Bacterial Growth and Metabolic Pathway Flashcards
What type of cell division does a rod-shaped bacteria undergo?
Binary fission
Describe binary fission in a rod-shaped bacteria:
- Cell elongation
- Septum formation
- Completion of septum; formation of walls; cell separation
Give examples of rod-shaped bacteria that undergo binary fission:
- Escherichia coli
- Salmonella typhi
- Pseudomonas aeruginosa
How can cell division differ in bacterial growth?
Different morphological forms
What are the two different morphological forms of cell division?
- Equal products of cell division
2. Unequal products are so division
Is binary fission an unequal product of cell division or an equal product of cell division?
Equal products of cell division
What are four types of unequal products of cell division?
- Simple budding
- Budding from hymphae
- Cell division of stalked organisms
- Polar growth without differentiation of cell size
What are the three main players that facilitate bacterial growth at a cellular level?
MreB
FtsZ
Min system
What is MreB?
Actin homologue - bacterial cytoskeleton protein
How does MreB facilitate bacterial growth?
Elongation growth by incorporation of new cell wall material along longitudinal axis
What is FtsZ?
Tubulin homologue - cytokinesis ring
How does FtsZ facilitate bacterial growth?
Fundamental element of septum formation, septum contraction and cell division
What is min system (MinC)?
Midcell selection
How does MinC facilitate bacterial growth?
Robust positioning of FtsZ at midcill and only midcill over the lifetime of each cell
Fill in the gap:
MreB, FtsZ and MinC are highly …… inside the cell
Dynamic
What is the motion of MreB directly coupled to?
Wall synthesis
How does bacterial growth differ with different bacterial species?
- Different shapes
- So different versions of cell division proteins
- and different cell wall-synthesising machines
What factors determine culture growth?
- Availability of nutrients
- Presence or absence of oxygen
- Temperature
How can we describe the growth of bacteria in one generations time?
- mass and cell number doubles
- exponential growth
What are the four phases of bacterial growth phases?
- Lag phase
- Exponential phase
- Stationary phase
- Death phase
What is an anoxic zone?
Lack of oxygen
What is an oxic zone?
Oxygen present and dissociates in liquids
What is the limitation of microorganisms that like to grow in low oxygen conditions?
Difficult to grow in lab due to sensitivity to oxygen
What is one of the most important factors of culture growth of bacteria?
Temperature
What can occur to growth of bacteria in a minimum temperature?
Membrane gelling; transport processes so slow that growth cannot occur
What can occur to growth of bacteria in optimum temperature?
Enzymatic reactions occurring at maximum possible rate
What can occur to growth of bacteria in maximum temperature?
Protein denaturation; collapse of cytoplasmic membrane; thermal lysis
Do all bacteria like the same temperature?
No, each species have their own optimum temperature
What are the three different sources of metabolic diversity?
- Energy source
- electron source
- carbon source
What are the two subtypes of energy sources?
- Phototrophs
- Chemotrophs
What is phototrophs?
Light
What is chemotrophs?
Oxidation of organic or inorganic compounds
What are the two subtypes of electron sources?
- Lithotrophs
- Organotrophs
What is lithotrophs?
Reduced inorganic molecules
What is organotrophs?
Organic molecules
What are the twosubtypes of carbon sources?
- Autotrophs
- Heterotrophs
What is autotrophs?
CO2 sole or principle biosynthetic carbon source
What is heterotrophs?
Reduced, preformed, organic molecules from other organisms
What are the 5 major nutritional classes?
- Photolithoautotroph
- Photoorganoheterotroph
- Chemolithoautotroph
- Chemolithoheterotroph
- Chemoorganoheterotroph
What is the carbon source of Photolithoautotroph?
Co2
What is the energy source of Photolithoautotroph?
Light
What is the electron source of Photolithoautotroph?
Inorganic e- donor
What is the carbon source of Photoorganoheterotroph?
Organic carbon
What is the energy source of Photoorganoheterotroph?
Light
What is the electron source of Photoorganoheterotroph?
Organic e- donor
What is the carbon source of Chemolithoautotroph?
CO2
What is the energy source of Chemolithoautotroph?
Inorganic chemicals
What is the electron source of Chemolithoautotroph?
Inorganic e- donor
What is the carbon source of Chemolithoheterotroph?
Organic carbon
What is the energy source of Chemolithoheterotroph?
Inorganic chemicals
What is the electron source of Chemolithoheterotroph?
Inorganic e- donor
What is the carbon source of Chemoorganoheterotroph?
Organic carbon
What is the energy source of Chemoorganoheterotroph?
Organic chemicals
What is the electron source of Chemoorganoheterotroph?
Organic e- donor
What is the carbon source for heterotrophs?
Organic carbon
Describe glycolysis (simply):
- Remove electrons from organic carbon and adds those to NAD, making NADH
- Produces 2 molecules ATP
- Geneterates pyruvate as a key molecule
What must be present for pyruvate to be oxidative to CO2?
Oxygen
What is the outcome of the citric acid cycle?
NADH
CO2
What cycle is the most important for the production of NADH?
Citric acid cycle
Why is a NADH important?
Electrons stored in NADH
What is the next cycle after the citric acid cycle?
Electron transport chain
What doe electrons in the electron transport chain reduce?
The terminal acceptor O2 to H2O
How is the membrane energised in the electron transport chain?
Protons are pumping across the membrane to the outside
What is the energy produced by the proton pump drive?
Oxidative phosphorylation through ATP synthase
How many ATP molecules are produced during the electron transport chain?
36
How do anaerobic respiration differ from aerobic respiration?
- Lack of oxygen
- Use of different terminal electron acceptors
What are the different terminal acceptors in anaerobic respiration?
-SO4^2-, NO3^-, CO2, Fumarate etc
What terminal acceptor is used in denitrification?
Nitrate
What is the reduced product of the electron acceptor nitrate?
Nitrite
When does termination occur?
If no oxygen as terminal electron acceptor
What occurs during fermentation in relation to the terminal electron acceptor?
Organic compound is both electron donor and acceptor
Is fermentation an efficient process?
No
How many molecules of ATP is produced through fermentation?
2
How is a NADH recycles?
Reducing pyruvate to lactate and other fermentation products
What is the process of the reduction of pyruvate to lactate?
Homofermentative
What is the process of reduction of pyruvate to mixed products?
Hetero-fermentative
What are the final results in electron transfer to nitrate?
Nitric oxide, Nitrous oxide and dinitrogen
What are the concerns of denitrification?
- Nitric oxide = ozone depleting gase
- Nitrous oxide = greenhouse gase
- Human intervention aka fertilisers
