The Bacterial Cell Flashcards
As a peptide is synthesized into a protein, _____________ structures may form spontaneously
higher-order
When do peptides denature?
When exposed to heat or placed in urea
What enzyme or strucure properly folds proteins?
DnaK
DnaJ
Molecular chaperone (GroEL, GroES)
Once the protein is made and folded properly, how does it leave the cell?
Sec pathway via the periplasm and containing a signal sequence - plasma fusion
Secretory pathway
- N-term SIGNAL Peptide targets protein to ER
- 80S ribosome bound to mRNA begins protein synthesis
- Molecular chaperone interacts with N-terminus to guide protein to ER or directs insertion to the ER membrane
- peptide may be processed in ER, passed to Golgi
- Vesicle containing mature proteins are trafficked to the plasma membrane, membranes fuse
Tat- twin arginine transport system
export of proteins. that have folded in the cytoplasm (powered by PMF)
Type 1 thru 6 secretion systems
important for interactions with other cells
Distinguishing characteristics and structures of the bacterial cell
- mesosome
- cytoplasm
- nucleoid
- plasmid
- ribosomes
- flagella
What is ideal growing conditions for E.coli?
37 C glucose minimal medium
Antibiotic
Low molecular weight chemicals that kill or inhibit growth of bacteria, can be taken into an animal’s body (ingested or injected) with minimal side effects
- some target bacterial structures
-some target core functions
Bactericidal
Kill
Bacteriostatic
Inhibit growth
How is growth measured in cells?
In cell number
Binary Fission
Typical reproduction (cell divison) in microbes: most bacteria, archaea, many protists
cells grows to about twice its size (replicates genetic material)
Molecular mechanisms ensure the faithful passage of the genome to offspring cells during __________
Binary fission
Partioning proteins
segregate chromosomes and plasmids to opposite sides of the cell
FtsZ
key protein that establishes the site of division and assembly of other divison machinery
Nucleoid occlusion
as the cell divides, additional proteins ensure that DNA is not damaged
