Microbiology 260 (LCC) Exam 1 (Questions and Answers) 100% Already Graded A+ Excel

Microbiology 260 (LCC) Exam 1 (Questions and Answers) 100% Already Graded A+ Excel List the three domains - CORRECT ANSWER-Archaea, Bacteria, and Eukarya Summarize the characteristics of archaea - CORRECT ANSWER-prokaryotic, lack peptidoglycan, live in extreme environments Summarize the characteristics of bacteria - CORRECT ANSWER-Prokaryotes, peptidoglycan cell walls, binary fission, org/inorganic chemicals or photosynthesis for energy Summarize the characteristics of algae - CORRECT ANSWER-Eukaryote, cellulose cell wall, photosynthesis for energy, prod. molecular O2 and organic compounds Summarize the characteristics of protozoa - CORRECT ANSWER-Eukaryotes, absorb/ingest org. chemicals, motile via pseudopods, cilia, or flagella Summarize the characteristics of fungi - CORRECT ANSWER-Eukaryotes, chitin cell walls, org. chemicals for energy, molds/mushrooms multicellular, yeast unicellular List at least 4 ways microbes affect our lives - CORRECT ANSWER-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 ANSWER-2 Contrast prokaryotic and eukaryotic ribosomes - CORRECT ANSWER-Prokaryotic (70S) ribosomes are smaller than eukaryotic (80S) ribosomes. Eukaryotic ribosomes are membrane bound to ER List some functions of bacterial inclusion - CORRECT ANSWER-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 ANSWER-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 ANSWER-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 ANSWER-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 ANSWER-O157 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 ANSWER-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 ANSWER-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 ANSWER-a barrier that prevent charged particles and large molecules from moving across them Describe the structure and function of a glycocalyx - CORRECT ANSWER-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 ANSWER-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 ANSWER-It helps protect the cell from phagocytosis Describe the functions of fimbriae - CORRECT ANSWER-Help bacteria attach, contribute to biofilms Describe the functions of (sex) pili - CORRECT ANSWER-Facillitate transfer of DNA from one cell to another Describe the structure and function of flagella - CORRECT ANSWER-tail-like structures not usually seen under a light microscope. Help some bacteria move What is the H antigen? - CORRECT ANSWER-The H antigen helps with cell adhesion Describe the results of a cell being isotonic - CORRECT ANSWER-No movement, cell membrane is attached to cell wall Describe the results of a cell being hypotonic - CORRECT ANSWER-Water particles move into cell, cell wall counteracts osmotic pressure to prevent swelling and lysis Describe the result of a hypertonic solution - CORRECT ANSWER-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 ANSWER-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 ANSWER-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 ANSWER-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 ANSWER-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 ANSWER-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