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Life 205 chpt 1-6
Life 205 Chapters 1-6 for the first exam
310
Microbiology
Undergraduate 2
02/16/2013

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Term
What are the living members of the microbial world? (microorganisms)
Definition
Bacteria, archaea, protozoa, algae, fungi, and some multicellular parasites.
Term
All surfaces of the human body are populated with characteristic communities of microbiata called _______ _______.
Definition
Normal microbiota
Term
Who disproved the idea of spontaneous generation? It took 200 years!
Definition
French Chemist Louis Pasteur did.
Term
How did Louis Pasteur disprove spontaneous generation?
Definition
He demonstrated that air is filled with microorganisms with his swan neck flask experiments.
Term
How do microorganisms maintain life on earth?
Definition
1. Convert nitrogen gas into a form that plants can use. It's a symbiotic relationship where nitrogen fixing bacteria grow in roots.
2. They replenish oxygen
3. They break down materials that no other living things can (ex. cellulose)
Term
This is the process by which living organisms degrade environmental pollutants.
Definition
Bioremediation
Term
disease causing microbes
Definition
pathogens
Term
What are some of the benefits of biotechnology?
Definition
We can make recombinant proteins for use in the medical field. (insulin)
Vaccines
genetically engineered plants
gene therapy
Term
What are the 3 domains of life?
Definition
Bacteria, Archaea, and Eucarya
Term
This type of cell does not contain a membrane bound nucleus or other membrane bound organelles, instead the genetic material resides in the nucleiod.
Definition
The prokaryotic cell.
Term
What domains of life have a prokaryotic cell?
Definition
Bacteria and Archaea
Term
What makes Archaea and bacteria so different?
Definition
Their chemical composition. Ex: Archaea do not have peptidoglycan in their cell walls.
Term
________ are known for their ability to survive and grow in extreme environments that kill most other living organisms.
Definition
Archaea
Term
Algae, fungi, and protozoa are members of the microbial world that fit into the domain of __________.
Definition
Eukaryotes
Term
______ is always capitalized in nomenclature and _________ is not, but both are italicized.
Definition
1. genus
2. species
Term
What are two features that distinguish prokaryotes from eukaryotes?
Definition
1. eukaryotes have a nuclues and other membrane bound organells. Prokaryotes do not.
2. bacteria multiply by binary fission, and usually have a specific shape with a rigid cell wall.
Term
What are the three members of the non-living microbial world?
Definition
1. viruses
2. viroids
3. Prions
Term
Why are viruses not considered living organisms?
Definition
Because by definition a living organism must be composed of one or more cells to be alive.
Term
these consist of a nucleic acid packaged within a protein coat.
Definition
viruses
Term
These consist of RNA and no protein coat. They cause plant diseases.
Definition
Viroids
Term
These are abnormal forms of cellular protein. They are infectious and bind together in brain to form fibrils.
Definition
Prions
Term
An extraordinarily resistant dormant cell produced by some bacteria.
Definition
An endospore
Term
The movement of a cell toward or away from a certain chemical in the environment.
Definition
Chemotaxis
Term
These bacteria have a cell wall characterized by a thin layer of peptidoglycan surrounded by an outer membrane: when gram stained they are pink.
Definition
Gram-negative bacteria
Term
Bacteria that have a cell wall characterized by a thick layer of peptidoglycan: when gram stained they are purple.
Definition
Gram-positive bacteria
Term
What are 3 reasons for re-emerging old diseases?
Definition
1. world travel
2. parents neglecting to vaccinate
3. increased elderly population and AIDS population.
Term
What do we call a collection of similar species?
Definition
genus
Term
What do we call a group of closely related isolates or strains?
Definition
species
Term
What is resolution in microscopy?
Definition
The ability to distinguish between objects that are very close together.
Term
This type of microscope directs light toward the specimen at an angle so cells appear as bright objects against dark background.
Definition
A dark-field microscope.
Term
This microscope amplifies the difference between refractive index of an object and surrounding medium so cells appear darker.
Definition
phase-contrast microscope
Term
This type of microscope uses UV light to see specimen that were either tagged with a flourescent dye or naturally flourecse.
Definition
Fluorescence microscope
Term
A _______ dye is used to bind negatively charged cellular components: nucleic acids, some proteins, and cell membrane surfaces.
Definition
Basic dyes
Term
What type of dyes are positively charged?
Definition
Basic dyes
Term
What are some examples of basic dyes?
Definition
1.methylene blue
2. crystal violet
3. safranin
4. malachite green
Term
An ______ dye binds positively charged structures: some proteins, and cytoplasm.
Definition
acidic
Term
Acidic dyes are _______ charged.
Definition
negatively charged
Term
cells repel this type of stain so the background is colored.
Definition
Acidic dye (negatively charged)
Term
These stains differentiates microbes into different categories depending on staining properties. Often utilize 2 or more stains.
Definition
Differential stains (ex: Gram stain, acid-fast stain)
Term
What stain is most commonly used for bacteria?
Definition
The gram stain
Term
What are the four steps to gram stain?
Definition
1.Crystal violet(primary stain)
2. Gram's iodine: increases affinity of cellular components for dye.
3. Alcohol: Wash
-removes crystal violet and grams iodine from gram negative bacteria only.
4. Safranin: counterstain
-stains gram negative cells pink
Term
What is the acid fast stain used for?
Definition
A small group of organisms that do not readily take up dyes. (Mycobacterium)
Term
The cell wall of these bacteria contains high concentrations of a waxy fatty acid called mycolic acid that prevents uptake of dyes such as those used in gram staining.
Definition
Mycobacterium
Term
acid fast staining can be used in clinical procedures to identify these bacteria, due to the fact that they are among a few organisms that actually retain this dye.
Definition
Mycobacterium
Term
A gel like layer that surrounds some microbes. It is a protective fxn and also increases an organisms pathogenicity.
Definition
A capsule
Term
An example of a capsule stain.
Definition
India ink
Term
what is the primary stain in acid fast staining?
Definition
carbolfuchsin
Term
What genera of bacteria form endospores?
Definition
Bacillus and Clostridium
Term
Do endospores stain with gram stain?
Definition
No, they appear as clear smooth objects within stained cells. Malachite green and safranin are often used to make the endospores more visible.
Term
A bacteria with a spherical shape.
Definition
coccus
Term
a bacteria with a cylindrical shape
Definition
rod
Term
s rod-shaped bacterium is often called a ______.
Definition
bacillus
Term
A bacterium that is so short it can easily be mistaken for a coccus is often called a ________________.
Definition
coccobacillus
Term
a bacterium shaped like a short, curved rod.
Definition
vibrio
Term
A curved rod, long enough to form spirals.
Definition
spirillum
Term
a long, helical cell with a flexible cell wall and a unique mechanism of motility.
Definition
spirochete
Term
bacteria that vary in shape are called _______.
Definition
pleomorphic
Term
Cocci that typically occur in pairs are routinely called ________.
Definition
Diplococci
Term
The surface layers of the prokaryotic cell called the ______ ______ consist of the cytoplasmic membrane, cell wall, and if present, the capsule.
Definition
cell envelope
Term
the fluid portion of the cytoplasm.
Definition
the cytosol
Term
The outer layer of the outer membrane on a gram-negative bacteria is made of _______.
Definition
lipopolysaccharide. (LPS)
Term
Although members of bacteria and archaea have the same general structure of their cytoplasmic membranes, how are they different?
Definition
The lipid composition is different. In archaea, the lipid tails are connected to glycerol by a different type of linkage and are not fatty acids.
Term
name 3 molecules that pass freely through the lipid bilayer.
Definition
1.water
2. oxygen, carbon dioxide and nitrogen
3. small hydrophobic molecules
Term
In a prokaryote, the two types of active transport are what?
Definition
1. Transport systems that use proton motive force
2. transport systems that use ATP.(called ABC transporters)
Term
What does ABC transport stand for?
Definition
ATP Binding Cassette. These systems use specific binding proteins that reside immediately outside of the cytoplasmic membrane to gather and deliver molecules to the respective transport complexes.
Term
A transport process that chemically alters a molecule during its' passage through the cytoplasmic membrane. Typically done by adding a phosphate group. (phosphorylation)
Definition
Group translocation
Term
the process of cells actively moving out certain proteins.
Definition
secretion
Term
the process of cells actively moving out certain proteins.
Definition
secretion
Term
what is a signal sequence?
Definition
A characteristic sequence of amino acids bound to a protein destined for secretion in order to let the cell know what needs to be done with it.
Term
why would a cell need to secrete proteins?
Definition
There are many fxns of proteins...one example is that of an extracellular enzyme used to break down macromolecules into smaller subunits small enough to enter the cell for use.
Term
The strength of the bacterial wall is due to what? What prevents bacteria from lysing?
Definition
the peptidoglycan found only in bacteria
Term
What is peptidoglycan made up of?
Definition
an alternating series of two major subunits: N-acetylmuramic acid (NAM) and N-acetylglusamine (NAG) They are covalently joined together to form a glycan chain. Attached to each of the NAM molecules is a tetrapeptide chain.(a string of four amino acids) that play and important role in the strength of peptidoglycan.
Term
What is the difference btwn gram negative and gram positive peptidoglycan chain?
Definition
In gram negative bacteria, the tetrapeptide are joined together directly. In gram positive, they are linked together indirectly by a peptide interbridge.
Term
regardless of it's thickness, what is peptidoglycan permeable to?
Definition
Sugars, amino acids, and many other substances
Term
this type of bacteria has teichoic acids that may serve as a cation reserve for enzymes outside the cell wall.
Definition
The gram positive bacteria.
Term
what connects the glycan chains in peptidoglycan?
Definition
tetrapeptide (a string of 4 amino acids)and a peptide interbridge in gram positive cells
Term
What is the outer layer of the gram negative cell composed of?
Definition
lipopolysaccharide (LPS)
Term
Why is LPS important from a medical standpoint?
Definition
Because it causes a sometimes deadly response in our bodies. They react so strongly that death often results if bacteria with LPS is actively growing inside.
Term
This is considered an endotoxin because of its lethal effect.
Definition
LPS (Lipopolysaccharide)
Term
What two parts of LPS are molecularly notable?
Definition
1.Lipid A Anchors the LPS in the lipid bilayer. This is the portion the body identifies as gram negative bacteria.
2. O antigen: portion of LPS directed away from the membrane. Made up of a chain of sugars that make each different species recognizable.
Term
specialized, channel forming proteins in the cell membrane.
Definition
Porins
Term
In the gram negative cell, the region btwn the cytoplasmic membrane and the outer membrane is called what?
Definition
periplasmic space
Term
the gel like substance that fill the periplasmic space.
Definition
periplasm
Term
what happens to proteins exported from the cytoplasmic membrane on a gram negative cell?
Definition
They build up in the periplasmic space unless specifically moved across the outer membrane.
Term
Compounds that interfere with the synthesis of peptidoglycan or weaken its structure are useful why?
Definition
The peptidoglycan can no longer keep the cell from lysing and it does not effect eukaryotic cells.
Term
why can mycoplasma bacteria survive without a cell wall and even be resistant to penicillin and lysozyme?
Definition
Their plasma has sterols in it, making them much stronger than most bacteria.
Term
Why and how does penicillin work on bacteria?
Definition
It is an antibiotic that interferes with the peptidoglycan synthesis. It fxns by preventing the cross-linking of adjacent glycan chains.
Term
None of the archaea have peptidoglycan, but they have a similar molecule called _________.
Definition
pseudopeptidoglycan
Term
how does the action of penicillin differ from that of lysozyme?
Definition
penicillin prevents the peptidoglycan chains from linking, lysozyme breaks down chains that already existed.
Term
a layer on the outside of a bacterial cell that is distinct and gelatinous.
Definition
A capsule
Term
A layer on the outside of a bacterial cell that is diffuse and irregular is called a ______ _______.
Definition
slime layer
Term
what are most slime layers and capsules made of?
Definition
polysaccharides called glycocalyx
Term
What is a biofilm?
Definition
A polymer-encased community of microbes
Term
some capsules allow bacteria to adhere to specific surfaces....true or false?
Definition
true!
Term
Some ______ allow bacteria to avoid host defense systems that otherwise protect from infection.
Definition
capsules allow bacteria to avoid host defense sometimes.
Term
Long protein structures responsible for most types of prokaryotic motility.
Definition
flagella- they can give the cell a competitive advantage.
Term
What are the three parts of a flagellum?
Definition
1. Filament
2. hook
3. and basal body
Term
When a cell has flagella over the entire surface of the cell it is called _______.
Definition
peritirchous
Term
a polar flagellum is known by its .....
Definition
Single flagellum at the end of the cell.
Term
What is the pattern of travel for most bacteria with flagella in chemotaxis?
Definition
They have runs and tumbles, either toward or away from nutrients or toxins.
Term
These are considerable shorter and thinner than flagella but their structure is familiar to flagella.
Definition
Pili
Term
What is/are the functions of pili?
Definition
1.they allow cells to attach to specific surfaces.(called fimbriae)
2. help some types of bacteria move on solid media.
3. or as a sex pilus
Term
What do sex pilus do?
Definition
hook together bacterial cells for DNA transfer.
Term
What is an example of a bacteria that uses pili?
Definition
Strains of E. coli that cause diarrhhea in the small intestine...they would be otherwise flushed out.
Term
Describe a prokaryotic chromosome
Definition
It is typically a single or circular double-stranded DNA molecule that contains all genetic info for the cell.
Term
The mass in the cytoplasm that forms a gel-like region. it is known as the _____.
Definition
nucleiod
Term
circular, super coiled double-stranded DNA molecules. (generally much smaller than a chromosome.)
Definition
A plasmid
Term
What type of ribosomes are found in prokaryotic cells?
Definition
7OS - the higher the S value, the greater the density.
Term
Why is it important to note that the ribosomes in prokaryotes are different than that of eukaryotes?
Definition
Medically, you can make antibiotics that will specifically target the prokaryotes ribosomes.
Term
Accumulations of high-molecular-weight polymers synthesized from a nutrient that a cell has in relative excess.
Definition
Storage granules
Term
Some aquatic bacteria produce small, rigid protein-bound compartments that provide buoyancy to the cell. What are they called?
Definition
Gas vesicles
Term
A unique type of dormant cell produced by members of the genera Bacillus and Clostridium.
Definition
Endospores
Term
What are some key facts about endospores?
Definition
They can survive for 100 years..maybe longer. They are not easily killed by boiling, and that can later germinate and enter a vegetative state.
Term
Endospore formation is called _____.
Definition
sporulation
Term
The site of oxidation of lipids and toxic chemicals in eukaryotes.
Definition
peroxisomes
Term
These digest macromolecules in eukaryotes.
Definition
lysosomes
Term
The site where macromolecules made in the ER are modified before being transported in vesicles to other locations.
Definition
The Golgi apparatus
Term
These are the power houses of the cell in eukaryotes.
Definition
mitochondria
Term
The site of synthesis of macromolecules in the eukaryote.
Definition
The Rough ER
Term
The site of lipid synthesis and degradation, also calcium ion storage.
Definition
The smooth ER
Term
The specific molecule a receptor binds to. (euk)
Definition
a ligand
Term
pinocytosis is a type of ______ that forms a small compartment in the cell and closes to digest certain macromolecules.
Definition
endocytosis
Term
What are the 3 types of EUK endocytosis?
Definition
1.pinocytosis
2.receptor-mediated endocytosis
3.phagocytosis
Term
The reverse of endocytosis
Definition
exocytosis-the cell expels things out of the cell
Term
What is the Euk ribosome?
Definition
80S
Term
The framework for a euk cell
Definition
cytoskeleton
Term
What are the 3 proteins that give structure to the cytoskeleton?
Definition
1.microtubules
2.microfilaments
3. intermediate filaments
Term
What do actin filaments (microfilaments) do inside the euk cell?
Definition
allow the cytoplasm to move and are key in psuedopod formation in phagocytosis.
Term
What is one purpose of microtubules in the euk cell?
Definition
They form the mitotic spindles in mitosis.
Term
The ribosomes in the mitochondria are what type? What did that lead scientists to believe?
Definition
They are 70S...like those in bacteria, leading scientists to believe that mitochondria evolved from bacterial cells.
Term
Where are chloroplasts found?
Definition
exclusively in plants and alae.
Term
The time it takes for a population to double in number.
Definition
The generation time
Term
What is the equation for figuring generation time if the two values are known?
Definition
Nt=No*2"
where Nt = The # of cells at a given time
No= the original # of cells
n = The number of divisions those cells have undergone.
Term
Explain why microbial growth refers to populations rather than cell size.
Definition
It doesn't matter what the cell size is, microbial growth is defined as an increase in the number of cells in a population.
Term
The mesh -like accumulation of polymers in a biofilm are called what?
Definition
EPS (extracellular polymer substances.
Term
What is a planktonic bacteria?
Definition
What that is "free floating"
Term
A population descended from a single cell.
Definition
A pure culture
Term
a procedure that minimizes the chance of other organisms being accidentally introduced in a culture.
Definition
Aseptic techniques
Term
a distinct mass of cells. It takes about 1 million to be seen by the naked eye.
Definition
a colony
Term
What is Agar and why is it used for cultures? (agar plate)
Definition
Agar is a polysaccharide used to solidify culture media because very few microbes can degrade it.
Term
The most commonly used technique for isolating prokaryotes. What is the goal?
Definition
The streak-plate method and the goal is to separate cells enough so that distinct, well-isolated communities will form.
Term
What properties make agar ideal for use in culture media?
Definition
1. few microbes can break it down
2. It stays solid at a wide range of temps.
Term
What is the estimated number of prokaryotes that can actually be grown in a culture?
Definition
only 1%
Term
What are the 5 phases of microbial growth? (growth curve)
Definition
1. lag phase
2. log or exponential phase
3. stationary phase
4. death phase
5.phase of prolonged decline
(LLSDP)
Term
What is a batch culture?
Definition
A culture that is a closed system where nutrients are not added and waste products are not removed.
Term
What is an open system? (continuous culture)
Definition
A culture where nutrients are added and waste products removed to allow for continual growth.
Term
What happens during the lag phase?
Definition
When a dilute culture is transferred into a different medium, the cells begin synthesizing enzymes required for growth.
Term
What happens in the log or exponential phase?
Definition
cells divide at a constant rate. this is when generation time is measured. Later in the log phase, as nutrients run out, cells produce endospores (if they are able) or they prepare for starvation conditions.
Term
Why is the log phase important medically?
Definition
because bacteria are most sensitive to antimicrobial medications at this time.
Term
From the commercial standpoint why is the log phase important?
Definition
Some of the molecules made by growing cells are valuable. (ex: amino acids can be sold as nutritional supplements)
Term
Small molecules made by cells as they multiply are called what?
Definition
primary metabolites
Term
compounds made during the end of the log phase for purposes other than growth.
Definition
secondary metabolites
Term
What are the most valuable secondary metabolites? (commercially)
Definition
antibiotics
Term
What happens during the stationary phase?
Definition
some cells are dying while others are still multiplying. the total number remains fairly constant. They continue producing secondary metabolites.
Term
What occurs in the death phase?
Definition
total number of viable cells drops at a steady rate. rate is exponential, but much slower than growth.
Term
what occurs in the phase of prolonged decline?
Definition
a fraction of cells usually survive and over time generates successive waves of slightly modified populations, each better equipped to survive than the previous.
Term
What is a chemostat?
Definition
A device that continuously drips fresh medium into a broth culture contained in a chamber. (for a continuous culture)With each drop in, a drop is removed.
Term
what is an extremophile?
Definition
usually archaea. they survive in very extreme environments.
Term
What are the main environmental factors that influence microbial growth?
Definition
temp
atmosphere
pH
water availability
Term
what are the five commonly divided groups based on temp range?
Definition
1.psychrophiles: -5 C and 15 C
2.psychrotrophs: optimum btwn 20 C and 30 C
3.mesophiles: 25-45 C
4.thermophiles: 35-40 C
5.hyperthermophiles: 45-70 C
Term
the refrigerator slows growth of what microbes?
Definition
limits growth of mesophiles, but psychrocphiles and psychrotrophs can still grow...it just happens more slowly
Term
these microbes have an absolute requirement for oxygen
Definition
Obligate aerobes
Term
These grow whether oxygen is present or not. better with oxygen.
Definition
facultative anaerobes
Term
these microbes CANNOT multiply if oxygen is present.
Definition
obligate anaerobes
Term
These microbes require small amounts of oxygen(2-10%) higher concentrations inhibit them.
Definition
microaerophiles
Term
these microbes are indifferent to oxygen. they can grow in it's presence but do not use it for energy.
Definition
aerotolerant anaerobes
Term
What is an ROS? describe it.
Definition
A reactive oxygen species. when an organism uses aerobic respiration, harmful derivatives form.(superoxide and hydrogen peroxide)
Term
What do cells use to protect against ROS?
Definition
The enzyme superoxide dismutase which converts superoxide to oxygen and hydrogen peroxide.
and the enzyme catalase, which convert hydrogen peroxide into oxygen and water.
Term
although they may grow in very different pHs, prokaryotic cells typically maintain an almost nuetral pH within the cell. true or false?
Definition
true!
Term
microbes that live and multiply within the range of pH 5 (acidic) to pH 8 (basic)and have a pH 7.
Definition
neutrophiles
Term
What is the bacterium that lives in the stomach and causes ulcers?
Definition
Helicobacter pylori
Term
microbes that live in pH lower than 5.5
Definition
acidophiles
Term
these microbes grow in pH above 8.5
Definition
alkaliphiles
Term
all microorganisms require water for growth...true or false?
Definition
true!!
Term
Why/how do salt and sugar render water unavailable to cells?
Definition
They interact with the water molecules rendering them unavailable.
Term
The phenomenon where solute concentration is higher in the medium than the cell and water diffuses out of the cell and causes the cytoplasm to dehydrate and shrink from the cell wall.
Definition
plasmolysis
Term
microbes that tolerate high concentrations of salt (up to 10%Nacl)
Definition
halotolerant
Term
microbes that require high levels of sodium chloride 3%
Definition
Halophiles
Term
Microbes that require 9% sodium chloride
Definition
extreme halophiles
Term
what is the fxn of the enzyme catalase?
Definition
Catalase breaks down hydrogen peroxide into oxygen and water.
Term
chemical elements that make up cell constituents are called what?
Definition
major elements
Term
What are the major elements?
Definition
carbon, hydrogen, nitrogen, sulfur, phosphorous, potassium, magnesium, calcium, and iron.
Term
prokaryotes that use organic carbon
Definition
heterotrophs (typically medically important)
Term
These use inorganic carbon in the form of carbon dioxide. They are critical in the cycling of carbon in the environment. They convert inorganic carbon to an organic form.
Definition
autotrophs
Term
The process of converting inorganic carbon to organic carbon.
Definition
carbon fixation
Term
The process of converting nitrogen to ammonia
Definition
Nitrogen fixation(only in prokaryotes)
Term
Why is nitrogen fixation essential to life?
Definition
Once the nitrogen is incorporated into cellular material, such as amino acids, other organisms can use it!
Term
a compound that has a carbon attached to a hydrogen atom with a covalent bond
Definition
organic compound
Term
nutrients that are available at the lowest concentration relative to need.(think choc chips in choc chip cookies)
Definition
limiting nutrients
Term
molecules needed by a cell that are found in the environment
Definition
a growth factor
Term
bacteria that have complicated nutritional requirements
Definition
fastidious
Term
What is an application of fastidious bacteria?
Definition
to measure how many vitamins in food products.
Term
organisms that harvest energy from sunlight.
Definition
phototrophs
Term
organisms that harvest energy from chemical compunds
Definition
chemotrophs
Term
this type of prokaryote uses the energy of sunlight along with carbon dioxide to make organic compounds. (primary producers)
Definition
photoautotrophs
Term
Type of prok that use energy of sunlight and carbon from organic compounds. some are facultative
Definition
photoheterotrophs
Term
This group of prok use organic cmpds for energy and derive their carbon from CO2. (often live in seemingly inhospitable places)
Definition
chemolithoautotrophs
Term
This group of prok use organic cmpds for both energy and carbon. THey are by far the most common group of microorganisms.
Definition
chemoorganoheterotrophs
Term
this media contains a variety of nutrients such as meat juices and digested proteins.
Definition
complex media
Term
media composed of exact amounts of pure chemicals
Definition
chemically defined media
Term
this type of media inhibits the growth of specific species making it easier to isolate the one being sought.
Definition
selective media
Term
this type of media contains substances that certain microbes change in a recognizable way.
Definition
Differential media
Term
clear zone of hemolysis
Definition
beta hemolysis
Term
zone of greenish partial clearing
Definition
alpha hemolysis
Term
an enclosed compartment maintained as an aerobic environment
Definition
anearobic chamber
Term
this is used to isolate an organism present as only a very small fraction of a mixed population.
Definition
an enrichment culture
Term
In the direct microscope count, how many cells must be present in order to count?
Definition
at least 10 million per milliter.
Term
an electronic instrument that counts cells in a suspension as they pass single file through a narrow channel.
Definition
a coulter counter
Term
this measures light scattered by cells as they pass a laser to count them.
Definition
flow cytometer
Term
the coudiness of a microbial suspension
Definition
turbidity
Term
What are the three types of direct counts?
Definition
1.Petroff-Hausser counting chamber
2.Membrane filters
3.coulter counter
Term
brief heat treatment that reduces the number of spoilage organisms and detroy
Definition
Term
Brief heat treatment that reduces the number of spoilage organisms and kills disease-causing microbes.
Definition
pasteurization
Term
Kills microbes
Definition
germicide
Term
Prevents the growth of, but does not kill bacteria
Definition
bacteriostatic
Term
Disinfectant
Definition
a chemical that destroys many microbes
Term
bactericidal
Definition
kills bacteria
Term
completely free of all viable microbes
Definition
sterile
Term
a chemical that detroys all microbes
Definition
sterilant
Term
a disinfectant nontoxic enough to use on skin.
Definition
antiseptic
Term
process of inhibiting microbial growth to delay spoilage.
Definition
preservation
Term
what is the most common and reliable method used to kill microbes?
Definition
heat treatment
Term
when chlorine and other chemicals react with naturally occurring chemicals in the water to form ______ ___ ________.
Definition
Disinfection by-products
Term
how is sterilization different from disinfection?
Definition
Sterilization is the destruction or removal of all microbes through physical or chemical means. disinfection is the elimination of most or all pathogens on or in a material. With disinfection, some such as endospores may remain.
Term
What types of microorganisms may be more resistant to antimicrobial procedures?
Definition
1.Endospores
2.protozoan cysts,
3. ocysts
4.mycobacterium:(resistant waxy cell wall)
Term
Instruments that come in direct contact with body tissues(needles and scalpels)MUST be sterile.
Definition
critical instruments
Term
instruments that come in contact with mucous membranes.
Definition
semicritical instruments
Term
these come into contact with unbroken skin and pose little risk for infection. (stethoscpes, countertops)
Definition
Non-critical instruments
Term
Boiling for 5 min kills most things, but may leave what?
Definition
endospores
Term
today most pasteurization is what kind?
Definition
High-temp short-time
Term
ultra pastuerization uses this.
Definition
ultra-high temp
Term
this method of sterilization uses steam and pressure to kill microbes
Definition
autoclave
Term
this type of heat is less effective that moist heat.
Definition
dry heat
Term
these remove microbes from air.
Definition
HEPA High-efficiency particulate air
Term
How does ionizing radiation work in sterilization?
Definition
It harms cells directly by destroying DNA and damaging cytoplasmic membranes.
Term
What is UV radiation most used for? how does it sterilize?
Definition
Used mostly to destoy microbes in the air and drinking water and to disinfect surfaces. It destroys the DNA.
Term
How does high-pressure sterilization work?
Definition
Used to decrease the number of microbes in commercial food products. It works by denaturing proteins and altering cell permeability. It does not alter flavor.
Term
What is the difference btwn the mechanism of a depth filter and that of a membrane filter?
Definition
the depth filter uses electrical charges to hold the microbes back.
Term
These destroy all microorganisms, endospores, and viruses; 6-10hrs
Definition
Sterilants
Term
Destroy vegetative microorganisms, viruses; not endospores; short time periods.
Definition
High-level disinfectants
Term
these destroy vegetative bacteria, mycobacteria, fungi, most viruses; not endospores.
Definition
intermediate level disinfectants
Term
These destroy vegetative bacteria, fungi, enveloped viruses; NOT ensospores or naked viruses.
Definition
Low-level disinfectants
Term
when selecting the appropriate germicidal chemical, what things should you consider?
Definition
1.toxicity to humans
2.activity in presence of organic material
3.compatability with material being treated
4.residue(will it ruin things?)
5.cost and availability
6.storage and stability
7.environmental
Term
What class of germicidal chemicals are used to sterilize instruments?
Definition
Aldehydes: also,Formalin is used to vaccine production and to preserve biological specimens.
Term
What class of chemicals are inexpensive, non-toxic and disinfect
Definition
Term
What class of chemicals are inexpensive, non-toxic and disinfectant?
Definition
alcohols
Term
What class of chemical is used as antiseptics in soaps, lotions, mouthwash, catheters, surgical mesh, and mucous membranes?
Definition
Biguanides
Term
What class of chemicals is used to sterilize medical equipment;penetrate hard to reach places, fabric,and heat or moisture sensitive items?
Definition
Ethylene oxide gas
Term
What class of chemicals is used to disinfect inanimate objects, surfaces, water and antiseptics?
Definition
Halogens (Chlorine and iodine are ex:)
Term
What class of chemicals are usually too toxic to use?
Definition
metals (usually used to disinfect burns)
Term
What class of chemicals decomposes quickly, and is used as a disinfectant for drinking and wastewater?
Definition
Ozone O3
Term
What class of chemicals are powerful oxidizers used as sterilants for pkgd juices , milk and are less toxic than ethylene oxide?
Definition
Peroxygens (ex: hydrogen peroxide)
Term
What class of chemicals are used to kill most vegetative bacteria, but are not reliable for all virus groups?
Definition
Phenolic compounds (active ingredients in lysol)
Term
What class of chemicals are non-toxic, and are used on food prep surfaces?
Definition
Quaternary ammonium compounds
Term
Why is it important to dilute iodine solutions as per recommendation?
Definition
because diltion effects the amount of free iodine available.
Term
What are some examples of chemical preservatives? How do they work?
Definition
Weak organic acids(benzoic, sorbic, propionic) They inhibit metabolism, alter the cell membrane function and control mold in foods and cosmetics.
Term
What
Definition
Term
What are chemicals that can be added to processed meats to inhibit endospore germination, vegetative growth?
Definition
Nitrate:it is carcinogenic and gives meat it's pink color
Term
How is preservation of perishable products done best?
Definition
Reduce the available water
Term
What are some methods of food preservation?
Definition
1.salting, adding sugar, drying foods
(this causes plasmolysis)
2.Lyophilization(freeze drying)
3.Drying (stops microbial growth, does not kill salmonella on outside of eggs)
Term
what is the most important function of nitrate in cured meat?
Definition
Most important fxn to inhibit germination of endospores and subsequent growth.
Term
The D value is the amount of time it takes to kill what percent of bacteria?
Definition
90% in the population
Term
a metabolic process that stops short of oxidizing glucose or other organic compounds completely, using an organic intermediate as a terminal electron acceptor.
Definition
Fermentation
Term
The sum total of all chemical reactions in the cell.
Definition
metabolism
Term
metabolic intermediates that can either be used to make the subunits of macromolecules or oxidized to generate ATP.
Definition
Precursor metabolites
Term
Organisms that harvest the energy of sunlight, using it to power the synthesis of organic compounds from CO2.
Definition
photosynthetic organisms
Term
These organisms obtain energy by degrading organic cmpds.
Definition
chemoorganotrophs
Term
chemical reactions that release energy
Definition
exergonic
Term
chemical reactions that require the input of energy.
Definition
endergonic
Term
the series of sequential chemical reactions that converts a starting compound to an end product.
Definition
A metabolic pathway
Term
The energy it takes to start a reaction.
Definition
activation energy
Term
_______ are proteins that accelerate the conversion of the ______ into another product.
Definition
1.enzymes
2.substrate
Term
What does ATP stand for?
Definition
andenosione triphosphate
Term
This molecule is composed of ribose, adenine, and three phosphate groups arranged in tandem.
Definition
ATP
Term
What is ADP?
Definition
adenosine diphosphate
Term
metabolic pathway where energy released in an exergonic rxnis used to power the addition of Pi to ADP.
Definition
substrate-level phoshporylation
Term
The energy of proton motive force drives the reaction in this pthway.
Definition
oxidative phosphorylation
Term
When electrons move from a molecule with low electron affinity to a molecule with high electron affinity, what is released?
Definition
energy
Term
The chemical that serves as the electron donor is what?
Definition
The energy source
Term
The chemical that ultimately accepts the electron is called what?
Definition
terminal electron acceptor
Term
the substance that loses electrons is ______
Definition
oxidized
Term
the substance that gains electrons is ________.
Definition
reduced
Term
cells remove electrons from the energy source through a series of _______ reactions.
Definition
redox (oxidation-reduction reactions)
Term
What are the electron carriers?
Definition
1.NAD+/NADH
2.NADP+ / NADPH
3. FAD/ FADH2
Term
why can electron carriers also be considered hydrogen carriers?
Definition
Because along with electrons, they carry protons
Term
What are the central metabolic pathways? (in Porkaryotes)
Definition
1.Glycolysis
2.Pentose phosphate pathway
3. tricarboxylic acid cycle (TCA cycle)
Term
______ transfers the electrons extracted from glucose to the electron transport chain.
Definition
Respiration
Term
organisms that use respiration either aerobic or anaerobic are said to ______.
Definition
respire
Term
in this process, cells break down glucose through glycolysis only and then use pyruvate or a derivative as a terminal electron acceptor. It yields relatively little ATP.
Definition
fermentation
Term
How does the fate of electrons carried by NADPH differ from the fate of Electrons carried by NADH?
Definition
NADH transport electrons to the electron transport chain, the e- carried by NADPH are used to reduce compounds during biosynthetic rxns.
Term
a non-protein component that assist enzymes. (Usually trace elements)
Definition
cofactor
Term
organic cofactors that fxn as loosely bound carriers of molecules or electrons. (FAD, NAD+, NADP+)
Definition
Coenzymes
Term
These are usually derivatives of vitamins
Definition
coenzymes
Term
Enzymes that can be controlled using other molecules that reversibly bind to and distort them.
Definition
allosteric (Allosteric regulation)
Term
How does allosteric inhibition work?
Definition
the enzyme has an active site as well as an allosteric site. When activity needs to be regulated, the allosteric inhibitor binds to the allosteric site, the enzyme changes shape, and the substrate cannot attach to the active site.
Term
in this, the inhibitor binds to the active site of the enzyme, blocking access of the substrate to that site.
Definition
Competitive inhibition
Term
What is an example of competitive inhibition in bacteria?
Definition
Antimicrobial medication called sulfa drugs inhibit an enzyme in the pathway bacteria use to synthesize folic acid. leading to death of bacteria.
Term
When the inhibitor binds to a site other than the active site to change the shape of the enzyme so the substrate cannot bind to it.
Definition
Non-competitive inhibition
Term
Explain the fxn of coenzymes.
Definition
The transfer of substances from one compound to another.
Term
For each molecule of glucose that enters the glycolysis pathway, how many pyruvates are produced
Definition
Two molecules of pyruvate.
Term
What does glycolysis generate?
Definition
-2 ATP by substrate level phosphorylation
- 2 NADH + 2H+
- six diff precursor metabolites
Term
WHat two phases are in glycolysis?
Definition
1. the investment/prep phase
2. the payoff phase
Term
Which central metabolic pathway yields the most reducing power?
Definition
The TCA cycle
Term
What is the primary role of the Pentose phosphate pathway?
Definition
Production of precursor metabolites, and NADPH
Term
What is the transition step? Where is it used?
Definition
Link btwn glycolysis and the TCA cycle. Used in aerobic and anaerobic respiration
Term
What is the yield of the transition step?
Definition
-2 NADH=6ATP (from Oxidative phosphsorylation)
-2 acetyl CoA
Term
What is the yield of the TCA per 1 molecule of glucose?
Definition
-2 ATP (1 per turn)
- 6 NADH (3 per turn)= 18 ATP through oxidative phoshorylation
- 2 FAD2 = 4 ATP (through OP)
- 2 diff precursor molecules
Term
What is the process by which the cell uses the NADH and FADH2 generated during glycolysis, the transition step, and the TCA cycle is called?
Definition
Oxidative phosphorylation
Term
What is the diff btwn where prokaryotes and euka pump their protons in the ETC?
Definition
Euk pump them into the inter-membrane space of the mitochondria, Pro pump them out of the plasma membrane.
Term
What is the energy of the electrochemical gradient called?
Definition
Proton motive force
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