Chapter 8 Flashcards
Why do cells have nucleic acids and proteins?
Central Dogma: DNA to RNA to Proteins
DNA replication basics:
Semiconservative replication, bidirectional, DNA polymerase, template, nucleotides, and primers.
What is DNA replication timed to?
Cell growth and division.
DNA gyrase:
Relieves positive supercoils.
Protecting the DNA works how?
- Microbial cells mark their DNA to identify it as their own.
ex. methylating adenine or cytosine - Restriction endonucleases in the immune system (Recognition site and triggers the complete degradation of the DNA by nucleases that attack exposed ends.
How do restriction endonucleases work?
It has a recognition site, that triggers complete degradation of DNA by nucleases that attack exposed ends.
Nuclease:
Enzyme degrading nucleic acids.
What are the unique features of prokaryotic gene expression?
Transcription and translation is coupled.
Why are transcription and translation coupled?
- No nucleus means translation can begin as soon as the RNA molecule is being made.
- Allows for an extra level of regulation, called attenuation.
What are the parts of initiation in transcription?
Promoter, sigma factor, RNA Polymerase, elongation, termination, (rho independent and rho dependent).
Where are many genes found together?
In operons.
What are the stable RNA types? What do they do?
tRNA and rRNA.
Information carriers, catalysts, and regulators.
What does no nucleus mean in prokaryotic gene expression?
No nucleus means that translation can begin as soon as the RNA molecule is being made. This allows for an extra level of regulation called attenuation.
Synthesis of RNA (transcription) initiation requires:
Promoter, sigma factor, and RNA polymerase
Synthesis of RNA (transcription) termination requires:
Rho independent and Rho dependent
Proteins-translation
How does processing work?
Covalent modification: may cleave termini, add chemical groups, signal peptides removed
*disulfide bonds
Proteins- translation: what are the basics?
mRNA, tRNA, ribosomes, proteins, and amino acids
- Initiation
- Elongation
- Termination
How does protein-translation initiation work? (2 parts)
- Shine-Dalgarno sequence
- Bacteria: N-Formylmethionine- AUG
How is 70S ribosome made?
Only in prokaryotes.
30S + 50S
How is 80S ribosome made?
Only in eukaryotes.
40S + 60S
Most genes are found in operons- what are operons?
Allows for coordinated expression of genes that function in the same biochemical pathway.
What are the types of protein processing?
Covalent modification: May cleave termini, add chemical groups, and signal peptides removed. Disulfide bonds.
Protein folding: chaperones
Degradation
How is the DNA protected?
- Many microbial cells mark their DNA to identify it as their own. Methylating adenine or cytosine.
- Restriction Endonucleases- Immune System. Recognition sites; triggers the complete degradation of the DNA by nucleases that attack exposed ends.
Antibiotic targets of steps?
Quinones Novobiocin, Rifampin, Tetracycline Streptomycin, Macrolides Chloramphenicol
