unit6 :principles of bacterial nutrition Flashcards
why should bacterial food be in solution
because it uses osmosis to pass through the cell wall and semi-permeable membrane
what affects bacterial cell population and growth when they are in a confined environment as compared to when they are in their normal nature
there is accumulation of waste products and depletion of nutrients when bacteria is in a test tube or agar plate
what does bacteria use to break down substances
enzymes which it secretes
differentiate between the 2 types of enzymes that bacteria uses to hydrolyse substances
1.exo-enzymes- pass outward from the cell
2.endo-enzymes : part of the cell itself or functions within the cell
what helps enzymes to function better
coenzymes
differentiate between constitutive and inducible enzymes
constitutive enzymes- synthesized irrespective of their environmental conditions and
inducible enzymes- synthesized only in the presence of their substrate
what are the 3 examples of enzymes
oxido-reductases
hydrolases
transferases
what is oxidation and how does oxidation state increase
oxidation is the loss of electron and this increases the oxidation state
which of the 3 enzyme examples catalyzes oxidation-reduction reactions
oxido-reductases
what does the enzyme hydrolases do
catalyzes hydrolysis of compounds
what does transferases do
catalyses transfer of chemical groups from1 compound to another
define catabolism
breakdown of molecules to obtain energy
what is the difference between reduction and oxidation
oxidation- loss of electrons
reduction- gain of electrons
does the oxidation number increase or decrease with a gain of electrons
it decreases because we are becoming more negative
what is oxidative phosphorylation
transfer of energy-rich phosphate bonds to ADP to form ATP through electron transport system
in the presence of oxygen( which acts as an electron acceptor) bacteria produce 2 toxic products what are they.
what is used by anaerobic bacteria which do not have oxygen
superoxides and peroxides
anaerobic bacteria use nitrate
what is termed the process in which energy is produced during passage of electrons from substrate to an inorganic electron acceptor.
and what are the waste products produced
fermentation
acid, alcohol and gas
how often does bacteria multiply
every 20min
what is the difference between Total count growth curve and viable count growth curve
total count - incl. both viable and non viable cells
viable count- incl. viable cells only
draw and label a total count growth curve
answer on notebook
what is the difference between a total count growth curve and a viable count growth curve
the viable count growth curve doesnt have a death phase cause it only measures the viable cells.
in 2 points describe what happens in lag phase
- no multiplication
- organisms still adapting to growth in a new medium
what is happening in log phase
cells divide at constant rate and theres high metabolism to maintain high rate of division
what are the 2 main ingredients of basal agar
hydrolysate of protein
2.source of growth factors and inorganic salts
