Chapter 5 (pdf 13) Flashcards
contains a variety of ingredients
-can be highly variable
complex media
examples of complex media
nutrient broth, blood agar, chocolate agar
composed of precise amounts of a pure chemical
-not practically for routine laboratory use
chemically defined media
Invaluable in research
-each batch is chemically identical
chemically defined media
inhibits the growth of unwanted organism, increase the chance of isolating the organism of interest
selective media
example of selective media
Thayer-Martin agar and MacConkey agar
For isolation of Neisseria gonorrhoeae
Thayer-Martin
For isolation of gram-negative bacteria
MacConkey agar
contains substances that bacterial growth alters in recognizable way
differential media
example of differential media
Blood agar and MacConkey agar
certain bacteria produce hemolysin to break down Heme from Red Blood Cells
blood agar
- bile salts and CV inhibit growth of gram positive
- contains indicator to identify bacteria that can utilize certain carbon sources
MacConkey agar
Measured with a spectrometer
turbidity
Measures light transmitted through a sample
-measurement is inversely proportional to cell concentraction
turbidity
Limitation of turbidity
more reliable with a high number of cells because both live and dead cells
direct microscopic count
-microscope and hemocytometer
direct cell count
use of cell counting instruments
direct cell count
Pros of direct cell count
- useful in determining total number of cells
- can differentiate cell types
Cons of direct cell count
- does not distinguish between living and dead cells
- contract issues?
used to contract living cells
-cells able to multiply - able to monitor bacterial growth
viable cell count
often used when counts are to low for other methods
viable cell count
increased time requirements
viable cell count
methods of viable cell count
- plate counts*
- membrane filtration
- most probable numbers
measures viable cells growing on solid culture media
plate count
count based on assumption that one cell gives rise to one colony
-number of colonies=number of cells in colony
plate count
ideal number to count in plate counts
between 30 and 300
sample of plate count normally diluted in
10 fold increments
what are the two plate count methods
pour plates and spread plate methods
Metabolism is broken down into two components
catabolism and anabolism
reactions that produce energy from the breakdown of larger molecules
catabolism
reactions involved in the synthesis of cell componenets
anabolism
these reactions require energy and ‘take from’ catabolic ATP yield
anabolic
a molecule that can store energy in high energy phosphate bonds
ATP
can produce ATP in three ways
- substrate phosphorylation
- oxidative phosphorylation
- phosphorylation
uses chemical energy to add phosphate ion to molecule of ADP
substrate phosphorylation
uses energy from proton motive force to add phosphate ion to ADP
oxidative phosphorylation
utilizes radiant energy from the sun to phosphorylate ADP to ATP
phosphorylation
three different types of electron carriers that represent redox molecules that are involved in energy production
• Nicotinamide adenine dinucleotide – NAD+ and NADH • Flavin adenine dinucleotide – FAD and FADH • Nicotinamide adenine dinucleotide phosphate – NADP+ and NADPH
the catabolic pathways are…
central and provide energy, reducing power, and precursor metabolites*
