Micro Metabolism Flashcards
Bacteria have how much DNA, haploid or diploid?
Haploid
What occurs in the lag phase and exponential phase of bacterial cell division? Why is this important?
Bacteria are gathering nutrients and multiplying. this is when they are susceptible to abx
How is cell density determined on agar plates?
Counts on plates, or turbidity
What are the two major categories of bacteria that are distinguished by their need for metabolites?
Anaerobic and aerobic
What does it mean for a bacteria to be a facultative anaerobe?
Will usually use oxygen, but is able to survive without it
What is the process that aerobic bacteria use to metabolize energy? What about anaerobic?
Aerobic = respiration
Anaerobic = fermentation
What does it mean for a microbe to be microaerophilic?
Grows best at low oxygen, but can grow without it as well
What are the enzymes that allow microbes to utilize oxygen without being damaged by oxygen radicals?
Superoxide dismutase
Catalase
What is the reaction that catalase catalyze?
hydrogen peroxide to water
What is the reaction that super oxide dismutase catalyzes?
superoxide to hydrogen peroxide
What is anerobic respiration?
Using a chemical other than oxygen as the final electron acceptor in the ETC
How can bacteria be identified by fermentation?
The type of product produced
What is folate, and why is it an important target for abx?
Nutrient created by bacteria involved in nucleic acid synthesis in bacteria–eukaryotes take this up in their diet, thus this is a target for abx
What is the bacterial enzyme that serves to unwind DNA, and is a target for abx? Which abx is it that targets this?
Gyrase, which is targeted by quinolones
Transcription and translation can occur simultaneously in bacteria because there is no nuclear membrane to separate the processes. The bacterial DNA-dependent RNA polymerase is inhibited by [BLANK] (an antibiotic often used in the treatment of tuberculosis).
Rifampin
Why is the peptidoglycan layer of the cell wall a good target for abx? (2)
Is it both unique and essential
What are the five areas of bacterial cells that serve as targets for abx?
- Cell wall synthesis
- DNA replication
- RNA synthesis
- Protein synthesis
- Antimetabolites
What causes the decline phase of bacterial growth?
build up of waste products of lack of nutrients. Cells stop growing, but are not yet dying
What happens in the decline phase of bacterial cells growth?
Cells die d/t metabolites
What is the target to inhibit protein synthesis replication in bacteria?
the 70s ribosome
What is different about transcription/translation in prokaryotes vs eukaryotes?
Transcription and translation occur simultaneously in prokaryotes
How many times more efficient is respiration over fermentation?
19x
What is the precursor subunit of peptidylglycan?
UDP-N acetyl muramic acid (UDP-NAM)
Where is UDP-NAM synthesized in the cell?
cytoplasm
What is the first step in peptidylglycan synthesis?
A lactyl group is added to carbon number three of UDP-N-acetyl-glucosamine to form UDP-N-acetyl-muramic acid
What is the next step in peptidylglycan synthesis after UDP-NAM is formed?
Five amino acids are added sequentially to UDP-NAM to form a pentapeptide side chain.
Are there tRNA and ribsomes used in the reaction that adds amino acids to UDP-NAM?
No
What is the next step in peptidylglycan synthesis after five amino acids are added to UDP-NAM?
The NAM pentapeptide is transferred from UDP to bactoprenol phosphate at the membrane surface.
What is the protein that is on the internal side of the plasma membrane in eukaryotes, that takes peptidylglycan subunits across the membrane?
Bactoprenol
What is the third amino acid that is attached to NAM?
L-lys or some other diamino acid
What is the step in peptidylglycan synthesis after NAM is attached to bactoprenol?
NAG is added to the NAM/bactoprenol complex
What is the next step in peptidylglycan synthesis after the NAG is added to NAM/bactoprenol complex?
The complex is carrier across the membrane
What happens to the NAM-NAG-bactoprenol complex after it is transported across the membrane?
The dissaccharide unit is attached to the growing end of a peptidylglycan chain by transglycosylases
What is the enzyme that attaches the NAM-NAG complex to a developing peptidylglycan molecule?
Transglycosylases
What is the final step in peptidyl glycan synthesis?
Pyrophophobactoprenol is converted back to phosphobactoprenol and recycled
Where does transpeptidation occur?
between the free amine of the diamino acid in the third position of the pentapeptide and the D-alanine at the 4th position of the other peptide chain
What are the drugs that target transpeptidation?
Penicillin binding proteins
What is transpeptidation?
the cross-linking of peptide chains by peptide bond exchange
During peptidoglycan synthesis, this occurs on the outer leaflet of the plasma membrane.
What is the mechanism of action of vancomycin?
binds to the D-Ala-D-Ala structure to block the transpeptidase reactions
