Midterm Flashcards
Robert Hooke
Micrographia (first book to show observations under a microscope)
Van Leeuwenhoek
See microscopic life through microscope for the first time
Louis Pasteur (4 things)
Fermentation
Vaccines can be created by weakening microbes
Disproved spontaneous generation (swan neck flask)
Pasteurization
Germ Theory
Pasteur,Koch,others
Many diseases caused by microorganisms, can be passed from person to person
Edward Jenner
Vaccinated a boy with cow pox to render immunity to smallpox
Robert Koch
Germ theory
4 postulates
Causes of anthrax, tuberculosis, and cholera
Bacillus anthracis
Mycobacterium tuberculosis
Vibrio cholera
Koch’s postulates
Microorganism must be found in abundance in all organisms with the disease, and not in healthy ones
Microorganism must be isolated from organism and grown in pure culture
Cultured microorganism should cause disaese when put in healthy microorganism
Microorganism must be isolated from new host, and should be identical to orgininal causitive agent
Joseph Lister
Antiseptics in surgery
Fanny Hesse
Agar as culturing medium
Alexander Fleming
Penicillin
Which microorganisms can synthesize vitamin B12
Archaea and bacteria only
Microorganism responsible for the plague
Yersinia pestis
Characteristics of life
Metabolism Growth Reproduction Homeostasis Evolution Adaptation
Cell membrane function
Homeostasis
Controls flow of molecules into and out of cell
Proteins
50-55% dry cell weight
Composed of amino acids
Catalyze most cell reactions
Structural components
Nucleic acids
RNA 15-20% dry weight
DNA 2-5% dry weight
Lipids
10% dry weight
Polysaccharides
6-7% dry weight
When did the earliest microbes appear (origin of life)
3.5-4 billion ya
First oxygen producing bacteria
3 billion ya
Atmospheric oxygen
2 billion ya
When did complex eukarya originate
1.5 billion ya
Experiment which showed how microbial life arised
Miller
Showed organic molecules found in living cells could be synthesized from a mimicked primordial atmosphere
Boiling flask = ocean
Electrical sparks = lightning
Organic molecules including amino acids in collected sample
Yeast bacteria
Saccharomyces cerevisiae
Vibrio
Curved rod shaped bacteria
Spirilla
Spiral shaped bacteria
Pleiomorphic
Irreular shaped bacteria
FtsZ
Helps in cell division
Monomers form a Z ring which directs cell wall synthesis and contracts as cells divide by releasing subunits
MreB
Provides structure during cell wall formation
Leads to elongated cylinder
Non-spherical bacteria
ParM
Dircts plamid movement during cell division
Ensures each daughter cell gets a copy
Hypotonic
Greater solute concentration in cell
Cell swells
Hypertonic
Greater solute concentration outside cell
Cell shrivels
Symport
Both substances moving in the same direction through cell membrane
Antiport
Substances moving in opposite directions through cell membrane
Facilitated diffusion
Using a protein channel to move particles with the concentration gradient
No energy
Sec pathway
Pathway which proteins are exported through
SecB signal sequence
Delivery to SecA and then Sec YEG channel
Peptidoglycan composition
N-acetylglucosamine (NAG)
N-acetylmuramic acid (NAM) with a small peptide chain
How is peptidoglycan made
NAM is made in the cytoplasm then linked to UDP then to bactoprenol
NAG is added
Bacteoprenol flips them to the periplasm
Polymeriztion and crosslinking
Bacitracin
Interferes with dephosphorylation of bactoprenol therefore interfering with peptidogylcan and cell wall synthesis
Lysozyme
Hydrolyzes beta1,4 linkages between NAG and NAM in bacteria
Degrades cell wall
Lysostaphin
Acts on peptidogylcan crossbridge
Beta lactam antibiotics
Bind to penicillin binding proteins preventing them from crosslinking peptidoglycan
Make cells prone to cell bursting
Acts on growing cells
Beta lactamase
Can hydrolyze C-N bond in beta lactam ring rendering antibiotic ineffective
Gram positive
Purple stain Thick peptidpglycan layer Narrow periplasmic space teichoic and lipoteichoic acids in peptidoglycan Large pores in peptidoglycan
Gram negative
Pink stain
Thin peptidoglycan
Varying periplasmic space
Outer membrane with lipopolysaccharides (LPS)
anchored peptidogylcan by lipoproteins
Porins or TonB proteins transfer molecules to periplasmic space
Type________secretion system similar to flagella transports proteins directly from __________ through _________
III
Cytoplasm
Inner and outer membrane
Other motility strategies
Gliding motility
Actin based motility (pushed by polymers of actin)
Other adhesion strategies
Stalks (tubular extensions of cell envelope)
Polysaccharides (ex. Capsule)
Model fungi
Saccharomyces cerevisiae
Cell walls of chitin
Used to make bread,beer, etc.
Penicillin is made by __________
Penicillium chrysogenum
Mould that appears in most homes
____________ species are of biomedical and industrial significance
Aspergillus
Model protozoa
Giardia lamblia
Old
Lacks mitochandria
Causes human disease (bever fever)
Model slime mold
Dictyostelium discoideum
Protozoan
Model algae
Chlamydomonas reinhardtii
Two flagella
Nitroimidazole
Antibiotic used for anaerobic bacteria and protozoan
Reacts with reduced ferredoxin
Reduced nitroimidazole intermediates form linkages with critical cysteine bearing enzymes deactivating them
Diseases caused by fungi and protozoa (eukaryal microbes)
Athletes foot, oral thrush, potato blight
Eukarya vs archaea nucleosomes
Eukarya: tetramer histone, 60 nucleotide length
Archaea: octaner, 160 nucleotide length
Archaeal plasma membrane
Gylcerol 1-phosphate rather than glycerol 3-phosphate
Isoprenoids instead of fatty acids
Ether not ester linkages
Archaeal cell wall
Pseudopeptidoglycan/pseudomurein
NAG and NAT subunits
Beta 1,3 linkages
L rather than D amino acids
Crenarchaeota
Archaeal phylum
20% of bacteria and archaea in marine environments
Thermophiles and hyperthermophiles (> 55 or 80 degrees)
Acidophiles
Barophiles (high pressures)
Many adaptations for survival
Mesophiles and psychrophiles (15-40 or <15 degrees)
Euryarchaeota
Methanogens
Reduce co2 to produce ch4 and water
Energy released to fix carbon
Found in human gut and swamps
Halophiles
Require NaCl at more than 1.5 M
Maintain high K+ concentration inside cell to offset high extracellular Na+ (to prevent denaturing proteins and DNA, high GC content and acidic proteins)
Nanoarchaeota
One of smallest genomes
Possibly one of the smallest living organisms on earth
Proteobacteria
Gram negative Flagellated Similar to mitochandrial ancestor MVP: E. coli, Yersinia pestis Rod
Firmicutes
Gram positive Low GC DNA content Endospores Round or rod MVP: bacillus Staphylococcus and streptococcus
Cyanobacteria
Gram negative
Oxygenic photosynthesis
Amcestor of chloroplast
No flagella
Actinobacteria
Gram positive
High GC DNA content
Common is soils
MVP: streptomyces (antibiotics)
Bacteroidetes
Gram negative
Human microbiome
Evidence of endosymbiotic theory
Mitochnadria and chloroplasts resemble bacteria in shape and size
Double membrane consistent with ingestion
Own DNA more similar to bacteria than eukary
Viruses are non-living
Replicate with host cell machinery
Metabolically inert
No homeostasis
Viral capsid
Protein around genome
Can be helical (contains ssRNA)
Icosahedral (20 sided polygon)
Enveloped virus
Plasma membrane around capsid
Mainly associated with animal viruses
Virus infection steps
Attachment Entry Gene expression and protein production Genome replication Assembly and exit host
Viral attachment
Uses attachment proteins
Tail fibers, spikes, capsid, etc
Viral entry
Depend on host cell
Animal: receptor binding and endocytosis
Bacterial: injecting DNA through cell wall and membrane
Lytic viruses
Infect cell, replicate, then released from cell
Lysogenic phage
Can integrate their genome into host chromosome after entry instead of immediately lysing the cell
Baltimore classification
Seperates viruses based on genome structure and replication strategy (7 categories)
ICTV
Groups viruses into order, family, subfamily, genus, species
Based on morphology, genome, replication, host range
Cultivating viruses: bacteriophages
Bacteriophages can added to liquid medium with bacteria to produce a lysate
Isolated with molten agar method
Cultivating viruses: animal viruses
Virus added to cultured cells
Where are most vaccines grow?
Chicken eggs
Purifying viruses
Differential centrifugation (centrifuge at low, medium, then high speed, virus in pellet) Gradient centrifugation (tube with layers of sucrose, centrifuged, band of debris and band of virus)
Quantifying viruses
Plaque assay (virus diluted and placed on cells, count plaques) Endpoint assay (amount of virus needed to induce cytopathic effect or to kill 50% of cells or subjects) Direct count, EM (directly count)
Macronutrients to build macromolecules
C, N, P, O, S
Micronutrients to support biochemical processes
K, Na, Cl, Mg, Mn, Fe, Zn, Co, Mo, Cu
Anabolism
Biosynthesis, small to large molecules
Catabolism
Large to small molecules
3 things for metabolism to occur
Electron supply
Carbon supply
Energy supply
Phototroph
Captures light energy to make ATP
Chemotrophs
Capture energy from oxidation of reduced organic or inorganic compounds
Organotrophs
Acquire electrons from organic molecules
Lithotrophs
Acquire electrons from inorganic sources
Autotrophs
Acquire carbon from inorganic sources
Heterotrophs
Assimilate carbons from preexisting carbon forms
Prototrophs
Cam synthesize all macromolecular precursors from single carbon source
Auxotrophs
Unable to synthesize macromolecular precursors, must be supplemented with them in growth media
Catalase
Decomposes toxic hydrogen peroxide
Superoxide dismutase
Partitioning of superoxide radical into hydrogen peroxide and molecular oxygen
Selective media
Isolation of microbes with particular properties
Ex crystal violet and bile salts inhibit gram positive bacteria
Differential media
Allows certain microbes to be recognized based on visual reactions in the medium
Ex. Neutral red and lactose
Measuring population growth
Direct count using a microscope slide or a Petroff-Hausser counting chamber
Viable cell counting by perfroming serial dilutions and counting colony forming units
Spectrophotometer to measure optical density
Chemostat (cell growth rate = dilution rate)
Phases of a growth phase
Lag
Exponential
Stationary
Death
CFU/ml equation
=(number of colonies)/ (dilution) x (volume plated in ml)
Generation time equation
=(time)/3.32 x (logNt - logN0)
Growth rate equation
= 3.32 x (logNt - logN0)/time
Equation to describe a bacterial population in the exponential phase
Nt =N0 X2^n
Where Nt = population at time t
N0 = initial population at time t = 0
n = number of generations that elapsed between t = 0 and time t
Equation for mean generation time (k)
k =n/t
Embden-Meyerhof-Parmas (EMP) pathway
Most common glycolytic pathway
Glucose to 2 pyruvate, 2 ATP, 2 NADH
Entner-Doudoroff pathway
Alyernative to EMP
Glucose to 2 pyruvate, 1 ATP, 1 NADH, 1 NADPH
Entry point for sugars into metabolism
Pentose phosphate pathway
Glucose to 1 ATP and 2 NADPH
Produces carbon sugar precursors for other pathways
Processes to oxidize NADH back to NAD+
Respiration (ETC) and fermentation
3 fermentation types
Lactic acid fermentation
Alcohol fermentation
Mixed acid fermentation
All produce NAD+
TCA/citric acid/krebs cycle
Oxidation of 1 molecule of pyruvate to produce 3 CO2 yields:
4 NADH, 1 FADH, 1 ATP
Twice this per glucose
ETC
As electrons carried by NADH and FADH are passed through molecules in the ETC with increasing reducing potentials, a proton gradient is generated which is used to produce up to 34 ATP via ATP synthase
Oxygen is the terminal electron acceptor in aerobic respiration
Protons pumped per NADH/NADPH
10
Protons pumped per FADH2
6
What powers the ETC and production of ATP
The proton motive force
2 steps of photosynthesis
Photophosphorylation (makes ATP) Carbon fixation (dark), makes CO2 into organic molecules using ATP
Photophosphorylation
Uses photopigments like chlorophyll which make up photosystems to capture energy from photons and transfers it to electrons (bacteriochlorophyll in bacteria)
PS I and II
I or II used for anoxygenic photosynthesis
Both used in oxygenix photosynthesis in chloroplasts and cyanobacteria
Calvin Cycle (dark reactions)
ATP and NADPH produced in light reactions used to produce carbon compounds from CO2
RuBisCO enzyme adds carbon from co2 to a 5 carbon, and the product is split to 3PG molecules which are converted to glyceraldehyde 3 phosphate used for biosynthesis
Uses 18 ATP, 12 NADPH per glucose
Amino acids are formed from _______
Many glycolysis, pentose phosphate, and TCA cycle intermediates
Lipids formed from________
TCA and glycolysis intermediates
Nucleotides formed from ______
Pentose phosphate intermediates
Bacteria, archaea and eukarya: Nuclear membrane
Bacteria and archaea no
Eukarya yes
Bacteria, archaea and eukarya: organelles
Bacteria, archaea: rare/a few
eukarya: yes, many
Bacteria, archaea and eukarya: plasma membrane
Bacteria and eukarya: similar
Archaea: different from both
Bacteria, archaea and eukarya: RNA polym
Bacteria: single polymerase
Archaea: single polymerase similar to eukaryal polym II
Eukarya: polymerase I, II, III
Bacteria, archaea and eukarya: histones
Archaea and eukarya: yes
Bacteria: histone like proteins
Components of LB broth
Peptone
Yeast extract
NaCl
LPS
Lipopolysaccharides
Lipids and polysaccharides
Stabilizes membrane of gram negative bacteria, illicits immune response in humans
Lipoteichoic acid
Lipid and polysaccharide
Illicits immune response in humans
Peptidoglycan layer of gram +
Peptidoglycan
Polysaccharide backbone crosslinked with peptides
Maintains cell shape and provides structure
TonB receptors and porins
Proteins
Gram - outer membrane
TonB: Active transport across outer membrane
Porins: diffusion of nutrients and water