Final Exam: Exam 1 Flashcards
Antoni van Leeuwenhoek
-handheld microscope
-microscope had one Lens
-300x magnification on microscope
Archaeal cell membranes
-hydrocarbon chains linked together via ether linkage
-monolayers formed in microorganisms that live in high temps
bacterial cell membrane
-anchor site for many proteins involved in cellular activity
-site of proton motive force
-act as permeability barrier
ABC transport mechanism
-only expressed if solute present
-only specific solute/subset will be transported by the transporter
-energy for transport provided by hydrolysis of ATP
group translocation transport
group of proteins work together to modify an incoming molecule resulting in sugar traveling down [ ] gradient
TAT system
-translocate folded proteins
-Tat A transporter forms after recognition of protein for delivery
-requires proton motive force for energy
Gram staining
-primary stain is crystal violet
-decolorizer is only applied for 5 seconds
-safranin will stain microorganisms pink
T/F bacteria and Archaea are more similar to each other than either is to eukarya
False
T/F bacterial cells tend to have smaller surface to volume ratio than eukaryotic cells
false
T/F if bacterium is not equipped to handle hypotonic environment water will leave the bacterial cell an and cause bacteria to shrivel and die
False
T/F fatty acids are found within the cell membrane of all prokaryotes amd eukaryotes
false
T/F both the Sec and Tat pathways require an N amino terminal signal peptide for the secretion of proteins
True
T/F bacterial flagella are rigid straight structure much like their eukaryotic counterparts
False
T/F the MS and C rings found within the basal body of a bacterium flagella have a helical arrangement of negative charges to allow rotation
False
Spontaneous generation theory was discovered by
Francesco Redi
What experiment was initially able to disprove spontaneous generation theory
-flies did not appear in jar when covered w mesh, poked holes, or closed completely
-flies appeared when jar was open
Who finally killed the idea of spontaneous generation theory and how
Pasteur, using a swan neck flask and amimacules
Semmelweis
observed women who went o midwives to give birth were less likely to get an infection compared to those in the hospital due to contamination and going from patient to patient in hospitals
Two reasons why rRNA worked for sequencing organisms for comparison
-universally distributed
-adequate length of reading frame
Woese was able to determine _______ by _______
-all living organisms should be classified into 3 domains
-sequencing rRNA
Haeckel
proposed 3 kingdom system
Whittaker
proposed 5 kingdom classification system
important discovery that lead to the 5 kingdom classification system
two different cell types: prokaryotic and eukaryotic, found by using the electron microscope
Falkow
development of the molecular Koch’s postulates
what were the molecular koch postulates helpful in determining
-genes important for pathogenesis
-creation of some antibiotics
Sarcina
round shaped organisms arranged into a makeup of 8 round cells
two other arrangements for cocci organisms
streptococci, staphylococci
what adds rigidity to eukaryotic cell membranes
sterols
what adds rigidity to prokaryotic cell membranes
hopanoids
symport and antiport
active transporters that use proton gradients to power movement across membrane
what adds rigidity to archaeal cell membranes
ring structures bound to branched isoprenes
siderophores
-low molecular weight molecules that are released by many bacteria to acquire iron
-ferrichrome and enterobactin
two alternating sugars in peptidoglycan strands
- N-acetylglucosamine
- N-acetylmuramic acid
alternative name for peptidoglycan
murein
In gram negative organism, what two amino acids are crosslinked and how are they crosslinked
- DAP to D-alanine
- direct connection
Lipoteichoic acids
polymers of ribitol or glycerol joined by phosphate group embedded in cell membrane of gram positive microorganisms
What is attached to lipoteichoic acids glycerol and ribitol
D-alanine
braun’s lipoprotein
-found in gram - organisms witin the inner leaflet of the outer membrane
-function to form connection between outer mem and peptidoglycan
porins are
trimeric
where are porins found
outermembrane of gram - bacteria and create 4 pores
T/F porins are the same as aquaporins found in cell mem of many bacterial cells
False
Lipid A
-portion of LPS located within outer leaflet of outer mem
-do not contain glycerol but a disaccharide of glucosamine phosphate
glucosamine phosphate connected to core polysaccharide via
Ketodeoxyoctanate and 10 sugars
final component of LPS molecules
O polysaccharide
India ink
used to visualize capsules
fimbrae
short, fine, bristle-like appendages that can be found around the perimeter of a bacteria cell
pilli
elongated tubular structures that transfer genetic material
lophotrichous
type of polar flagellation where there is a tuft of flagella found at one pole of the cell
Koch first postulate and a flaw associated with it
-All infected organisms will show signs of infection and it would not be seen in a healthy individual
-flaw: asymptomatic/carrier forms of pathogens
T/F robert Koch himself realized that his postulates were flawed
true
Sec A and SRP int he Sec pathway
-Sec A is an external peripheral membrane protein
-SRP is an integral membrane protein
How and why are bacterial cells are under more osmotic pressure than eukaryotic cells and why they require envelopes
there are no membrane bound organelles
How are bacterial cell walls resistant to our prteases
bc bacteria alternate between L amino acids and D amino acids and our proteases can only break down L
why was penicillin only effective against gram + bacteria when it first came out
Penicillin acts in the cell wall and outer membranes are not present in gram + organisms So penicillin ha direct access to the cell wall of the bacteria
why is bacterial count and results of blood culture important
Gram - release of lipid A
What is the decolorizer in a gram stain
alcohol with 95% ethanol
how will the appropriate amount of decolorizer affect gram positive bacteria
in gram + the decolorizer will dehydrate the stain and lock in the purple color
what makes cell envelope structure of mycoplasma unique compared to most other bacteria
mycoplasmas utilize sterols to add rigidity to their cell membrane because there is no cell wall
one difference and one similarity between peptidoglycan of mycobacterium and gram - organisms
-both mycobacterium and gram - have a thin peptidoglycan layer
-mycobacterium has a higher degree of crosslinking within peptidoglycan than gram -
what is found between peptidoglycan layer and mycomembrane
arabinogalactan
why do mycobacteria take so long to grow
they have mycolic acid in their inner leaflet and phenolic glycolipids in the outer leaflet that forms a very hydrophobic environment, the arabinogalactan forms a dense sugar network as well making it hard to take in nutrients
acid-fast staining
staining procedure that determines the presence of mycobacteria
peptidoglycan glycan sheets
-use NAG and NAM
- beta 1,4 glycosidic linkages
-L-ala branches from NAM (see L and D forms of AA)
pseudopeptidoglycna glycan sheets
-use NAT and NAG
-beta 1,3 glycosidic linkages
-only utilize L forms of the AA
what is the most common structure in archaeal cell envelopes
S layers
Chemoreceptors that recognize nutritional changes will signal to ______ proteins involved in flagellar motion
Eli
who coined the term cell
Hooke
who was the first person to use the term bacteria
Cohn
2 ways that filament of archaellum are different from filament of flagellum
-archaeal filament is not hollow, bacterial filament is
-bacteria filament uses flagellin protein, archaeal filament used 7-12 other proteins that arent flagellin
