Micro 146 Bloom Exam 3 Ch 13

Front 1

Obligatory intracellular parasites

Back 1

Absolutely require living host cells in order to multiply

Front 2

Virus

Back 2

1. contain a single type of nucleic acid (DNA or RNA)
2. Contain a protein coat that surrounds the nucleic acid
3. Multiply inside living cells by using the synthesizing machinery of the cell
4. Cause the synthesis of specialized structures that can transfer the viral nucleic acid to other cells

Front 3

Do Viruses contain enzymes for protein synthesis and ATP generation?

Back 3

No. Rely on host cell

Front 4

Host Range of a virus

Back 4

the spectrum of host cells the virus can infect

Front 5

Viruses that infect bacteria

Back 5

Bacteriophage or phage

Front 6

Virion

Back 6

a complete, fully developed, infectious viral particle composed of nucleic acid and surrounded by a protein coat that protects it fro the environment and is a vehicle of transmission from one host cell to another

Front 7

Properties of Viral Nucleic Acid

Back 7

1. Can have EITHER DNA or RNA, never both
2. Can be single or double stranded
3.Can be linear or circular

Front 8

Name the 2 types of Capsids

Back 8

1. Polyhedral Capsid
2. Helical Capsid

Front 9

Capsid

Back 9

the protein coat protecting the nucleic acid of a virus

Front 10

Capsomeres

Back 10

protein subunits which compile the capsid

Front 11

Envelope

Back 11

usually composed of some combination of lipids, proteins and carbohydrates which covers the capsid

Front 12

Polyhedron

Back 12

Most common Capsid, up to 20 sides (icosahedron)

Front 13

Nonenveloped Virus

Back 13

Viruses whose capsids are not covered by an envelope

Front 14

Helical Virus

Back 14

resemble long rods that may be rigid of flexible, viral nucleic acid is found within a hollow, cylindrical capsid that has a helical structure

Front 15

Polyhedral Virus

Back 15

(many sided virus) most are icosahedron (20 triangular faces)

Front 16

Complex Virus

Back 16

Some, esp bacterial viruses, with complicated structures (i.e. bacteriophage)

Front 17

Viral Species

Back 17

a group of viruses sharing the same genetic information and ecological niche or host range

Front 18

Burst Size

Back 18

the mean number of bacteriophage particles set free per infected bacterium upon lysis of phage-infected cells

Front 19

Lytic Cycle

Back 19

Attachment, Penetration, Biosynthesis, Maturation, Release (lysis and death of host cell)

Front 20

Attachment (lytic cycle)

Back 20

Chance collision between phage particles and bacteria, an attachment site on the virus attaches to a complementary receptor site on the bacterial cell, this is a chemical interaction in which wear bonds are formed between the attachment/receptor sites

Front 21

Penetration (lytic cycle)

Back 21

phage injects DNA and an enzyme (phage lysozyme) into the bacteria

Front 22

Biosynthesis (lytic cycle)

Back 22

phage uses host cell's nucleotides and enzymes to synthesize many com pies of phage DNA for biosynthesis of phage enzymes and capsid proteins. phage DNA are transcribed into mRNA during the multiplication cycle

Front 23

Maturation (lytic cycle)

Back 23

phage DNA and capsids are assembled into complete visions, the viral components essentially assemble into a viral particle spontaneous. Phage heads and tails are assembled separately from protein subunits, head is filled w/DNA and attached to tail

Front 24

Release (lytic cycle)

Back 24

lysozyme (encoded by a phage gene) breaks down the bacterial cell wall and the host cell breaks open (lyses) releasing the newly produced bacteriophage to infect other cells

Front 25

Lamda Phage/Lysogenic Cycle

Back 25

An alternate for some viruses which is similar to the lytic cycle but does not destroy the host cell

Front 26

Attachment (lysogenic cycle)

Back 26

phage attachés vía receptors to the bacterial host

Front 27

Penetration (lysogenic cycle)

Back 27

Viral Genome enters the host cell (nucleic acid from phage released) genome.
Integration of the host and viral genome

Front 28

Prophage (lysogenic cycle)

Back 28

The integrated host and phage DNA

Front 29

Duplication/Reproduction (lysogenic cycle)

Back 29

Host cell duplicates normally but all the daughter cells have the integrated DNA/Genome

Front 30

Latent VIrus

Back 30

Enters into a latent state and needs a stressor. Integrates into nerve cells, sits until a stressor causes the virus to express itself via lytic cycle.

Front 31

Temperate Phage

Back 31

ability of a bacteriophage to display a lysogenic lifestyle.

Front 32

Productive Phage

Back 32

ability to undergo a lytic lifestyle

Front 33

Where does replication, transcription and maturation take place in DNA animal viruses?

Back 33

The nucleus

Front 34

What is a Naked Virus

Back 34

An animal virus without an envelope

Front 35

Animal Virus Attachment

Back 35

Virus attaches to proteins embedded in the plasma membrane

Front 36

Animal Virus Penetration

Back 36

Nucleocapsid enters by endocytosis or fusion

Front 37

Endocytosis

Back 37

Host cell closes around and bring vesicle into the cell

Front 38

Fusion

Back 38

When the viral envelope fuses with the plasma membrane and releases the capsid into the cell's cytoplasm

Front 39

Uncoating

Back 39

The separation of the viral nucleic acid from its protein coat once the vision is enclosed within the vesicle. The capsid is digested when the cell attempts to digest the vesicle's contents.
Nonenveloped capsid may be released into the cytoplast of the host cell

Front 40

Virus release

Back 40

Budding or rupture

Front 41

Budding

Back 41

during biosynthesis, proteins adhere to the plasma membrane creating embedded spikes, the capsid meets the host membrane and is enveloped by the membrane and once fully enclosed it pinches off and breaks away. Does not kill the host cell

Front 42

DNA Virus Replication Cycle

Back 42

1. Viral DNA is released into host nucleus
2. Transcription and replication occur
3. Translation takes place in the cytoplasm; structural proteins are synthesized
4. Viral components enter nucleus where assembly takes place

Front 43

Retrovirus

Back 43

an RNA virus that is duplicated in a host cell using the reverse transcriptase enzyme to produce DNA from its RNA genome. The DNA is then incorporated into the host's genome by an integrase enzyme. The virus thereafter replicates as part of the host cell's DNA.

Front 44

Reverse Transcriptase

Back 44

Enzyme that transcribes ss RNA into ss DNA. Then also helps create the double helix DNA

Front 45

Provirus

Back 45

a virus genome that is integrated into the DNA of a host cell, hidden from the host immune system or antiviral drugs.
Replicates with host chromosome and remains latent. Needs a stressor to emerge

Front 46

Animal Virus Infection Cycle

Back 46

1. Attachment via an embedded rote in in the plasma membrane
2. Penetration - nucleocapsid enters
2a. Uncoating
2b. Fusion (when has envelope)
3. DNA viral genome can integrate into nucleus of host as a provirus (is latent). RNA viral genome doesn't enter nucleus and starts biosynthesis begins immediately and ends in death of cell
4. Assembly/Maturation
5. Release
a. DNA - budding, drips off cell (must be enveloped)
b. RNA- rupture, destroys the cell

Front 47

How does a naked virus enter the animal cell

Back 47

Endocytosis

Front 48

How does an enveloped virus enter the animal cell

Back 48

Fusion

Front 49

DNA Virus Replication

Back 49

1. Transcription must occur in the nucleus
2. need RNA polymerase so it must be in nucleus
3. Replication (DNA polym., RNA) in nucleus

Front 50

Where does Translation occur

Back 50

Cytoplasm

Front 51

How many families of viruses cause human disease

Back 51

20

Front 52

Acute infection

Back 52

rapid onset, short course (i.e. common cold)
Virus released by lysis so host cell dies

Front 53

Persistant Infection

Back 53

Continually increasing its problematic nature. Virus usually released by budding so cells survive.

Front 54

Latent Infection

Back 54

Integrated viral DNA, Chronic, returns with periods of remission/exacerbation

Front 55

Normal Cells to Tumor cells

Back 55

Integrated viral DNA. Normals cells transformed into tumor cells. Oncogenic virus, cause tumor growth.