Unit 3

Question 1

Obligate intercellular parasite

Answer 1

(All viruses) require a living cell to multiply do this using cell machinery, replication uses causes cell death.

Question 2

Capsid

Answer 2

Protein coat that protects viral nucleic acid all viruses have polyhedral or helical or complex

Question 3

Envelope

Answer 3

Capsid surrounded by a membrane lipid bilayer with proteins. Usually has spike structure

Question 4

Viral characteristics

Answer 4

Have nucleic acid organized into genes. Can have enzymes. No ribosomes. Usu. smaller 400 um.

Question 5

Lyric life cycle

Answer 5

Attachment/ absorption-require specific bind between capsid protein and host cel. Penetration-inject DNA into cytoplasm capsid no enter. Replication- syn using host cell stuff usu host cell stops making own pros. Assembly-mature particles spontaneously assemble. Release- virus induced lysis of cell release virus.

Question 6

Lysogenic virus

Answer 6

Once injected no replicate. Incorporated into host cell DNA to be activated at a later time. Inserted DNA = prophage. Activation often evmtal events. E.g. Radiation.

Question 7

Lysogenic conversion

Answer 7

Infection changes from non pathogenic to pathogenic. Can b expressed in novel proteins, changes in phenotype or produce new toxins/ enzymes.

Question 8

Transduction

Answer 8

Bacterial DNA transfer btw cells via virus. If bacterial DNA accidentally incorporated into viral DNA.

Question 9

Viral life cycle : animal

Answer 9

Attachment-specific membrane proteins determines specificity and host range. Penetration- direct, endocytosis-pseudopods surround and bring in via vesicles common 4 naked OR fusion envelope fuses w/ pm. Replication. Release- lysis: naked virus lyses cell, budding: exocytosis, doesn’t kill surrounded by piece of host cell pm which usually incl some spikes from inserted by viral replication.

Question 10

Multiplication retrovirus

Answer 10

Release viral enzymes reverse transcriptase, integrate and protease. Reverse transcriptase copies viral rna into two strand DNA. New DNA moves to nucleus and integrated using integrase. If transcripted, new genome and rna for all parts of virus. Viral proteins processed by protease moved to membrane.

Question 11

Cancer causing virus

Answer 11

Hepadnaviridae hepatitis B virus> liver cancer

Question 12

DNA Viruses

Answer 12

Poxviridae orthopoxvirus (UL) smallpox virus. 
Adenoviridae adenovirus (UL) upper respiratory infection. Herpesviridae human herpes virus 3 (Ul) varicella zoster virus- chicken pox/ shingles.

Question 13

Rna Viruses

Answer 13

Retroviridae lentivirus (UL) human immunodeficiency virus - HIV/AIDS 
Flaviviridae flavivirus ( UL) Zika virus
Filoviridae ebolavirus (UL) Zaire ebolavirus

Question 14

Prion

Answer 14

A proteimacous infectious particle that causes degenerative neurological disease. E.g. Mad cow or chronic wasting disease

Question 15

Normal microbiota

Answer 15

Microbes that are permanent resident on the body but don’t normally cause disease

Question 16

Opportunistic microbiota

Answer 16

Will nit normally cause disease but do under certain circumstances.

Question 17

Pathology

Answer 17

Study of disease

Question 18

Infection

Answer 18

Colonization of body by pathogens

Question 19

Disease

Answer 19

Abnormal state where body is not functioning normally

Question 20

Etiology

Answer 20

Study of causes of disease

Question 21

Pathogenicity

Answer 21

The ability to cause disease

Question 22

Virulence

Answer 22

The extent of pathogenicity/ intensity of disease caused by pathogen

Question 23

Koch s postulates

Answer 23

Are used to prove cause of disease links specific microbe with specific disease. Pathogen must B present in every case>isolated and grown in pure culture>cause same disease when pure cult used to inoculate healthy animal> paths isolated lab animal show same.

Question 24

Opportunistic patho=disease

Answer 24

Immunocompromised, non normal location, disturbances e.g. AntiBs

Question 25

Primary vs secondary infer

Answer 25

Acute infection cause initial illness( true pathogen). Opportunistic infection after primary predisposing.

Question 26

Acute chronic sub acute infection

Answer 26

Acute develops rapidly. Chronic vv

Question 27

True pathogen

Answer 27

Microbe capable of causing disease in healthy person

Question 28

Stages of infectious disease

Answer 28

In cubation- no signs or symptoms, prodronal- mild ss short. Period of illness. Period of decline- ss goes down can get secondary infection. Period of convalescence.

Question 29

Principal portals of entry and exit

Answer 29

Entry-mucous membrane, skin, paternal route. Exit-respiratory tract>cough/sneeze; Gi tract-feces/saliva, genitourinary-urine/vaginal secretions, skin, blood-biting Arthropods + needles.

Question 30

Reservoir of infection +carrier + examples

Answer 30

Where infectious agent normally lives, multiplies and serves as continual source of infection. Human-in apparent/latent e.g. AIDS. Animal-occurs primarily in vertebrates can be transferred to humans (zoonoses) e.g. Rabies. No living-soil/substances e.g. Tetanus. C-ppl who harbor patho can transmit w/out exhibiting SSS

Question 31

Methods disease transmission

Answer 31

Contact: direct-kissing, indirect-fomite/needle, droplet Vehicle: water-feces, food borne-food prep, vector-arthropod

Question 32

Mechanical vs biological vector transmission

Answer 32

Mechanical houseful flies carries on its feet, biologica-parasite multiplies in vector.

Question 33

Epidemiology

Answer 33

Study of disease and where it comes from

Question 34

Frequency of disease

Answer 34

Sporadic, endemic-always present. Epidemic-many ppl acquire | Short period of time. Pandemic-worldwide.

Question 35

Nosocomial infections

Answer 35

Acquired as a result of time spent in healthcare. 5-15%

Question 36

Virulence factor ex

Answer 36

Physiological and structural characteristics that help microbes cause disease and infection. Mycolic acid (waxy lipid) resist intercellular digestion by neutrophils and macrophages. Mycobacterium tuberculosis (UL). Adhesions/ligands help bind to host e.g. Streptococcus pyogenes M Protein.

Question 37

Toxin

Answer 37

Poisonous substance produced by certain orgs.

Question 38

Endotoxins

Answer 38

Gram-, lipids>lipopolysaccharides>Lipid A, toxic only high doses, specific can do receptor binding more widespread effects than exo

Question 39

Exotoxins

Answer 39

Mostly gram +, proteins, very potent in smaller number, very specific.

Question 40

Septic shock

Answer 40

Shock (massive drop in Bp) caused by massive release of bacterial endotoxin.

Question 41

IgG

Answer 41

Most common, phagocytic, neutralize toxins and Viruses

Question 42

IgM

Answer 42

2nd most common, 1st to appear post antigen, agglutinate antiGs, indicates current new infection

Question 43

IgA

Answer 43

Mucus memb, body secretions, localized protection of mucousal surfaces no colonization.

Question 44

IgD

Answer 44

Receptor on B cells intimate immune response

Question 45

IgE

Answer 45

Small % allergic reactions, bind to mast cells, destroy parasitic worms.

Question 46

B cells

Answer 46

Antibody mediated immunity, used against antigens (toxins) and pathogenic organisms

Question 47

Cytotoxic T Cells (TC)

Answer 47

T cells which destroy abnormal/pathogenic cells cell-mediated, can enter tissues

Question 48

T helper cells (TH)

Answer 48

Stimulate T and B cell response. Creates cytokines that promote B cell division and T cell maturation and division.