Lecture 5 Flashcards
The cell membrane allows what kind of molecules to pass through?
It depends on their chemical characteristics
Can non-polar molecules pass through phospholipid membrane? If yes, is it fast or slow
-Yes
-Fast
Can small polar molecules pass through phospholipid membrane? If yes is it fast or slow
-Yes
-Slow
Can large polar or charged molecules pass through the phospholipid membrane?
No
-They need a transporter
-Charged molecules CANNOT pass through
What is active transport
Molecules move against their concentration gradient and require ATP
-Low to high concentration
What is diffusion?
Molecules move from an area of higher concentration to an area of lower concentration until the concentration is equalized
-No ATP/energy needed
Why does the doctor recommend to take ampicillin without food?
-medicine is absorbed quickly into bloodstream if there is no food in stomach
-food can bind to ampicillin and will not be absorbed properly
-stomach acid can break down ampicillin before it is absorbed by body
What is bactoprenol
Highly hydrophobic molecule
-inserts cell wall precursors
What is transpeptidation
-final step of peptidoglycan biosynthesis
-peptide crosslinks
Gram (-) bacteria characteristics
-Outer membrane
-Thin peptidoglycan
-Periplasm
-Porins–> 600 daltons or less
Why Vancomycin, an antibiotic that inhibits peptidoglycan synthesis cannot penetrate Gram (-) cells
-Vancomycin is too large to fit through the porins which only let molecules that are less than 600 daltons
True or false: Gram (-) is not resistant to vancomycin
False
-Gram (-) bacteria is naturally resistant to to Vancomycin b/c it is too large to fit through the porins in bacteria
Is there a selective barrier for molecules to enter the peptidoglycan wall?
No
-Peptidoglycan has large pores, so molecules can pass through
Archaea cell membrane characteristics
-Outer membrane
-periplasm
-plasma membrane
-vesicle
True or false: The outer membrane for archaea is the same as the outer membrane of gram (-) bacteria
False
-They have nothing in common
How do Beta lactam antibiotics work?
They prevent peptidoglycan crosslinking which weakens the cell wall structure
-inhibits transpeptidation
Why do we use folic acid metabolism as a target for antibiotics
Humans do not make folic acid, but bacteria cells do so we can target them this way
Where is the folic acid metabolism trying to go and how does it get there?
It is trying to go to the cell membrane
-gets there by by going through outer membrane, periplasm, peptidoglycan (no selective barrier)
What are hopanoids/what can they do?
-sterol like molecules
-stiffen the membrane–>makes it hard for sulfa drugs to diffuse through
