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83 Cards in this Set
- Front
- Back
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Define: exremophiles
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Organisms that can grow under harsh conditions that would kill most other organisms
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What are the environmental factors that we are concerned with when it comes to the livelihood of microorganisms?
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Osmotic concentration, pH, temperature, oxygen concentration, pressure, radiation
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Define Hypotonic
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An aqueous environment that has a low amount of solute in it. This causes the water to flow into the cell
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define hypertonic
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an aqueous environment that has a high amount of solute in it which causes water to flow out of the cell
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How do cells adapt to a hypertonic environment
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Increase internal solute concentration to increase their internal osmotic concentration
They use solutes which are compatible with metabolism and growth |
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How do cells adapt to a hypotonic environment
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reduce osmotic concentration of cytoplasm mechanosensitive channels in p-membrane to allow solutes to leave
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Define: Halophile
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microbe that grows optimally in the presence of NaCl or other salts at a concentration of ABOVE .2M
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Define: Extreme Halophile
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Require salt concentrations of 2M to 6.2 M
Cell with extremely high concentration of potassium |
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Define: exremophiles
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Organisms that can grow under harsh conditions that would kill most other organisms
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What are the environmental factors that we are concerned with when it comes to the livelihood of microorganisms?
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Osmotic concentration, pH, temperature, oxygen concentration, pressure, radiation
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Define Hypotonic
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An aqueous environment that has a low amount of solute in it. This causes the water to flow into the cell
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define hypertonic
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an aqueous environment that has a high amount of solute in it which causes water to flow out of the cell
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How do cells adapt to a hypertonic environment
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Increase internal solute concentration to increase their internal osmotic concentration
They use solutes which are compatible with metabolism and growth |
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How do cells adapt to a hypotonic environment
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reduce osmotic concentration of cytoplasm mechanosensitive channels in p-membrane to allow solutes to leave
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Define: Halophile
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microbe that grows optimally in the presence of NaCl or other salts at a concentration of ABOVE .2M
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Define: Extreme Halophile
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Require salt concentrations of 2M to 6.2 M Cell with extremely high concentration of potassium
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How would an extreme halophile maintain stability within cell?
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cell wall, proteins, plasma membrane all require a high salt concentration
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Define: Halotolerant
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Can tolerate salt concentrations better than non-halophiles. They won't grow well in the concentrations, but they will still grow.
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Where is a halotolerant organism's optimum?
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a low salt range
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Define pH
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Measure of relative acidity of a solution
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Acidophiles
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Optimum growth: pH 0-5.5
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Neutrophiles
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Optimum growth: 5-5.7
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Alkaliphiles
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Optimum growth: 8.5 - 11.5
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Autotroph
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CO2 sole or principle bio synth carbon source
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Heterotrophs
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reduced preformed, organic molecules from other organisms
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Example of a Heterotroph
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Humans
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Phototroph
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Uses light as an energy source
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Chemotrophs
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Uses oxidation of organic/inorganic compounds as an energy source
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Lithotroph
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Reduced inorganic molecules as an electron source
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Organotrophs
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Organic molecules as an electron source
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What are the classes of major nutritional types? Which is the most studied?
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Photolithoautotroph Chemolithoautotroph Chemoorganoheterotroph **this is the most studied**
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Why are chemoorganoheterotrophs important
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Majority of pathogens are chemoorganoheterotrophs They are the most studied
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What is the basic similarities between organisms
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ATP for energy Electrons made by reducing power for chemical reactions Metabolites for biosynthesis (carbon typically)
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what are the three main processes of getting organic molecules for energy?
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Aerobic respiration Anaerobic respiration Fermentation
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Respiration
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Use of an ETC to create a proton gradient to synthesize ATP
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How is ATP synthesized during respiration?
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Oxidative phosphorilation
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What are the three important amphibolic pathways?
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Emden Meyerhof Pathway Pentose Phosphate Pathway Tricarboxylic acid Pathway
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What is the net return from the Emden Meyerhof Pathway?
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2 ATP and 2 NADH
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What is the net yeild of the Entner Duodoroff Pathway?
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1 ATP, 1 NADPH, 1 NADH
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what is the net yield for the Pentose phosphate pathway?
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Erythrose 4 phosphate Ribose 5 phosphate
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What two pathways can work simultaneously?
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Pentose phosphate and Entner Duodoroff
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What is the net yield of the TCA? (Citric acid cycle) **Per 1 Molecule of Glucose**
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4 CO2 6 NADH 2 FADH2 2 GTP (or ATP)
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What is the net yeild of the TCA? (Citric acid cycle) **Per 1 molecule of Acetyl CoA***
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2 CO2 3 NADH 1 FADH2 1 GTP (or ATP)
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What does Aerobic respiration produce?
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ATP and high energy electron carriers
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Where is most of the ATP produced during aerobic respiration?
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Indirectly via the electron transport chain
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FtsZ
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Tubulin
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What does FtsZ do
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forms ring during septum formation in cell division
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MreB
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Actin
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What does MreB do
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maintains shape positioning peptidoglycan synthesis machinery
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Cres
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Intermediate filament
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What does CreS do?
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maintains shape in curved bacteria
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How do eukaryotic microbes reproduce?
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Haploid or diploid Asexually and sexually
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How do bacteria and archaea reproduce?
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Haploid, Asexually Binary fission), budding, filamentous
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What are the steps of binary fission
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1 Chromosome with a young cell Parent cell prepares for division by enlarging cell wall. Elongation and replication start here Separate into 2 separate chromosomes that start to move to poles and cell wall forms in between Septum forms Cell splits Woo hoo you did the thing.
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What do bacteria and archaea must do to the genome before replication?
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replicate and segregate
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What must chromosomes do before replication
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replicate and segregate into different cells
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Exponential Growth
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Growing population is doubling at regular intervals
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Generation time
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Number it takes for a microbial population to double in number
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What is generation time also known as
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Doubling time
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What two pathways can bacteria use to divide?
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DNA Replication and partition Cytokenesis
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Define DNA replication
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Replicating the chromosomal dna in the bacterial cell you start at the origin of replication you end at terminus
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How many origin of replications are there?
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One. Only one. Ever.
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What is the terminus
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The spot opposite of the origin site where replication ends
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Replisome
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Group of proteins needed for DNA synthesis
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replication fork What is it and how many are there in a bacteria
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The Y shaped structure where DNA is replicated There are two replication forks in a bacteria
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Where does the origin move to?
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The opp sides of the cell
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Chromosome partitioning
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condensation of chromosomes at opp ends of the cell
Varies w/ bacterial species |
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Is MreB involved in chromosome replication?
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NO.
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Is MreB involved in chromosome segregation?
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Yes!
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If MreB is mutated what happens to the chromosomes
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They do not segregate
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Semi Conservative
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Each cell gets 1 original strad, and one second strand
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Septation
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The formation of cross walls between daughter cells
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List the steps
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1. assembly of site for septum formation 2. Assembly of Z ring
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Autolysins
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Enzymes that degrade peptidoglycan in a controlled manner. It cleaves between Nam and Nag
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How does Cocci cell wall growth differ from Rod?
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Cocci contains 1 hemisphere of the old cell wall and one hemisphere formed by the newly synthesized peptidoglycan Rods: The new peptidoglycan forms at the poles
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What plays a critical role in determining rod shape?
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MreB
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How does MreB play a critical role in determining cell shape?
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Distributes helices along the length of the cell but not at all at the poles.
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Is MreB in Cocci?
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No
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What animal cell homologus do Vibrio cells contain?
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FtsZ and MreB Also Crescentin
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Crescentin
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Intermediate filament homologue Localizes to one side of the cell Reduces the rate of peptidoglycan synthesis The asymmetric cell wall synthesis will form a curve The side containing this will always be the short side of the cell
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Transpeptidases |
Peptidoglycan crosslinking enzymes Binds and preforms crosslinking It is a target for penicillin. |
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How do autolysins work in a controlled manner? |
They only break down enough of a cell wall go break down the edges so you can get a new cell. It doesn't destroy the cell itself. |
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Septum |
Partition that forms during cell division to divide daughter cells |
