Microbiology Exam Iii Study Guide

Front 1

Constitutive genes

Back 1

their products are constantly produced at a fixed rate.

Front 2

Promoter

Back 2

region of DNA where RNA polymerase initiates transcription.

Front 3

Operator

Back 3

region of DNA; “stop” or “go” signal for transcription of structural genes.

Front 4

Operon

Back 4

Operator and promoter sites and the structural genes they control.

Front 5

Repression

Back 5

inhibits gene expression; decreases synthesis of enzymes.

Front 6

Vertical gene transfer

Back 6

genes are passed from an organism to its offspring.

Front 7

Horizontal gene transfer

Back 7

genes passed to other microbes of the same generation.

Front 8

What are Three types of Horizontal Gene Transfer:

Back 8

1. Transformation.
2. Conjugation.
3. Transduction

Front 9

Transformation

Back 9

transfer of genes between bacteria as “naked” “DNA.

Front 10

Competence

Back 10

recipient cell is in a state that allows it to take up DNA.

Front 11

Plasmid

Back 11

circular piece of DNA; replicates independently from chromosome.
● Carry genes that are not essential for normal growth of cells.

Front 12

Resistance factors (R factors)

Back 12

plasmids that carry toxin, antibiotic resistance, etc. genes.

Front 13

Pathology

Back 13

study of disease.

Front 14

Etiology

Back 14

the cause of disease.

Front 15

Pathogenesis

Back 15

the way a disease develops.

Front 16

Infection

Back 16

invasion or colonization of body by a pathogen.

Front 17

Disease

Back 17

occurs when infection results in change of health.

Front 18

Normal microbiota

Back 18

colonize the body but don’t normally produce disease.

Front 19

Transient microbiota

Back 19

present for days-weeks and then disappear.

Front 20

Microbial antagonism

Back 20

normal flora prevents overgrowth of harmful microbes.

► Protect host against colonization by:
• Competing for nutrients.
• Producing substances harmful to other microbes.
• Affect pH and available oxygen.

Front 21

Symbiosis

Back 21

relationship between normal microbiota and host.

Front 22

Commensalism

Back 22

one organism benefits, other is unaffected.

Front 23

Mutualism

Back 23

benefits both organisms.

Front 24

Parasitism

Back 24

one organism benefits at the expense of the other.

Front 25

Opportunistic Pathogens

Back 25

don’t cause disease in their normal habitat.

Cause disease if they:
► Gain access to other body sites.
► Host is weakened.

Front 26

Koch’s Postulates

Back 26

used to study the etiology of any infectious disease.

Front 27

Symptoms

Back 27

subjective changes not apparent to observer (pain, malaise).

Front 28

Signs

Back 28

objective changes doctor can observe and measure (lesions, fever).

Front 29

Syndrome

Back 29

specific group of symptoms or signs; always accompany particular disease.

Front 30

Communicable disease

Back 30

spreads from one host to another.
• Chickenpox, tuberculosis, genital herpes.

Front 31

Contagious disease

Back 31

easily spread from one person to another.
• Chickenpox, measles.

Front 32

Non-communicable disease

Back 32

not spread from one host to another.
• Tetanus.

Front 33

Sporadic disease

Back 33

occurs occasionally (typhoid fever).

Front 34

Endemic disease

Back 34

constantly present in the population (common cold).

Front 35

Epidemic disease

Back 35

many people in a given area get the disease in a short period of time (influenza, AIDS).

Front 36

Pandemic disease

Back 36

worldwide epidemic (influenza).

Front 37

Acute disease

Back 37

develops rapidly, lasts a short time (influenza).

Front 38

Chronic disease

Back 38

develops slowly, often less severe, likely to be continual or recurrent (mononucleosis).

Front 39

Subacute disease

Back 39

between acute and chronic (subacute sclerosing panencephalitis).

Front 40

Latent disease

Back 40

agent inactive for a time, becomes active, produces symptoms (shingles).

Front 41

Immunity of a population determines:

Back 41

► The rate at which a disease spreads
► Number of individuals infected.

Front 42

Vaccination

Back 42

enough people in a population are protected to prevent rapid spread.

Front 43

Herd immunity

Back 43

many immune individuals present in a population.

Front 44

Local infection

Back 44

microbes limited to a small area (boils, abscesses).

Front 45

Systemic infection

Back 45

microbes and their products spread through body by lymph/blood (measles).

Front 46

Focal infection

Back 46

local infection spreads to another area where its confined (arise from teeth, tonsils).

Front 47

Sepsis

Back 47

toxic inflammatory condition from spread of microbes or their toxins from an infected area.

Front 48

Septicemia

Back 48

blood poisoning; systemic infection from multiplying pathogens in the blood.

Front 49

Bacteremia

Back 49

bacteria in the blood.

Front 50

Toxemia

Back 50

toxins in the blood (tetanus).

Front 51

Viremia

Back 51

viruses in the blood.

Front 52

Reservoir

Back 52

source of pathogens for infectious disease.

Front 53

Transmission

Back 53

to susceptible host; direct contact, vehicle, or vector.

Front 54

Invasion

Back 54

microbe enters host and multiplies.

Front 55

Pathogenesis

Back 55

microbe injures host.

Front 56

Incubation period

Back 56

interval between infection and appearance of signs or symptoms.

Front 57

Prodromal period

Back 57

short period in some diseases; early, mild symptoms.

Front 58

Period of illness

Back 58

clear signs and symptoms, disease is most severe; immune system or treatment end this period or patient dies.

Front 59

Period of decline

Back 59

signs and symptoms subside; vulnerable to secondary infection.

Front 60

Period of convalescence

Back 60

body returns to prediseased state.

Front 61

Reservoirs of Infection

Back 61

source of disease causing organisms.

Front 62

Zoonoses

Back 62

disease that occurs in animals, can be transmitted to humans.

Front 63

Direct contact transmission

Back 63

physical contact, no intermediate object involved.

• Kissing, touching, sexual intercourse.

Front 64

Indirect contact transmission

Back 64

transmitted via a nonliving object (fomite).

• Tissues, towels, bedding, cups, money.

Front 65

Droplet transmission

Back 65

spread in mucus droplets that travel short distances.

• Sneezing, coughing, talking.

Front 66

Vehicle Transmission

Back 66

disease transmitted by a medium; food, water, blood, etc.

Waterborne, Airborne, Foodborne

Front 67

Vectors

Back 67

Animals/insects that carry pathogens from one host to another.

Front 68

Nosocomial (Hospital-Acquired) Infections Result from an interaction of:

Back 68

► Microbes in the hospital.
► Compromised hosts.
► Chain of transmission in the hospital.

Front 69

Epidemiology

Back 69

study of when and where diseases occur and how they’re transmitted in populations.

Front 70

Morbidity

Back 70

number of people that contract the disease during a particular period of time.

Front 71

Mortality

Back 71

number of deaths that occur from those diseases.

Front 72

Adhesins (ligand)

Back 72

surface molecule on pathogen that binds to receptors on host tissue cells.

Front 73

Surface receptors

Back 73

molecule on host cell that is specific to host cell tissue; complementary to the adhesin.
► Mostly carbohydrates.

Front 74

Phagocytosis:

Back 74

host cell engulfs and destroys microbes.

Front 75

Coagulases

.

Back 75

convert fibrinogen in blood plasma to fibrin; fibrin clots blood.

Front 76

Kinases

Back 76

breaks down fibrin; digest clots.

Front 77

Hyaluronidase

Back 77

breaks down hyaluronic acid.

Front 78

Collagenase

Back 78

breaks down collagen.

Front 79

Antigen

Back 79

foreign substance/molecule.

Front 80

Siderophores

Back 80

Iron-binding proteins secreted by pathogens.

Front 81

IgA proteases

Back 81

destroy IgA antibodies made against pathogens.

Front 82

Exotoxins

Back 82

produced inside and secreted. Gm(+) AND gm(-)

• Signs and symptoms depend on type of exotoxin; no fever results except from superantigens.

Front 83

Endotoxins

Back 83

part of gram (-) cell wall. ONLY gram (-) →→ LIPID A
>>Results in Fever<<

Front 84

Three types of exotoxins:
(#1) A-B toxins:

Back 84

• Two polypeptide parts (A and B); A is enzyme; B is binding portion.
• Bacteria releases A-B exotoxin.
• B part binds to receptor on host cell.
• A-B toxin transported into host cell by pinocytosis.
• A & B separate.
à A inhibits protein synthesis; cell death.
à B is released from cell.

Front 85

Three types of exotoxins:
(#2) Membrane-disrupting toxins:

Back 85

• Lyse host cells by disrupting plasma membrane.
• Form pores in membrane (S. aureus) or disrupt phospholipids (C. perfringens).
• Some are hemolysins: disrupt membrane of red and white blood cells = cell lysis.
• Streptococci sp. and staphylococci sp.

Front 86

Three types of exotoxins:
(#3) Superantigens:

Back 86

• Bacterial proteins that provoke intense immune response
• Result in: fever, nausea, vomiting, diarrhea, shock and death.
• Staphylococcus aureus toxin: toxic shock.

Front 87

Shock

Back 87

life-threatening decrease in blood pressure.

Front 88

Immunity

Back 88

ability to fight off disease caused by microbes and their products.

Front 89

Leukocytosis

Back 89

increase in total white blood cell count during infection.

Front 90

Leukopenia

Back 90

decrease in total white blood cell count during infection.

Front 91

● Fixed macrophages

Back 91

located in certain tissues and organs of the body (liver, lungs, etc.)

Front 92

● Wandering macrophages

Back 92

roam tissues and go to sites of infection.

Front 93

Natural Killer (NK) cells

Back 93

kill wide variety of infected body cells and some tumor cells.

Front 94

Perforin

Back 94

makes channels in membrane and causes fluids to flow into cell = cell lyse (cytolysis).

Front 95

Granzymes

Back 95

cause target cell suicide (apoptosis).1

Front 96

Chemotaxis

Back 96

chemical attraction of phagocytes to microbes.

Front 97

Adherence

Back 97

attachment of phagocyte to microbe.

Front 98

Opsonization

Back 98

coating of microbes with serum proteins; aids phagocytosis.

Front 99

What Are Four signs and symptoms of inflammation?

Back 99

► Redness, pain, heat, and swelling.
► Sometimes a fifth: loss of function.

Front 100

Acute inflammation

Back 100

cause is removed over short period of time; response is intense.

Front 101

Chronic inflammation

Back 101

cause is difficult to remove; response is longer, but less intense.

Front 102

Edema

Back 102

swelling caused by fluid build up.

Front 103

Margination:

Back 103

phagocytes stick to inner surface of blood vessels.

Front 104

Emigration

Back 104

collected phagocytes squeeze between cells of blood vessels to injured area.

Front 105

Lectins

Back 105

proteins that bind to carbohydrates.

Front 106

Induction

Back 106

turns on transcription of a gene or genes.

Inducer: molecule that turns on transcription.

Front 107

Carriers

Back 107

carry and transmit pathogen without showing signs of illness.

Front 108

cytokines

Back 108

chemical messengers produced by immune cells.
Ex: (IL-1 and TNF-a)

Front 109

Phagosome

Back 109

sac surrounding the microbe.

Front 110

Phagolysosome

Back 110

Fuses with lysosome containing digestive enzymes

Front 111

Induction

Back 111

turns on transcription of a gene or genes.

Front 112

I gene

Back 112

regulatory gene; encodes repressor protein.

Front 113

Antigenic variation

Back 113

alteration of surface antigens by some pathogens.

► Host immune response against pathogen.
► Pathogen alters surface antigens and is unaffected by antibodies.

Front 114

Abscess forms

Back 114

localized collection of pus (dead cells, body fluids).