micro exam 2 Flashcards
metabolism
sum of all chemical reactions in living cells
catabolic reaction
bonds in large molecule are broken to form small molecules.
Ex. Energy for synthesis of ATP
Anabolic reaction
small molecules joined by bonds to form small molecules, requires input of Energy from hydrolysis of ATP.
ATP
the energy storage molecule/currency of cells, used to do useful work
why are anabolic and catabolic reactions interdependent?
energy from catabolic is useful of anabolic reaction
metabolic pathway
sequence/series of chemical reactions
enzymes
large proteins that act as biological catalysts, substances that speed up.
ex. increase the rate of chemical reactions in living organisms by lowering the activation energy
How are enzymes specific for their substrate
active site
do all enzymes end in -ase?
no, pepsin/trypsin
enzymes work best(reaction rate/enzymatic activity peaks)
at optimal temp. and Ph
when enzymes in microorganisms are subjected to denaturing agents such radiation, heat, 70% alcohol, strong acid or strong bases, what happens?
DENATURATION
denaturation
change in protein 3D shape and function
when microorganisms are subjected to refrigerator or freezing temp. enzymatic activity(reaction rate) declines causing?
microbial metabolism and growth to be slowed and inhibited
Holoenzymes
are activated, whole enzymes, once inactive apoenzyme combine with coenzyme activator.
Co-enzyme
are organic factors,
ex: NAD or FAD, derived from vitamins, such as B vitamins
Purpose of NAD and FAD in cellular respiration
produce a lot of ATP during the last stage of cellular respiration
are co-factors associated with all enzymes
no
catabolic pathways
type of pathway in cells of living organisms that serves to break down and oxidize glucose or other nutrients in order to synthesize ATP in cells of living organisms
aerobic cellular respiration
type of catabolic pathway used to break down and oxidize glucose or other organic nutrients(ex. fats, proteins) in the presence of o2 to release energy for the synthesize ATP
Transition step
2 pyretic acid—-> 2 acetyl Co-A + 2 NADH + 2 Co2
Krebs cycle
2 Acetyl Co-A—-> 4 Co2 + 2ATP + 6 NADH + 2 FADH2
Oxidative Phosphorylation(ETC)
10 NADH + 2 FADH2 oxidized -> e-s passed along ETC —> 32-34 ATP + 6 H2O
Glycolysis
glucose(split) —> 2 pyruvic acid + 2NADH + 2ATP(pyruvate is end product; NADH & ATP are by-products)
What is the final electron acceptor molecule of the ETC in aerobic cellular respiration?
OXYGEN
Anaerobic cellular respiration
is similar to aerobic respiration except the final electron acceptor is different. The final electron acceptor is NITRATE, CARBON, SULFATE
Fermentation(Anaerobic glycolysis)
the breakdown of glucose or other sugar in the absence of O2. Which yields less energy than cellular respiration. only 2 ATP. Does not use kerb cycle or ETC.
Fermentation(by product/end product)
glucose(split) —-> 2 pyruvic acid —> acids, alcohol, gases(Co2), NAD+, 2ATP
What is the final electron acceptor molecule of the fermentation pathway
acid and alcohol(both are organic)
enzymes found in bacterial or yeast cells ferment sugars in fruits, vegetables, grains or milk into alcohol or acids. list general uses fermentation.
- alcohol beverages
- dairy products
- spoilage of food
nutritional groups
categories into which organisms are placed based on their energy and carbon source required for growth
photoautotrophs
- use sunlight as energy source
- Co2 as C source
- glucose + 02(photosynthetic organisms)
chemoheterotrophs
- use organic compounds
- ex. glucose as E and C source, needed for ATP synthesis
chemoheterotroph
- divided into 2 groups
- depending upon where they live and obtain their food
saprophytes
-free living bacteria or fungi in soil, water or air which compose
symbionts
microbes that live in close relationships with their host, a process called symbiosis
3 types of symbiotic relationships
- paratism
- mutalism
- commensalism
parasitism
microbe benefits and host is harmed
commensalism
- most common
- microbe benefits and host is uneffective
mutualism
both microbe and host benefits from the relationship
normal flora
- referes to all the symbiotic microbes that adapt to, colonize and become permanent residents of our skin & MM.
- transient flora: temporary residents that are quickly lost by host defenses
how do saprophytes become facultative parasites(opportunists)?
-host immunocompromised moist warm environment(condition favorable for growth) or host is in weakened state
4 ways members of our normal flora can become pathogenic parasites(opportunist)?
- host is immunocompromised
- Displacement: microbes in body location where they do not normally reside
- Access to sterile tissues: microbes gain direct access to sterile tissue fluids beneath the skin or mucous membranes through a wound.
ex. surgery, cut, excoriation, or burn - Overgrowth: over-use of antibiotics suppresses normal flora growth, and allow resistant microbes, such as candida albicans or clostridium difficile to overgrow, resulting in super-infections
inoculation
the transfer of culture from one medium to another
pure culture
one organisms is present
mixed culture/specimen
2 or more different organisms present; 2 types: clinical and non-clincial
contamination
the presence of unwanted organisms
incubation
allows bacteria to grow at a certain temp and gaseous environment
isolation
to separate out one organism from a mixture
morphological characteristics of colonies used for ID
size, shape, color, margin, texture
solid media
a nutrient broth to which agar has been added. growth appears in colonies
liquid media
a nutrient broth or other solution. growth appears cloudiness(turbidity), graininess, puffballs
transmittance
amt of light passed thru bacterial suspension
absorbance
amt of light absorbed/ blocked by suspension
turbidity(cloudiness)
using spectrophotometer: instrument used to measure turbidity(cloudiness) of solution, indicative of ant. of light passed thru bacterial suspension.
culture media
a nutrient preparation used in the lab to grow most microbes, esp. bacteria and fungi
streak plate method
used to isolate pure colonies from from a mixed clinical specimen
viable plate count
colonies on agar plate are counted to determine # of bacteria cells in initial liquid sample
direct microscope count
microbes are counted in a measured volume of liquid on microscope glass slides
2 disadvantages: dead cells and clumping of cells
advantage: no incubation period
lag
bacterial cells are actively metabolizing nutrients
- increase in size
- but no increase in cell growth and thus no increase in curve
stationary
growth rate and curve levels off b/c # of bacterial cells dividing = number of bacterial cells dying
log
bacterial cells are increasing in number exponentially, growth and curve increase
death
number of bacterial cells dying outnumber new cells dividing, growth rate and curve decline
microbal growth
- reproduction
- cell division
- increase in number of cells
binary fission
cells splits into 2 cells w/ identical DNA(bacterial cell)
generation time
time required for a single cell or population of cells to divide, double in number.
average growth rate(generation time) for most bacteria is ?
20-30min
growth rate for mycobacterium tuberculosis?
12-24hrs
