Disease Flashcards
How do bacteria replicate?
3 ways to classify bacteria.
Staining
Shape
Clustering
2 staining outcomes.
Gram +
Gram -
4 bacteria shapes.
Cocci (spherical cells)
- diplo = pairs
- strepto = chains
- staphylo = clusters
Bacilli (rod shaped)
Spirilla (spiral shaped)
Vibrio/filamentous (like a comma)
3 types of bacterial clusters.
Diplococci (pairs)
Streptococci (chains)
Staphylococci (cluster)
How do viruses replicate?
5 steps of viral replication.
- Adsorption
- Penetration
- Replication
- Assembly
- Release
Describe the 1st stage of viral replication (adsorption).
Viral binds to the host cell.
Describe the 2nd stage of viral replication (penetration).
Virus injects its genome into host cell (DNA or RNA).
Describe the 3rd stage of viral replication (replication).
Viral genome replicates using the host’s cell machinery.
Describe the 4th stage of viral replication (assembly).
Viral components and enzymes are assembled into coats.
Genome is packaged inside.
Describe the 5th stage of viral replication (release).
Host cell lyses and many more viral particles can infect other cells within host.
Describe reverse transcriptase.
Some viral particles containing RNA use it to replicate
- RNA is converted to DNA.
- They use the host cell machinery to replicate their genome (make their protein coats and RNA genome).
What cells do viruses infect?
Any type of cell.
Define bacteriophages.
Viruses that infect bacteria.
How are viruses classified?
Their genome
Eg: double stranded DNA, single stranded DNA, single stranded RNA, etc.
Define diseases.
Any malfunctions of the body/part of the body of an organism.
Define pathogens.
Disease causing agents.
Define infectious/communicable diseases.
Diseases that:
- Can be transmitted from one organism to another.
- Are caused by pathogens.
Define non-infectious diseases.
Diseases that:
- Cannot be transmitted from one organism to another.
- Aren’t caused by pathogens
2 non-cellular pathogens.
Viruses
Prions
Describe viruses.
Contains DNA or RNA
Molecule encased in a protein (or two protein layers) that may be covered in a lipid layer.
Shape varies greatly.
Much smaller than bacteria (0.5 to 0.01 times the size).
Can only reproduce inside a living host.
Describe prions.
Small infectious proteins
Example of a prion.
vCDJ (variant Creutzfeldt-Jakob disease)
4 cellular pathogens.
Bacteria
Fungi
Protists
Minor groups of parasites
- Endoparasites
- Ectoparasites
Describe bacteria.
Microscopic
Unicellular
Prokaryotic
No membrane bound organelles and nuclei.
Cell wall made of sugars and amino acids.
Single ‘spaghetti-like’ strand of DNA
Describe fungi.
Eukaryotic
Generally multicellular
Microscopic fungi are generally larger than bacteria.
Reproduce using spores.
Cell walls made of chitin (carbohydrate).
Contain hyphae (branching threads) that form a mass called a mycelium.
Hyphae are usually divided along their lengths by walls called septa that have pores in them to allow nutrients to pass from one cell to adjacent cells
Describe protists.
Eukaryotic.
Can be unicellular or multicellular
Reproduce sexually and asexually.
Have no complex systems.
Have a variety of shapes depending on their locomotion.
Generally cannot move themselves.
Describe endoparasites.
Live inside another organism – usually intestines
Some use other animals as intermediate hosts and humans are the definitive host.
Examples of endoparasites.
Flatworms
Roundworms
Flukes
Describe ectoparasites.
Live on the surface of another organism.
Many are vectors for other diseases such as the plague (bacteria).
Examples of ectoparasites.
Fleas
Ticks
Lice
Define virulence.
The intensity of the effect of the pathogen.
Define susceptibility/resistance.
The level of response of an organism to a pathogen.
Define symptoms.
Characteristic effects of a pathogen on the body.
Signs of the disease in the host.
Define incubation period.
The time between infection and the onset of symptoms.
4 parts of a pathogenic infection.
- Infection
- Incubation
- Symptoms
- Recovery
Define endemic diseases.
Occur at a relatively constant rate within a population
Define sporadic diseases.
Uncommon
Occur irregularly
Define epidemics.
Occur when there is an increase in the number of cases of a disease within a population is above normal
Rapidly spread.
May be triggered by:
- Increased virulence
- Introduction into a novel setting
- Changes in host’s susceptibility
Define pandemics.
An epidemic
Infects large numbers of humans over multiple populations/continents/worldwide.
Rapid spread over multiple populations/continents/worldwide.
Factors involved in the spread of disease.
Climate
Population density (urbanisation)
Infrastructure
Urban areas susceptible to epidemics and pandemics
What are the hosts of Influenza (virus)?
Numerous animals
- Humans
- Mammals
- Birds