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59 Cards in this Set
- Front
- Back
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What does obligate intracellular parasite mean?
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Must enter the cell to become active
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Virion
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single virus particle
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What composes nucleocapsid?
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Protein capsid,and the nucleic acid it contains
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What kind of outer coat does a naked virus have?
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Nucleocapsid
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What kind of viruses have spikes on their outer layer?
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Enveloped viruses
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What kind of nucleic acids can viruses have? (3 Categories)
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DNA/RNA
Double/single stranded circular/linear/fragmented acid |
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What is an example of a fragmented RNA virus? How many pieces is it broken into?
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the flu
8 Pieces |
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What kind of nucleic acid does the flu virus contain?
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Fragmented RNA (8 pieces)
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Are the majority of viruses naked or enveloped?
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Enveloped
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What helps the viruses attach in enveloped viruses?
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Spikes
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What is the envelope made up of?
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Lipids
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What is a capsid made up of?
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proteins capsomeres
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What do capsid detemine in a virus?
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The virus's shape
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What 2 main things make up a bacteriophage?
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Nucleocapsid head
Tail (sheath and tail fiber) |
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How do viruses' sizes compare to bacteria and a RBC?
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Even smaller than the bacteria and RBC.
A lot smaller |
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Why do viruses typically only infect one type of cell in a host?
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Need certain required proteins and nucleic acids that the cell supplies
The environment the cell lives in is productive for the virus to multiply Specific attachments sites available |
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What are 3 general stages of a productive Infection?
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Take over a cell
Reproduce Destroy cell upon leaving (lysis) aka Lytic |
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What is an example of a productive infection?
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Virulent phage T4
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What are 4 general characteristics of a latent infection?
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Insert nucleic into host DNA
Multiply with the host Live communally with the host while it creates the virus' products No signs the host is infected (most of the time) |
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What is an example of a latent infection?
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Temperate phage Lambda
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What is another term for productive phage?
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Lytic phage
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What is another term for latent phage?
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Temperate phage
Lysogenic phage |
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What are the 5 steps of the Lytic Cycle?
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Attachment
Penetration Biosynthesis Maturation Release |
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Attachment
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Phage attaches by tail fibers to host cell
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Penetration
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Phage lysozyme opens cell wall
Tail sheath contracts, forces DNA into cell |
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Biosynthesis
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Production of phage DNA and proteins
(mRNA produced, DNA of host destroyed, DNA, enzymes, and parts of phage created) |
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Maturation
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Assembly of phage packages (spontaneous)
"Puts together the new phage" |
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Release
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Lysozyme breaks the cell wall
Phages enter environment |
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Eclipse period
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Decrease of virions detected in the body
When viruses enter the host cells and are multiplying before they are released |
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When are the virions most susceptible to antibiotics?
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When they are outside the host cells
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Are latent infections noticeable? Why/why not?
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Not noticeable due to longer growth period
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What is the main characteristic of the lysogenic phage/temperate phages in pertinence to the host cell?
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Live in harmony with host cell
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Lysogen
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Host
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Prophage
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Virus DNA inserted into a host (lysogen)
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Advantages of lysogeny on host cells (4)
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Protects cell from other similar phages from infecting the cell
No direct lysis of cell Lysogenic Conversion Transduction |
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Lysogenic Conversion
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The Lysogen (host cell) obtaining new properties that are beneficial to its survival
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Steps of Lysogenic Cycle (4)
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Attachment
Penetration Prophage Getting out of Lysogeny |
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What are 2 examples of Lysogenic conversion?
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Corynebacterium diphtheriae --> toxin for diphtheria
Streptococcus pyogenes --> toxin for scarlet fever Salmonella --> toxin for food poisoning Clostridium botulinum --> botulism Vibrio cholerae --> cholera |
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Mechanism to induce lytic cycle for temperate phage (3)
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Environment
Damage to host cell's DNA Removal of prophage from lysogen's DNA |
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Transduction
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Transducing (transporting) new DNA from another host into a new host.
Gives a host new DNA |
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Two ways receptors on a bacterial cell can protect against Phages
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Mutation of receptor not allowing phage to bind
Lysogenic conversion changing the receptors on the cell and preventing binding |
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Steps of Multiplication of animal viruses (6)
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Attachment
Penetration Uncoating Biosynthesis Maturation Release |
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How grow Bacteriophages in lab?
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Plaque method
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Plaque method
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Mix bacteriophages with host and nutrient agar
After several round of multiplication, bacteria surrounding virus are dead and it is called a plaque |
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How are plaque measured?
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Plaque forming units (PFU's)
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What is the ratio of plaque to viral particle?
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Each plaque = 1 viral particle
1/1 |
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How grow animal viruses in lab? (2 ways)
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In Living animals/embryonate eggs
Cell culture |
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Cell Culture (3)
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Enzymes separate cells
Suspended in culture medium Normal cells grow in monolayer, transformed cells do not |
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What are how long do acute infections last and how do they affect the host cell in the long run?
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relatively short duration, host can develop long-lasting immunity
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Acute Infection pathway (6)
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Attachment- with membrane
Entry- Whole virion enters cell Uncoating- inside cell Replication Maturation Release- not by virus directly lysing cell |
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How are persistent infections released and how does this relate to symptoms?
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Continuously present and released
Released by buddying Continuous symptoms |
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How are latent infections released and how does this relate to symptoms?
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Symptoms all appear at once
Single release of viruses |
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Examples of persistent Infection (7)
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Cervical Cancer
HIV/AIDS Liver Cancer Hep B Echovirus Rubella Virus Measles virus |
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Examples of Latent Infection (3)
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HSV 1 and 2 (Cold sores)
HTLV 1 and 2 (Leukemia) Herpesvirus (Shingles) |
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Tumors
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swelling induced by abnormal growth of cells
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Oncogenes (2)
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Viral genes responsible for cell transformation
Like proto-oncogenes but mutated and don't regulate cell replication properly |
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Oncoviruses
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Transport the proto-oncogene mutated into an oncogene into a new host cell
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Prions (3 things)
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Only contain protein and no nucleic acid
Cause slow diseases (latent infections) Fatal human diseases (brain diseases) |
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Viroids (4 Things)
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Small, single stranded RNA molecule
No Protein coat Circular Resistant to nuclease |
