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Micro 275 final (2nd half of class)

Substances that are naturally produced by certain microorganisms that can inhibit or destroy other microorganisms are called


Antibiotics are derived from all of the following except


Antibiotics ARE derived from

Bacillus, Cephalosporium, Streptomyces, Penicillium

Important characteristics of antimicrobial drugs include

-low toxicity for humans
-stable & soluble in body tissues and fluids
-do not cause serious side effects in humans
-high toxicity against microbial cells

Selective toxicity refers to

damage to the target organism but not vertebrate cells

Microbial resistance resulting from mutation occurs because

-prokaryotic genomes undergo mutation often and rapidly
-short generation times accumulate mutations in populations
-mutations are passed between organisms

A ratio of the dose of the drug that is toxic to humans vs the minimum effective dose for that pathogen is assessed to predict the potential for toxic drug reactions. This is called the

Therapeutic index (TI)

Ampicillin, amoxicillin, mezlocillin and penicillin G all have

a beta-lactam ring

The cellular basis for bacterial resistance to antimicrobials include

-synthesis of enzymes that alter drug structure
-alteration of drug receptors on cell targets
-prevention of drug entry into the cell
-bacterial chromosomal mutations

A clinical microbiologist makes serial dilutions of several antimicrobials in broth, and then incubates each drug dilution series with a standard amount of a patient's isolated pathogen. What is this microbiologist setting up?

Minimum inhibitory concentration (MIC)

Each of the following result in drug resistance except

drug used as a nutrient by the cell

All of the following result in drug resistance

-drug blocked from entering the cell
-drug inactivated
-drug pumped out of the cell
-drug binding site altered

Each of the following is a mechanism for drug resistance transfer between microorganisms except


Mechanisms for drug resistance transfer


Which TI value would be the drug of choice?


The multidrug resistant pumps in many bacterial cell membranes function by

removing the drug from the cell when it enters

Drug susceptibility testing

determines the pathogen's response to various antimicrobials

If pathogen A is more resistant to an erythromycin disc on a Kirby-Bauer plate compared to pathogen B, then pathogen A will have a(n) _____ zone of inhibition compared to pathogen B.


Infection occurs when

pathogens enter and multiply in body tissues

The human body typically begins to be colonized by its normal biota

during and immediately after birth

Resident biota are found on the

skin, mouth, nasal passages, large intestine

Normal biota includes each of the following except

All are correct: bacteria, fungi, protozoans, viruses

The effect of "good" microbes against invading microbes is called

microbial antagonism

Opportunistic pathogens

cause disease in compromised individuals

Pathogenic microbes that cause disease in health people are called

true pathogens

The minimum amount of microbes in the inoculating dose is the

infectious dose

Which of the follow in not a method of adhesion?


Once a microbe has entered a host, what process performed by certain white blood cells will attempt to destroy the microbes?


Virulence factors include all the following except


Virulence factors include

Capsules, exoenzymes, endotoxins, exotoxins

Microbial hyaluronidase, coagulase and streptokinase are examples of

Exotoxins?? Should be exoenzymes I believe pg 373

Exotoxins are?



are secreted by pathogenic organisms

An endotoxin is

indicative of Gram negative organisms

_____ are toxins that are the lipopolysaccharide of the outer membrane of gram negative cell walls.


The subjective evidence of disease sensed by the patient is termed a/an


The objective, measurable evidence of disease evaluated by an observer is termed a/an


Infections that go unnoticed because there are no symptoms are called


The primary, natural habitat of a pathogen where it continues to exist is called the


Someone who inconspicuously harbors a pathogen and spreads it to others is a


A _____ is an infection indigenous to animals that can, on occasion, be transmitted to humans.


______ carriers are shedding and transmitting pathogen a long time after they have recovered from an infectious disease.


An inanimate object that harbors and transmits a pathogen is a


Which of the following is transmission of disease from mother to fetus?


When would Koch's Postulates be utilized?

Determination of the cause of a new disease in a microbiology research lab

The study of the frequency and distribution of a disease in a defined population is


The principal government agency responsible for tracking infectious diseases in the United States is

Centers for Disease Control and Prevention

The number of new cases of a disease in a population over a specific period of time compared with the healthy population is the ?

Incidence rate

The total number of deaths in a population due to a disease is the _____ rate.


Nonspecific chemical defenses include

-Lactic acid and electrolytes of sweat
-Skin's acidic pH and fatty acids
-Stomach hydrochloric acid

The chemical found in tears and saliva that hydrolyzes the peptidoglycan in certain bacterial cell walls is


The body region where a ciliary escalator helps to sweep microbes trapped in mucus away from that body site is the

Respiratory tract

The reticuloendothelial system

-Is a support network of connective tissue fibers
-Originates in the cellular basal lamina
-Provides a passageway within and between tissues and organs
-Is heavily populated with macrophages

Immune system cells differentiate between self and foreign cells by their


The most numerous WBC's, that have multi-lobed nuclei and are very phagocytic are


Hematopoiesis is the

Production of white blood cells, red blood cells and platelets

What structures are found along lymphatic vessels and are heavily clustered in the armpit, groin and neck?

Lymph nodes

Which gland shrinks in size during adulthood and has hormones that function in maturation of T-lymphocytes?


Diapedesis is the

Migration of white blood cells from the blood out to the tissues

A foreign molecule that causes a specific immune response is a/an


Acquired specific immunity involves the response of

B and T lymphocytes

The progeny cells of a B-cell clone are called

Plasma cells

Helper T cells

Activate B cells and other T cells

The histocompatibility complex proteins function in

Recognition of self

The molecular fragment on an antigen molecule that a lymphocyte recognizes and responds to is called a/an


Which process involves antibodies covering surface receptors on a virus or toxin molecule thereby disrupting their activity?


Which process involves antibodies cross-linking cells or particles into large aggregates?


Which process involves antibodies coating microorganisms in order to facilitate phagocytosis?


_____ is the most abundant class of antibodies in serum.


What process provides many B cells and T cells that are activated against specific antigens?

Clonal expansion

Which lymphocytes lack specificity for antigen and are cells that attack cancer cells and virus-infected cells?

Natural killer cells (NK)

Cytotoxic T cells

Secrete granzymes and perforins that damage target cells

The beauty of specific immunity is the production of ____ that provides long-lasting protection

Memory cells

The embryonic yolk sac, the liver and the bone marrow are sites where

Stem cells give rise to immature lymphocytes

Plasma cells

Secrete antibodies

Cell surface markers involved in immune reactions

-Are the result of genetic expression
-Function in recognition of self molecules
-Receive and transmit chemical messages among other cells of the system
-Aid in cellular development


-Possess MHC antigens for recognizing self
-Have membrane receptors that recognize foreign antigens
-Gain tolerance to self by destruction of lymphocytes that could react against self
-Develop into clones of B and T cells with extreme variations of specificity

Properties of effective antigens include all the following EXCEPT

Large polymers made up of repeating subunits

Properties of effective antigens include all the following

-Foreign to the immune system
-Molecular complexity
-Large molecules with a minimum molecular weight of 1,000
-Cells or large, complex molecules

Antigen presenting cells

-Include dendritic cells
-Include macrophages
-Engulf and modify antigen to be more immunogenic
-Hold and present processed antigen on their cell membrane surface

The science called _________ studies interactions between microbes and their environment and how those interactions affect the earth.

Microbial ecology

A collection of organisms together with their physical and chemical factors are called a/an


Organisms that inhabit soil or water and breakdown and absorb the organic matter of dead organisms are called


Which of the following are primary photosynthesizers?

-Green sulfur bacteria
-Purple sulfur bacteria
-Purple nonsulfur bacteria

The conversion of gaseous nitrogen (N2) to ammonia (NH4+) occurs during

Nitrogen fixation

The oxidation of ammonia (NH4+) to nitrate (NO3-) and nitrite (NO2-) is called


The conversion of nitrate (NO3-) to nitrogen gas (N2) is called


The zone of soil around roots of plants is called the


The mutualistic partnership between plant roots and microbes are



- Encourages heavy surface algal blooms
-Causes massive die-off of fish and invertebrates
-Can block the O2 supply to the lake
-Occurs when there are excess nutrients in aquatic ecosystems

Clostridium perfringens


Clostridium botulinum


Bacillus anthracis


Escherichia coli


Salmonella enteritidis

Typhoid fever

Streptococcus pyogenes

Scarlet fever

Neisseria meningitidis


Streptococcus pneumoniae


Treponema pallidum


Neisseria gonorrhea


Trypanosoma brucei

Sleeping sickness

Vibrio cholera


Plasmodium falciparum


Bordetella pertussis

Whooping cough

Yersinia pestis


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