This document contain notes and summaries taken from class which summarize: micro-organisms; viral structures; viral replication; HIV transmission and treatment.
Micro – organisms
Different types of Micro – organisms:
• Virus.
• Bacteria.
• Fungi.
• Protists.
What are micro – organisms?
➢ Organism which are too small to be seen What are they measured in?
with the human eye. - Micrometers {Чм}
➢ They are not all pathogenic. - Nanometers {nm}
➢ Some are harmful
➢ Some are used in industry.
Viruses:
- Not cells
- Non living
- Ubiquitous but inactive outside host cell.
- Use host cell to replicate.
- Pathogenic in plants and animals.
Viral structure:
# Between 20-450 mm.
# Has DNA or RNA enclosed in a protein coat
Capsid head DNA or RNA
{capsid}.
# Protein sheath is made up of sub-units called
capsomeres. Protein sheath Capsomeres
# Different viruses have different numbers of
capsomeres.
# Tail fibres and pins allow for attachment and entry
into the host cell.
Tail fibres
, Characteristics of viruses:
- They are ultramicroscopic.
- They are able to pass through ultra-filters other organisms
cannot.
- Active only within cell.
- Can only replicate within the host cell. {genetic parasites}
- Passes either DNE or RNA.
Two types of viral replication:
1. Lysogenic cycle
2. Lytic cycle {host cell dies}
Name and explain Viral replication steps:
1. Adsorption: Viruses attaches to wall of host cell.
2. Penetration: penetrates cell wall by means of its tail fibres and injects viral-
DNA into host cell.
3. Replication: Viral DNA replicates using host cell.
4. Assembly: Viral components begin to assemble.
5. Maturation: Viral components are assembled & viruses are fully developed.
6. Lysis: The numerous viruses are expelled from the host cell which is
destroyed.
Lysis: means to
“breakdown”
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through EFT, credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying this summary from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller kayleevandyk. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy this summary for R85,00. You're not tied to anything after your purchase.
