Ch 17: Bacteria and Archaea (Exam 2) Flashcards
Why are bacterial biofilms medically important?
-because biofilm can form in catheters, on teeth, and on the mucus membranes of lungs and sinuses
-bacterias in biofilms are much more resistant to immune deficiencies and antibiotic treatment then individual cells
-the more scientist learn, they may be able to develop new treatments to combat medically important bacteria
Compared to Eukaryotes, identify the organelle which all Prokaryotes lack (and is thus the defining characteristics of the Prokaryotes)
Eukaryotes-multi-celled organisms (has nucleus)
Prokaryotes-single-celled organisms that (lack a nucleus) and membrane bounded organelles
-the two prokaryote domains are BACTERIA and ARCHAEA
What is the evolutionary origin of Chloroplasts and Mitochondria according to the Endosymbiotic Theory?
-Mitochondria and Chloroplasts likley evolved from engulfed prokaryotes that once lived in independent organsisms
-this contributed to O2, creating the protective ozone layer and paving the way for aerobic respiration
-this made bacteria give rise to the Chloroplasts and Mitochondria of Eukaryotic cells
Plasmids
circles of DNA apart from the chromosome
Identify the Prokaryotic cellular structures which assemble proteins inside the cell
Ribosomes-are the structures that use the information in RNA to assemble proteins
Explain why not completing a full treatment of antibiotics may lead to drug resistance
this would lead to only the weakest bacteria dying, leaving the strongest to reproduce and spread
What is the external, rigid barrier surrounding most Prokaryotic cells?
The Cell Wall-is the rigid barrier that surrounds the cells of most bacteria and archaea
Explain why Methicillin (a type of penicillin) is a suitable antibiotic for humans (given the specific method of action)
Methicillin was suspected to exert its bacteria killing actions by inhibiting bacteria cell wall synthesis
Identify the compound in Prokaryotic cell walls that allows for Gram staining to differentiate cells
Gram Staining-this reaction distinguishes between two types of cell walls
-after a multistep staining procedure, gram POSITIVE cells retain a VIOLET stain, whereas gram NEGATIVE cells bacteria stain PINK
Explain how Pili allow Escherichia Coli and Salmonella to persist in human intestinal tracts
Pilis-hair like projections made of protein, that enable cells to adhere to objects
-it attaches to the human intestinal wall
Describe the purpose of Flagellum in bacteria
Flagellum-cells that can move
-they have a whiplike extension that rotates like a propeller, which allows them to move
-they drive the cells to favorable environments
Describe the purpose of Endospore in bacteria
Endospore-dormant, thick-walled structures that can survive harsh conditions
-It allows the bacterium to produce a dormant and highly resistant cell to preserve the cell’s genetic material in times of extreme stress
-they can withstand boiling, drying, ultraviolet radiation, and disinfectants
Is Cyanobacteria a Heterotroph, Autotroph, or both?
Cyanobacteria is an AUTOTROPH
Autotroph-“self feeders” they assemble their own organic molecules using inorganic carbon sources such as Carbon Dioxide (CO2) (plants and algae)
Heterotroph-“other feeders” acquiring carbon by consuming organic molecules produced by other organisms
-plants and cyanobacteria are photoautotophs, they use sunlight (photo) for energy and CO2 (auto) for carbon
Explain why Clostridium Tetani is an Obligate Anaerobe
Clostridium Tetani-the bacterium that causes tetanus when it infects a deep puncture wound (it is an obligate anaerobe)
Obligate Anaerobes-microorganisms that are killed by normal concentrations of oxygen (for them O2 is toxic) and they live in habitats that lack it (clostridium tetani is the perfect environment)
Binary Fission
it is an asexual process that replicates DNA and distributes it and other cell parts into two daughter cells (this occurs in prokaryotes)
