ch 3 notes protein synthesis

proteins give a cell structure and function…

includes enzymes

linear, double stranded DNA directs protein synthesis:

central dogma

central dogma:

DNA to RNA to protein

transcription means..

copy

DNA nucleotide monomers

sugar, phosphate, nitrogen base + (A,T,C,G) = 1 nucleotide

T-C are..

pyrimidines (single carbon and nitrogen ring)

A-G are..

purines (2 rings)

RNA nucleotides

single strand made via DNA template → participates in protein synthesis at ribosomes (which are made of RNA themselves)

transcription of a gene:

inside nucleus → make mRNA for that gene/protein

a gene has a TATA nucleotide sequence of DNA called..

promoter

transcription factors (proteins)..

assemble here to bring RNA polymerase to gene

RNA polymerase uses..

DNA template and base pairing to make mRNA single stranded

before mRNA leaves nucleus it is…

spliced → introns cut out → not used in protein (post transcription modification) exons are spliced together = express

spliced

cut out

transcription factors

allow different cells to differentiate and activate different genes

introns

always interrupt → cut out

exons

express

TATA/promoter is..

upstream from your gene

different exon order =

different protein = different function

translation

occurs in cytoplasm (liquid of cell) -> @ ribosomes on the rough ER

ribos (made of rRNA)..

translate an mRNA codon (3 nucleotides) into 1 amino acid

translate

make aminos into protein

ribosome catalyzes..

peptide bond b/t amino acids via dehydration synthesis → protein

process does not start until..

ribosome reads a start codon (AUG)

tRNA brings the amino acid to a..

ribosome that corresponds to mRNA codon sequence

stop codon:

mRNA terminates the process

stop codon =

1 extra codon

there’s no _ in RNA

T