Infection biology! Flashcards
Where does all life stem from?
One universal ancestor
What are the two domains of prokaryotes?
Bacteria and archaea
Describe a “mutualistic” relationship
A relationship between two organisms where both benefit
Describe “commensalism” in terms of a relationship
A relationship between two organisms where one benefits and the other remains relatively unaffected.
Describe “parastitism”
A relationship between two organisms where one benefits and the other is harmed.
Name the three relationship types of symbiosis.
Mutualism, commensalism and parasitism.
Name at least three ways in which microbes are used.
Agriculture, disease, food, energy/environment, biotechnology
What instrument is needed to be able to view prokaryotic cells?
Light microscope.
Where do Prokaryotic and Eukaryotic cells store their genetic information?
Prokaryotes = plasmids or bacterial chromosomes. Eukaryotes = Nucleus
Give three examples of membrane-bound organelles.
Mitochondrion, chloroplasts, Golgi apparatus.
Name the three main components of a flagellum.
The basal apparatus, the filament, the hook.
what is the function of a Fimbriae?
Allows them to stick to their substrate or others in the colony.
What is the function of Sex Pili?
Allow prokaryotes to exchange DNA.
What are 2 benefits of bacterial cell wall structures?
Protect the cells from osmotic lysis and toxic sustances.
What are the two types of Gram strains? What does this depend on?
Positive and negative. Depends on the composition of bacterial cell walls.
where do viruses reproduce?
In a host cell.
Define virus.
A very small infectious particle.
why would a virus be called a “DNA virus” or an “RNA virus”?
Depends on whether or not they have (double or single-stranded) DNA or RNA.
What is a capsid?
Protein shell which encloses the viral genome, made up from smaller protein units called capsomeres.
What are bacteriophages?
Viruses which infect bacteria.
What is the lytic cycle
The phage reproductive cycle that culminates in host cell death as viral genome leaves the cell. Virulent phage only reproduce by this cycle.
describe the lysogenic cycle
Viral DNA is incorporated into host cell chromosome, called a prophage. Every time the host cell then divides, it copies the viral DNA too. Environmental factors then trigger the lytic cycle.
Describe some of the features of animal virus reproductive cycles.
The viral genome enters the cell and begins to use the cells organelles to make new viruses
Name and describe one way viruses evade immune detection
Viral envelopes. Surround viruses to help evade detection.
What enzyme do retroviruses use to copy their RNA genome into viral DNA?
Reverse Transcriptase
What is the name once the viral DNA becomes integrated into the host?
Provirus
what can happen if there are major changes to surface antigens on influenza?
Large regional outbreaks or global pandemics
Name the two major surface antigens of influenza
HA (hemagglutinin) and NA (neuraminidase)
Why are viral strains that jump species so harmful to the new host?
They can exchange genetic info with other viruses to which they have no immunity to.
What are Viroids and what to they infect?
Viroids are extremely simple infectious agents - single circular RNA molecule.
What are Prions and how do they affect humans?
They are slow-acting, virtually indestructible infectious proteins which cause brain damage in mammals.
True or false: Each body location provides a different environmental niche in which microbes can grow.
True
Where do you find the highest concentration of bacteria in the body?
The large bowel
Name two ways normal microbiota protect us.
Protect from physical colonisation from: Other humans, other animals, the evolution of organisms.
Define the microbiome
Microbes, their genomes + environmental interactions in a defined environment
Are changes in the human microbiome associated with human health or disease?
Both are affected. Linked to diabetes, obesity, heart disease etc.
What does the human host provide for the gut microbiome?
Warmth, food and a physical place for the biome to exist
Name three ways microbes are passed between humans.
Sneezing, saliva, sex, failing to wash hands after the toilet, insect bites, cuts in the skin
Name the 5 principles of pathogenesis
- Invade the host 2. Evade the innate immune response and spread 3. Multiply 4. Evade the adaptive immune system long enough to complete life cycle 5. Spread to a new host.
Name two ways that help prevent infection
High-quality hygiene and Vaccines
When vaccines are unavailable, what is another type of medicine that can kill bacteria?
Antibiotics - causes bacteria to lyse under osmotic pressure.
Name a problem with antibiotics
Some bacteria are becoming resistant to antibiotics.
Describe the condition on which anti-viral agents work
They must inhibit the multiplication of the virus but not the whole host cell.
Name 3 food processes microbes are essential for
Bread (yeast), Beer & wine (yeast), vinegar (Acetobacter)
What bacterial protein is used to make Quorn?
Pruteen
How are microbes used in sweage works?
To break down the organic material in sewage
What do autotrophs use as a carbon source and what do they use for energy?
Autotrophs require CO2 as a carbon source and use inorganic compounds for energy
What do heterortrophs use to make organic compounds and what do they use for energy?
Heterotrophs require an organic nutrient to make organic compounds and they use organic carbon as an energy source.
What is Bioremediation?
The use of microbes to break down dangerous chemicals.
True or false: Bacteria cannot be used to make biodegradable plastics?
False. yes they can.
Name two ways that bacteria can be said to be great microbial factories
- Can produce useful compounds already encoded in bacterial genome 2. Can be genetically manipulated to make them produce useful exogenous molecules
Name three pharmaceutical products made using microbes
Vaccines, complex vitamins, antibiotics
Name one way in which viruses can be used for good
They are sometimes used as vectors to deliver genes in specific cell types e.g. bone marrow
What would happen if a Viral vector loaded genes near an oncogene?
Cancer could be triggered.
Is human gene therapy easier to use for single or multi-gene disorders?
Single gene disorders are more easily treated.
