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Question 1 1 / 1 point Semiconservative DNA replication means that the sequence of a DNA molecule is preserved as it is being replicated the cell can proofread its newly synthesized DNA only part of the time each strand of a double-stranded DNA molecule is replicated differently each daughter DNA molecule is composed of one original strand and one new strand nucleotides are constantly being recycled as cells make DNA Question 2 1 / 1 point What process of genetic material transfer is represented by this figure? Transduction
Transformation Conjugation Translation Question 3 1 / 1 point The bacterial chromosome is usually circular found in a nucleoid found in a nucleus both circular and found in a nucleoid both circular and found in a nucleus Question 4 1 / 1 point You start with a bacterial culture containing 10 cells. Knowing that they have a generation time of 15 minutes, and you incubate the culture for 10 hours. After 10 hours, how many cells are present in the culture? 160 1500 327, 1,1 X 10^13 More information is needed
a capsule Question 8 0 / 1 point All of the following are associated with nucleic acid structure EXCEPT uracil phosphate hydrogen bonds ionic bonds ribose Question 9 1 / 1 point In prokaryotes, the genetic material is (Choose all that apply) Double stranded DNA Circular DNA Haploid Single stranded DNA Diploid Question 10 1 / 1 point Sterilization is done by autoclave, consisting of exposure to steam at about 170°C
100°C
121°C
200°C
150°C
Question 11 0 / 1 point The operator is Region of DNA that a repressor or activator binds to A protein that coordinates gene expression Region on the DNA where RNA polymerase initiates transcription A substance that induces transcription of genes Another name for terminator Question 12 1 / 1 point This type of mutation creates a stop codon in the middle of a protein, resulting in the production of an incomplete protein. Silent mutation Missense mutation Transition Transversion Nonsense mutation
Chloramphenicol Polymyxin B All of the above Question 15 1 / 1 point The target of the sulfonamides is Cytoplasmic membrane proteins RNA polymerase DNA gyrase Folic acid synthesis Peptidoglycan biosynthesis Question 16 1 / 1 point Allolactose induces the lactose operon by binding to a(n) Repressor Activator RNA polymerase Operator Permease Question 17 0 / 1 point
You have chosen to measure the number of viable cells in a soil sample using the plate count technique and the following serial dilution protocol. How many cells per ml did the original sample contain? Plating 8,000 1,086 278 12 0 (CFU) 278,000 CFU/ml E. Impossible to determine 120,000 CFU/ml 8,000 CFU/ml 278 CFU/ml Question 18 1 / 1 point A bacterium that expresses a capsule can be virulent because
It blocks transcription by inhibiting bacterial RNA polymerase Question 21 1 / 1 point The following is the recipe for what type of medium? Component Amount Beef extract 1.5 g Yeast extract 3.0 g Peptone 6.0 g Glucose 1.0 g Agar 15.0 g Water 1,000 ml pH 6. Enrichment Complex Reducing Chemically defined Question 22 1 / 1 point During DNA replication, the ________ strand must be replicated using Okazaki fragments. Parental Leading Polymerase Lagging
Helix Question 23 1 / 1 point The unwinding of the 2 strands of the parental DNA during replication is performed by this enzyme Helicase DNA polymerase Topoisomerase RNA polymerase Permease Question 24 1 / 1 point Preserving food by using salts and sugars works by? Depleting nutrients Creating an hypotonic environment Raising pH Creating and hypertonic environment Lowering osmotic pressure Question 25 1 / 1 point Which of the following disinfectants acts against cell membranes? Phenol
_
within host cells __ 1 _ _ attaches to the host cell and digest the cells and tissue fluids Question 28 1 / 1 point Pasteurization is used to eliminate all of these pathogenic microorganisms from food products EXCEPT Escherichia coli Mycobacterium tuberculosis Brucella melitentis Staphylococcus aureus Question 29 0 / 1 point Agent A acting on Staphylococcus aureus has a D-value of 5 minutes. If the population of microorganisms started a at cell density of 5 X 108 cells/ml, how many viable cells will remain after 15 minutes? 1 X 10^7 cell/ml 5 X 10^6 cell/ml 5 X 10^7 cell/ml 1 X 10^6 cell/ml 5 X 10^5 cell/ml Question 30 1 / 1 point
Ethanol is most efficient as an antimicrobial agent at what concentrations? 70% 100% 10% 25% 50% Question 31 1 / 1 point Which of the following statements is NOT true of A-B exotoxins? The B portion of the toxin binds to surface receptors on host cells. They are produced only by gram-negative bacteria. Many exotoxins are A-B toxins. The A portion of the toxin is the active component. They consist of two polypeptide components. Question 32 1 / 1 point β-lactamase production is an example of which of the following types of resistance? Overproduction of an enzyme in a key metabolic pathway Change in the permeability of the drug Inactivation of the drug Removal of the drug via a pump
Thermal death time Thermal death temperature Thermal death point Decimal reduction time The K value Question 36 0 / 1 point Which one of these pairs is NOT correctly matched? collagenase; breaks down connective tissue siderophore; traps iron coagulase; lyses fibrin clots leukocidin; lyses white blood cells membranes IgA protease; digest antibodies Question 37 1 / 1 point Beta-lactam antibiotics have an effect on which of the following types of cells? both animal and fungal cells virus-infected cells bacterial cells animal cells fungal cells
Question 38 1 / 1 point Associate the microorganisms on the left with the appropriate entry route into the host __ 2 _ _ Gastrointestinal route __ 3 _ _ Respiratory route __ 1 _ _ Parenteral route __ 4 _ _ Conjuctiva
HIV-
Vibrio cholerae 3 . Bordetella pertussis 4 . Staphylococcus aureus Question 39 1 / 1 point Why is sodium thioglycolate added to a reducing medium? It prevents Gram-negative from growing It combines with and inactivates dissolved oxygen It inhibits the growth of fungi It maintains a neutral pH It gives a nice red coloration to the medium Question 40 1 / 1 point The process in which RNA is made from DNA is called _____, and is carried out by _____. replication; DNA polymerase
Question 43 1 / 1 point What is the mechanism of action of rifampin? Inhibits protein synthesis by binding to the 30S ribosome Inhibits cytoplasmic membrane function by binding to phospholipids Inhibits transcription by binding to bacterial RNA polymerase Inhibits replication by binding to the DNA polymerase Inhibits cell wall synthesis by binding to the transpeptidase Question 44 1 / 1 point Silvadene, a topical treatment for burns, contains 1% silver. What category of chemical control agent is in Silvadene? surfactants aldehydes heavy metals halogens oxidizing agents Question 45 1 / 1 point The transport of bacterial DNA to other bacteria via bacteriophages is called Translation
Transduction Transformation Conjugation Replication Question 46 0 / 1 point A medium containing lactose and a pH indicator onto which Escherichia coli forms red colonies, while Salmonella and Shigella form white colonies is a Selective medium Liquid medium Solid medium Enrichment medium Differential medium Question 47 0 / 1 point How does penicillin kill bacteria? It inhibits the elongation of peptidoglycan strands It blocks transcription by inhibiting bacterial RNA polymerase It dissolves phospholipids and disrupts the cytoplasmic membrane integrity It blocks the crosslinking of peptidoglycan strands
