Holmes lectures 1 2 Flashcards
T or F: Bacteria have a nucleus.
FALSE
T or F: Bacteria have a Golgi apparatus.
FALSE
T or F: Bacteria do not have mitochondria.
TRUE
What are the three branches of the tree of life (possibly outdated material).
Bacteria, Archaea, Eukarya
What does Gram positive and Gram negative mean?
The response to the Gram stain. Gram+ retain the stain and look blue and purple. Gram? no not retain the stain and look pink.
Describe the difference between the surface characteristics of Gram+ and Gram? bacteria.
Gram+: one membrane covered in peptidoglycan strands, many layers of cross linked peptidoglycans and teichoic acid strands. Gram ?: two membranes (inner and outer), fewer peptidoglycan strands, not as much cross linking.
What determines the shape of a bacteria?
The rigid peptidoglycan layer and the cytoskeleton. Proteins: FtsZ (equiv to tubulin), MreB (actin), CreS (intermediate filaments)
What is peptidoglycan?
Very unique to bacteria, composed of alternating hexose sugars cross-linked by amino acids. Sugars: N-acetylglucosamine, N-acetylmuramic acid Cross-links: DAP (Gram-) and L-Lys (Gram+) to D-alanine
What is endotoxin made of?
Lipopolysaccaride from the cell outer leaflet of the outer membrane.
What type of bacteria make endotoxin?
Gram negative
How can you visualize capsules?
Stain with India ink - capsule excludes the india ink.
What do capsules do?
Help a bacteria become slimy and resistant to phagocytosis.
What amino acids are only found in bacteria peptidoglycans?
meso-diaminopetide (DAP), D-glutamic acid, D-alanine
Where is the bacteria electron transport chain?
Plasma membrane
Where to bacteria transport H+ from their electron transport chain?
Outside of their plasma membrane.
What is polycistronic?
The ability to encode more than one protein on a single RNA, unique to bacteria
T or F: Extrachromosomal plasmids often encode genes for antibiotic resistance.
TRUE
What is a prophage?
A senescent virus within a bacteria.
What are the differences between the lytic and lysogenic cycle?
Lytic means the virus takes over and uses the bacteria to make more viruses, which then break out of the cell resulting in lysis. Lysogenic means that the virus is dormant within the cell and is replicated along with the bacteria.
What is phage conversion?
The ability of an encoded phage to alter a bacteria. Ex. C. diphtheria produces diphtheria toxin due to phage.
What are the major types of secretion systems in Gram-negative bacteria?
Type 2, 5: Specific for individual proteins, proteins are transported through a pore, protein is free between membranes. Type 1, 3,4: Needle systems which deliver protein or plasmids through a channel directly into other cells or into extracellular environment.
What is the lag phase of bacteria growth?
The phase in which the bacteria is sensing its environment and turning on genes necessary to survive in its environment.
What are the typical phases of bacteria growth?
Lag, exponential, stationary, death
Which types bacteria can grow in both aerobic and anaerobic conditions?
Indifferent (ferment in presence or absence of O2), facultative (respires with O2, ferments in absence of O2), microaerophilic (grows best at low conc of O2) bacteria
What are the two forms of energy in a bacteria?
ATP (biosynthetic interconversion) and PMF (proton motive force, flagellar rotation, transport)
What is fermentation?
Catabolic process win which organic compounds serve as both electron donor and electron acceptor.
What is respiration?
Process in which the terminal electron acceptor is typically molecular O2. Usually need a non-organic molecule to reduce, which is usually O2, but some bacteria can use nitrates.
What is a spore?
Form of dormant bacteria which allows long term survival under adverse environmental conditions.
Which drugs target the peptidoglycan layer?
fosfomycin, cycloserine, vancomycin, penicillin. Makes the bacteria unstable and prone to lysis.
What ribosome subunits do bacteria have?
30S and 50S
