AP Bio Unit 6

adenine

purine

guanine

purine

thymine

pyrimidine

cytosine

pyrimidine

pyrimidine

single ringed

purine

double ringed

plasmids

small double-stranded, circular DNA molecules.

nucleotide structure

5 carbon sugar, phosphate group, nitrogenous bases

base pairing

a-t, c-g, a-u

5’ end

phosphate group

3’ end

OH group

DNA strands are linked by

hydrogen bonds

genome

all of the dna for a species

chromosome

each separate chunk of DNA in a genome

histones

proteins that organize DNA into chromatins

nucleosomes

histones are bunched together in groups

euchromatin

active genetic material in the loose form

heterochromatin

genetic material is fully condensed into coils, inactive and tight

helicase

unzips

topoisomerase

alleviates tension by cutting and rejoining DNA strands

DNA polymerase

adds nucleotides to an existing strand, adds them to 3’ end

RNA primase

enzyme that synthesizes short RNA primers to initiate DNA synthesis

leading strand

the continuously synthesized DNA strand during replication that runs in the 5’ to 3’ direction.

lagging strand

the discontinuously synthesized DNA strand during replication that runs in the 5’ to 3’ direction.

Okazaki fragments

DNA nucleotides synthesized on the lagging strand during DNA replication, which are later joined together by DNA ligase.

semiconservative

e each new double helix consists of one original strand and one newly synthesized strand.

telomeres

bits of unimportant DNA at the ends of a molecule.

Ligase

joins Okazaki fragments together