CH13: Viruses

what are complete, fully developed viral particles?

virion

what all goes inside of cell?

DNA and RNA

where does all DNA and RNA go into during a virus?

specific cell

What do virsues only contain?

Genetic material: DNA or RNA

what's protein's purpose?

protection

\_____ are obligate intracellular parasites

virus

\_______ are completely inert when not in host cell

virus

when is virus completely inert?

when not in a host cell

\__________:
- obligate intracellular parasites (are completely inert when not in a host cell)
- very small (filterable)
- Acellular
- viral size

virus general characteristics

\________:
- contain a single type of nucleic acid (RNA or DNA)
- contain a protein coat which surrounds the nucleic acid...Capsid with Capsomeres
- sometimes the coat is surrounded by a lipid envelope
- multiply inside living cells by using cell's own molecular machinery

virus general characteristics

where was virus discovered?

tobacco plant

\_______ is smaller than bacteria

virus

is virus cellular or acellular?

acellular

is prion cellular or acellular?

cellular

what does virus not have?

cell.
cell wall.
ATP generating system.
ribosomes or means of protein syntheis

what has no rule in making you sick?

protein

what does virus contain?

protein coat which surrounds the nucleic acid

what is the protein coat called in a virus?

capsid

what stays out of cell?

protein

why couldn't they classify virus?

no ribosomes

Some \_____ have spikes

viruses

Most \_______ infect only specific types of cells in one host

viruses

what do most viruses only infect?

specific types of cell in 1 host

what must every virus do?

attach to specific cell

What does flu attach to?

nose cells

what does covid attach to?

lung

Most viruses infect (attach to) only \__________

specific types of cells in 1 host

Define bacteriophages (or phages)

virsues which infect bacteria

define host range

most viruses can only infect a limited range of cell types (usually only one host species)

\______ - most viruses can only infect a limited range of cell types (usually only one hose species)

host range

How is host range determined?

receptors

Where are receptors found?

surface of the host cell

define receptors

specific binding of the virus to particular structures

give example of receptors in bactera

cell wal proteins, flagella, and fimbrae.

give example of receptors in human

protein in the membrane

what is the role of protein in membrane?

receptor

how exactly does a virus bind to the receptor?

hydrogen bonding

define virion

complete, fully developed viral particle

what is virion composed of?

nucleic acid surrounded by a protein coat (capsid)

what is every protein?

a complete full virus

how do we classify virus structures?

type of nucleic acid.
type of protein coat or envelope.
nmorphology.

how do we classify viruses based on their nucleic acids?

- single-stranded DNA viruses.
- double-stranded DNA viruses.
- positive single-stranded RNA virues (+ strand).
- negative single-stranded RNA viruses
- double-stranded RNA viruses

which viruses able to directly synthesize proteins from their genome?

positive single-stranded RNA viruses

What makes proteins?

ribosomes (RNA)

define positive single-stranded RNA viruses

able to directly synthesize proteins from their genome

which viruses not able to directly synthesize proteins from their genome?

negative single-stranded RNA viruses

which viruses transcribe a + strand to serve as mRNA before synthesizing proteins?

negative single-stranded RNA viruses

how does negative single-stranded RNA viruses transcribe a positive strand and then synthesize protein?

reverse transcriptase

Define reverse transcriptase

going from RNA --\> DNA vs
(DNA --\> RNA--\> proteins)

define double-stranded RNA viruses

depending on the virus, the nucleic acid can be linear or circular (some, like influenza virus, have multiple nucleic acid segments)

which viruses can have linear or circular nucleic acid?

double-stranded RNA viruses

which viruses is connected to influenza virus?

double-stranded RNA viruses

define capsid

protein coat surrounding the nucleic acid of the virus

\______ is protein coat surrounding the nucleic acid of the virus

capsid

\______ are protein subunits of the capsid

capsomeres

define capsomeres

protein subunits of the capsid

what is an envelope surrounded by?

lipid, protein, and carbohydrate

define envelope

capsid of some viruses is surrounded by a lipid, protein, and carbohydrate envelope

\_______ is the capsid of some viruses is surrounded by a lipid, protein, and carbohydrate envelope

envelope

define spikes

composes of protein-carbohydrate complexes on the surface of the envelope

\______ - composed of protein-carbohydrate complexes on the surface of the envelope

spikes

give the purpose of spikes?

1. attach to host cells
2. identification of viruses
(ATTACH & IDENTIFY)

how did covid attach to our cell?

spike

what is virus mainly classified by?

shape

where can viruses only multiply in?

host cells

where can viruses not grow(multiply) in?

culture media

what grows in liquid cultures of bacteria or in bacterial cultures on solid medium?

bacteriophages

where do bacteriophages grow in?

liquid cultures of bacteria or in bacterial cultures on solid medium ...bacteria

in a bacterial lawn on a plate, viruses can be detected by the formation of \_______

plaques

in \________ on a plate, viruses can be detected by the formation of plaques

bacterial lawn

what multiply within minutes? (min:5-6/ max:9)

viruses

\_____ are zones of clearing produced by the killing of bacteria

plaques

define plaques

zones of clearing produced by the killing of bacteria

what is colony counting in bacteria similar to?

plaque-forming unit

what is plaque-forming unit similar to?

colony counting in bacteria

each plaque represents one viral infection, or \_________

plaque-forming unit

what is counting the viruses called?

plaque-forming unit

what has the 2 cycles of Lytic Cycle and Lysogenic Cycle?

bacteriophage

define Lytic Cycle

ALL INFECTED cells are lysed and killed

deinf Lysogenic Cycle

MOST INFECTED cells are lysed and killed

what does the lysogenic cycle ultimately become?

lytic

what cycle stay/become dormant?

lysogenic cycle

define lysogeny

some cells have a phage which inserts in the chromosome and becomes dormant (a prophage)

where do some cells' phage insert into?

chromosome

what virus cycle involves instant kill?

lytic cycle

what virus stays as dormant and after that, it is killed?

lysogenic cycle

\______ - cell replicates normally; at some later time, phage can enter lytic cycle

lysogenic cycle

which virus cycle makes transduction possible?

lysogenic cycle

what process does the lysogenic cycle make possible?

transduction

what is the function of specialized transduction?

transfers specific genes

what are the General Steps for Animal Viruses?

1. attachment
2. penetration
3. uncoating
4. biosynthesis
5. maturation and release

what are animal virus steps similar to?

bacteriophages

what are bacteriophages virus steps similar to?

animal viruses

where do you work on the viruses?

primary cell lines

define primary cell lines

die out after a few generations

which Line die out after a few generations?

primary cell lines

which Line is derived from human embryos?

diploid cell lines

which Line is maintaied for up to 100 generations?

diploid cell lines

define diploid cell lines

- derived from human embryos and
- maintained for up to 100 generations

what are diploid cell lines derived from?

human embryos