of a host cell, using their resources and energy.
Outside of a host they are considered intert.
When are Viruses considered to be "alive"? - Answer When they are inside of a host cell.
When inside, their nucleic acid (ONLY RNA OR DNA) become active.
*Virus replicates
Obligatory Intracellular Parasites - Answer Require livinghost cell in order to multiply - Such as
Viruses.
Defining a Virus - Answer 1) Contains 1 Nucleic Acid (DNA or RNA)
2) Protein coat surrounds the DNA or RNA
3)Multiply within host using host machinery
---because they don't have the ways of making/obtaining their own nutrients. like ATP or
enzymes.
Virus Characteristics - Answer *Some are enclosed by an envelope which consists of lipids,
proteins, carbohydrates
*some have spikes
*only infect the cells of ONE host.
Host Range - Answer The spectrum of host cells that a virus can infect.
-invertebrates
-vertebrates
-plants
-protist
-fungi
,**Host range is determined b specific attachment sites on the host cell's surface
Bacteriophages - Answer Bacteria that is infected by a virus
How do Viruses attach to a host cell - Answer Through receptors on the host cell's surface.
There must be an interaction.
Capsid - Answer Protein coat that surrounds the Nucleic Acid of a virus. (not the whole virus
itself. That's an envelope.)
****Made up of individualized Capsomeres****
*accounts for most of the mass of a viral cell.
Capsomeres - Answer Protein subunits that make up a capsid
(think of tiny balls that come together to make a huge coating around the Nucleic Acid)
*capsomeres can be made up of multiple types of proteins or one single type of protein
Envelope - Answer Surrounds the virus as a whole.
*Synonymus to a somatic cell's Plasma Membrane. But around a virus.
***Composed of proteins, lipids and carbs.
*Could be covered in spikes
NOT ALL VIRUSES HAVE ENVELOPES
Spikes - Answer Cover the envelope of the cell
Composed of protein and carbohydrates.
, Spikes differ, and can be identified as different virus by the host body. That's why you can get
the flu more than once a year, there's a change in spikes.
-Can be used for identification for some virsus under microscope.
Helical Capsid - Answer Long rods that are flexible and rigid
These surround the Nucleic Acid.
*Capsids are hollow cylinders surrounding the nucleic acid.
*CAN OR CANNOT HAVE A ENVELOPE.
Without envelope = they look like long noodles, because it's just the capsid and no sphereical
shape
WITH the envelope = they look like balls, but with their Nucleic acids all tangled inside.
Polyhedrical Capsid - Answer These are icosahedron, and are 20 triangle shapes, with 12
corners.
THEY CAN BE WITH OR WITHOUT ENVELOPE
-Without envelope, you can see their individual caposomere and their many different triangular
faces of the Capsid
WITH envelope, they appear ordinarily spherical, and like a normal cell. (Some have spikes)
Complex Capsid - Answer They have a variety of weird shapes within the one virus cell, and
look just straight up weird.
They can be bacteriaphages and just look mutuant
Family names suffix for Taxonomy - Answer -viridae
Ex. Herpesviridae