Micro Lecture 21

Front 1

a small particle consisting of a nucleic acid molecule surrounded by a protein rod
-can range b/t 20 to 1000nm (few 10,000); need what kind of microscope to be seen?

Back 1

Virus

Electron Microscope

Front 2

-May be either DNA or RNA
-may be single stranded or double stranded
-circular or linear

Back 2

Nucleic Acid
-Viral Structure

Front 3

proteins that enclosed the viral genome
-may be an aggregate of one or more poteins
-often assembes into an _________ structure

Back 3

Capsid
-icosahedron structure

Front 4

Envelope viruses contain a _________ that surrounds the capsule, usually derived from the cytoplasmic membrane of the host
-envelope virus may or may not be covered with _______.

Back 4

1. Lipid Bilayer
2. Spikes

Front 5

carbohydrate-protein complexes that project from surface of envelope

Back 5

-Spikes

Front 6

1. resemble long rods that may/may not be rigid
-viral nucleic acid found within the hollow

2. have additional structures added to the head

Back 6

1. Helical viruses

2. Complex viruses

Front 7

Virion often carries ________ that are injected into the host at the same time viral's nucleic acid
-aids in taking over host, or aids viral DNA to be transported to the nucleus

Back 7

Enzymes

Front 8

What are the two life cycles of the replication of Bacteriophages (viruses)?

Back 8

1. Lytic phage (Ex. T4)
2. Lyogenic phage (Ex. lambda)

Front 9

-complex virus
-icosahedron head
-tail, core sheath, tail fibers
-DNA encodes for app. 200 genes

Back 9

T4 Virus --Lytic phage

Front 10

Name the stages involved in the life cycle of T4..
1.
2.
3.
4.
5.

Back 10

T4
1. Attachment
2. Penetration
3. Biosynthesis
4. Maturation
5. Release

Front 11

What stage of the life cycle of T4..
-Tail fibers attach to the cell surface of the bacterium
-Tail is aligned with the surface

Back 11

Stage 1: Attachment

Front 12

What stage of the life cycle of T4..
-Tail contact allows a lysozome-like enzyme to digest the peptidoglycan
-Sheath contact pushing core into the cytoplasm
-T4 dsDNA injected into the host

Back 12

Stage 2: Penetration

Front 13

What stage of the life cycle of T4..
-Phage DNA is transcribed into RNA and proteins are made
-Synthesis of early proteins take over the host
-Synthesis of intermediate proteins - primarly involved in _____________.
-Synthesis of late proteins - phage heads and tails, then cell lysis proteins

Back 13

Stage 3: Biosynthesis
-DNA replication

Front 14

What stage of the life cycle of T4..
-assembly of phage particle
A. Phage DNA fills the head particle
B. Tail attaches
C. Tail fibers attach

Back 14

Stage 4: Maturation

Front 15

What stage of the life cycle of T4..
-Enzyme digest into peptidoglycan
-The cell lyses releasing phage

Back 15

Stage 5: Releasing

Front 16

-When a single injected cell is mixed with thousands of uninjected cells
-the lysis of the injected cell releases new phages which injects into surrounding cells
-these cells lyse releasing more phage
-resules in a HOLE in the bacterial lawn

Back 16

Plaque

Front 17

A lysogenic phage=Lambda
has two cycles
1. ____: make more phage
2. ____: phage DNA integrates into chromosome and becomes dormant

Back 17

1. Lytic
2. Lysogeny

Front 18

1. Integrated viral protein is called ________.

2. Cells within lambda in the chromosome are called _______.

Back 18

1. Prophage
2. lysogens or lysogenic cells

Front 19

-A change in enviromental conditions can cause the prophage to come out of the chromosome
-a repressor becomes degraded allowing phage gene expression
-results in: phage enters lyic cycle and produces more phages that release once the cells lyse

Back 19

Induction of a lysogen

Front 20

cells gain new properties (ex. altered surface components), when they becomes a lysogen of a phage

Back 20

Lysogenic Conversion

Front 21

Lysogenic stains of Corynebacterium diphtheriae produce a potent exotoxin hat is the cause of ________.

2. '' Steptococcus produces _____.

3. '' Clostridium botulinum produces _______.

Back 21

1. Diphtheria
2. Scarlet Fever
3. Botulinum toxin

Front 22

What are some similaries between animal virus replication and phage replication?

Back 22

-Attachment of plasma membrane
-Penentration of whole virus
-Uncoating*
-Replication of DNA / RNA viruses
-Envelope acquisition

Front 23

Bacteriophage or Animal Virus..?

-Tail fibers attach to cell wall proteins

Back 23

Bacteriophage: Attachment

Front 24

Bacteriophage or Animal Virus..?

-Attachment of spikes, capsid or envelope to cell surface receptors

Back 24

Animal Virus: Attachment

Front 25

Bacteriophage or Animal Virus..?

-whole virus enters the cell; endocytosis or fusion with cell membrane

Back 25

Animal Virus: Penentration

Front 26

Bacteriophage or Animal Virus..?

-DNA injected into host cell

Back 26

Bacteriophage: Penetration

Front 27

Bacteriophage or Animal Virus..?

-Does not require uncoating...

Back 27

Bacteriophage

Front 28

Bacteriophage or Animal Virus..?

-Enzymatic removal of capsid proteins

Back 28

Animal Virus: Uncoating

Front 29

Bacteriophage or Animal Virus..?

-occurs in cytoplasm, host cell activity ceases, DNA replicated, viral components synthesized

Back 29

Bacteriophage: Biosynthesis and matruation

Front 30

Bacteriophage or Animal Virus..?

-In nucleus (DNA virus) or cytoplasm (RNA virus) often cell activity ceases

Back 30

Animal Virus: Biosynthesis and matruation

Front 31

Bacteriophage or Animal Virus..?
-Some cell lyse; envelope viruses bud through host cell membrane

Back 31

Animal Virus: Release from host cell

Front 32

Bacteriophage or Animal Virus..?
-Cells lyse when viral enzymes weaken it

Back 32

Bacteriophage: Release from host cell

Front 33

Some viruses like ________ replicate entirely in the cytoplasm.

Other DNA viruses (Herpesvirus) replicated ______ and _______ into nucleus for assembly.

Back 33

Poxviruses

-nucleus and capsid

Front 34

____ viruses may also integrate into chromosome.
-Viral DNA is known as _______. Example: Retroviruses

Back 34

Animal viruses
-Provirus

Front 35

-RNA is copied into DNA by _______ __________.
-Single stranded DNA is converted into double-stranded DNA.
-DNA is integrated into the host genome
-Viral DNA is transcribed into mRNA and RNA molecules for new viruses.
-Viral particles are then assembled.

Back 35

Retroviruses
-Reverse Transcriptase

Front 36

Virus family names end it ... ?

Genus names end in... ?

Back 36

Virus = -viridae
Genus = -virus

Front 37

What system consists of these viruses?

Influenza, adenovirus, rhinovirus infections

Back 37

Respiratory System
-Pneumotropic

Front 38

What system consists of these viruses?

Chickenpox, herpes simplex, measles, mumps, smallpox, rubella

Back 38

Skin and Subcutaneous tissue
-Dermotropic

Front 39

What system consists of these viruses?

Yellow fever, dengue fever, infectious mononucleosis, hepatitis A, hepatitis B, AIDS

Back 39

Blood and visceral organs
-Viserotropic

Front 40

What system consists of these viruses?

Rabies, polio, encephalopathy, arboviral encephalitits

Back 40

CNS
-Neurotrophic

Front 41

Compared to bacteria detention of viruses is more _______ and __________. Pathogenic human viruses often replicate where?

Back 41

Time-consuming and expensive
-only in human cells

Front 42

_______ postulates CANNOT be applied to a viral disease b/c viruses cannot be cultivated in pure culture.

Back 42

Koch's postulate

Front 43

Filtrates the infectious material not shown to contain bacterial or other cultivatable organisms that must produce the disease

Back 43

River's postulate

Front 44

1. Search for viral antibodies
2. Cytopathic effects
3. Inoculations to fertilized eggs
4. Inoculation of tissue cultures
5. Observe with electron microscope

What is this?

Back 44

Detection of Viruses

Front 45

Indirect method to search for viral antibodies in patient's ______.
-Certain viruses: influenza, measles, mumps have ability to aggulutinate red blood cells, this is called ??
-________________ test indicates antibodies against virus in blood serum

Back 45

Serum

Hemagglutgination (HA)

Hemagglutgination-inhibition test

Front 46

Viruses + red blood cells --> ___________.

Back 46

Hemagglutgination

Front 47

Viruses + Antibodies in serum --> Viruses coated with antibodies + RBCS --> __________.

Back 47

Hemagglutgination Inhibition

Front 48

Chills, fever, headache and muscular aches

Back 48

Influenza virus
-Influenza

Front 49

Upper Respiratory
Common cold disease...

Back 49

Adenovirus Coronavirus

Front 50

Upper respiratory, 50% of all colds caused _________.

Back 50

Rhinovirus
-Head virus

Front 51

Minor upper respiratory illness
Disease = Common cold

Back 51

Parainfluenza

Front 52

Serious respiratory disease of infants

Back 52

Respiratory syncytial (RSV) virus

Front 53

_________ are damage to infected host cells caused by infecting viruses.
-Viral infection can lead to cell abnormalities (biochemical and morphological) and/or cell death.

Herpesviridae, adenovirdae, picornaviridae, Rhabdovirdiae --> ____ & ______ of cells from culture.

Back 53

Cytophatic Effects (CPE)

Rounding and detachment of cells from culture