Structure-Function relationships in bacteria Flashcards
What is the main limitation in size for bacteria?
Lack of complex organelles - have to diffuse nutrients in and wastes out - thus limited by surface to volume ratio
What happens to the volume:surface area ratio as something gets bigger? Why is this an issue?
As something gets bigger, the volume gets way bigger for a smaller increase in area - this is limiting to diffusion.
A greater surface to volume ratio allows greater ________ activity.
metabolic
Hydrophobic extracellular polysaccharides or protein polymers
Capsules (or slimes)
Organized structure which aids bacteria in resisting phagocytosis
Capsule
Amorphous polymers in large amounts.
Slime layers
What are other words for slime layers?
Glycocalyx, vegetations, plaque, biofilms
The cytoplasmic membrane of bacteria is similar to that of eukaryotes. How is it different?
it has mesosomes (invaginations)
What is the purpose of cell walls in bacteria?
Function as osmotic barriers to prevent the influx of water
What is the main stiffener of the cell wall of gram +ve bacteria?
Peptidoglycan
What is the gram positive cell wall composed of?
Peptidoglycan matrix with some polymers (especially teichoic acid), exterior to the cytoplasmic membrane
What is peptidoglycan composed of?
Alternating subunits of NAG and NAM (monosaccharides), cross linked at NAM by peptide chains
How are gram negative cell walls different from those of gram positives?
The gram negative cell wall has a thin layer of peptidoglycan anchored inside the outer membrane by murein lipoprotein.
In which type of bacteria is LPS found in?
gram negatives
What is LPS also known as?
endotoxin
What are the components of LPS?
O antigen, core polysaccharide, lipid A
When is LPS or endotoxin released?
When the gram negative cell lyses and dies
Physiological response of the body to overwhelming infection - systemic inflammatory response syndrome due to infection.
Sepsis
Sepsis is also called what?
Cytokine storm
What is the toxic part of LPS?
Lipid A
What part of LPS is used for sero-typing?
O antigen
What is the staining term for mycobacterial cell walls?
Acid fast
How are the cell walls of mycobacteria different from gram positive cell walls?
Contain more lipids, including long chain B-hydroxylated fatty acids called mycolic acids
What is the main organism that causes tuberculosis?
mycobacterium tuberculosis
