Nutrition of microbes Flashcards
explain microbe nutrition requirements
microorgnisms require about 10 elements in large quantities to construct carbs, proteins, lipids and nucleic acids and other elements are needed in small amounts and are part of enzymes and cofactors
what are nutrients
substances in the environment used by organisms for catabolism and anabolism
what are macronutrients
required n large amounts- e.g carbon, oxygen, hydrogen, ntrogen, sulfur and calcium
what are micronutrients
required in very small amounts- e.g iron, copper, molybdenium and zinc and these are trace elements and are essential for the activity of certain enzymes, usually as cofactors
what is also needed for growth
contaniments in water, glassware and regular growth components are adequate for growth
what are growth factors
amino acids= protein synthesis
purines and pyrimidines= nucleic acid synthesis
vitamins= forming part enzyme cofactors and only very small amounts are needed for growth
heterptrophs
CHO- organic carbon
autotrophs
CO2
Microorganisms have extraordinary….
flexability
omnivores
use over 100 carbon compounds
fastidious
catabolise only a few carbon compounds
phototrophs
use light as an energy source
chemothrophs
obtain energy from oxidation of chemical compounds
lithotrophs
use reduced inorganic substances as their electron source- energy
organotrophs
extract electrons from organic compounds
photoautotrophs
use light energy, inorganic hydrogen and CO2 carbon source as sources of energy and found in algae and purple and green bacteria
photoheterotrophs
uses light energy and organic carbon source and sources of energy and found in green sulfur bacteria and purple nonsulfur bacteria
chemoautotrophs
chemical energy source and CO2 carbon source as sources of energy and found in sulfur-oxidising bacteria and hydrogen bacteria
chemoheterotrophs
chemcial energy source and organic carbon source as sources of energy and found in most bacteria, fungi and protozoa
what can nutrients frequently not pass
the selectively permeable plasma membrane through passive diffusion
what are nutrients carried through (the mechanisms)
passive transport (simple difusion), facilitated difusion, active transport and group translocation
what is passive diffusion
molecules move from a region of higher concentraiton to one of lower concentration due to thermal agitation-no energy used and no carieer protein used
what is facilitated diffusion
difusion process is aided by a carier and involves careier proteins, permeases and higher con to a lower con
no energy input
what are permeases
they are embedded in the plasma membrane and are carier proteins that increases the rate of diffusion across selectively permeabke membranes
what is active transport
transport of solute molecules from low concentrations to high concentration and involves permeases and energy ATP
explain protein gradients
symport- linked transport of 2 substances in the same direction
antiport- linked transport of 2 substances in the opposite direction
uniport- one substance enters
what is group translocation
a process in which a molecule is transported into the cell while being chemically altered- e.g PTS transports sugars to prokaryotic cells while phosphorlating them using PEP
Explain siderophores
low molecular weight and iron chelating compounds able to complex with ferric iron and supply it to the cell. microbes secrete siderosphores when little iron is avaliable
what are the types of media
culture, synthetic or defined, complex, solid, selective and differential
what is culture media
a solid or liquid preparation used to grow, transport and store microbes. Used in the isolation and identification, the testing of antibiotic sensitives and water and food analysis
what is synthetic media
media in which all componenets are knwown
what is a complex media
some ingrediants of unknown chemical ocmposition like peptones, meat and yeast extract. Peptones are protein hydrolysates
what is the solid media
includes agar and 40-42 degrees harden and 80-90 degrees melt. most microbes cannot degrade it. Silica gel is used for autotrophic bacteria and is a drying agent used to absorb moisture and condensationfrom the surrounding environment
what is the selective media
favours the growth of particular microorganisms and have componenets that inhibit the growth of unwanted bacteria and have components that promote the growth of favoured bacteria
what is differentail media
can distinguish between different groups of bacteria e.g MacConkey agar
what is the thermal death time for most organisms
15 mins
