question

Microbial Growth

answer

Increase in number of cells, not cell size

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Physical Growth Requirements

answer

temperature, pH, osmotic pressure

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Psychrophiles

answer

Like to grow in the cold (-10 to -20 C)

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Psychotrophs

answer

Not used in general microbiology, used for food spoilage

question

Mesophiles

answer

Moderate temperature loving (10 to 50 C)

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Thermophiles

answer

Like it hot (40 to 70 C)

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Hyperthermophiles

answer

LOOOOVVEEE heat (70 to 110 C) Usually archea, not bactera. Above boiling point.

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Optimum temperature for most bacteria

answer

37 C

question

Optimum pH level

answer

6.5-7.5

question

acidophiles

answer

pH tolerant, grow at low pH

question

alkalinity

answer

inhibits microbial growth , but is rarely used

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phosophate salts

answer

used as buffers for most bacteria. non-toxic and provide phosphorus which we need.

question

osmotic pressure

answer

physical growth requirement use to lyse or shrink cells

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plasmolysis

answer

when the plasma membrane in cytoplasm shrinks up due to the high salt concentration in solution causing water to rush out of cell

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bacteria and lysis

answer

most bacteria resist due to rigid cell wall

question

obligate

answer

require a certain item (salt, oxygen, etc.) to grow

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facultative

answer

do NOT require item (oxygen, water, etc.) to grow, but can tolerate it

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halophiles

answer

love salt and are obligate. mostly archea. red or pink color.

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Chemical Requirements

answer

Carbon, nitrogen, sulfur, and phosphorus, trace elements, organic growth factor, and oxygen

question

Carbon

answer

source of energy. "structural backbone of all living matter". help to grow other organic materials.

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Nitrogen

answer

Used for enzymes, amino acids, proteins, and nucleic acids

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Sulfur

answer

Used to make cystine (amino acids) to form di-sulfide bonds for structure of proteins

question

phophorus

answer

used for ATP, backbone of RNA/DNA, NEED IN LARGE QUANTITIES

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trace elements

answer

cofactors, inorganic, need in small amounts. includes iron, copper, molybedenum, and zinc

question

Organic growth factor

answer

vitamins, cofactors, need in small amounts

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oxygen

answer

only to some microbes is oxygen important

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obligate aerobes

answer

oxygen is required for growth

question

facultative aerobes

answer

growth in the presence of oxygen is best, but do not need it to grow

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obligate anaerobes

answer

must live without oxygen

question

aerotolerant anaerobes

answer

tolerate some oxygen, but not much. growth occurs evenly.

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microaerophiles

answer

oxygen require in low concentration

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biofilms

answer

communities of microbial organisms that live on hard sufaces

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biofilm community

answer

produce slime like capsule, share nutrients, and are sheltered from harm. communicate through quorum sensing.

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biofilms found in/on

answer

teeth, contact lenses, catheters, mechanical heart valves, etc.

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culture medium

answer

nutrient material used to grow microorganisms on in a lab

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inoculum

answer

microbes introduced into culture medium to initiate growth

question

culture

answer

microbes that grow or multiply on the culture medium

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agar

answer

complex polysaccharide that is used because baceria cannot metabolize. comes in a power form, but liquefies at 100C and solidifies at 40C

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chemically defined media

answer

exact chemical composition is known

question

complex media

answer

varies from batch to batch. extracts and digests of yeasts, meat, or plants. Nutrient agar or nutrient broth.

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selective media

answer

done by chemicals, salts, dyes. Encourage growth of desired microbes and suppresses growth of unwanted microbes.

question

differential media

answer

distinguishes between colones of different microbes

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anaerobic culture methods

answer

reducing media: contains chemicals (thioglycolate or oxyrase) that combine oxygen. Anaerobic chamber, anaerobic jar, or oxyplate.

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living animal culture

answer

can only grow about 1% of bacteria that we know of in lab so must grow some on living animals. ex: armadillos to study lepresy.

question

capnophiles

answer

microbes that require high co2 conditions such as in the lungs or GI tract. CO2 packet or jar, or special incubator with CO2 tank

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Biosafety Level 1

answer

Trained microbiologist there at all times, low risk

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Biosafety Level 2

answer

Ex: hepatitis, influenza. Moderate-high risk. Anything genetically modified.

question

Biosafety Level 3

answer

Serious or potentially lethal diseases, but treatments available. Ex: SARS, TB, anthrax. Cabinets to prevent airborne transmission.

question

Biosafety Level 4

answer

dangerous, exotic, fatal diseases with no cure. Ex: hemmarhogic fever, small pox. Sealed, negative pressure.

question

Biosafety Level Labs

answer

15 in US most government or military run labs. Kstate has one, 2-3 texas, mainly east cost, few in canada.

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pure cultures

answer

no contaminants

question

dilute culture

answer

do until one isolated colony that has grown from one bacteria

question

deep freezing

answer

preserve bacterial cultures by putting in cold storage that is -50 to -95

question

lyophilization (freeze-drying)

answer

frozen -54 to -72 and dehydrated in a vacuum. (mix with media and put on plate) 2 years max.

question

ultra low freezer

answer

preserving bacterial cultures for an indefinite time.

question

binary fission

answer

no phases. primary method of division for prokaryotes. elongates, constricts, cross-wall forms, cells separate.

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generation time

answer

time it requires for an individual cell or group of cells to undergo binary fission. usually very fast in bacteria.

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growth curve

answer

can plot as number or logrhythmic scale.

question

lag phase

answer

little or no cell division

question

log phase

answer

exponential growth

question

stationary phase

answer

nutrients are being depleted, some cells are dying

question

death phase

answer

more cells dying than being produced

question

measure microbial growth

answer

plate count, most probable number, direct microscopic count, turbidity

question

serial dilutions (for plate count methods)

answer

dilute each tube of broth by a factor of 10. pull out 1ml from each tube and place in next one.

question

plate count

answer

not used that often. pour diluted solution on plate and count colonies

question

most probable number

answer

use statistical table. used for environmental samples ex: tap water

question

direct microscopic count

answer

quickest way, but not the easiest. microscope slide with measure grid on it and count cells in squares times by volume in that area. differs for each slide

question

turbidity

answer

easiest method. using spectrophotometers, shine light through control which gives absorbance number then go to table. must know the species.

question

sterilization

answer

removing of all contaminants

question

sepsis

answer

any sort of microbial contamination

question

asepsis

answer

careful, remaining sterility. a disinfectant treated at living tissue.

question

disinfection

answer

for non-living surfaces

question

antisepsis

answer

destroy things on living tissues

question

degerming

answer

mechanical removal of microbes ex: washing hands

question

sterilant

answer

a sterilizing agent

question

commercial sterilization

answer

limited heat treatment

question

biocide/germicide

answer

designed to kill germs. -cide meangs kill

question

bacteriostasis

answer

inhibiting microbial growth and multiplication

question

factors influencing effectiveness of antimicrobial treatments

answer

number of microbes, environmental influences, time of exposure, and microbial characteristics

question

alteration of membrane permeability

answer

cellular contents leak into surrounding medium and interferes with growth

question

damage to proteins and nucleic acids

answer

denature proteins. DNA and RNA destroyed and can't replicate or metabolize.

question

heat

answer

boiling, autoclavin, can have wet and dry

question

thermal death point (TDP)

answer

lowest temperature at which all the microorganisms in a particular liquid suspension will be killed in 10 minutes

question

filter sterilize

answer

filtration, physically removing, not killing

question

autoclave

answer

steam under pressure to sterilize culture media, instruments, dressings, etc.

question

low temperatures

answer

inhibit growth

question

high pressure

answer

denature proteins

question

direct flaming

answer

dry heat sterilization

question

hot-air sterilization

answer

dry heat.. oven

question

dessication

answer

inhibits growth, viruses can be destroyed, drying out process

question

osmotic pressure

answer

plasmolysis. cell shrinks inside cell wall to inhibit growth.

question

radiation

answer

wavelength, intensity, duration are all factors. ex: blue light, UV lamps

question

radiant energy spectrum

answer

gamma rays, x rays, uv, visible light, infrared, microwaves, radio waves

question

ionizing radiation

answer

gamma rays, x rays, or high-energy electron beams have shorter wavelengths but carries much more energy

question

nonionizing radiation

answer

wavelength longer

question

phenol

answer

local anesthesia ex: throat sprays. irritation properties that injure plasma membrane. active ingredient is lysol. good at killing mycobacterium.

question

bisphenol

answer

2 phenols together, lessens irritation effects, used in lotions for NICU. tryclosan in cutting boards and kitchen utencils.

question

halogens

answer

iodine and chlorine. denatures proteins. used in wound treatments. 2-4 drops of bleach to h20 per gallon to treat it

question

alcohols

answer

dissolve lipids and denature proteins. evaporate quickly and leave no residue. need water to work properly.

question

heavy metals

answer

silver, mercury, copper, zing. denature proteins. starting to put silver in athletic wear and military uniforms. copper in interior paint.

question

surface-active agents

answer

soap. mechanical removal. emulsifying oils wash away germs. quats disrupts cytoplasmic membrane.

question

chemical food preservatives

answer

inhibit growth of fungal microbes. nitrates preserved red color in meat and prevents germination of botulism.

question

nitrates

answer

thought to be carcinogens

question

antibiotics

answer

added to preserve food-Nisin and Natmycin. Most often used in cheeses.

question

aldehydes

answer

formaldehyde-usually used to preserve animals to prevent decay. most effective disinfectants and they are carcinogenic and can become allergic.

question

chemical sterilization

answer

ethylene oxide gas to sterilize equipment, can be done at low temperatures. Takes a long time, but used for big things and can penetrate deeply unlike steam in autoclave.

question

quats

answer

most widely used surface-active agents in cationic detergents. clean cation portion of molecule.

question

plasmas

answer

gas (4th state of matter) ionized gases. sterilizing plastics, catheters, endoscopy instruments.

question

supercritical fluids

answer

compress CO2 so has a liquid and gas properties at the same time and at low temps

question

forms of oxygen

answer

hydrogen peroxide, ozone, oxidized messes with metabolism and form free radicals.

question

genetics

answer

the study of what genes are, how they carry information, how information is expressed, and how genes are replicated

question

gene

answer

a segment of DNA that encodes a functional product, usually a protein

question

chromosome

answer

structure containing DNA that physically carries hereditary information; the chromosomes contain the genes. aka chromatin/chromatids

question

genome

answer

all the genetic information in a cell

question

genomics

answer

the molecular study of genomes

question

genotype

answer

the genes of an organism (italicized)

question

phenotype

answer

expression of the genes (not italicized)

question

model organism

answer

e. coli. most of what we know comes from studying e. coli.

question

supercoiling

answer

coil DNA up until it starts to coil on top of each and twisting together called a coiled coil. way to organized and pack DNA into cell

question

central dogma of molecular biology

answer

DNA transcribed into RNA translated to protein

question

polymer of nucleotides

answer

adenine, thymine, cytosine, guanine

question

"backbone" of DNA

answer

deoxyribose-phosphate

question

strands of DNA

answer

held together by hydrogen bonds between A-T and C-G

question

nucleotides bonded

answer

covalently links to one another by phosphate-5-carbon bond

question

A-T hydrogen bonds

answer

2

question

C-G hydrogen bonds

answer

3

question

anitparallel

answer

mirror images, run in opposite directions. important in dna replication because machinery runs in one directions

question

DNA replication runs from

answer

5 prime to 3 prime

question

semiconservative replication

answer

each strand of parent DNA as a template to make daughter cells

question

DNA is copied by

answer

DNA polymerase

question

initiate DNA copying

answer

RNA primer

question

leading DNA strand synthesized

answer

continuously

question

lagging strand synthesized

answer

discontinuously

question

okazaki fragments

answer

from lagging strand. short fragments of discontinuously synthesized strands

question

proofreading

answer

done by DNA polymerase to make sure everything is right. only 1 in 10 to the tenth is wrong

question

all 40 million bases can be copies in

answer

40 minutes

question

replication bubble

answer

two replication forks. where polymerase does its job. runs in different directions to replicate.

question

at replication fork

answer

unzipping of DNA molecule. DNA polymerase sits on leading strand and replicates new DNA strand

question

transcription

answer

using DNA as a template to make RNA

question

no thymine, just urosil

answer

transcription

question

promoter

answer

recognition codon telling DNA polymerase where to dock and unwind to access sequence

question

terminator

answer

recognition codon telling DNA polymerase "you are done"

question

codons and amino acids number

answer

64 codons and 20 amino acids. Gives a level of protection

question

start codon

answer

AUG

question

stop codons

answer

UAA, UAG, UGA

question

"wobble" position

answer

third position of codon because sometimes almost anything can go there and can get the right code still

question

eukaryotes transcription separated by

answer

space and time

question

simultaneous transcription

answer

happens at the same time, no separation. unique about prokaryotes. makes bacteria effecient and can respond to environmental conditions quickly.

question

translation

answer

initiation, elongation, termination

question

a site

answer

docking point where the tRNA is attached with an amino acid

question

p site

answer

where codon shifts down after a site

question

e site

answer

exit site

question

constitutive genes

answer

expressed at a fixed rate ex: genes for glucose catabolism. ALWAYS TURNED ON

question

genes expressed only as needed

answer

respressible, inducible, and catabolite respression genes

question

operon

answer

a group of coordinately regulated structural genes with related metabolic functions plus promoter and operator site that controls their transcription

question

external signal

answer

inducer; enters cell and binds with repressor at secondary bind site causing it to change shape and leave operator so structural genes can be made

question

induction

answer

deals with lacoperon and site using glucose or lactose

question

lacoperon

answer

usually turned off. want to use glucose, not lactose if glucose is present

question

normal state

answer

when lactose is not present

question

lactose

answer

inducer (allolactose) when present

question

respression

answer

repressor operon is always turned on unless something is present ot urn it off. helps cell regulate production of something to conserve energy.

question

catabolite respression

answer

need lactose and no glucose for this to work. control expression of the genes.

question

CAP (catabolic activator protein)

answer

always present in cell, but inactive. needs cAMP to become active

question

cAMP

answer

acts as an alarm when something is wrong, only produced when glucose runs out. actives CAP

question

glucose vs. lactose

answer

glucose always expressed and what e. coli wants to use first. lactose will not turn on repressor until all of the glucose is used.

question

mutation

answer

a change in the genetic material. may be neutral, beneficial, or harmful. two basic types: point and insertion/deletion

question

mutagen

answer

agent that causes mutations

question

spontaneous mutations

answer

occur in the absence of a mutagen ex: transcription errors

question

base substitution

answer

change in a single nucleotide

question

result of base substitution

answer

1. mess up composition of amino acids, nothing messed up down or up stream.

2. change codon to a nonsense/stop codon. messes everything up down stream and can be detrimental/harmful

question

deletions and insertions

answer

inserting or deleting genetic material. results in framshifts problems

question

result of deletions and insertions

answer

changes entire sequence by shifting reading frame up or down. VERY DETRIMENTAL. changes the entire protein.

question

causes of mutations

answer

uv light, radiation, cigarette smoke, chemical, chemicals in fried foods, oil spills

question

unintentional exposure to mutagens

answer

most exposure is unintentional in everyday life. pie chart.

question

frequency of mutation

answer

spontaneous mutation is 1 in a billion replicated base pairs or 1 in a million replicated genes

question

low rate of spontaneous mutation

answer

beneficial because provides genetic variability

question

photoreactivation repair

answer

uses enzyme-phoyolyase-uses energy of sun to be activated to repair. like self-checking system. only in prokaryotes.

question

nucleotide excision repair

answer

"dark repair" don't need sun (uv light) dimers are out and replaced by DNA polymerase

question

mismatch repair

answer

DNA polymerase proofreads hydrogen bonds and fixes ones that are wrong

question

xeroderma pigmentosum

answer

system that is used to repair mutations gets a mutation itself causing mutations to increases. can't be exposed to uv light.

question

identifying mutants

answer

detection by phenotype

question

positive selection

answer

detecting mutants by physiology. find mutant this is resistant to antibiotic from mutation you introduced.

question

negative selection

answer

replication plating, look for nutritional deficiency, comparitive, time consuming

question

Ames Test for Chemical Carcinogens

answer

quality control assurances, find out if carcinogen or not, used to use animals, but ow use bacteria that already contain mutation, used by rx companies

question

genetic transfer and recombination

answer

ways bacteria can introduce a level of genetic diversity to community to become resistant to antibiotics and develop unusual metabolism

question

vertical gene transfer

answer

growth and reproduction. parent cell to daughter cells, normal cell growth process

question

horizontal gene transfer

answer

transfer of genetic material between cells in same generation with no dividing. transformation, conjugation, transduction

question

transformation

answer

ability to take up naked DNA from environment and see if it is helpful and will keep if it is. use to make every lab strain component and use to our benefit when making rx

question

conjugation

answer

"bacterial sex" use sex pillus and transfer genes through the hollow tube (gram negative) use mating bridge, must make physical contact, no sex pillus (gram positive)

question

transduction

answer

similar to transformation. use virus to transfer genetic information. man-made process.

question

plasmids

answer

short, circular pieces of DNA, not part of chromosome. can self replicate. way to play with genetics so don't ruin chromosome. keep genes there "just in case"

question

transposons

answer

"transposable elements" way for bacteria to play with genomes. how we learn to manipulate genetic material of bacteria. method of movement

question

transposons are found in

answer

chromosomes, plasmids, and in the genetic material of viruses.

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