Acellular pathogens

Exam 3

what is the structure of a virus?

size-smaller than bacteria, and are different shapes, infectious particle called virion contains nucleic acid, and protein coat (capsid), and sometimes an envelope.

What are the 4 types of genomes a virus can have?

single-stranded DNA or RNA , double- stranded DNA or RNA

Capsid

The protein coat protecting the genetic information in a virus, composed of protein called capsomeres. Forms a cage, takes different shapes. 

Envelope

A lipid-bilayer apart of plasma membrane surrounding the capsid of some viruses, composed of lipids, proteins, and carbohydrates. Spikes are attached to it, an important molecule for the virus

Spike

receptor on envelope, consists of glycoprotein and some sugars. Important for adhesion and internalization (key for entry)

viral enzymes

copies genetic info, important for reproduction

Between an envelope and non-envelope, which is more harder to get rid of?

Non-envelope viruses are harder to eliminate due to disinfectants target envelopes being leading to the destruction of the spike and not able to infect, in non-envelope the spike stay because they are attached to proteins.

Nucleic acid

linear, circular chromosome or RNA, serving as the genetic material of the virus to make new viruses.

Name the two types of viruses

differs in structures; envelope vs non-envelope viruses

HIV Life cycle

1. Adhere and enters cells: uses their receptors to attach to CD4 T-helper cells and brings virus in (controls immune system) no symptoms present, except immunosupression

2. Reproduction: uses its viral enzymes to copy the genetic information (Rtase) RNA to DNA. Next enzyme, Integrase, integrates into the host cell's genome, allowing it to replicate with the host's cellular machinery. Lastly, Protease, processes viral proteins for assembly and release.

3. Assembly: all viral component made, merge to make a whole viral particle

4. Leaves cell: The virus buds off from the host cell, acquiring an envelope if present, and can infect new cells, continuing the cycle.

What is the morphology groups of the virus?

Helical, polyhedral, enveloped, complex

What would NOT be found as a component of a bacteriophage?

envelope

Are viruses located in the Domain system?

No, viruses are not classified within any domain as they are considered acellular and must use host machinery to multiply.

What defines viral species?

population of viruses with similar characteristics (morphology, genes, enzymes) that occupy a particular ecological niche.

Is there specific epithets used?

NO

How is Taxonomy for virus grouped?

based on nucleic acid type, its replication strategy, and morphology.

How DNA/ RNA viruses are taxfied?

single or double stranded, envelope or non, capsid: helical or icosahedral

How is the family name picked for viruses?

Family name is taken from the viruses who represents the most within the family.

what is -ales

order names

Because viruses have common names, what is typically paired with the species?

subspecies are designated by a number. 

Which of the following infectious particles do NOT have protein in their structure?

Viroids and prions.

Virulence factors on viral diseases

are molecules produced by viruses that enhance their ability to cause disease in a host.

Types: tropism and adhesion, very specific and adheres via its spikes; inhibiting cell death: apoptosis (disables this by neutralizes Tc & NK cells); Replication: some can multiply so fast or not (immune system at work); Immune evasion: attack WBCs directly; Inflammation; antigenic variation: able to change constantly, genetic shuffling occurs between two strains and mutations allow for evasion of host immunity.

What is important about attenuated vaccines?

contain live pathogens that have been weakened so they cannot cause disease but still provoke a strong immune response. They help build immunity by stimulating the body's immune system without causing illness.

What is the problem with attenuated vaccines?

They may cause disease in immunocompromised individuals or revert to a pathogenic form.

Where do viroids and prions fall within the system?

They dont have a category, we dont know enough to classify them.

prion

infectious proteins that cause neurodegenerative diseases in animals and humans

viriod

a small, circular RNA molecule that infects plants and leads to disease.

Tropism

The specificity of a virus for a particular host tissue or cell type.

HIV

Human Immunodeficiency Virus, a virus that attacks the immune system and can lead to AIDS.

Bacteriophage

A type of virus that infects bacteria, typically consisting of a capsid and tail fibers.

Viral Assembly

The process by which viral components are assembled into new virus particles within a host cell.

Chromosome Integration

The process where viral DNA integrates into the host's chromosome, often leading to latency.

Viral Replication Cycle

The series of steps a virus goes through to reproduce, including attachment, entry, replication, assembly, and budding.