Transcription Flashcards
what is transcription?
DNA to RNA
what is translation?
RNA to protein
what is the central dogma?
DNA->RNA->protein
amount of proteins depends on?
amount of transcription
what is RNA?
a polymer of 4 diff nucleotides linked together by phosphodiester bonds. (sugar, base, phosphate group) 5’-3’
how are RNA molecules bonded?
phosphate group to -OH group
what are 3 differences between DNA and RNA?
RNA contains ribose, DNA contains deoxyribose, RNA has uracil as appose to thymine, RNA is single stranded (does base pairing with itself, has a secondary structure) while DNA is double stranded
how does transcription occur?
DNA unwinds and one strand is used as a template. RNA chain is produced by adding 1 ribonucleotide at a time via complementary base pairing
what is a transcript?
the growing RNA chain off of a DNA
in what direction is the template strand read?
3’-5’
what is RNA polymerase?
an enzyme that zips down a DNA strand to construct transcript RNA
can many different RNA polymerases make RNA on the same DNA strand?
yes
what are some differences between RNA and DNA polymerase?
RNA polymerase catalyzes ribonucleotides, not deoxyribonucleotides
RNA polymerase can start a RNA chain without a primer
DNA polymerase has rare mistakes
DNA and RNA polymerase are not structurally related
RNA is much shorter than DNA
RNA strand does not remain H-bonded to DN template (DNA helix reforms)
what is a primer?
DNA polymerase needs primer to latch on DNA
what is the final product of noncoding RNA?
RNA as final product
what is the final product of mRNA?
protein
what is the function of mRNA?
used to ribosomes to make proteins
what is the function of rRNA?
form basic structure of ribosomes
ribosomes have how many subunits?
2
what rRNA does the small subunit have?
18S
what rRNA does the large subunit have?
5S, 28s, 5.8S rRNA
how do you make rRNA?
precursor rRNA undergoes chemical modification and then cleavage
what is tRNA?
transfer RNA, adaptors between mRNA and amino acids
what is snRNA?
small nuclear RNA, used for splicing
what is snoRNA?
small nuclelor RNA, used when you want to modify the rRNA precursors
do different cell types have different genes?
no, cell “fate” is determined by with proteins get turned on, regulated by transcription
what is holoenzyme complex?
RNA polymerase and sigma factor
describe bacterial transcription
- homoenzyme assembles and locates promoter
- DNA starts unwinding
- transcription begins
- after 10 nucleotides, polymerase breaks off frfom sigma factor and promoter sequence
- polymerase zooms down DNA
- stops transcription at termination sequence
- everything leaves
how does the RNA polymerase know when to start?
promoter sequence