Microbiology Lecture Practical 1 Part 4; Chap 1, 4, 5, & 6
Naked viruses are released by
lysis
Together, nucleic acid and capsid are referred to as _____.
nucleocapsid
Viruses that consist of only a nucleocapsid are considered
Naked viruses
What are the two structures of viruses?
Naked viruses and enveloped viruses.
The entrance of the virus inside the host cell
Penetration
Refers to being able to take multiple shapes.
Pleiomorphic
_____ are enzymes that are involved in DNA and RNA protein synthesis.
Polymerase
The latent or inactive stage of viral DNA when incorporated into the bacterial chromosome is called
Prophage
A viral disease that lasts a specific amount of time not long maybe a few days or weeks and usually resolves by itself. It usually caused by naked viruses but can be enveloped virus too.
Acute infection
What are the 3 viral disease patterns?
Acute infection, persistent infection, and transformation
protruding molecules, called ______ are essential for the attachment of viruses to the next host cell.
Spikes or peplomers
The entry of viral nucleic acid stops host cell DNA replication and protein synthesis and viral DNA and protein is replicated instead
Synthesis
Under the control of viral genes, the cell makes new viral components: RNA molecules, capsomers, and spikes
Synthesis: replication and protein production
This type of persistent infection has the virus enter the host cell and permanently alters genetic material
Transformation
Having an affinity for a tissue or cell type is called
Tropism
T or F? The envelope is a modified section of the host cell membrane.
True
T or F? The function of the capsid/ envelope of a virus is to protect the genetic material from degradation, introduce genetic material into the host cell, and stimulate the immune system for antibody production.
True
The general steps in a viral multiplication cycle are a. Adsorption, penetration, synthesis, assembly and release b. Endocytosis, replication, assembly and budding c. Adsorption, duplication, assembly and lysis d. Endocytosis, penetration, replication, maturation and exocytosis
a. Adsorption, penetration, synthesis, assembly and release
A prophage is a/an ______ stage in the cycle of ________. a. Latent, bacterial viruses b. Infective, RNA viruses c. Early, poxviruses d. Late, enveloped viruses
a. Latent, bacterial viruses
Bacteriophages attaches to host cell surface
adsorption
The multiplication cycle of a bacteriophage includes
adsorption, penetration, synthesis, assembly, and release
Viral multiplication consists of multiple steps
adsorption, penetration, uncoating, synthesis, assembly, and release
All component assembled into finished viruses
assembly
In general, RNA viruses multiple in the cell _______ and DNA viruses multiple in the cell _______. a. Nucleus, cytoplasm b. Cytoplasm, nucleus c. Vesicles, ribosomes d. Endoplasmic reticulum, nucleolus
b. Cytoplasm, nucleus
The envelope of an animal virus is derived from the ________ of its host cell. a. Cell wall b. Membrane c. Glycocalyx d. Receptors
b. Membrane
Enveloped viruses carry surface receptors called a. Buds b. Spikes c. Fibers d. Sheaths
b. Spikes
The 2 types of persistent infections are
chronic and latent
This type of persistent infection has the virus actively multiplying and last years
chronic infection
Viruses are known to infect a. Plants b. Bacteria c. Fungi d. All organism
d. All organism
The capsid is composed of protein subunits called a. Spikes b. Protomers c. Virions d. Capsomers
d. Capsomers
Which of these is NOT a general pattern of virus morphology? a. Enveloped, helical b. Naked, icosahedral c. Enveloped, icosahedral d. Complex, helical
d. Complex, helical
The nucleic acid of a virus is a. DNA only b. RNA only c. Both DNA and RNA d. Either DNA or RNA
d. Either DNA or RNA
A virus is a tiny infectious a. Cell b. Living thing c. Particle d. Nucleic acid
d. Nucleic acid
The nucleic acid of animal viruses enters the host cell through a. Injection b. Fusion c. Endocytosis d. b and c
d. b and c
Penetration via _____ cell engulfing the virus and once inside virus is enclosed.
endocytosis
Persistent infections are caused by
enveloped viruses
Viruses that possess additional covering external to the capsid is called
enveloped viruses
Penetration can be via _____, viral envelope fuses directly with the host cell membrane.
fusion
The exposure to certain environmental causes prophage to progress into viral replication cycle is called
induction
The virus attaches to its host cell by specific binding of its spikes to cell receptors.
Adsorption
The host cell accumulates damage after using its energy on the virus and dies is called
Cytopathic effects
T or F? The genetic material can be both RNA and DNA.
False. The nucleic acid of the viral genome is either DNA or RNA but not both.
most common type of viral infection of GI caused by Rotavirus.
Gastroenteritis
An example of a chronic infection
HIV, Hepatitis B
What are the 2 different arrangement of capsids?
Helical and Icosahedral
Rod-shaped capsomers that bind together to form a series of hollow disc resembling a bracelet is called
Helical capsid
_____ receptors that allow the virus to bind to the respiratory epithelium.
Hemagglutinin
An example of latent state infection is
Herpes simplex that causes cold sore and genital herpes
An example of transformation infection is
Human papilloma virus
The capsids are arranged in a three-dimensional, symmetrical polygon with 20 sides and 12 evenly-spaced corners are called _____. I can be naked or enveloped.
Icosahedral capsid
An example of acute infection by enveloped virus is
Influenza (flu)
The nucleic acid is injected through the bacterial cell wall and membrane and empty capsid remains
penetration
Bacteriophages have a _____ capsid head, a collar, body of sheath, helical tail with pins, and tail fibers that allow the phage to land on the bacteria.
polyhedral
Some examples of viral enzymes are
polymerase and reverse transcriptase
The host cell is packed with viruses and viral enzymes weaken the host cell wall causing lysis and mature virions are
released
The fusion of multiple host cell into a large cell containing multiple nuclei is called
syncytia
This viral infection of the upper respiratory affects
throat, larynx, trachea, and larger bronchi
Some regular membrane proteins are replaced with _____ during the virus assembly process.
viral proteins
What are mature, released viruses that can infect another cell.?
Virions
This crop pathogen is a naked strand of RNA and is extremely small around 1/10 size of a virus.
Viroids
A virus that affects bacteria is called
Bacteriophages
Huge viruses with 2500 genes are called
Pandoraviruses
This type of persistent infection has the virus inactive most of the time
Latent state
The acquisition of phage genes by bacteria cause its phenotype to change is called
Lysogenic conversion
The host bacterial chromosome carries the bacteriophage viral DNA is called
Lysogeny
_____ is considered a less deadly form of infection as it allows the virus to spread without killing its host.
Lysogeny
List viruses from largest to smallest.
Megavirus, Poxvirus, Herpes simplex, Rabies, HIV, Influenza, Adenovirus, T2 bacteriophage, Poliomyelitis, Yellow fever, Hemoglobin molecule.
_____ allows virus to penetrate through the mucus to access the epithelial cells.
Neuraminidase
_____ is the common cause of gastroenteritis in contained settings like cruise ships and schools.
Norovirus
_____ refers to synthesizing DNA from RNA enzymes.
Reverse transcriptase
An example of acute infection by a naked virus is
Rhinovirus
This virus from the family Coronaviridae is a + strand RNA virus, has an enveloped helical capsid and is pleiomorphic. It binds to the respiratory cells and has 4 important proteins: S protein, M protein, E protein, and N protein.
Sars-CoV2
depend on other viruses for repication
Satellite viruses
naked and enveloped viruses are released via lysis or budding.
Viral release
release if viral capsid/ nucleic acid into the cytoplasm.
Uncoating
In this step of viral multiplication, the capsid is laid down and genetic material is inserted in the capsid. In enveloped viruses, glycoprotein spikes are inserted into the host cell membrane.
Viral assembly
_____ refers to proteins that speed up the rate of reaction.
Viral enzymes
_____ are obligate intracellular parasites of bacteria, protists, fungi, plants, and animals.
Viruses
In lower respiratory infections, the virus enters the
bronchioles and lungs
Enveloped viruses are released by
budding or exocytosis
Viruses that persist in the cell and cause recurrent disease are considered a. Oncogenic b. Cytopathic c. Latent d. Resistant
c. Latent
What do you call the protein coat of a virus that surrounds the nucleic acid?
capsid