Unit 1 Short Answer Questions
Pasteur boiled broth in long, twisted neck flasks that kept the broth sterile by allowing air to be exchanged, but kept airborne microbes from entering due to them getting caught in the twists of flask
(3.1) Explain in your own words Pasteur's swan-neck flask experiment.
Virchow and Remak believed in modern cell theory (cells divide) while Schleiden and Schwann believed that cells crystalized.
(3.2) How did the explanation of Virchow and Remak for the origin of cells differ from that of Schleiden and Schwann?
people did not get re-infected
(1.1) What did Thucydides learn by observing the Athenian plague?
a way of showing how different organisms are thought to be related to one another from an evolutionary standpoint
(1.2) What is a phylogenetic tree?
evolutionary history, genetics, metabolic pathways, and cell wall and membrane composition
(1.3) Describe the differences between bacteria and archaea.
Janssen was very secretive of his work and never published
(2.2) Why is Antonie van Leeuwenhoek's work much better known than that of Zaccharias Janssen?
perform an acid-fast stain (will show up pink/red)
(2.4) How could you identify whether a particular bacterial sample contained specimens with mycolic acid-rich cell walls?
they help move the bacteria towards the chemical attractant
How do bacterial flagella respond to a chemical gradient of an attractant to move toward a higher concentration of the chemical?
prokaryotic flagellum are stiff while eukaryotic flagellum are more flexible eukaryotic flagellum are composed of nine parallel pairs of microtubules surrounding a central pair of microtubules
Name at least two ways that prokaryotic flagella are different from eukaryotic flagella.
biochemical tests, DNA/RNA analysis, and serological testing methods
Name some techniques that can be used to identify and differentiate species of bacteria.
cilia, flagella, and pseudopods
Name three structures that various protozoa use for locomotion.
water flow would go towards a more hypertonic environment cell walls help organisms maintain cellular morphology and protect them against changes in osmotic pressure
(3.3) What is the direction of water flow for a bacterial cell living in a hypotonic environment? How do cell walls help bacteria living in such environments?
they have the same 70S ribosomes
(3.4) What existing evidence supports the theory that mitochondria are of prokaryotic origin?
viruses- up to 10x smaller than bacteria bacteria- 1 micrometer plant/animal cell- 10 micrometers
Describe the actual and relative sizes of a virus, a bacterium, and a plant or animal cell.
Needham didn't boil his broth long enough to kill the pre-existing microorganisms and sealed all of his flasks. Spallanzani used sealed and unsealed flasks but without the swan neck flasks, his sealed broth became "dirty" when he exposed it to air.
Explain why the experiments of Needham and Spallanzani yielded in different results even though they used similar methodologies.
ferment foods such as beer, bread, cheese, and wine
What are some ways people use microbes?
the mitochondria and chloroplasts of eukaryotic cells are genetically similar to those of prokaryotic cells
What evidence exists that supports the endosymbiotic theory?
small subunit ribosomal RNA
What molecule did Woese and Fox use to construct their phylogenetic tree?
10%-20% mortality rate in hospitals (staffed by doctors, medical students) 1% mortality rate in wards with individual midwives He proposed that doctors should wash their hands after touching their patients and successfully dropped their patient mortality rate to 1%.
What were the differences in mortality rates due to puerperal fever that Ignaz Semmelweis observed? How did he propose to reduce the occurrence of puerperal fever? Did it work?
prokaryotic- kingdom Monera eukaryotic- kingdoms Fungi, Protista, Plantae, and Animalia
Which of the five kingdoms in Whittaker's phylogenetic tree are prokaryotic, and which are eukaryotic?
they were dead with only the cell wall as a structure
Why did the cork cells observed by Robert Hooke appear to be empty, as opposed to being full of other structures?
they have more organelles that need to be bound together
Why do eukaryotic cells require an endomembrane system?
microbes cannot be seen with the naked eye
Why was the invention of the microscope important for microbiology?
