Microbiology Exam PDF

1.Which phase represents exponential growth? a) a) Log Phase b) b) Lag Phase c) c) Death Phase 2.Which method of determining growth rate is an Indirect method? a Plate count b Most probable Number (MPN) c Direct Microscopic count d Turbidity e Filtration A sample of milk is...

1.Which phase represents exponential growth? a) a) Log Phase b) b) Lag Phase c) c) Death Phase 2.Which method of determining growth rate is an Indirect method? a Plate count b Most probable Number (MPN) c Direct Microscopic count d Turbidity e Filtration A sample of milk is tested for its bacterial content in a plate count assay. A one-milliliter sample of the milk is diluted in a 1:10 dilution series. One milliliter of the third dilution tube is plated in a pour plate. After incubation, the plate has 54 colonies, indicating that the original milk sample contained a 54 cells per milliliter. b 540 cells per milliter. c 5,400 cells per milliliter. d 54,000 cells per milliter. e 540,000 cells per milliliter. Saccharomyces cerevisiae grows best at which pH range: a рН 6.5-7.5 b pH 5 and 6 c pH less than 4 d pH greater than Which of the following growth requirements allows for microorganism to survive in oxygen but they cannot a) obligate anaerobes b)obligate aerobes c) facultative anaerobes d) microaerophiles e) aerotolerant Which of the following terms refers to culture medium that exhibits no living microbes? a) Sterile b)Agar c)Inoculum Most pathogenic bacteria are thermophiles. True false Which of the following temperature classification of microorganisms contains human pathogens? a)Psychrophiles b)Psychrotrophs c)Thermophiles d)Mesophiles Which of the following is NOT a trace element? a) zinc b) vitamin c) molybdenum d) enzyme cofactor Question 11 Which type of media suppresses unwanted microbes and encourages desired microbes? a) Selective media b) Differential media c)Non-synthetic media d) Synthetic media Which of the following is needed for synthesis of cell membranes and nucleic acids? a) Sulfur b) Carbon c)Nitrogen d)Phosphorus Which method of determining growth rate requires the presence of colony forming units after a series of culture dilutions? a) Most probable Number (MPN) b) Turbidity c) Filtration d) Direct Microscopic count e) Plate count An obligate halophile requires which of the following growth conditions? a) Hypertonic Environment b) Hypotonic Environment c) Isotonic Environment Which pH range is good for Escherichia coli? a) pH 5 and 6 b) pH less than 4 c) pH greater than 8 d) pH 6.5-7.5 Agar is used as a solidifying agent in microbiological media since few bacteria can degrade it. True Flase If cells are grown in media containing amino acids labeled with radioactive nitrogen (15N), most of the radioactivity will be found in the cells' a) DNA. b) proteins. c) phospholipids. d) DNA and proteins. e) DNA and phospholipids. Which of the following pairs is mismatched? a) Ag - wound dressings b) CuSO4 - algicide c) H202 - open wounds d) alcohols — open wounds Which of the following terms means to inhibit microbes not necessarily killing microbes? a Bacteriostasis b Antisepsis c Sanitization d Degerming All of the following are methods of food preservation EXCEPT a) high pressure. a microwaves. b desiccation. c osmotic pressure. d ionizing radiation. Which of the following microbial structures is only found in mycobacteria? a) Waxy cell walls b) LPS layer  c)Prions d)Endospores Ethylene oxide a) requires high heat to be effective. b) is a good antiseptic. c)is a sterilizing agent. d) is the active chemical in household bleach. e) is not sporicidal. Which of the following terms means destroying harmful microorganism usually from surfaces? a) Biocide (Germicide) b) Sterilization c)Disinfection d) Antisepsis Which of the following terms means the mechanical removal of microbes from a limited area? a) Sanitization b)+ b) Degerming c) Bacteriostasis d)Antisepsis Which of the following physical microbial Control Methods does not involve heat? a) Incineration b) Pasteurization c)Autoclaving d) Membrane Filtration Which of the following has no bearing on the effectiveness of treatment to remove reduce microbes? a) the environment b) *b) the cost c) the time of exposure d) the number of microbes Which of the following is NOT an action of Microbial Control Agents? a) alters reproduction b) alteration of membrane permeability c)damage to nucleic acids d) damage to proteins Which of the following methods is used to determine the efficacy of chemical agents?  a) Disk-Diffusion Method b) Turbidity c)Gram-staining d) Streak-plating Which of the following terms means the removal and destruction of all microbial life? a Sterilization b Disinfection c Antisepsis d Biocide (Germicide) Which of the following structures is resistant to autoclaving? a) Endospores b) Waxy cell walls c)LPS layer d) Prions Binary fission is used in which of the following DNA transfers? a) Conjugation b) Crossing Over c)Horizontal Gene Transfer d) Vertical Gene Transfer Which stage of translation is the UGA codon in the A-site of the ribosome? a) elongation stage b) initiation stage c)translocation d) d) termination stage A Gene that expresses a repressor is what type of gene? a) inducible genes b) regulatory genes c)repressible genes d) constitutive genes Which of the following structures is self-replicating circular piece of DNA? a) genetic recombinant b) plasmid c)selective marker d) Transposon Genetic change in bacteria can be brought about by a) mutation. b) conjugation.  c) transduction. d) transformation. e) All of the answers are correct. Conjugation differs from reproduction because conjugation a) transfers DNA horizontally, to nearby cells without those cells undergoing replication. b) transfers DNA vertically, to new cells. c)transcribes DNA to RNA. d) replicates DNA. e) copies RNA to make DNA. Which enzyme separates the strands of DNA during DNA Replication? a) Ligase b) DNA Polymerase c) RNA polymerase d) Helicase How many sense codons are there? a) 3 b)20 a) 61 c) 1. What is a phenotype? a) It is an enzyme b) It is the expression of a chromosome. c)It is the expression of a gene(s) d) It is the same thing as a genotype Which of the following increases the mutation rate from 10 to 1000 times? a) a) radiation b)b) auxotroph d)photolyase c) d) nucleotide excision repair Which of the following structures is a movable piece of DNA? a) genetic recombinant b) selective marker c)plasmid d) Transposon Which of the following DNA transfer methods require a bacteriophage?  a) Conjugation b)Crossing Over c) Transduction d)Transformation. gene is best defined as a) any random segment of DNA. b) b) a sequence of nucleotides in DNA that codes for a functional product. c)three nucleotides that code for an amino acid. d) d) a sequence of nucleotides in RNA that codes for a functional product. e) the RNA product of a transcribed section of The Central Dogma is represented by which of the following? a) Protein→DNA→RNA b) RNA-DNA→Protein c) Protein →RNA→DNA d)DNA+RNA →Protein. Which of the following mutagens is a structurally similar nucleoside to the original nucleoside and can be incorporated in the base-pairing process? a) nucleoside analog b)thymine dimers c) nitrous acid d)radiation. During transcription in eukaryotes, which of the following statements is FALSE? a) Transcription produces an intermediate RNA that needs to be processed to create mRNA. b) mRNA is single-stranded. c) mRNA is produced in a nucleus. d) mRNA once transcribed is used for translation immediately Which of the following pairs is mismatched? a) RNA polymerase - makes a molecule of RNA from an RNA template b) DNA polymerase - makes a molecule of DNA from a DNA template c)c) DNA gyrase — uncoils and untwists DNA d)DNA ligase - joins segments of DNA Which of the following DNA transfer methods require "naked DNA"? a) Crossing Over b) Conjugation c) Transformation d) Transduction One of the first commercial successes of recombinant DNA technology was the production of human insulin using genetically engineered E. coli. a) False b) true The Bt toxin derived from Bacillus thuringiensis has been introduced into some crop plants to make them resistant to insect destruction. a) True b) False A restriction fragment is a) a segment of DNA. b) a segment of tRNA. c)a gene. d) cDNA. Biotechnology involves the a) use of microorganisms to make desired products. a) b) use of animal cells to make vaccines. b) development of disease-resistant crop plants. c) use of microorganisms to make desired products and the use of animal cells to make vaccines. d) +All of the above In recombinant DNA technology, a vector is a self-replicating segment of DNA, such as a plasmid or viral genome. a) True b) False Question 24 The term biotechnology refers exclusively to the use of genetically engineered organisms for the production of desired products. a) True b) False A shuttle vector is a plasmid that is used to move pieces of DNA among organisms, such as bacterial, fungal, and plant cells. a) False  b) True In Figure 9.2, the enzyme in step 1 is a) DNA polymerase. b) DNA ligase. c) reverse transcriptase. a) RNA polymerase. e) spliceosome. Bioinformatics is the use of computer technology to compare and analyze genome sequence. a) True b) False An advantage of cDNA over genomic DNA is that it a) can form very large DNA segments. b) contains selectable markers. c)is very easy to isolate. d) lacks introns. Which of the following are used to silence specific genes and hold promise for treating cancer or viral diseases, such as hepatitis B? a) RNA interference (RNAi) b) reverse transcriptase PCR (rtPCR) c) DNA fingerprinting d) tumor-inducing plasmids (Ti plasmids) e) complementary DNA (cDNA) How many pieces will EcoRI produce from the plasmid shown in Figure 9.1? a) 1 b) 2 c) 3 d) 4