Lecture 4 Unit 1 Flashcards
what makes an RNA molecule slightly less stable
the oxygen molecule makes the RNA slightly more charged making it less stable
what is the difference in the sugar in DNA and RNA
DNA the sugar is deoxyribose, RNA the sugar is ribose
what is the difference in bases in DNA and RNA
DNA has thymine RNA has uracil
what is the difference at the 5’ end in DNA and RNA
DNA has a monophosphate RNA has a triphosphate
what is the difference in size between DNA and RNA
DNA is very large RNA is smaller
what is the difference in strands of DNA vs RNA
DNA has double strands RNA has single strands
how is the template strand read in transcription
from 3’ to 5’
how is the RNA strand synthesized in transcription
5’ to 3’
where does transcription start and end
starts at the promotor sequence ends at the terminator sequence
what are housekeeping genes
genes that are needed for basic cellular function and are transcribed all of the time
what happens in eukaryotic promotor recognition
- general transcription factors bind to the promotor and transcriptional activator proteins bind to enhancers
- transcriptional activator proteins, mediator complex, RNA pol 2, and general transcription factors are brought close
what does RNA polymerase 2 do?
adds nucleotides to the 3’ end
how does the polymerization reaction (the adding of nucleotides) occur?
1 incoming ribonucleotides are accepted if they correctly base pair
- the 3’- OH of the growing strand attacks the high energy phosphate bond of the incoming ribonucleotide, providing the energy to drive the reaction
- the two phosphates of the incoming ribonucleotides are released as pyrophosphate
what does polycistronic mean
there are multiple genes on a primary transcript
how does transcription and translation occur in prokaryotes
they are coupled, so translation begins before transcription is completed
what does polyadenylation do
add a poly A tail to the 3’ end
how is the 5’ end modified
adds a special nucleotide called the 5’ cap
what do the 5’ cap and polyA tail do
stabilizes the RNA transcript since the single strand in unstable and susceptible to breakdown by enzymes
what happens in RNA splicing
intron removal
what catalyzes intron removal
spliceosomes
what are spliceosomes made of
a complex of RNA and protein
what does rRNA do
found in all ribosomes that aid in translation
what does tRNA do
carries individual amino acids for use in translation
what does snRNA do
found in eukaryotes and involved in spacing, polyadenylation, and other processes in the nucleus
