BI 305 Exam 1 Chp 1-3 Flashcards
Definition of Microbiology
Microbiology=study of organisms too small to be seen with the naked eye.
Why are microbes important?
Contribute to human health
Digesting food we can’t, providing vitamins for us, and so much we don’t know.
There is some evidence that can contribute to our mood and overall general health.
Nutrient cycling.
Carbon, nitrogen, etc.
Provide oxygen.
While plants do this as well, cyanobacteria still provide a lot of oxygen.
Break down waste.
Can be seen as part of the cycling they play a role in.
What are bacteria? Some common characteristics?
Has a cell wall of peptidoglycan.
Peptidoglycan=peptide linked sugar molecules that restrict expansion of the cell to maintain cell turgor.
Replicate through binary fission.
Eat organic substances, inorganic substances, or photosynthesize.
What are archaea?
They don’t have organelles or a nucleus but they don’t have any peptidoglycan.
Live in extreme environments.
Ex: Methanogens, thermophiles, halophiles.
What are protoza?
Protoza=unicellular eukaryotic microorganisms.
What are algae?
Algae=photosynthetic eukaryotes.
Can complete asexual and sexual reproduction.
Cell walls contain cellulose.
What are fungi?
Fungi=unicellular or multicellular eukaryotic organisms.
Cell wall made of chitin.
Asexual and sexual reproduction.
Obtains food by absorbing it from the environment.
What are viruses?
Viruses=acellular microbe.
DNA or RNA as genetic material.
Only reproduces through a host.
Parasites
Only does things required by the “living” definition inside of a host.
Thus, one argument is that viruses are only alive when they are inside of a host.
What is a +RNA virus?
+RNA virus=contains mRNA that can be directly translated into proteins.
They contain the sense strand.
No transcription needed.
5’-3’.
What is a -RNA virus?
-RNA virus=contains antisense RNA that is complementary to mRNA.
Needs to be transcribed then translated.
3’-5’
What are some reasons that viruses are alive?
They need energy to survive.
Evolved from cells.
Not for all viruses but for some of them.
They make copies of themselves.
What are some reasons that viruses are not alive?
They need a host to survive.
Can only replicate while inside of a host.
They are not a cell.
What significant experiment is Carl Woese do?
Used 16S RNA as a molecular clock to understand the evolution of microorganisms.
Proposed the 3 domain idea between bacteria, archaea, and eukaryotes.
16S RNA was used because it mutates at a slow but stable rate.
By comparing microorganisms, he could see how different their 16S RNA was, how closely they were related to each other, and when they diverged.
Who used faster sequencing techniques to sequence the entire genome of H. influenza?
Claire Fraser-Legget
Who was Florence Nightingale?
Most notable known as a nurse.
In addition, she founded medical statistics by showing how many soldiers die more from infections than on the battlefield.
Who was Robert Hooke?
First used a microscope to see cells.
Named the term cells.
Who was Antoine van Leeuwenhoek?
Antoine van Leeuwenhoek generated better microscopes up to 300X to see microbes.
How have microbes shaped humans and human history?
Plagues such as the bubonic plague.
In our gut to influence us.
We use microorganisms for fuel, and research into medicines, antibiotics, and antivirals.
What is spontaneous generation? Why did people believe this?
Spontaneous generation=living things suddenly generate from non-living matter.
People thought that microorganisms did this since they seemed to randomly appear.
What were some experiments to disprove spontaneous generation?
Experiments included:
Letting meat sit in a closed container vs an open one.
The open one was spoiled.
Pasteur’s S-shaped flask.
The air was allowed in and out but microorganisms could not.
Who was Pasteur?
S-neck flask to prove that microorganisms couldn’t grow on boiled broth.
Founded autoclaving.
Autoclaving=killing microbes in high heat.
The high heat is achieved by increased pressure.
Discovered yeast developed alcohol by fermentation.
Before this, people couldn’t determine why some products became an alcohol and some didn’t.
Developed vaccine for rabies.
Who was Joseph Lister?
First to propose handwashing and sanitation for doctors.
What are Koch’s postulates?
See if the people with the same symptoms have the same microbe.
This microbe must be absent in healthy individuals.
Microbe must be isolated from the diseased host.
Put isolated microbe from the diseased host into a healthy individual.
Do they develop the same disease?
Isolate microbe from the newly infected host.
Is it the same?
How are Koch’s postulates viewed today?
Still holds up okay today.
The major issue is ethical problems with infecting someone who is healthy.
Other methods such as contract tracing can show how people got sick.
What did the Hesse couple develop?
Developed agar as an organic solid substrate for culturing microorganisms.
What are single colonies? Why are they important?
Single colonies=colonies grown from a single microbe.
They are more likely to be genetically similar.
How does immunization work?
The virus is attenuated (slightly alive but weakened by being left outside of a host), uses an mRNA vaccine, heat the virus to kill it, or inoculate someone with a small piece of the virus.
What was the first immunization/vaccine?
Edward Senner first vaccinated people from smallpox by infecting them with cowpox.
Cowpox was a similar but much less dangerous disease.
This occurred 70 years before Koch.
Why did it take so long for people to realize that microbes cause disease?
They couldn’t see the microorganisms so they didn’t know they existed for a long time.
Because they were so small and it was hard to separate them, it was hard to see what was a pathogen and what was a healthy microbe.
What were some innovations to connect microbes to disease?
Microscopes.
Culturing microorganisms
Agar.
S-shaped flasks.
What is immunity?
Immunity=protection from the disease by recovering from it or getting a vaccine.
Immunity does not guarantee that you can’t still get it, be asymptomatic, and spread it to others.
What is chemotherapy?
Chemotherapy=treating diseases with a chemical substance.
What are synthetic drugs? What was the first synthetic drug?
Synthetic drugs=chemicals manufactured in a lab.
Salvarsan by Paul Ehrlich was the first synthetic drug.
Treated syphilis.
What are antibiotics? What was the first antibiotic?
Antibiotics=chemicals produced by bacteria that are toxins to other bacteria.
Alexander Fleming made the first antibiotic, Penicillin.
What experiment led to the discovery of viruses?
Dmitiri Ivanosky identified the virus causing tobacco-mosaic disease.
Ivanosky used smaller and smaller filters until no bacteria were small enough to go through.
The only thing that it could be was a virus because viruses are smaller than bacteria.
What are Winogradsky columns?
Winogradsky columns=studies microbio ecology by observing how microorganisms arrange themselves in the environment and what they produce.
What are chemolithotrophs?
Chemolithotrophs=mircobes that feed on inorganic substances.
Cannot grow on agar because it is organic.
Enrichment cultures can grow chemolithotrophs.
What is nitrogen fixation?
Bacteria turning N2->NH3 for plants to use it.
What are endosymbionts?
Endosymbioant=organism living inside of a larger organism.
Who proved that mitochondria and chloroplasts are endosymbionts? What was the evidence for this theory?
Lynn Margulis proposed this theory.
Evidence:
Same size as bacteria.
Same DNA and RNA as bacteria.
What is biofilm?
Biofilm=microbial community containing several different species adhered to a surface.
What is gene therapy?
Gene therapy=inserting a missing gene into a genome to provide the missing instructions whose lack of presence is causing a disease.
Delivered through a depleted virus.
What is the difference between antiseptics and antibiotics?
Anti-septics kills off all microbes (including human cells) while anti-biotics kill only certain bacteria.
What types of organisms live at the top of Winogradsky columns? What types of organisms live at the bottom of Winogradsky columns?
Aerobic; anaerobic.
What is the difference between the microbiota and the microbiome?
Microbiota=ecological community of microorganisms living on or within an organism.
The microbiome is very similar to microbiota but emphasizes their collective DNA sequences.
Why is it hard to classify microbe species? When do two microbes become different species?
It is hard to classify microbial species because they produce asexually and can exchange genetic information with other species.
A working definition to classify includes that two different microorganism species will not be more than 95% alike.
What is the chemiosmotic theory?
Chemiosmotic theory=energy storage for redox reactions comes from the movement of H+ ions across a membrane.
Like in photosynthesis and cellular respiration.
Who was Rosalind Franklin?
Used X-ray crystallography to determine the structure of DNA.
Watson and Crick used her data of the structure of DNA but denied it.
She died of ovarian cancer before the Nobel Prize could be awarded to her.
What is resolution?
Resolution=smallest difference where two separate objects can be distinguished as separate.
Naked eye resolution is around 150 um.
What is detection? How is it different than resolution?
Detection=an object is determined as present.
We can detect what we can’t resolve.
Ex: See bacterial colonies but can’t see the individual cells.
What is magnification?
Magnification=increases the image of the object so our eye can resolve the object.
What is a millimeter?
1 millimeter=10^-3
What is a micrometer?
1 micrometer=10^-6
What is a nanometer?
1 nanometer=10^-9
