WEEK 5 Flashcards
Gene
entire nucleic acid sequence (usually DNA) that is necessary for the synthesis of a protein (and its variants) or RNA. Genes are segments of DNA that are transcribed into RNA.
Two types of genes that when transcribed…
one results in RNA that encodes for a protein and the second type results in RNA that functions as RNA.
Where is the active site located in the RNA polymerase complex
closer to the front
How is RNA polymerase similar to DNA polymerase? How is it different?
- RNAP also has a backspace function (exonuclease repair)
- doesn’t need a primer
What is formed transiently during RNA transcription
a DNA RNA duplex
Difference between DNA and RNA
DNA is missing the O of the hydroxyl group on its 2’ carbon
What does the 5’ end of RNA have?
3 phosphate groups and then a sugar
RNA is linked by… and is held to DNA with…
- phosphodiester bonds
- base pairing
RNA polymerase relies on
base pairing and nucleoside triphosphates
- cuts off pyrophosphate when NTP joins 3’ OH to 5’ carbon
Bacterial Transcription
- Sigma factor binds to core enzyme and binds to promoter
2. Localized unwinding of DNA
Holoenzyme
Sigma factor and RNAP core enzyme together
Bacterial promoter
found at nucleotides -35 to -10 (where holoenzyme binds). The very first nucleotide that is transcribed is designated as +1.
Abortive transcription
holoenzyme transcribes +1 to +10 multiple times and casts off RNA strands restarting. Sigma factor releases and RNAP enters processive mode.
RNA termination
Reaches hairpin structure (also called a stem loop structure) followed by loose As and Us which pry polymerase off DNA.
AUG
is the start of translation not transcription
