Test 1 Flashcards by Chris Flores

Elements of Life

CHNOPS and Iron

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How does reduction/oxidation drive bioenergetics?

Can be derived from reductive/ oxidative chemical reactions in the cystol/ membrane gradient like +NAD + 2H –> NADH + H+

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When was earth formed and when did life begin

4.5 billion years ago earth was formed

4 billion years ago life began

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When were Photosynthetic prokaryotes and cyanobacteria formed?

5 billi Photo Pro (Non oxygenic)

2. 8 bill- Photo Cyano(Oxygenic)

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When were Aerobic bacteria and unicellular eukarotes formed?

2.4 bill- Aerobic bacteria

2 bill-Unicelullar Eukaryotes

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When were Multicellular Eukaryotes and plants and animals formed?

.8 bil-multicellular eukaryotes

.5 bill- plants and animals

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What did Carl Woese contribute?

Phylogenetic tree
2 Pro- Archaebacteria and Eubacteria
16S/ 18S rRNA tree

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Formal Definition of species

DNA to DNA reassociation btwn 2 isolates is 70% or greater.
16 S rRNA has to be greater than 97%
(Bacteria and Archaea)

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Open genomes

sequence isolate, see gene never seen before

Note: New genes mean different than the norm for the species

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Closed Genomes

sequence another isolate, barely see differences. No more than 1% new genes in total sequence.

(Note: New genes mean different than the norm for the species)

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Core Genome

Genes on all genes of strain of patho

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Usual environment for Archaea

Extreme environments, High Temp/ high salt concentration

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How does Archaea’s environment support Woese’s hypothesis for 3 domains of life

Woese- archaea= extreme

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What does Archaea’s environment say about early evolution on earth?

Archaea=survive
humans, animals,other organisms= dead
lack of O2 and being toxic.

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How does Archaea having no established pathogens support Woese’s hypothesis

Since Archea is suited for extreme environments and has already found it’s niche in the world, it is not pathogenic for plants or animals.

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Minimal Medium

Minimal amount needed for an organism to grow. Usually results in slow growth.

E.Coli on this medium will oxidize glucose and O2 to produce 50% CO2 and 50% biomass

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Defined Medium

Made of Pure Chemicals
Exact contents
Requirement 4 Growth

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Undefined Medium

Can contain a mixed amount of nutrients or the exact contents/ amounts are unknown.
Yeast extract- cheap undefined, fast growth bc rich
Brain-heart infusions are another example

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Rich medium

Plenty Nutrients

Large Growth

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Prototroph

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Doesn’t require a specific nutrient to grow.

Can convert any carbon source to fulfill it’s needs.

Definition of Cell Growth

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Change in Mass (weight)

Inc Cell # doesn’t = growth

Turbidity/Optical Density

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Measure light scattered in spectrophotometer- # cells

Assumes all cells are equal in size and linear over a range of concentrations

Total Cell Counts

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Uses a counting chamber (glass slide with defined area and depth) to count number of cells.

Electronic- cells through Electric Field, count by resistance

Cons- Cant tell apart live and dead
Cant count low dense culture

Viable Cell Counts

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Cells grown,plated on a growth medium.
Each colony represents a viable cell
However, clumps of cells will be represented by a single colony and most bacteria grow in clusters. Also, some cells don’t plate very well.

Dry Weight/ Protein

Cells harvested by centrifugation, dried weighed. Not typically used in today's lab since they can't assess a culture's growth at several points

Lag phase

Rich --> minimal media. | Takes about 2 hrs of regulation while the cells start to make everything before they can slowly increase in size

Exponential phase

Grow as fast as possible with nutrients available Cells are dividing and accumulating biomass. Enters stationary phase, the number of cells increases without a change of mass/ no growth

Stationary phase

Stop Growth bc Toxic/ 0 Nutrients

What is stationary phase sigma facter

RpoS - global regulator for synthesis of around 30 proteins. Increases during starvation

Role of Fis and H-NS

DNA binding proteins (Fis is specific, H-NS is nonspecific) Fis activates rRNA gene transcription and is inhibited by H-NS H-NS increases during stationary phase so less ribosomes are synthesized while Fis is high in actively growing cells

What is (p)ppGpp?

Magic Spot" or the stringent response. Causes ribosomes to stall and slows tRNA/rRNA transcription. Mechanism- if a ribosome cannot read hrough a codon, it's not charged or efficiently charged. Can trigger the arrest of the replication fork"

What is the mechanism behind Diauxic Growth?

cAMP/CRP complex global transcription regulator. cAMP Inc bc- Carbon starvation mediated by Adenylate cyclase enzyme- start by PTS system.

What is the role of oriC, DNA-A, and Par/MukB

DNA-A= On DNA synth by bind to oriC- opens DNA duplex Other Rep= Complex Par and MukB- chromosome split & seperation Form Septum, inward growth, seperate, septation, parallel

How does DNA replication occur in fast growing cells vs slow growing cells?

Many Rep Forks= DNA Rep Fast | DNA Rep begins in previous generations

What effect do the amounts of DNA, RNA and protein have on growth rates

Inc Pro= Inc Synth | Inc Pro. & RNA= Fast Growth

What is growth yield, Y?

W(Cells Made)/W(Carbon used) E.coli- glucose, aerobic conditions. Y= 0.5 (50% biomass, 50% carbon dioxide)

Chemostat

``` Restricts growth Limit Addt. Nutrients Dilution rate= growth yield Study Cell in diff growth rates More Control ```

What is ftsZ?

Bacteria, Archae and Eucarya. 3D structure Forms protofilaments (tubulin), Ring- hire protein Localizes in center of cell division.

Substrate level phosphorylation

Cytosol. Electrons donors to acceptors. Is coupled to ATP synthesis

Oxidative level Phosphorylation/ Membrane gradients

In Membrane Electrons from donor to accept. coupled to ATP synthesis

What did Peter Mitchell propose?

Proton Gradiant

What were the principles of Peter Mitchell's proposal?

1. CM impermeable to H+ & OH- 2. Enzymes that translocate H+ outside; form electrochemical gradient = inside the membrane + use Exergonic rxn drive proton translocation 3. Form EC Gradient by action of pH gradient/ CM potential

What is the Proton motive force equation?

p = "ﾨ 60"pH

What is the difference between ∆Ψ and ∆ pH?

``` ∆Ψ= CM potential for + ion outside cell ∆pH= Acid & Base outside ```

What are the 3 types of transporters

Anti- 2; oppo Sym- 2 same Uni- 1

What does DiNitroPhenol do to a living cell?

``` Symport In= H+ Out= Nothing Collapse Proton Gradient Off-oxidative phosphorylation, Cell Unable use Coupled ATP synthesis Death ```

How are Valinomycin and potassium used generate a ∆Ψ in membrane vesicles?

Inc K+ efflux, Gradient- + outside; - inside Determine if ∆Ψ drives transport substrate through Cell Membrane

How do lipophilic dyes or lipophilic fluorophores can be used to determine delta psi experimentally?

Fluoro Dye measures change in ∆p to find ∆Ψ. Quenching- 1. F Dye seen inside cell bc low conc 2. Measure Op Density INC Dye= Inc PMF

Test 1 Flashcards

(48 cards)