007 Bacterial structure and properties Flashcards
What is the difference between a gram positive and gram negative cell wall?
Gram positive cell wall contains techoic acid and is located outside the outer membrane. Gram negative cell wall contains lipopolysaccharide on its cell wall and outer membrane. The cell wall is in between the outer and inner membrane, and there is a periplasm space that is located between cell wall and inner membrane.
Which cell wall is susceptible to penicillins and why?
Gram positive cell wall due to the techoic acid that is found on the peptidoglycan layer on the cell wall.
Why can’t mycobacterium be stained by normal staining, and what method is used?
It has too much lipid 60%. It must be heated with Zeihl Neelson stain.
What is acid fastness?
When there is resistance to decolorization by laboratory techniques during staining.
How do lipopolysaccharides produce septic shock?
This is an endotoxin, containing lipid A which activates macrophages to produce pyrogenes, activates complement cascade causing inflammation, and also activated blood factors resulting in disseminated intravascular coagulation and haemmorhage.
What are endospores?
Very resistant dormant structures that have a core wall of peptidoglycan, spore coat and exosporium. The dehydrated core contain a few ribosomes and enzymes to kick start protein metabolism during germination.
