AP bio unit 6

DNA/RNA

Who contributed to the founding of the DNA structure?

Chargaff, Wilkins, Franklin main workers

Watson and crick came up with conclusions

purines

adenine and guanine

pyrimidines

cytosine and thymine

dna helicase

unzips DNA, separating it into two structures

topoisomerase

relaxes supercooling; prevents DNA ahead of rep fork from being too tightly wounded as DNA opens up (prevents DNA from being too tight)

nucleotide triphosphates

building blocks for forming new DNA strands

dna polymerase lll

extends primers, adding to the 3 end making the bulk of new dna (does most of synthesis)

rna primase

makes rna primer complementary to the template that provides a 3 end for DNA polymerase to work on, adding nucleotides

leading strand

5 →3

towards rep fork, made continuously, moves in same direction

(continuous replication)

lagging strand

3 → 5

away from fork, made in fragments, opposite directions

(discontinuous replication)

DNA ligase

gaps between DNA fragments are sealed together by DNA ligase

dna polymerase 1

rna primers are removed and replaced with DNA by DNA pol 1 (other polymerase involved in replication)

single stranded binding proteins

coat the separate strands of DNA near rep fork keeping them from coming back together into a double helix

semiconservative

each strand of dna in helix acts as a template for synthesis of new complimentary strand (½ old ½ new)

replication bubble

gap between 2 strands once hydrogen bonds broken

replication fork

point where two strands start to separate

okazaki fragments

fill up missing spaces on lagging strand

central dogma process

dna →rna →protein; describes flow of info in cells

types of RNA made during transcription

mRNA, tRNA, rRNA

DNA rep steps

I: helicase binds to origin and opens dna

E: RNA primers set down and DNA and DNA pol 3 extends strands

T: DNA pol 3 done, DNA pol 1 replaces primers and ligase seals knicks

dna and RNA have what shape

Uniformed; irregular shapes

aminoacyl

matches tRNA molec with specific amino acids

anticodon

tip of tRNA molec recognizes codon on mRNA molec

plasmids

small double stranded circular dna molec

base pairing

predictable matching of bases

a-t and c-g make how many h bonds

2;3

introns ___ and exons __

leave; stay and get spliced

what process puts exons together?

splicing

what protein does splicing

spliceosome

what is added to ends to mRNA after splicing

5’ GTP cap and 3’ poly-a-tail

to prevent breakdown

promoter gene

where rna pol binds to being transcription

operator

region that controls whether transcription will occur; where repressor binds

no lactose present

the repressor binds to the operator, blocking transcription of the lac operon.

lactose present

transcription turned on, activating further synthesis on tryptophan

tryptophan absent

the repressor is inactive, allowing transcription of the trp operon to occur, leading to the synthesis of tryptophan.

tryptophan present

the repressor binds to the operator, inhibiting transcription of the trp operon and stopping tryptophan synthesis.

nonsense mutation

original codon becomes a stop codon, causing early termination

missense mutation

original codon altered and produces a different amino acid

silent mutation

codon codes for the same amino acid and doesn’t change the protein sequence

frameshift mutation

caused by the insertion or deletion of nucleotides that alters the reading frame, leading to significant changes in the protein produced.