabilized by hydrogen bonds
- the 2 polynucleotide strands are oriented in opposite directions
11
Q
what does it mean that it is a semi-conservative model of replication
A
- means that each DNA strand of the double helix is used as a template strand for the synthesis of 2 new strands
12
Q
why does your cell replicate its DNA
A
- your body needs to make more cells:
- for: different growth stages, pregnancy, repair of injury
