Microbiology Final (Worksheet Questions) Flashcards
Name one place on earth where microbes are not or should not be present?
In an environment that does not support life
Inner tissues, like the bloodstream (in humans and animals)
Presumably inside a volcano
Super acidic, super hot saline pond in Ethiopia
Can we hope that one day in the future we will have a planet free of microbial diseases? Explain your answer.
A) new microbes that we don’t have treatments for B) microbes become resistant to antibiotics; they mutate
Why smaller microbes (e.g. bacteria) are able to adapt to a changing environment (e.g. presence of antibiotics) faster than other living organisms like humans? (clarification: growth refers to increasing the number and not the size)
Simpler structures
More generation (divide at a faster rate) at a given time; able to mutate faster
Mutation is key to adaptation
Greater surface area
Do you think gram-negative or gram-positive bacteria would be more sensitive to organic antibiotics? Why?
Gram-positive bacteria are more sensitive to antibiotics because it is missing the second plasma membrane.
Because the gram-negative bacteria has two plasma membranes, it is harder for the antibiotic to gain entry.
Read the following sentence about Anthrax. What do you think makes anthrax capable of surviving for such a long time? Do you think anthrax is a gram-positive or gram-negative bacterium?
Gram positive - only gram positive bacterium can make endospores. It can live for such a long time because it can make endospores.
Why finding drugs that can cure fungal infection inside the human body is more challenging than finding antibiotics for the same job?
Because fungi are eukaryotic cells and humans are eukaryotic cells
Can harm our ribosomes and do damage - getting a drug that attacks the fungus also damages the human cell
Bacteria are prokaryotic, so they are different than humans
Give two reasons why it is hard to develop a vaccine for malaria
Need mass amounts to produce a vaccine; limitation is that for a vaccine to be produced, you have to mass produce malaria
- Difficult because it is in mosquitos
- Difficult to amass that amount
Bacteria, fungi, and multicellular protists all have a cell wall. Why can we not use an antibiotic that destroys bacterial cell walls to kill a fungus or a multicellular protist?
Targeting the cell wall - but the chemical structures are different (bacteria = peptidoglycan, fungus = chitin, multicellular protist = cellulose), so they aren’t as effective on both.
Why antibiotics are not effective in curing viral infections?
Antibiotics specifically target the machinery found in bacteria. Since viruses do not contain any of this machinery, the antibiotic does not have a target to attack.
While the viral structure is very different than human cell structure, why finding antiviral drugs is usually more challenging than finding antibiotics?
Viruses don't have a lot to target They get inside a human cell They can shoot your own cells Shut down your own ribosomes This is bad You damage your own cells before you can deal with the virus
Knowing that some RNA viruses have to convert their RNA genome to DNA before they are able to reproduce in the host cell, why would a virus have an RNA genome in the first place (i.e., what advantage(s) does an RNA genome have for a virus?). One reason is enough.
Its about mutation RNA mutates faster than DNA Therefore it increases genetic diversity E.g. RNA polymerase: doesn’t have proofreading mechanism, therefore lots of errors and resulting genetic modification E.g. flu virus morphs all the time
People who lack CCR5 are healthy and are resistant to HIV because HIV cannot infect a cell lacking CCR5. How can this knowledge be used to design a drug against HIV in people who have CCR5?
Cover the receptor, then the virus can’t bind.
How can bacteriophages associated with human body be indirectly harmful to human health?
Through horizontal gene transfer method of transduction, can make bacteria resistant to antibiotics that weren’t previously.
A nurse who has been working with CJD patients for 20 years has developed Creutzfeldt-Jakob Disease (CJD). There is no family history of CJD in his family and the genetic analysis shows there is no mutation in his genes (his genes are healthy). The nurse thinks that he got the disease from CDJ patients while working in the hospital. Based on this information, can we be certain that he is right?
No, why? It can happen sporadically as well, so while there is a possibility that she contracted it through the hospital, it is not with certainty
For what purposes microbial cultures are used in medical microbiology?
Determine the type of organism, its abundance in the sample being tested, or both.
It is one of the primary diagnostic methods of microbiology and used as a tool to determine the cause of infectious disease by letting the agent multiply in a predetermined medium.
