07 - unfinished

define oriC. what process is it involved in?

the origin of chromosomal replication in bacteria; the specific DNA sequence where DNA replication begins. (Process: DNA replication)

define sigma factor. what process is it involved in?

a protein subunit of RNA polymerase that recognizes and binds to promoter sequences, allowing initiation of transcription. (Process: Transcription)

what are the –35 and –10 regions? what process is it involved in?

conserved promoter sequences located about 35 and 10 bases upstream of the transcription start site. They are recognized by the sigma factor to position RNA polymerase correctly. (Process: Transcription)

what is a promoter? what process is it involved in?

a DNA sequence upstream of a gene where RNA polymerase binds to start transcription. (Process: Transcription)

what is rho (ρ)? what process is it involved in?

a termination protein that binds to specific RNA sites and helps end transcription by separating RNA polymerase from the DNA template. (Process: Transcription)

what is the Shine-Dalgarno sequence? what process is it involved in?

a ribosome-binding site on bacterial mRNA located just upstream of the start codon; it helps align the ribosome with the correct start site for translation initiation. (Process: Translation)

what are start and stop codons? what process is it involved in?

• Start codon (AUG): Signals the beginning of translation, coding for methionine.

• Stop codons (UAA, UAG, UGA): Signal termination of translation, releasing the completed polypeptide.
  (Process: Translation)

what are chaperones? what process is it involved in?

proteins that assist other newly made polypeptides in folding into their proper 3D structures and preventing misfolding or aggregation. (Process: Protein folding, post-translation)

what is a signal sequence? what process is it involved in?

a short amino acid sequence at the beginning of certain proteins that directs the protein to specific locations (e.g., membrane or secretion). It is usually removed after transport. (Process: Protein targeting/secretion)

how is fidelity (an extremely low error rate) maintained during DNA replication?

complementary base pairing, proofreading activity, and mismatch repair systems

errors in DNA replication result in _______ _______ (2 words).

genetic mutations

why do bacteria produce restriction enzymes?

to protect themselves from foreign DNA, such as viral (bacteriophage) DNA, by cutting it at specific recognition sequences.

how do bacteria protect their own genome from restriction enzymes?

bacteria methylate their own DNA at the restriction enzyme recognition sites, which prevents the enzyme from cutting their own genetic material.

how is transcription different in eukaryotes vs. in bacteria?

bacteria transcription occurs in the cytoplasm and in eukaryotes its in the nucleus; bacteria have one rna polymerase while eukaryotes have three; mrna is not processing in bacteria while mrna undergoes capping, splicing, and polyadenylation before leaving the nucleus in bacteria; bacteria uses sigma factors to recognize promoter sequences and eukaryotes use transcription factors and tata boxes for promoter binding

how is translation different in eukaryotes vs. in bacteria?

bacteria have 70s ribosome and eukaryotes have 80s ribosome; bacteria mrna encodes for multiple proteins while mrna in eukaryotes encode for one protein; ribosomes bind to the shine dalgarno sequence in bacteria and ribosomes bind to the 5’ cap and scans the first AUG start codon in eukaryotes; bacteria initiator carries fMet in bacteria and Met in eukaryotes

what is the purpose of the “signal sequence” in bacteria?

the signal sequence is a short stretch of amino acids at the N-terminus of certain proteins that directs the protein to the cell membrane or for secretion outside the cell

what is the role of the Sec system?

the Sec system (secretion system) is responsible for transporting proteins with signal sequences across or into the cytoplasmic membrane. It recognizes the signal sequence, threads the unfolded protein through a Sec translocon channel, and uses ATP and the proton motive force to drive translocation.