FLS Flashcards
Which steps of glycolysis are not reversible?
- glucose –> glucose-6-phosphate by hexokinase
- fructose-6-phosphate –> fructose-1,6-bisphosphate by phosphofructose kinase
- phosphoenol pyruvate –> pyruvate by pyruvate kinase
How can step 10 of glycolysis be reversed?
pyruvate carboxylase converts pyruvate to oxaloacetate
phosphoenol pyruvate carboxykinase converts oxaloacetate to phosphoenol pyruvate
How can step 3 of glycolysis be reversed?
fructose-1.6-bisphosphatase converts fructose-1,6-bisphosphate to fructose-6-phosphate
Howcan step 1 of glycolysis be reversed?
glucose-6-phosphatase can be used to convert glucose-6-phosphate to glucose
What is the corrie cycle?
Glucose is sent from stores in the liver to exercising muscles where it is used and converted to lactate. Lactate is then taken to the liver where it can be converted back to glucose by gluconeogenesis
Why is the corrie cycle important?
prevents lactic acidosis in the muscles
regenerates NAD+ to be used in glycolysis
What does the pyruvate dehydrogenase complex do?
converts pyruvate into acetyl CoA by pyruvate decarboxylation so that it can be used in the Krebs cycle
What is the PDH complex formed of?
24 transacetylases in trimers
24 pyruvate dehydrogenase in dimers
12 dihydrolipoyl dehydrogenases in dimers
What are some targets for antibacterial action?
- Cell wall synthesis inhibitors - enzymes that form peptidoglycan cell wall
- cell membrane
- nucleic acid synthesis
- protein synthesis
Give 6 examples of antibiotics in clinical use
glycopeptides beta-lactams aminoglycosides tetracyclines chloramphenicol macrolides
How to determine for susceptibility of an antibiotic?
Disc susceptibility - place antibiotic disc on agar plate and maeasure diameter of cleared zone
E-test - concentration range is high to low, where the bacteria crossses is the minimum inhibitory concentration
What is the minimum inhibitory concentration of an antibiotic?
The dilution of a drug that
Why are some bacteria particularly hard to kill with antibiotics?
Some have pores on the outside that act as molecular sieve
Some vacuums anything out
What is the breakpoint concentration of an antibiotic?
The concentration at which it will be effective
What are phase variable genes and what are some mechanisms?
Able to turn genes on or off which occurs as a result of ‘programmed’ mutations
- genomic rearrangement - if promoter changed then transcription won’t occur
- Strand slippage - transcriptional or translational, results in nucleotide repeats
- Methylation - methyl group added to DNA
By what mechanisms can DNA be exchanged in bacteria?
Conjugation
Transduction
Transformation
How can DNA be exchanged in bacteria by conjugation?
Physical connection formed between 2 cells
Plasmid passed from one cell to another
How can DNA be transferred by transponsons?
Transponsons are pieces of DNA that are moved from one location to another
copy and paste method: sequence copied to RNA the to DNA (by reverse transcriptase) then inserted elsewhere
cut and paste method: transponsons cut out of DNA and inserted elsewhere
How can DNA be transferred by transduction?
- bacteria infected by virus (phage)
- phage injects own DNA into bacterial chromosome
- phage replicates inside cell
- bacteria lyses releasing particles
- infects new cell
How can DNA be transferred by transformation?
uptake of naked DNA from environment
What are the 4 phospholipids that make up the plasma membrane?
Phosphoglycerides: phosphatidylserine phosphatidylaethanolamine phosphatidylcholine Sphingoipids: sphingomyelin
What is the shape of a free fatty acid and what shape would a group form in water?
Cone
Forms a micelle in water
What is the shape of a phospholipid and what shape does a group form in water?
cylindrical
phospholipid bilayer
A phospholipid bilayer is energetically unstable because the sides are exposed so they would tend to fold into a ball to form a sealed compartment`
Where are phospholipids synthesised?
SER - in the outer cystolic leaflet
