diversity + bacteria Flashcards
what is the use of using 16s RNA sequence
visualise differences between different groups of bacteria and then using PCR to sequence and produce phylogenetic tree
what are characteristics of the cell membrane
-osmotic barrier
-transport of solutes
-synthesis of wall polymers + lipids
-protein secretion
-respiratory electron transport
what are characteristics of the cell wall
-rigid layer
-resists osmotic pressure + determines cell shape
-signals to innate immune system of bacterial presence
what colour is produced with a gram +ive stain
purple
what colour is produced with a gram -ive stain
pink
what 2 bacterial classification do gram +ive/-ive stains result in
-cocci
-rods
what is the difference in peptidoglycan in +ive stains
peptidoglycan is thicker
what do the terms OM, PG, and CM stand for
OM - outer membrane
PG - peptidoglycan
CM - cell membrane
what is peptidoglycan
complex polymer of sugars with side chains of amino acids
what role does peptidoglycan have with bacteria
-role in bacterial replication
-target for some antibiotics
what are the three parts of lipopolysaccharide (LPS, endotoxin)
-lipid A
-core polysaccharide
-O-polysaccharide
what are plasmids capable of
autonomous replication = provide selective advantage
what are features of the flagella
-provide mobility
-energy provided by proton motive force
what are external structures found on bacteria
pili and fimbriae
what are the main differences between pili and fimbriae
-pili longer than fimbriae
-fimbriae more abundant per cell than pili
what is a function of fimbriae and an example of it in action
adhesion e.g required for e.coli strains to adhere to urethra to cause UTI
what is a function of pili and an example of it in action
twitching motility e.g extension and retraction of pili = move along solid surface
what is the sex pilus involved in
DNA transfer in conjugation - longer pili
what are features of capsules
-tightly bound to bacterial wall
-can be in both gram +ive/-ive
-contains water => prevents desiccation
how are molecules transported through passive transport
–simple diffusion
-facilitated diffusion (require channel or carrier protiens)
how is simple diffusion carried out
through membrane with small hydrophobic molecules e.g O2, CO2, ammonia, H2O
what does antiport mean
ion and substances move in opposite direction
what does symport mean
both move in the same direction
what are the 3 types of active transport
-ion coupled transport
-ABC transport
-group translocation
what is the role of ABC transporters (ATP-binding cassette)
hydrolysis of ATP drives transport with specific binding proteins
what is the role of group translocation
transport and modify the sugar to maintain the concentration gradient
