Microbiology 260 (LCC) Exam 1Questions With Correct Answers Success Guaranteed Pass At First Attempt.

List the three domains - correct answers Archaea, Bacteria, and Eukarya Summarize the characteristics of archaea - correct answers prokaryotic, lack peptidoglycan, live in extreme environments Summarize the characteristics of bacteria - correct answers Prokaryotes, peptidoglycan cell walls, binary fission, org/inorganic chemicals or photosynthesis for energy Summarize the characteristics of algae - correct answers Eukaryote, cellulose cell wall, photosynthesis for energy, prod. molecular O2 and organic compounds Summarize the characteristics of protozoa - correct answers Eukaryotes, absorb/ingest org. chemicals, motile via pseudopods, cilia, or flagella Summarize the characteristics of fungi - correct answers Eukaryotes, chitin cell walls, org. chemicals for energy, molds/mushrooms multicellular, yeast unicellular List at least 4 ways microbes affect our lives - correct answers Decompose organic waste Produce ethanol and acetone Produced fermented foods such as vinegar, cheese, and bread Produce cellulase and insulin How many chromosomes does a typical bacterium have? - correct answers2 Contrast prokaryotic and eukaryotic ribosomes - correct answers Prokaryotic (70S) ribosomes are smaller than eukaryotic (80S) ribosomes. Eukaryotic ribosomes are membrane bound to ER List some functions of bacterial inclusion - correct answers Energy storage, Co2 fixation in photosynthetic bacteria, buoyancy in aquatic prokaryotes, align along magnets field Contrast the structure of gram positive and gram negative cell walls and describe the function of the cell walls - correct answers Gram positive cell walls don't have an outer membrane where as gram negative cells do, and the Peptidoglycan layer is thin in gram negative cells and thick in gram positive cells. The cell wall prevents osmotic lysis What is teichoic acid? - correct answers A carbohydrate chain that helps stabilize peptidoglycan by increasing it's rigidity What does the lipopolysaccharide in the outer membrane of Gram negative bacteria consist of? - correct answers LPS, Lipid A, O side chain composed of sugar-like molecules. Does this help you understand why E coli O157 :H7 has an O in it? - correct answersO157 means this is the 157th kind of O antigen found in E coli, the antigens found on the tail (or flagella) are called H antigens, meaning there was 7 H antigens What is the clinical significance of Lipid A? - correct answers It is responsible for the toxicity of gram-negative bacteria, and its hydrophobic nature allows it to anchor the LPS to the outer membrane Describe the structures and functions of the prokaryotic plasma membrane - correct answers Surrounds the outside of the cell and is made up of a double layer of phospholipids and controls the movement of various substances into and out of the cell Phospholipids - correct answers a barrier that prevent charged particles and large molecules from moving across them Describe the structure and function of a glycocalyx - correct answers Surrounds the cell, helps cells adhere to surfaces and each other, contributes to biofilms and protects cell from phagocytosis What is the difference between a capsule and slime layer? - correct answers A capsule is attached tightly to the bacteria as where a slime layer is loosely attached with the bacteria How can a capsule make an organism a better pathogen? - correct answers It helps protect the cell from phagocytosis Describe the functions of fimbriae - correct answers Help bacteria attach, contribute to biofilms Describe the functions of (sex) pili - correct answers Facillitate transfer of DNA from one cell to another Describe the structure and function of flagella - correct answers tail-like structures not usually seen under a light microscope. Help some bacteria move What is the H antigen? - correct answers The H antigen helps with cell adhesion Describe the results of a cell being isotonic - correct answers No movement, cell membrane is attached to cell wall Describe the results of a cell being hypotonic - correct answers Water particles move into cell, cell wall counteracts osmotic pressure to prevent swelling and lysis Describe the result of a hypertonic solution - correct answers Water particles move out of the cell, cell membrane shrinks and detaches from cell wall Define taxis and explain how it affects bacterial survival - correct answers an oriented movement toward or away from a stimulus, this affects bacterial survival because it makes the bacteria move away something bad or move towards food or light There are two genera that produce endospores: Bacillus and Clostridium. Describe the process of endospore formation, and explain the function of endospores - correct answers DNA replicates, membrane forms around DNA, foreshore forms add. membranes, protective cortex forms around spore, protein coat forms around the cortex, spore is released. Resistant to drying, heat, chemicals, ensure survival of bacteria List evidence that supports the endosymbiotic theory - correct answers Mitochondria has own DNA, flora works for us, have their own ribosomes List the phases in a bacterial growth curve, and describe what is happening in each phase. - correct answers Lag Phase: no increase in number of living bacterial cells Log phase: big increase in number of living bacterial cells Stationary phase: plateau in number of living bacterial cells, rate of death and division roughly equal Death or decline phase: exponential decrease in number of living bacterial cells Calculate how many bacteria are present based on initial numbers and generation time - correct answers Bacteria double every generation time. 9pm = 17 million 9am = 280 trillion In 36 hrs there would be a layer of bacteria 1ft deep over the entire earth 48 hours = 2.4 x 10^24 tons of bacteria 2+2=4 4+4=8 8+8=16... Define biofilm and explain the advantage of biofilms to microorganisms - correct answers A biofilm is a complex community of one or more microorganism species, forming as a slimy coating att. to a surface bc of prod. of an extra polymeric substance that attaches to a surface or at the interface between surfaces. Advantages are that biofilms are resistant to antibiotics, exchange plasmids, protect from the immune system, and communicate between cells Describe quorum sensing - correct answers Cells in biofilms communicate through quorum sensing, by releasing chemicals called autoinducers. Bacterial cells can sense when the cell population reaches a certain number (quorum). When a quorum is reached certain genes are activated Explain the difference between the trophozoite and cyst stages of protozoa. How do these stages affect the survival of protozoa? - correct answers The trophozoite stage is where protozoa are feeding and growing, when conditions get to harsh for the trophozoite, it can become encapsulated within a protective wall and become a cyst. Trophozoite stage is when the protozoa dries out if taken out/away from source (body) and the cyst stage is where the protozoa forms a shell and can survive outside of the source (body). Differentiate between an imtermediate and definitive host - correct answers An intermediate host supports the immature or nonproductive form of a parasite where as a definitive host s