Exam 2 review Flashcards
Effect of pH on microbial growth?
H+ conc. in cell —-> most microbes prefer neutral pH = 6-8 (neutrophiles)
Effect of pressure on microbial growth?
Atmospheric pressure is the most common at (1 atm)
Oxygen effects on microbial growth
Oxygen serves as the terminal e- acceptor for the Electron Transport Chain
Obligate vs Facultative
Must vs May
Aerobe
Likes Oxygen
Anaerobe
Hates Oxygen
Temp. effects on microbial growth?
Each individual species has an optimal (cardinal) temperature for growth.
*Proteins are susceptible to high + low temps
Denature
Fall apart or break up
Mesophile
Likes Human Body temp level temperatures
Thermophile
Likes slightly warmer temps
Extreme Thermophile
Likes extremely warm temps
Planktonic growth
Cell grows individually in liquid
Biofilm
Cell growing in slimy group
Will an antibiotic be more effective against a biofilm or a planktonic growth?
It will be more effective against planktonic growth because it is easier to penetrate
Quorum sensing
cell to cell communication
Autoinducer
Chemical signal used for bacteria to communicate
Symbiotic
A relationship between two or more organisms
Parasitic
One organism called the PARASITE receives nutritional or other advantages at the expense of the HOST.
Mutualism
Both species benefit from the interaction
Commensalism
One species benefits and the other is not harmed or benefits
Amensalism
One species actively harms or produces a compound to inhibit growth of another species
Metabolism
Chemical workings of cell that generate of harness energy through the thousands of cellular biochemical reactions
Anabolic/endergonic
Reactions that consume energy (Synthesis of large Biomolecules)
Energy + A + B —–> AB
Catabolic/exergonic
Some reactions release energy (Breakdown large Biomolecules into smaller parts)
X + Y —> XY + energy
Catabolism
Breakdown large Biomolecules into smaller parts. Releases energy
Anabolism
Synthesis of large Biomolecules. Requires input of energy.
What changes covalent bonds on one or more substrates in biochemical reactions
Enzymes
Enzymes
Protein that catalyze most of the chemical reactions of life
*Lower Ea
* increase rxn rate
*Not altered or consumed during the rxn
Substrate
Reactant molecules in which enzymes act upon
Active site
Where the enzyme binds to the substrate
Induced fit
enzyme correctly orients itself to change the bonds
Substrate level phosphorylation
Reaction that produces ATP by transfer of a Pi to ADP from a substrate
Oxidative phosphorylation
Electron transport linked to phosphorylation
electron carrier molecules
Much of the work of electron capture and transport in metabolic pathways falls to molecules with enhanced affinity for electrons that readily accept electrons from one substrate and donate them to another substrate
- NAD+ FAD2+ NADP+
What molecule is the source of electrons in photosynthesis
H20 by NADPH
Photosynthesis
6 CO2 + 6H20 –(Sun)—> Glucose (C6H1206) + 6O2
1.) Energy from sun is absorbed which causes water to split due to photolysis (gives off O2). This energy released drives photophosphorylation which synthesizes ATP and NADPH.
2.) At the same time C02 is taken in which is fixed into glucose (uses ATP from photophosphorylation).
1.) Glycolysis (fermentation) or fermentor
Overview:
1 glucose + 2 ATP + NAD+ —–> 2 3-Carbon Pyruvate + 4 ATP + 2 NADH —-> Net + 2 ATP
*NAD+ used and converted to NADH
*Occurs in Cytoplasm for both eukaryotes and prokaryotes
*no o2 is needed
*UNIVERSAL FOR ALL LIFE!!
Oxidation
Loss of e-
Reduction
Gain of e-
2.) Krebs cycle
Overview:
1 acetyl coA –> 3 NADH, 1 FADH2, 1 ATP, 2 CO2 (1 turn)
Goes through 2 turns so 2x products
6 NADH 2 FADH2 2 ATP 4 CO2
*Uses both NAD+ and FAD+
*Takes place in Mitochondria (Eukaryotes), and in the cytoplasm/cell membrane (prokaryotes)
*Substrate level phosphorylation
3.) Electron Transport Chain
*Electron Carrier molecules NADh and FADH2 are oxidized and the transport proteins are reduced
*series of redox reactions in the ETP that pump H+ in which a hydrogen ion gradient forms
*H+ diffuse down conc. gradient through ATP synthase which phosphorylates ADP to ATP
*NET RESULT IS OXIDATIVE PHOSPHORYLATION - THE PROD. OF ATP THROUGH REDOX RXNS
Produces:
*34 ATP and 6H20
Location:
Eukaryotes—> Mitochondria
Prokaryotes–>Cell membrane and cytoplasm
Respiration
- Glycolysis
- Krebs cycle
- ETC
Chemioosmosis
high conc. of H+ flowing down its conc. gradient to low conc.
Proton-motive force
H+ ion gradient, H+ ions flow though ATP synthase to ADP + P —> ATP
ATP
A high energy and universal compound for managing energy
Generated through:
Substrate level phosphorylation
Oxidative phosphorylation
Photophosphorylation
NADH = ?ATP
3
FADH2 = ?ATP
2
Final e- acceptor for aerobes
O2
Transition step
The inbetween for glycolysis and the krebs cycle
Pyruvate converted to acetyl coA
Produces:
2 acetyl coA
2 NADH
2 CO2
Aerobic respiration
Glycolysis, Krebs Cycle, ETC —-> O2 is final e- acceptor
Anaerobic respiration
Glycolysis, Krebs cycle, respiratory chain —-> O2 is not the final e- acceptor
Fermentation
Glycolysis, organic compounds are the final e- acceptors
*DONE IN THE ABSENCE OF O2
Infection
A microbe that invades a human or other organism & causes illness or disease
Ways for Eukaryotes to reproduce?
Asexually (mitosis)
Sexually (meiosis)
Ways for Prokaryotes to reproduce?
Binary Fission
Binary fission
1.) Parent cell duplicates chromosomal DNA
2.) Chromosomes separate
3.) Septum forms and causes the cells to separate
4.) Daughter cells form
What maximizes the rate of population growth?
Optimization of growth conditions
Generation Time
Time required to go through the complete fission cycle “Birth of Daughter cells” —–> Birth of next daughter cells
Formula for generation time
G = t/n
Growth = Time per gen / number of gen
Exponential growth
Growth that doubles each generation
Formula for predicting pop size over time
Nf = (Ni)*2^n
Lag phase
“flat” period of adjustment, enlargement; little growth
Exponential growth phase
A period of max growth when cells have adequate nutrients and a favorable environment
Stationary phase
rate of growth equals the rate of cell death caused by depleted nutrients and O2 excretion of organic acids and pollutants
Death phase
As limiting factors intensify, cells die exponentially, rate of death exceeds the rate of growth.
Blood culture test
The patient blood sample was used to inoculate rich liquid media that support the growth of bacteria, then incubated 24-48 hrs to check for growth
Results from Blood culture test
Specimens from the patient’s blood sample look like the growth of bacteria from a patient blood sample
Gameplan
Use of different streak plating as a first pass to ID bacteria (selective and/or differential media) and to obtain isolated colonies so that additional tests can be performed.
What kind of plating is used on agar media plates?
Streak
Colony
A group of individual cells
Blood Agar
Rich medium containing 5% sheep blood that can differentiate bacteria based on their hemolytic properties
Types of hemolysis
Alpha
Beta
Gamma
Alpha hemolysis
Partial destruction
Light colored green around colonies
Beta hemolysis
Total destruction
clear zones around colonies
Gamma hemolysis
No damage
No changing on the plate
Magnification
The extent of image enlargement
Light Microscopy
Simple technique
Visible light wavelength 400 nm - 750 nm
Between 40x - 2000x
Total magnification
Ocular lens x Objective lens
Electron Microscopy
5000x and 1000000x magnification
electrons passing through an object as a beam
very expensive
Kirby Bauer diffusion assay
Discs of different antibiotics or medicine are placed on a plate with a control (water). If a zone of inhibition develops then the antibiotic is effective.
