Bio182: Viruses, Chapter 27

What are the 5 stages of the lytic cycle?

1. Attachment of virus to bacterium 2. Injection/penetration — entry of viral genome 3. Replication — viral components are put together 4. Assembly — components are put together inside cell 5. Lysis/Rupture — Viral exit, rupture of host cell

So what 2 ways does a virus enter a plant?

1. Enter in damaged tissue (the cell wall has to be damaged in order for the virus to get in) 2. Enter using insect vector (meaning the insect can damage the plant, and the virus can use that to get in)

Animals viruses are based on what 3 classifications?

1. Genetic material 2. Shape of the virus (helical or icosahedral) 3. Enveloped or naked

What are the two basic shapes of a virus?

1. Helical 2. Icosahedral (is a symmetrical shape that makes 20 identical triangles)

Bacteriophage expresses which 2 reproductive cycles?

1. Lytic cycle 2. Lysogenic cycle

What are 3 infection symptoms of a plant RNA virus?

1. stunting of growth 2. distortion of growth 3. loss of chlorophyll/pigment (spotting, variegation)

What is harder to kill: a virus or a bacteria?

A virus is harder to kill than a bacteria

When was AIDS first reported?

AIDS was first reported in the USA in 1981

What is bigger: virus or bacteria?

Bacteria is larger than virus

This defines... "A virus that infect bacteria"

Bacteriophage

What is an example of a virus?

HIV (Human Immunodeficiency Virus)

What does HIV cause?

HIV causes acquired immune deficiency syndrome (AIDS)

What is an example of a lysogenic virus?

Herpes virus

This defines... "When a virus goes from lytic to lysogenic"

Induction

Describe how the HIV looks like

Is an RNA single stranded virus (there are always 2 of them)

This defines... "virus incorporates its DNA genome into the cell's genome, without otherwise harming the cell"

Lysogenic reproductive cycle

Is nucleic acid single-stranded, or double-stranded? Circular or linear?

Nucleic acid can be all 4!

Is nucleic acid DNA or RNA? (trick question!)

Nucleic acid can be both DNA or RNA!

All viruses have two components... What are they?

Nucleic acid core surrounded by a protein coat (capsid)

Plant viruses... Are they usually RNA or DNA viruses?

Plant viruses are usually RNA viruses

This defines... "the phage DNA that is integrated into the bacterial DNA, only in lysogenic cycle"

Prophage

This defines... "Does transcription in reverse, basically (goes from RNA to DNA for transcription, instead of the normal DNA to RNA way)"

Retrovirus

True or false: "virion" and "viral particle" are the same thing

TRUE

True or false: HIV is a reterovirus

TRUE

True or false: plant viruses cannot cross plant's cellulose cell wall

TRUE

True or false: viruses are not considered to be alive

TRUE

When was AIDS first reported?

TRUE, only bacteria is susceptible to antibiotics!

True or false: viruses can only reproduce inside a cell

TRUE, they cannot reproduce outside of a cell

Temperate phages can undergo... Which cycle? Lytic, lysogenic, or both?

Temperate phages can undergo BOTH the lytic and the lysogenic cycles

What is the capsid of a virus made up of?

The capsid of a virus is made up of PROTEIN

Many viruses have an envelope. What is this envelope called as another term?

The envelope that surrounds a virus is actually a phospholipid bilayer

Which bacteriophage reproductive cycle has prophage in it?

The lysogenic reproductive cycle contains prophage

Which bacteriophage reproductive cycle kills its host?

The lytic cycle kills its host

The capsid and nucleic acid together is called a...

Virion

Virulent phages can undergo... Which cycle? Lytic, lysogenic, or both?

Virulent phages can only undergo the LYTIC cycle

Are viruses cells? Why or why not?

Viruses are NOT cells. There's no cytoplasm within the envelope, it's literally just protein with a chunk of nucleic acid and a membrane around it

What are viruses measured in?

Viruses are measured in nanometers

The shape of viruses is dependent on...

What shape the capsid creates

When a virus has an envelope it's called a ______ virus. When it does NOT have an envelope, it's called a ______ virus.

When a virus does have an envelope, it's called an enveloped virus. When it doesn't have an envelope, it's called a naked virus.