ch6/27 microb

how is energy captured and what are the two types of ways

phototrophs capture light for energy
chemotrophs use potential energy in chemical energy for energy
chemolitotrophs - inorganic, and chemoorganotrophs - organic compounds

the two types to obtain carbon

autotrophs - make their own carbon copoumds starting with co2
heterotrophs - obtain carbon compounds from other orgs

the carbon cycle

what is nitrogen important for for the cells

important for making amino acids(proteins)and nucleic acids

the nitrogen cycle; what are the three main steps

nitrogen fixation - turning n2 gas into nh4 ammonium
nitrification - turning ammonium to nitrate no3-
denitrification - tunring nitrate to n2 gas

what is assimilation and decomposition in the nitrogen cycle

assimilation - how useeful forms of nitrogen are taken up by other orgs
decomp - how nitrogen is released back into the cycle

what is nitrogenase

nitrogenase is the enzyme that catalyzzes nitrogen fixation and is very sensitive to o2

aerobe vs anaerobes

aerobes like oxygen, anaerobes don’t

the types of anaerobes and aerobes

strict anaerobe - must have no O2
strict aerobe - must have o2
microaerophile - prefers lower o2
facultative anaerobe - perfers o2, but has the option to grow without
aerotolerant anaerobe - doesn’t use o2 but tolerates it

what are ROS, SOD and Catalase gotta do with aerobes vs anaerobes

ROS are reactive oxygen species produced as byproducts of aerobic metabolism - damages dna, proteins, membranes
SOD and Catalase break down ROS

the 5 types summarized

What are the oxygen requirements of different types of microbes?

• Obligate anaerobe: Does not use O₂; has anaerobic options; cannot tolerate O₂

• Aerotolerant anaerobe: Does not use O₂; uses anaerobic metabolism; can tolerate O₂

• Facultative anaerobe: Uses O₂ when available; can also grow anaerobically; tolerates O₂

• Obligate aerobe: Requires O₂; no anaerobic option; tolerates/needs O₂

• Microaerophile: Uses O₂, but only at low concentrations; cannot tolerate normal atmospheric O₂ levels

what are essential nutrients and auxotrophy

essential nutrients are must needs that gathers from immediate environment

auxotrophy is when a microbe cannot synthesize a essential nutrient - it must be added to help them aka growth factors

differ xomplex media and chemically defined media

compex media is often dead things(yeast, plant, tissue extract)
chemically defined media is when all of it is known completely

the typical physiological conditions for microbes are what

room temp to body temp
water ph
salt conc of 1%
ample nutrients

what are the temperature curves for microbes and why aren’t they symmetrical?

physcrophile - 0 to 20
mesophile - 12 - 45
thermophile - 40 - 70
hyperthermophile - 65 - 100+

what are the barophiles, and how do they survive

microorgs that can survive at very high pressures
they survive from adapted membranes and amino acid sequences in proteins

what are halophiles and how did they adapt

microorgs that require high conc of salt, they adapted to have additional dodium ion pumps to maintain osmotic balance and avoid plasmolysis

how does acdidity work with classification

0-5 ph acidophile
9-14 are alkaliphiles
6-8 are neutralophiles

how did the acid/base extremophiles adapt

have pump protons into or out of cell to maintain a neutral internap pH

what is bacterial growth and how do they do it

bac growth - is measured as increasing no of cells in a pop

most reproduce by binary fission - one parents becomes two daughters

eukarytotic cells divide by mitosis usually

how quick does binary fission grow

is exp growth - 2^n, and doubling time is the time it takes for the pop to double or for a cell to complete a round of division

what is the bavterial growth curve

primary metatboites - lag phase
secondary metabolites - stat phase

what is an example of log phase in our bods

how do we measure growth in the lab

can measure the biomass (indirect) or directly count cells with instruments
or plate counts - cfu with serial dilution and filtration

what are biofilms

Biofilms are polymer-encased communities of microbes attached to a surface.

• Start with initial attachment/adherence

• Cells secrete EPS (extracellular polymeric substances) such as polysaccharides and DNA

• EPS production is regulated by quorum sensing, especially at high cell density/late log phase

• Matrix protects cells from antibiotics, host immunity, and physical flow

• Channels allow movement of nutrients and wastes

• Can contain multiple species or even different domains

• Pieces can detach and spread

• Different from planktonic cells, which are free-living in suspension

• Example: dental plaque

examples of biofilms

abundant on basically everything, in humans can be tissue, teeoth, medical implants/devices - many of infections are from it

what are the time capsules for bacteria

an endospore - which are super resistant to many things
called the cells resting state - formed via sporulation - process cued by environmental cond usually starvation
and germination where the the endospore returns to vegetative normal growth

sporulation and germination cycle

Sporulation = a vegetative bacterial cell forms an endospore when conditions become unfavorable, such as nutrient depletion.

Germination = the endospore returns to a vegetative cell when conditions become favorable again.

differ food spoilage vs food contam

food spoilage is when microbial changes and metabolism affect hte foood chem - can’t be eaten

food contamination is the presence of pathogens or harmful microbes in a food - leading to food borne illness

different ways to fight the microbes

bactericidal - lethal effect - killing the microbe
bacterialstatic - agents that slow or stop the metabolism
preservation - delays spoilage og foods or perishable products

ways to preserve the things

organic acids - lowering the ph
using other organic compounds - like alcohol - cinnamon,cloves, plant compounds
inorganic compounds - can have harmful effects on humans

bacteriostatic way or water limitation

desiccation (dehydration)
-removal of water prevents growth
-can be combined with sugar or salt, causes cells to plasmolyze

controlled or modified atmosphere - food packed in low o2, or high n2 or co2 limits aerobic growth and prevents abiotic oxidation

bacteriostatic ways of cold temps

refreigeration - 4-8c - most pathogens are mesophilic - but some still grow
freezing - inhibits growth
freezedrying - food is quickly frozen at low temp in a vacuum

controlling growth via physical methods

pasteurization - goal is to kill spoilage bacteria - bactericidal - kills/destroys microbes - but doesn’t steriilze fully

canning - uses high pressure and heat - bactericidal -