BioSc221/325 Exam 1 Name ______________________________Multiple choice. (1 point each) Choose the one best answer to each of the following questions.____ Based on evidence from fossilized stromatolites, the earliest microorganisms came into existence at least A. 6000 years agoB. 3 million years agoC. 60 million years agoD. 3.5 billion years ago____ Thiomargarita namibiensis (sulfur jewel of Namibia) holds the current worlds record as the largest prokaryotic organism (some cells are greater than one millimeter in diameter). Why are prokaryotic organisms of this size unusual?A. The low surface of volume ratio of such large cells creates problems for intracellular transport processes.B. The membranes of such large cells become very unstable.C. Synthesis of the peptidoglycan polymer for making the cell wall becomes limiting.D. The organelles of such large cells become too large.____ Escherichia coli strain O157:H7 is a dangerous strain that can cause severe illness, particularly in young children, immunocompromised adults and the elderly. The O157 part of the strain designation refers to A. the location where the strain was isolatedB. the number of the gene that produces the bacterial toxin which causes the severe symptomsC. a specific polysaccharide component of the lipopolysaccharide found on the surface of the bacteriumD. the first outbreak was associated with a contaminated bottle of Heinz 57 steak sauce used at Jack-in-in-the-Box.____ The diamino acid containing pentapeptide involved in cross-linking adjacent peptidoglycan polymers is associated with which component of the peptidoglycan chainA. NAMB. NAGC. N-acetyl --LysineD. bactoprenol____ The enzyme lysozyme which is found in human tears helps protect the eyes from bacterial infection. Lysozyme damages bacteria byA. penetrating the cytoplasmic membrane and lysing the cell from withinB. degrading porin proteins in the outer membrane and preventing nutrient uptakeC. cleaving the -1,4 linkage of the peptidoglycan polymerD. degrading lipoteichoic acid____ Which of the following would be found in the cell wall of Gram-negative but not Gram-positive bacteria?A. lipopolysaccharide B. teichuronic acid C. teichoic acid D. fimbrae ____ Which of the following distinguishes prokaryotic flagella from eukaryotic flagella?A. Prokaryotic flagella are make entirely of proteinB. Prokaryotic flagella are not surrounded by a cell membraneC. Prokaryotic flagella rotate like a motorD. All of the above distinguish prokaryotic flagella from eukaryotic flagella____ Approximately 2 billion years ago, a dramatic increase in biodiversity is observed in fossilized stromatolites. This coincides with what significant event?A. The sudden appearance of eukaryotic organisms.B. The sudden appearance of photosynthetic organisms.C. An significant increase in molecular oxygen in the atmosphere.D. The sudden appearance of animalsE. The sudden appearance of plants.____ Where is lipopolysaccharide found?A. In the cytoplasmic membraneB. In the periplasmC. In porinsD. In the outer membrane ____ What is a protoplast?A. A bacterial cell that has lost its peptidoglycan layer causing it to round up and become osmotically sensitiveB. An intracellular structure containing chloroplastsC. A round bacterial cellD. The first bacterial cell____ Which of the following is NOT an intracellular feature of bacteria? A. gas vacuoles B. poly--hydroxybutyric acid (PHB) C. metachromatic granules D. fimbrae____ Curved bacteria that are shaped like a simple "bent rod" are called A. spirilla B. spirochaetes C. vibrios D. commas____ The Winogradsky column is A. an enrichment culture B. named for a microbiologist C. a way to see growth and succession of anaerobes D. all of the above____ An organism that uses light as its energy source and carbon dioxide as its carbon source is called a A. PhotoautotrophB. PhotoheterotrophC. ChemoautotrophD. Chemoheterotroph____ Sergei Winogradsky discovered chemoautotrophic organisms by setting up enrichment cultures containingA. Only H2S as an energy source and only CO2 as a carbon sourceB. Only glucose as an energy source as well as a carbon sourceC. Only H2S as an energy source and only glucose as a carbon sourceD. Only light as an energy source and only glucose as a carbon source____ MacConkey medium is a common medium used in the clinical microbiology laboratory. MacConkey medium contains peptone, lactose and a pH indicator so that lactose fermenting organisms turn red and oxygal, a compound that inhibits the growth of Gram-positive bacteria. MacConkey would best be described as a ___ medium.A. definedB. differentialC. selectiveD. both selective and differential____ Which of the following is not a technique for isolating a pure culture of a specific bacterium?A. Streak plateB. DilutionC. EnrichmentD. All of the above techniques are used for isolating bacteria____ Which of the following is the most accurate method for counting bacteria?A. Direct countB. Viable countC. TurbidityD. Cell mass measurement____ A chemostat is used forA. large scale batch culturing of bacteria for commercial useB. enriching for chemoheterotrophsC. continuously counting bacteriaD. continuous culturing of bacteria under constant, defined conditions____ Which of the figures below shows the behavior of bacteria [viable count (solid line) and total count (dashed line] after addition of a bacteriostatic agent?A. Figure AB. Figure BC. Figure CD. None of the Above.____ Catalase activity is a classic diagnostic tool for certain groups of bacteria. The function of catalase in a bacterial cell isA. to detoxify the toxic oxygen species - hydrogen peroxideB. to protect the cell from osmotic stressC. to protect the cell from elevated pHD. to cause cat-scratch disease____ Halophilic bacteria protect themselves from potentially dangerous osmotic imbalance by either producing or acquiringA. a thick cell wallB. a high G+C content in their DNAC. new phospholipidsD. compatible solutes____ Listeria monocytogenes grows optimally at 30 degrees centigrade but also grows at 4 degrees centigrade, it would be bestdescribed as A. PsychrophilicB. MesophilicC. ThermophilicD. Hyperthermophilic____ Which of the following is not a strategy used by bacteria to tolerate elevated growth temperatures?A. Changing the lipid composition of their cytoplasmic membraneB. Producing and acquiring compatible solutesC. Having DNA composed of a high G+C contentD. Modifying critical enzymes to be more