DNA STRUCTURE + REPLICATION

DNA

information storage molecule. double helix, consisting of 2 very long strands of nucleotides, hydrogen bonded together (nucleotides = monomer, DNA = polymer)

nucleotide

monomer of DNA. each one has a phosphate, a 5 carbon sugar, and one of 4 possible nitrogenous bases

sugar phosphate back bone

nucleotides on a single strand are connected by covalent bonds between the phosphate on one and the sugar on the nucleotide above/below it. establishes the order of the bases on a single strand

strands

double helix, run opposite directions (anti parallel). ends that have a phosphate are called 5’, ends with sugars are called 3’. ends provide info that help the cell know which direction to read the DNA in

sequence

on a single strand, can be any combo/order of basses. allows us to write any words/info

A goes with

T

T goes with

A

C goes with

G

G goes with

C

5’ and 3’ strands are

anti-parellel, going opposite ways

DNA binding proteins

protiens that bind specific short DNA sequences (different proteins copy, read, or repair DNA after binding)

chromosome

a single, long, continuous double stranded DNA polymer

helicase

protein that unzips the hydrogen bonds between complementary strands

primase

protein that adds primers to both original strands

primer

short nucleotide strand that complements an original strand

DNA polymerase

reads along a template strand toward the 5 end, adds new nucleotides and extends the 3 end of the primer, linking sugar to phosphate to sugar. this new strand base pairs with the old strand

new primer

primers are added and extended to back gaps

ligase

protien that links up all the partial strands onto long continuous new one