Micro Exam 2

Reservoir definition

Provide the correct conditions and nutrients for the pathogen to replicate and survive and are usually not harmed by the pathogen thus it is not always apparent what the reservoir is for a particular pathogen

Class of organisms that would display optimal growth in the following environments: in a refrigerator (4 degrees C)

Psychrophile

Class of organisms that would display optimal growth in the following environments: in the ocean along the coast of Antarctica

Psychrophile

Temp Psychrophiles/psychrotrophs grow

Psychrophile prefer a cold enviroent while psychrotrophs (associated with food spoilage) prefer a more moderate temp range

Class of organisms that would display optimal growth in the following environments: in a bowl of macaroni salad at a picnic (22 degrees C)

Psychrotroph

How is antibiotic resistance gene used in a plasmid for gene cloning

R plasmid which may contain genes that code for enzymes that can modify to inactivate a drug

Process of transcription/translation in prokaryotes

RNA polymerase binds to the promoter and DNA unwinds at the beginning of a gene, RNA is synthesized by complementary base pairing of free nucleotides with the nucleotide bases on the template strand of DNA, the site of synthesis moves along DNA: DNA that has been transcribed rewinds. Transcription reaches the terminator, RNA and RNA polymerase are released, and the DNA helix re-forms

Which tube is representative of an obligate aerobe?

Tube 1

Which tube is representative of an obligate anaerobe?

Tube 2

Which tube is representative of a facultative anaerobe?

Tube 3

Which tube is representative of an aero tolerant microorganism?

Tube 5

One ________ is the division of one cell into two.

generation

All of the following are used by bacteria to attach to host cells EXCEPT:

Coagulase

Which of the following statements is FALSE?

Coagulase destroys blood clots

Importance of virulence factors: are enzymes

Coagulase, kinases, hyaluronidase, collagenase, IgA proteases

Can result in the conversion of a cell from F- to F+

Conjugation

Delivers a plasmid to an F- cell

Conjugation

Requires contact between bacterial cells.

Conjugation

Endemic diseases

Constantly present in a population

Direct transmission of a pathogen requires:

Contact

What is a method by which you could verify the number of bacteria (cfus/mL) in the samples in the above question? Explain your reasoning for the method you choose.

Could use the plate count or serial dilution method so we can isolate the colonies and dilute them to be able to see how many colonies grow when it's diluted.

How to do the equation

2n*initial #

Generation time formula

2n*initial number of bacteria=total number of bacteria present after n generations

The enzymes involved in transcription and DNA replication read nucleotides in the _____________ direction.

3'-5'

The enzymes involved in transcription and DNA replication build nucleotides in the _________ direction.

5'-3'

Transmission of a pathogen by a flea bite occurs through:

A biological vector

Direct methods of measuring cell growth: plate counts

A culture is serially diluted and then placed onto nutrient media to allow for the growth of colonies. A math equation is used to relate the number of colonies back to the original culture. ONLY COUNTS LIVE CELLS

Turbidity (indirect method of measuring cell growth)

A light shown through the sample to determine the absorption of the sample, the higher the amount of organism, the more light will be absorbed

A fly lands on a contaminated surface then onto food consumed by a host. The fly is an example of:

A mechanical vector

Temp mesophiles grow

A mid level temp

Briefly state how the following terms are similar and how they are different: reservoir and host

A reservoir is an inanimate object like water/air that contain a disease and can spread to people. A host is what viruses and arterial use to infect someone who they can live inside of. Both are used to harbor bacteria and make the disease stronger.

Direct methods of measuring cell growth: filtration

A sample is poured through a filter to collect the bacteria then the filter is placed onto a plate contains the appropriate media to encourage the growth of the organism

An organism needs phosphate in order to build:

ATP and nucleic acids

Epidemic diseases

Acquired by many people in a given area in a short time

A healthcare-associated infection (traditionally known as a nosocomial infection) is:

Acquired during hospitalization

Nosocomial infection

Acquired while receiving treatment in a healthcare facility

Two important proteins involved in the division of bacterial cells are:

Actin and myosin

Describe the processes of polymerase chain reaction (PCR)

Add primers, nucleotides, and DNA polymerase Incubate 94c for 1 min, will separate the strands Incubate at 60c for 1 min, allows primers to attach to single-stranded DNA Incubate at 72c for 1 min, DNA polymerase copies the target DNA Repeat the cycle of heating and cooling to make more copies of target DNA

Briefly state how the following terms are similar and how they are different: airborne versus droplet transmission

Airborne transmission is from microbes that stick onto dust particles and droplet transmission is from sneezing or coughing as droplets of spit leave your mouth. Both can transmit diseases and cause illness.

RNA sequencing

Allow you to look at all the mRNA that have been produced within an organism

Sanger sequencing

Allows you to sequence one gene

Compare conjugation between F+ x F-

An F+ cell will produce a mating bridge that allows for the transfer of a copy of the conjugation plasmid to an F- cell

Possible consequences of base substitution (point) mutations: silent mutation

An abnormal gene is transcribed in host cell, siRNA binds mRNA. RISC breaks down the RNA complex and no protein expression occurs

Which one of the following does NOT directly contribute to the incidence of healthcare-associated infections?

Antibiotic resistance

Mechanical vectors

Arthropods carries pathogen on its feet, then land on something like food then will be consumed by host

Use the following figure to determine the concentration of the original culture in CPU/mL

Cfu*dilution over mL plated

Consequences of a frame shift mutation

Changes the reading frame of the codons by the ribosome

Noncommunicable disease

Not transmissible through contact with an infected individual but rather come either from an opportunistic pathogen or from the entry of the pathogen from outside the body where it causes disease

Process of transduction

Bacteriophage will accidentally incorporate host DNA rather than viral DNA. This bacteriophage will the inject its host DNA into a recipient cell thus introducing new genetic information to this host cell

If an inserted gene interprets the function of the LacZ gene on the pUC19 plasmid, the transformed colonies will be _______________.

Blue

In which of the following patterns of disease does t he patient experience no signs of symptoms?

Both incubation and convalescence

mutualism

Both organisms benefit

How can the microbiome prevent the activity of pathogens

By directly competing with incoming pathogens for nutrients and other required components. Can produce and release compounds into its surroundings that can repel invading microbes

Briefly state how the following terms are similar and how they are different: communicable versus Noncommunicable disease

Communicable disease is something you can pass onto others like the flu or a cold. Noncommunicable disease is something that cannot be transmitted to person to person, it is not contagious like food poisoning and botulism poisoning. Both are ways of making someone sick and cause discomfort.

RT-PCR

Can be used to look for certain RNAs

Oxygen requirements/tolerance: microaerophiles

Can grow in the presence of low level of oxygen. Atmospheric oxygen levels are toxic to these organisms. They also have oxygen sensitive enzymes and molecules that are harmed by higher levels of oxygen

What is the advantage to an organism in a biofilm?

Can make antibiotic treatment difficult and species of bacteria found in a biofilm is 1000x more tolerant to anti microbial substance

Oxygen requirements/tolerance: obligate aerobes

Can only produce energy through aerobic cellular respiration

Next-gen sequencing

Can sequence the entire genome

Oxygen requirements/tolerance: obligate anaerobes

Cannot use oxygen for respiration purposes and lack the necessary enzymes to breakdown some of the harmful forms of a a molecular oxygen. Cannot be in the presence of molecular oxygen

Importance of virulence factors: Can prevent phagocytosis

Capsules

Virulence factors can include:

Capsules, exotoxins, and endotoxins (all of the above)

Human reservoir

Carriers may have inapparent infections or latent diseases

Direct methods of measuring cell growth: Direct microscopic count of bacteria w/ a Petroff-Hausser cell counter

Cells can be counted in certain numbers of squares present on the slides, a math equation is used to determine the number of organisms found in the sample. CANNOT TELL IF ALIVE OR DEAD

Assign the appropriate phase to the description of activity within a culture: death of cells is occurring after than the growth of cells

Death phase

Assign the appropriate phase to the description of activity within a culture: nutrients have been exhausted and toxins have built up to high levels

Death phase

Phases of a microbial growth curve #4

Death phase: population numbers are decreasing at a logarithmic rate, organisms are running out of nutrients and waste products are building up which results in an overall decrease in the population numbers

Basic process and use of DNA sequencing

Determining the exact sequence of nucleotides. Encodes the biological information that cells use to develop and operate

Acute disease

Develops quickly but lasts for a short time

Chronic disease

Develops slowly and may continue for long periods of time or recurs for long periods of time

Notifiable infectious diseases

Diseases in which physicians are required to report occurrence

Emerging infection

Diseases that are new, increasing in incidence, or showing a potential to increase in the near future

Oxygen requirements/tolerance: aerotolerant anaerobes

Do not use oxygen but are not harmed by oxygen, they will often have superoxide dismutase to help deal with any reactive oxygen species that might develop in the presence of oxygen

A cold transmitted by a sneeze is an example of:

Droplet transmission

a biofilm can be composed of:

Multiple different species of both eukaryotes and prokaryotes

A sudden increase in the number of influenza cases in the United States would be considered:

Endemic

Rhinoviruses, which cause the common cold in the United States, can be thought of as a/an:

Endemic

Importance of virulence factors: Can lead to overstimulation of the inflammatory system

Endotoxins

Briefly state how the following terms are similar and how they are different: Endotoxin and Exotoxins

Exotoxin makes the microbes inside itself and releases them. Endotoxins only release when they multiply, from gram- bacteria, causing microscopic holes in cell for it to leave. Both can cause harm and septic shock.

Importance of virulence factors: Have both binding and enzyme activity

Exotoxins (include A-B toxins)

How nosocomial infection occur

Exposed to microbes through an invasive procedure

An Hfr can transfer its genetic material to a(n):

F- cell

Process of transformation

Naked DNA is taken up either naturally by an organism or through manipulation of the bacterial cell,

An organism that is found on the surface of a biofilm could be classified a a(n):

Obligate aerobe

Biological vectors

Gets into host through a bite or contact with the vectors fecal matter

Role of an epidemiologist

Getting a disease back under control when it emerges or expands from localize to epidemic

Latent disease

Have periods of no active disease follow by times of acute disease

If a conjugation plasmid incorporates into the bacterial chromosome, the cell is now labeled:

Hfr

Peroxidase

Hydroxyl radical OH: H2O2+2H+-peroxidase->2H2O

Class of organisms that would display optimal growth in the following environments: Within a rim of a boiling hot spring in Yellowstone National Park

Hyperthemophile

Which of the following is a fomite?

Hypodermic needle

You are responsible for determining the concentration of bacteria (cfus/mL) found in milk being produced by a particular dairy farm to determine if it falls within a safe limit. State the name of a method you could use to determine the concentration of bacteria. Explain your choice.

I would use the filtration method because filtration allows for the milk to be ran microbes to be ran through onto a silter then it is transferred to a nutrient agar plate to be analyzed for colony growth ad we can count to see if the colonies are within a safe limit from what was filtered from the milk.

Why is it necessary to include the following in a recipe for bacterial growth: Phosphorous

In DNA, RNA, ATP, and membrane

Why is it necessary to include the following in a recipe for bacterial growth: Nitrogen

In amino acids and proteins, most bacteria decompose proteins, some bacteria use NH4- or NO3-. Often found in soil, they are capable of fixing the nitrogen found in air and making it available for plants to use

Why is it necessary to include the following in a recipe for bacterial growth: Sulfur

In amino acids, thiamine, and biotin and most bacteria decompose proteins

Process of transcription/translation in eukaryotes

In the nucleus, a gene composed of exons and introns is transcribed to RNA by RNA polymerase, processing involves snRNPs in the nucleus to remove the intron-derived RNA and splice together the exon-derived RNA into mRNA, After further modification, the mature mRNA travels to the cytoplasm, where it directs protein synthesis

Stages involved in the development of a disease

Incubation period (initial infection and first signs/symptoms), Prodromal period (early, mild symptoms), period of illness (disease is most severe), Period of decline (signs and symptoms subside), period of convalescence (body returns to pre-diseased state)

What are transposons

Jumping genes, responsible for creating the enzyme needed for this process

Importance of virulence factors: digest membrane components

Kinases

How is LacZ used in a plasmid for gene cloning

Lactose deference

Assign the appropriate phase to the description of activity within a culture: cells are preparing for growth

Lag phase

Assign the appropriate phase to the description of activity within a culture: phase right after inoculation into a new culture

Lag phase

Phases of a microbial growth curve #1

Lag phase: cells are getting ready to divide and over all there is not a steady increase in the population numbers

Organisms found not found in a biofilm tend to be ________ to antibiotics than those found in a biofilm.

Less resistant

LD50

Lethal dose for 50% of a sample population

In order for a microbial organism to build macromolecules, it would need:

Lipids and nuclei acids

Assign the appropriate phase to the description of activity within a culture: antibiotics, such as like penicillin, has a greater affect during this phase

Log phase

Assign the appropriate phase to the description of activity within a culture: growth of cells occurring faster than the death of cells

Log phase

Phases of a microbial growth curve #2

Log phase: right after the inoculation of a fresh culture, exponential growth occurs and there is a significant increase in the overall numbers of organisms present

Direct methods of measuring cell growth: most probable number

Look at low concentrations of organisms which might be likely in food products

Class of organisms that would display optimal growth in the following environments: Inside the intestinal tract of a human being

Mesophile

Possible consequences of base substitution (point) mutations: nonsense mutation

Met-> stop

What is a biofilm?

Microbial communities that act as a biological systems in which members can protect themselves and each other and share genetic information within them

Eukaryotic microorganisms divide most cells by __________ while most prokaryotic organisms utilize _____________.

Mitosis... binary fission

Polio is transmitted by ingestion of water contaminated with feces containing polio virus. What portal of entry does polio virus use?

Mucous membranes only

Portals of entries for pathogens

Mucous membranes, skin, and parenteral route

Which organisms below would need superoxide dismutase?

Obligate aerobes only and facultative anaerobes only

Sporadic diseases

Occurs only occasionally

Parasitism

One organism benefits at the expense of the other

Compensalism

One organism benefits, and the other is unaffected

Invitation of DNA replication occurs in prokaryotes and eukaryotes at the ___________.

Origin

Endotoxins are:

Part of the Gram-negative cell wall

Catalase

Peroxide anion O2 2-: 2H2O2-catalase->2H2O+O2 (obligate aerobes, facultative anaerobes

Define bacterial growth including binary fission

Prior to division, the DNA will replicate. FTS are important in this process. FTSZ start the division of of the cell by forming a ring around the center of the cell in the space between the duplicated DNA nucleotides. FTSK and other proteins segregate the two copies of the chromosome into the developing new daughter cells as they elongate. A septum forms between the new daughter cells along the area of the FT Z ring. The cells are separate to form 2 new cells. One generation has occurred.

If a bacterium acquires a conjugation plasmid, it has the potential to:

Produce a specialized pious called a sex or mating bridge

Initiation of transcription occurs at the ______________.

Promoter

What is an exotoxin

Proteins produced and secreted by bacteria (hemolysins)

How does a biofilm form?

Random contact with a surface due to collisions and eventual attachment with either pili or fimbriae. Attachment triggers production of new gene expression, including an auto inducer known as AI-2, then quorum sensing

LD50 measures _________________________.

Rate of death in a population

What is an endotoxin

Release during bacterial multiplication and when gram negative bacteria die (septic shock)

Compare conjugation between Hfr x F-

Replication and transfer of part of the chromosome, replication and transfer of part of the chromosome, then in the recipient recombination between the Hfr chromosome fragment and the F- chromosome (F- will not get access to the entire conjugation plasmid)

Direct transmission

Requires close association between the infected and a susceptible host, physically touching

Methods an organism can exit a host

Respiratory tract, gastrointestinal tract, genitourinary tract, skin, and blood

Which of the following definitions is INCORRECT?

Secondary infection: a long-lasting illness

The antibiotic resistance gene on the pUC19 plasmid is used for:

Selection

How is complementary DNA (cDNA) used in a plasmid for gene cloning

Selective for bacteria

Nonliving reservoirs

Soil and water

A sudden outbreak of Ebola in the United States, where it is not normally found, would be known as:

Sporadic

Communicable disease

Spread through direct or indirect contact w/ an infected individual

Indirect transmission

Spreads to a host by a non living object called a fomite

Invitation of translation occurs at the ______________.

Start codon

Assign the appropriate phase to the description of activity within a culture: death of cells is occurring at the same rate as growth of the cells

Stationary phase

Phases of a microbial growth curve #3

Stationary phase: the time of equilibrium, the number of microbial deaths are balanced with the production of new cells resulting in a flatline phase of growth

Why is it necessary to include the following in a recipe for bacterial growth: Carbon

Structural organic molecules, energy source. Serve as potential oxidizing agents in anaerobic repiration

Process of DNA replication in prokaryotic cells, including leading and lagging strands

Supercoil the chromosome using specific enzymes in order to get it to fit insides, the lagging strand is synthesized, discontinuously. The leading strand is synthesized continuously from the primer by DNA polymerase

Superoxide dismutase (SOD) is responsible for the conversion of:

Superoxide anions to hydrogen peroxide and oxygen

If an organism is an obligate aerobe, you would expect it to possess:

Superoxide dismutase and catalase enzymes

Superoxide dismutase

Superoxide free radical O2-: O2-+O2-+@H+-superoxide dismutase->H2O2+O2 (obligate aerobe, facultative anaerobes, and aerotolerant anaerobes)

Real-time (qPCR)

Tell you the number of RNAs present in a specimen

The LD50 of the toxic component of chocolate is 1000mg/kg for humans but only 300mg/kg for dogs. These means that:

The chemical is more toxic to dogs than humans

the ID50 is:

The dose that will cause an infection in 50 percent of a population

All of the following are examples of entry via the parenteral route EXCEPT:

The mouth

Using what you know of transmission of infectious diseases, briefly explain, using terms to be describe transmission, how a student's professor could contract a cold from the student's child if the child never came to class with the parent.

The student's kid could have sneezed causing droplet particles to get onto the parent. When the parent went to class they closely come into contact with the teacher and pass it via indirect transmission like from borrowing a pencil or direct transmission from shaking hands.

Uses a bacteriophage

Transduction

May involve the use of chemicals or electricity

Transformation

Results in bacteria taking up DNA from the environment

Transformation

The difference between transformation and electroporation

Transformation involves the binding of foreign DNA, electroporation, an electric pulse creates pores and a temporary electric field that pulls the DNA t the more positively charged end

Vehicle transmission

Transmission by an inanimate reservoir (airborne, waterborne, foodborne)

Droplet transmission

Transmission via airborne droplets less than 1 meter

Results in movement of genetic information from one area of the genome to another

Transposon

DNA is constructed of _________.

Two strands of nucleotides running antiparallel

How can nosocomial infections be avoided

Universal precautions, standard precautions (hand washing, coughing into our elbows, PPE), and contact precautions (to limit direct contact with a patient's bodily fluids)

Regular PCR

Used to make multiple copies of a piece of DNA through the enzymatic process of DNA replication

Water, food, and air are examples of:

Vehicle transmission

Temp thermophiles/hyperthrmophiles grow

Very warm temp (usually in the Domain Archaea, a group that is known to prefer extreme environments)

Describe the control mechanisms for the lac operon

When lactose is present in the environment, will bind to the repress or and prevent it binding to the operator. This allows the RNA polymerase to produce the structural genes needed for the processing of lactose

Describe the control mechanisms for the tryptophan operon

When tryptophan becomes too high, it will bind to the repress or changing its shape. This new shape allows for binding to the operator and thus prevention of the activity of the RNA polymerase. Will go away when the tryptophan levels become lower

Pandemic diseases

Worldwide epidemic

Animal reservoirs

Zoonoses are diseases transmitted rom animals to humans

Possible consequences of base substitution (point) mutations: missense mutation

amino acid sequence: Met->Lys->Phe->Ser (instead of Gly)

Dry weight (indirect method of measuring cell growth)

bacteria are filtered, dried, and weighed; used for filamentous organisms

Microaerophiles:

cannot tolerate normal atmospheric levels of oxygen

Distinguish chemically defined and complex media

chemically defined medium: one whose exact chemical composition is known. Complex media: made up of nutrients including extracts from yeast, meat, or plants, or digest of proteins from these and other sources. the exact chemical composition varies slightly from batch to batch.

How can transposons contribute to genetic changes

contain insertion sequences for cutting and resealing DNA and allow for the carrying of genes from one region of a DNA to another

Oxygen requirements/tolerance: facultative anaerobes

flexibility in terms of their ability to generate ATP, they are able to use molecular oxygen in an aerobic respiration system or they can use alternative metabolism to generate ATP if oxygen is not available

ID50

infectious dose for 50% of a sample population Used as a measurement of the virulence of a microorganism

A disease in which the causative agent remains inactive for a time before producing symptoms is referred to as:

latent

Metabolic activity (indirect method of measuring cell growth)

measure metabolic product and assume it is in direct proportion to the number of bacteria present

Endotoxins contaminating injectable drugs could cause:

septic shock symptoms