exam.docx

1\. **What is axenic culture?** 2\. **Mycelium are**   3\. **Which of the following genera produces bacterial endospores?**   4\. **Cocci, rods and spiral are**   5\. **Psychrophiles are organisms which grow best** A. At low temperatures B. In sulphur-rich media \* * 6\. **The core of a b...

1\. **What is axenic culture?** 2\. **Mycelium are**   3\. **Which of the following genera produces bacterial endospores?**   4\. **Cocci, rods and spiral are**   5\. **Psychrophiles are organisms which grow best** A. At low temperatures B. In sulphur-rich media \* * 6\. **The core of a bacterial endospore contains**   7\. **Which differential medium is used in the selective cultivation of bacteria from the** **intestines?** A. Nutrient agar B. McConkey agar C. Starch agar D. Antibiotic disc medium. E. Casein agar 8\. **A phage is** A. B. C. 9\. **Denaturing Gradient Gel Electrophoresis (DGGE) is a method which** A. Is based only on protein sequence analysis B. Can be used to create molecular fingerprints for microbial community analysis C. Measures the melting temperature of DNA D. Will allow organisms to be distinguished at sub-species level E. Was used in the late 19^th^ century 10\. **Which of the following is an example of a chemical sterilization technique** A. Use of ethylene oxide B. Autoclaving C. *Irradiation with gamma rays* D. *Pasteurization* E. None of the above 11\. **One way in which bacteria generated ATP, is by** A. The pumping of protons out of the bacterial cell across the cell membrane by bacteriorhodopsin in response to light stimulation B. By the rotation of the flagella C. Utilization of a proton gradient by ATP synthase D. Using symporters E. Breakdown of the DNA 13\. **Phototrophs are** A. Organisms which only use CO~2~ as the sole source of C B. Organisms which harvest energy from light C. Organisms which only use N from fixed atmospheric nitrogen D. spore-forming Gram negative bacteria E. All of the above 14\. **A nosocomial infection is one which**   15\. **Nitrogen is said to fixed, for example by *Rhizobium,* when**    16\. A prop**hage is** A. Anaerobic microbial processe B. Phage that integrated its genome into the host's genome   17\. **A common method to reduce the number of microorganisms in drinking water is**     18\. **What is a coliform?**   19\. **Which of the following effluent treatments results in the release of methane?**   20\. **A macrophage is a**   21\. **A commensal bacterium is** 22\. **A bacterial enterotoxin is** 23\. **A virus capable of causing cancer is called** A. Prophage B. Bacteriophage C. Can trick the cell into dividing D. All of the above E. Onco-virus 24\. **Scrapie is an example of a** 25\. **Thirty-eight colonies grew in nutrient agar from 0.1 ml of sample withdrawn from a culture diluted to 10^-4^ in a standard plate count procedure. How many cells were in each millilitre of the original sample?** 26\. **If you start out with a population density of 400 CFU/ml of a bacterium that divides every 40 minutes, what will the population density be at the end of two hours, assuming the cells are in the log phase of growth?** 27\. **What is a plasmid?** 28\. **Which of the following is a micronutrient?** 29\. **Addition of Eosine-methylene blue to a culture medium only allows coliform bacteria to grow. This is an example of a** 30\. **The** **term obligate aerobe refers to an organism that** 31\. **Which of the following is bactericidal?** 32\. **What is being compared during DNA hybridization studies of two bacteria?** 33\. **Bacteria that use organic carbon as the source of cellular carbon are called** 34\. **Members of which bacterial genus contribute to plaque, caries, gingivitis, and periodontal disease?** 35\. **Gram positive cells** 36\. **Which of the following does destroy endospores?** 38\. **Extensive sequential nucleotide analysis of rRNA has divided the living world into three domains called** 39\. **Protists is a group of organisms that belong to** A. The eukaryotes B. The coliforms C. The prokaryotes D. The enterobacteriaceae E. The firmicutes 40\. **Which organisms are carriers of malaria?** A. Motts B. Mosquitos C. Ticks D. Cats E. Cattle 2\. Who first developed the process of colony purification on solid media? F. A. Gert Baur G. B Paul Erlich H. C. Robert Koch I. D Anton von Leeuwenhoek J. E Helmut Hess 3\. What was the first successful solid medium reported for colony purification of bacteria? K. A. Agar L. B. Boiled potato M. C. Rice paper N. D Cooked meat O. E Silica gel 5\. What was the first virus shown to be the specific cause of a disease? A. Small pox virus B. Hepatitis A virus C. Polio virus D. Chickenpox virus E. Tobacco mosaic virus 7\. In bacterial cells, ribosomes are packed into the cytoplasmic matrix and also loosely attached to the plasma membrane. What is the function of ribosomes? A. mRNA synthesis B. tRNA synthesis C. Polypeptide synthesis D. DNA synthesis E. amino acid synthesis 8\. What is a plasmid? A. Self-replicating segment of circular double stranded DNA B. Algal single stranded circular RNA C. Fungal circular mini-exon DNA D. Yeast DNA dependent RNA polymerase E. Viral unsheathed circular RNA 9\. The 70S prokaryotic ribosome consists of A. Two 40S subunits. B. A 50S and a 30S subunit. C. A 40S and a 30S subunit. D. A 50S and a 20S subunit. E. A60S and a 20S subunit. 10\. One of the principal functions of bacterial pili is A. Attach bacteria to cells and surfaces via specific receptor molecules B. Help bacteria move through viscous fluids. C. Sense changes in environmental nutrient concentration. D. Act as channels for secretion of exoenzymes. E. Actively promote gliding motility. 11\. The term lysogeny refers to what? A. Entry of the bacterial cell into the endospore phase B. Asexual reproduction in dimorphic yeast C. rRNA replication prior to conjugation D. The condition of a host bacterium that has incorporated a phage into its own genetic material E. Integration of viral transposons into algal genomes 12\. The significance of the plasma membrane is that A. It selectively allows some molecules to pass into the organism B. It prevents movement of molecules out of the organism C. It is a site of lipid synthesis D. Answers A and B are correct E. Answers A, B and C are correct 14\. Addition of blood to a culture medium allows any haemolytic bacteria that grow on the plate to be picked out. This is an example of a A. Differential media. B. haemostatic media C. Chemically defined media. D. Haemophilic media. E. Complex media. 15\. *Listeria monocytogenes* is a A. Gram positive, psychrotolerant, facultative anaerobe B. Gram positive mesophilic facultive anaerobe C. Gram positive psychrotolerant microaerophile D. Gram positive psychrotolerant, obligate anaerobe E. Gram positive psychrotolerant, aerotolerant anaerobe 16\. Addition of salt to a culture medium only allows the salt-tolerant bacteria to grow. This is an example of a A. Complex media B. Chemically defined media C. Osmotically enriched media D. Differential media E. Selective media 17\. Which of the following is the best definition of generation time? A. The length of time it takes for lag phase to end B. The length of time it takes for a population of cells to double C. The maximum rate of doubling divided by the initial count D. The duration of log phase. E. The time it takes for nuclear division 18\. The term facultative anaerobe refers to an organism that A. Doesn\'t use oxygen but tolerates it. B. Is killed by oxygen concentrations above 10% C. Uses oxygen when present or grows without oxygen when oxygen is absent. D. Requires less oxygen than is present in air but needs 10% CO~2~ E. Prefers to grow without oxygen, but can grow in 50% nitrogen 19\. Which of the following is bactericidal? A. Chloramphenicol B. Oxytetracycline C. Ampicillin D. Erythromycin E. None. They are all bacteriostatic