Lecture 19- Bacterial Metabolism, Growth, & Metabolism Flashcards
C H O N& P make up how much by mass % in the body?
97%
What do bacteria need to make organic molecules, and what molecules do they use these organic molecules for?
Bacteria need C source & energy source to make macromolecules such as
- Proteins
- Carbohydrates
- Nucleic acids
- Lipids
- comples such as glycolipids
Give examples of supramolecular structures present in bacteria
- Cell Wall
- Ribosome
- Cell membrane
What is one thing all Autrotrophs have in common?
Their C source is inorganic CO₂
What are Photoautotrophs and give examples of some and how they react
use light to fix CO2
- Cyanobacteria containing plant-type chlorophyll use water and CO2 TO MAKE (CH₂O)n & O2
- certain protists such as algae
Others (green Sulfur bacteria, purple bacteria) contain bacteriochlorophyll (photosystem I)- use CO2 & H₂S to make (CH₂O)n & S (live in anaerobic conditions such as muddy marsh bottom)
What are Chemoautotrophs and give examples
- They are microorganisms that use Inorganic CO₂ as a C source and get energy by oxidizing inorganic compounds (H₂S S H₂ NH₃ nitrite)
- example reaction is CO₂ + H₂O+H₂S+O2–> (CH₂O)n +H₂SO₄
- They are bacteria (mostly archaea)n that live in extreme environments such as deep sea vents
- examples are halophiles,Methanogens, Sulfur reducers , and SolfOslo is
What is one thing all heterotrophs have in common?
C source is organic
What are photoheterotrophs and give examples
mircroorganisms that use organic molecules as C source & derive energy from light (proteorhodopsin)
Examples include prokaryotes such as Rhodobacter, Chloroflexus
Are all plants autotrophs?
no, some are heterotrophs
What are chemoheterotrophs and give examples
Organisms that derive energy from organic molecules (such as glucose) and their C source is organic
examples include:
- many prokaryotes such as Clostridium
- protistists
- fungi
- animals & some plants
- disease causing bacteria
- Saprotrophs- environmental - decompose rotten food
Which type of organisms may be either free living or symbiotic & describe the 3 types of symbiotic
heterotrophs can be either symbiotic or free living
- Mutualist- both help each other examples include bacteria in cows stomach that produce cellulase & N fixing bacteria in root nodules )
- Commensalist- one gets help from the other- there are no true commensalists, they are only opportunitistic ones. Some of them modify environment to suit their needs such as E coli
- Parasite- one takes help & harms host
What type of bacteria is E coli (free living, mutualism,etc?
Commensals- lives in small intestine
What do Bacteria need N for, and how do they obtain it?
for amino acids & nucleotides
most obtain from sorroundings along with other nutrients (rate limiting)
Some called nitrogen fixing can utilize N₂ & convert organic N forms
- Symbiotic Rhizobia (bacteria in legume root nodules)
- Non symbiotic bacteria Azotobacter, Clostridium
Explain mechanism of how N fixing bacteria fix N₂
- Nitrogenase (a metalloprotein complex) catalyze reduction of N₂ to NH₃ by ferrodoxin & ATP
Active nitrogenase is formed form 2 polypeptide chains
- FeMo-protein (dinitrogenase)
- Fe-protein (dinitrogenase reductase)
- 2 Fe-Mo cofactors also required
- N₂ + 8H+ 8é+16ATP –> 2NH₃ + H₂ + 16ADP + 16Pi (highly energy consuming)
- NH₃ can be assimilated by glutamine synthase catalysing NH₃ + Glutamate–> Glutamine or NH₃ can be converted to nitrite–> nitrate - can be used to make other molecules such as amino acids
How do Aerobic bacteria respire?
breakdown organic molecules with oxygen as an acceptor of é’s (Terminal electron acceptor, TEA)
How do spherical bacterial cells grow and divide, and how does it affect how they look under microscope?
cocci grow near the site of division (septum or cross wall)
cocci may divide in any of several planes- resulting in different geometries of the daughter cells
- if they divide in 1 plane they will form pairs or chains of cells (Streptococci)
- If they divide in 2 planes it will make square of one-cell-deep packet of cells (Micrococcus)
- if they divide in 3 planes it will. Are cubes (Sarcina)
- if they divide irregularly it will make grape clusters (Staphylococci)
What are the 4 growth phases?
- Lag- slow growth as bacteria adapt
- Exponential/Log phase- exponential growth, doubled in minutes
- Stationary phase- more competition, less nutrients growth stops
- Death Phase- toxic waste products accumulate food depleted bacteria die
