Virus Structure, Classification, and Cycle of Infection - PowerPoint Presentation

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Virus Structure, Classification, and Cycle of Infection

By: Maddy Connell, Ava

Taurino

, and Shane Landue

Overview 

 What is a virus? Structures of viruses

 How viruses reproduce Cells infected by viruses Diseases caused by RNA viruses

 The Lytic Cycle The Lysogenic Cycle Lytic Cycle vs. Lysogenic Cycle

What is a Virus? 

Virus= infective agent reproduced in cellsNon-living particleMade of lipids, proteins, nucleic acids  Protein Capsule- genetic material 

Can be DNA or

RNA

MC

How do Viruses Differ from One Another?

Different types- Lytic, Temperate,  and Latent

Variety of sizes Transmit using DNA or RNA

Different forms of virions 

MC

What Structures do all Viruses Contain? 

1. Nucleic Acid Genome Synthesize proteins Produces

new viruses 2. Protein Capsid Protects

nucleic acid Surface-virion attachment to host cellProvides proteins- virion goes to host cell

MC

Why are Viruses Not Considered Living?

Don't contain cell structureCapable of autonomous reproduction Rely on cells to

reproduceNeed a host cell

to surviveMC

How Viruses Reproduce

 Viruses reproduce by infecting living cells Attack the host cell 

Host Cell= cell where the virus multiplies Genetic information, copying itself

 Viruses replicate with variation

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Cells Viruses Infect

1. Prokaryotic Infected by bacteriophages- viruses that infect

bacteria 2. eukaryotic

Animal and plant cells

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The Common Cold

Capsid settles on a cell making new copies of RNA

Virus attacks with a fast-acting infection

Symptoms: congestion, a runny nose, and a sore throat Rhinovirus

- virus causing the common cold

Treatment is not needed

SL

HIVAIDS

is caused by HIVRetrovirus = RNA viruses inserting a DNA copy into the host cellHIV destroys

the system that would fight the infectionSymptoms: rapid weight loss, continual fevers, and extreme fatigue

HIV antiviral- slows down progression

Steps of the Lytic Cycle

Attachment – Virus attaches to the bacterium's surfacePenetration – The virus

injects its genetic material into the bacteriumReplication

–Makes new proteins and genetic material from the virusAssembly  – New proteins and genetic material assemble

into new viruses

Lysis

– Bacterium

bursts

and the new viruses go to infect other cells

AT

1.

2.

3.

4.

5.

Steps of Lysogenic Cycle

AT

Attachment

– Virus attaches to the bacterium's surface

Viral DNA goes into the

bacterial chromosome

 prophage

Prophage might

replicate

for generations

Prophage

exits

chromosome and goes into Lytic Cycle

Penetration

– The virus injects its genetic material into the bacterium

Replication

–Makes new proteins

and genetic material from the virus

Assembly 

– New proteins and genetic material assemble into new viruses

Lysis

– Bacterium bursts and the new viruses go to infect other cells

AT

Lytic vs Lysogenic

Symptoms of viral infection

No symptoms of viral infection

Destroys one host cell

Destroys many host cells

Introduction of virus to cell

Basic form of viral multiplication

Rare form of viral multiplication

Visual of Both Cycles 

AT

Lysogenic Cycle =

8 steps (Includes Lytic cycle)Lytic Cycle = 5 steps

ABC'S

What are viruses made of?A) LipidsB) ProteinsC) Nucleic Acids D) All of the above

MC

ABC'SWhat does the Nucleic Acid Genome produce?

A) VirionB) New viruses C) ProteinsD) Digestive Enzymes 

MC

ABC’sWhat kind of cells are infected by viruses?

A) Prokaryotic cellsB) Animal cellsC) Plant cellsD) All the above

SL

ABC’sWhat do retroviruses do?

A) DNA virus inserts a copy of RNA into the host cellB) DNA virus inserts a copy of DNA into the host cellC) RNA virus inserts a copy of DNA into the host cellD) RNA virus inserts a copy of RNA into the host cell

SL

ABC’sHow many steps are in the Lytic Cycle?

A) 6B) 7C) 5D) 8AT

ABC’sWhat is the step in the lytic cycle that the cell explodes?A) Lysis

B) AttachmentC) PenetrationD) ReplicationAT

Overview 

 What is a virus? Structures of viruses

 How viruses reproduce Cells infected by viruses Diseases caused by RNA viruses

 The Lytic Cycle The Lysogenic Cycle Lytic Cycle vs. Lysogenic Cycle