DNA, RNA, Proteins Flashcards
What is the role of precurser metabolites?
so the cell can make all other building blocks
What are the 3 things E.coli is mostly made from?
RNA, lipids, Proteins
DNA synthesis occurs
5’-3’
DNA synthesis is catalyzed by
DNA polymerase
Semiconservative
Each DNA strand acts as template for synthesis of a new DNA strand
Bacteria has _____ number of ______ chromosomes
1 circular
replication begins with ____ and occurs _______
the origin of replication and occurs bidirectionally
DNA replication is regulated by
The frequency of initiation at the origin
How is high fidelity maintained during DNA replication?
through 3’-5’ exonuclease (proofreading) activity of DNA polymerase
DNA gyrase
removes positive supercoils
restriction enzymes
cut DNA, producing a souble strand break at a specific recognition sequence
What are restriction enzymes produced by?
bacteria to degrade invading DNA,
What protects a bacteria from its restriction enzymes?
Methylation
errors in DNA replication result in
Spontaneous mutations
What proteins are not present in a bacterias nucleosome?
no nucleosomes or histones
What does an archaea have in the nucleosome that bacteria does not?
Histone-like proteins
Prokaryotes have one ____
RNA pol, DNA-dependent RNA pol
Sigma factors
Let RNA pol recognize specific promoters to initiate transcription
Euk. have multiple
RNA pols
promoters
a specific genetic region involved in the binding of a RNA polymerase to initiate transcription
Do archea have promters? If not what do they have instead?
No, they have TATA box like eukarya
Operon
Bacterial genes found on a chromosome in clusters with related functions in transcriptional units
what does an operon have that is specific?
its own regulatory regions
Bacterial mRNA has no _____, _____ ,______
has no introns, Poly A tails, or 5’ caps
Rho independent termination
sequence motifs in prok that make transcription stop
compared with euks, proks have
________
________
________
- smaller ribosomes with diff structure, fewer initiation factors
- coupling of transcription and translation
- polycistronic mRNA
Ribosomes are made of
rRNA and proteins
translation begins at the ____ codon
start codon (AUG)
WHat initiator tRNA is for bacteria?
f-Met
what initator tRNA is for euk?
MET
the _________ sequence is found only in bacteria
shine del garno
what is the shine del garno sequence?
it is the ribosome binding site
The ______ sequence is only found in euk
Kozak sequence
protein processing
converts polypeptide into mature protein
covalent modification
cleavage, disulfide bond formation
folding
involves chaperones such as GroEL and GroES
translocation
movement of molecule from one location to another
protein export
translocation out of cytoplasm
protein secretion
translocation through all membranes to extracellular environment
Signal sequence
a sequence of 15-30 amino acids found at n-terminus of polypeptides destined for export from the cytoplasm
Type III SS (T3SS)
- genes encoding this T3SS are usually encoded on a pathogencity island or virulence plasmid
- effector proteins are delivered directly to the cytoplasm of a euk host or into the extra cellular space
Tir
improves E.coli adherence to intestinal cells
SopE
salmonella, GEF
YopT
Yersinia, cleaves protease
Type IV secretion
- related to bacterial conjugation systens (for transferring DNA)
- can transfer DNA, protein or DNA-protein complexes
