What is botany?
It is the study of plants and plant products.
What is the smallest organism known and when was it discovered?
The Prion. 1983 - 1984
Classify in order of size: Virus, Viriods, Prion
Prion, Viriods, Virus
When did Linnaeus classify life into Plantae and Animalia
1776
When was the virus discovered?
1952, after the development of the electron microscope
Characteristics of prions
- They are misfolded proteins with the ability to transmit their misfolded shape onto normal variants of the same protein
- They contain proteins but lack nucleic acids
- They are responsible for a number of degenerative diseases in humans.
What are the diseases caused by prions?
- Scrapie
- Bovine Spongiform Encephalopathy (BSE) in cattle (commonly known as “mad cow disease”)
- Creutzfeldt–Jakob disease (CJD) in humans (Kuru)
Describe Viroids
- Small, highly-structured RNA genome-lacking protein capsules
- They are mainly RNA
- Preserved and transmitted to cells where they are replicated.
How many ribonucleotides do viroids have?
245 to 375
Diseases caused by viroids
Potato spindle tuber
Avocado sun blotch
Coconut cadang-cadang
What is a major difference between viruses and viroids?
Viroids introduce far less genetic information into host cells.
When did we get a hint of the existence of viruses?
1884 by Charles Chamberland with the incention of bacteria filters
What makes replication of viruses unique?
They lack cell structures or organelles/
What is the only characteristic of living things that viruses possess?
Reproduction, more accurately, replication
Which cell organelle do viruses use in replication?
Golgi apparatus of the host
How many types of nucleic acids can a virus have at a time?
Just one… DNA or RNA
Why are viruses referred to as obligate parasites? What else are they called?
They can only replicate inside living cells.
Absolute parasites
What is the difference between plant and animal viruses?
Plant - Only RNA
Animal - Only DNA
How do viruses infect their host?
- They take over the protein synthesis of the host and commands the host to produce more viral protein than host protein
- Once incorporated into the host system, it begins to kill or eradicate it.
What is replication?
It is the use the use of metabolic apparatus of the host to produce more of the virus.
General characteristics of viruses
- Cannot be seen with the naked eye
- Can only be seen with electron microscope. Their size is 20 to 300nm
- Cannot live in cell-free region
- Either DNA or RNA
- Contain naked chromosomes only found in living host
- No organelles
- No nuclear membrane, Prokaryotes
What are the criteria used for classifying viruses?
- Morphology
- Serology and electrophoresis
- Bichemistry
- Disease symptom
- Mode of transmission
What are the modes of transmission of viruses?
Mechanical
Insect or animal
How can we handle viral diseases?
- Vaccination
- Immunization
- Exclusion from infected person
