Microbiology Exam 2 Practice Test 47 Questions with Verified Answers,100% CORRECT, Exams of Nursing

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Microbiology Exam 2 Practice Test 47 Questions with

Verified Answers

Salts and sugars work to preserve foods by creating a a. hypertonic environment b. hypotonic environment c. lower pH d. lower osmotic pressure e. depletion of nutrients - CORRECT ANSWER a. hypertonic environment The term facultative anaerobe refers to an organism that a. uses oxygen or grows without oxygen b. requires less oxygen than is present in air c. is killed by oxygen d. doesn't use oxygen but tolerates it - CORRECT ANSWER a. uses oxygen or grows without oxygen Most bacteria grow best in pH a. 1 b. 9 c. 7 d. 5 e. 14 - CORRECT ANSWER c. 7 A culture medium consisting of agar, human blood, and beef heart is a a. complex medium b. reducing medium c. differential medium d. selective medium e. chemically defined medium - CORRECT ANSWER a. complex medium

Which of the following pairs is mismatched? a. psychotroph - growth at 0C b. mesophile - growth at 25C c. thermophile - growth at 37C d. psychophile - growth at 1C e. none of the above - CORRECT ANSWER c. thermophile - growth at 37C During which growth phase will gram-positive bacteria be most susceptible to penicillin? a. stationary phase b. lag phase c. log phase d. death phase e. the culture is equally susceptible during all phases - CORRECT ANSWER c. log phase Which group of microorganisms is most likely to spoil a freshwater trout preserved with salt? a. thermophiles b. halophiles c. psychrophiles d. anaerobes e. none of the above - CORRECT ANSWER b. halophiles This organism is killed by atmospheric O a. obligate anaerobe b. aerobe c. aerotolerant anerobe - CORRECT ANSWER a. obligate anaerobe Bacterial death will result from danger to which of the following structures? a. plasma membrane b. nucleic acids

c. proteins d. cell wall e. all of the above - CORRECT ANSWER e. all of the above Which of the following does not achieve sterilization? a. formaldehyde b. dry heat c. ethylene oxide d. pasteurization - CORRECT ANSWER d. pasteurization Which of the following affects the elimination of bacteria from an object? a. temperature b. presence of organic matter c. number of bacteria present d. pH e. all of the above - CORRECT ANSWER e. all of the above Which of the following organisms can grow in 7% salt and spoil food? a. E.coli b. Staphylococcus aureus c. viruses d. streptococcus fecalis - CORRECT ANSWER b. Staphylococcus aureus ________ is added to make media solid a. beef extra b. agar c. bolld d. salt - CORRECT ANSWER b. agar Boiling a solution for a few minutes may not kill ______? a. amoeba b. Bacterial endospores

c. E.coli d. protozoa - CORRECT ANSWER b. Bacterial endospores A heavy metal that can kill bacteria is? a. copper b. chlorine c. iodine d. sulfer - CORRECT ANSWER a. copper True or false- Bacteria can grow fastest during their lag phase - CORRECT ANSWER False Most human pathogens would be classified as _______? a. psychophiles b. thermophiles c. Mesophiles d. patofiles - CORRECT ANSWER c. Mesophiles High osmotic pressure by salt or sugar removes water from cells. This is called? a. Plasmolysis b. cell rupture c. hydrolysis d. salting - CORRECT ANSWER a. Plasmolysis 50% of a bacteria cell is composed of _____? a. nitrogen b. DNA c. carbon d. water - CORRECT ANSWER c. carbon Which of the following is a trace element? a. carbon b. iron

c. vitamin B d. ATP - CORRECT ANSWER b. iron What percent of bacteria from a natural sample is culturable? a. 50% b. 30% c. 20% d. 10% - CORRECT ANSWER d. 10% Most bacteria reproduce by a process called? a. fermentation b. binary fission c. binary fusion d. transformation - CORRECT ANSWER b. binary fission A chemical used to kill vegetative cells on living tissue is called? a. Antiseptic b. degermation c. chlorine d. disinfectant - CORRECT ANSWER a. Antiseptic The best method to kill bacteria endospores is? a. boiling b. autoclaving c. heatfixing d. pasteuriztion - CORRECT ANSWER b. autoclaving Pasteurization is often used in the production of? a. can food b. milk c. jams d. grass - CORRECT ANSWER milk

Which of these is a common halogen used to kill bacteria? a. hydrogen b. chlorine c. sulfur d. copper - CORRECT ANSWER chlorine If a species contains 23% A in its DNA, what is the percentage of guanine it would contain? a. 23% b. 46% c. 25% d. 44% e. 27% - CORRECT ANSWER e. 27% The amount of adenine is always equal to the amount of a. cytosine b. uracil c. guanine d. thymine e. ATP - CORRECT ANSWER Which of the following statements about DNA replication is not correct a. unwinding of the DNA molecule occurs as hydrogen bonds break b. replication occurs as each base is paired with another exactly like it c. the process is known as semiconservative replication because one old strand is conserved in the new molecule d. the enzyme that catalyzes DNA replication is DNA polymerase e. complementary base pairs are held together with hydrogen bonds - CORRECT ANSWER b. replication occurs as each base is paired with another exactly like it

34. Because one original strand of the double stranded helix is found each daughter cell, the

replication process is called a. proofreading b. semiconservative c. redundant d. freeing of DNA e. mutation positive - CORRECT ANSWER b. semiconservative T or F - There are two kinds of nucleic acids, DNA and DNase - CORRECT ANSWER False Which of the classes of RNA molecules carries the genetic information as it is needed for the construction of a protein? a. ribosomal RNA b. transfer RNA c. messenger RNA d. primary mRNA transcript - CORRECT ANSWER c. messenger RNA Which of the classes of RNA molecules carries the amino acids that are added to the growing polypeptide chain? a. ribosomal RNA b. transfer RNA c. messenger RNA d. primary mRNA transcript - CORRECT ANSWER b. transfer RNA Which of the classes of RNA molecules is linked with proteins in forming the large and small subunits of cytoplasmic structure? a. ribosomal RNA b. transfer RNA c. messenger RNA d. primary mRNA transcript - CORRECT ANSWER a. ribosomal RNA

Prior to protein synthesis, the DNA a. attracts tRNA's with appropriate amino acids b. must first undergo replication c. contains anticodons that must become codons d. serves as a template for the production of mRNA e. adheres to ribosomes for protein synthesis - CORRECT ANSWER d. serves as a template for the production of mRNA Transcription of a part of DNA molecule with a nucleotide sequence of A-A-A-C-A- A-C-T-T results in an mRNA molecule with the complementary a. G-G-G-A-G-A-A-C-C b. U-U-U-G-U-U-G-A-A c. T-T-T-G-A-A-G-C-C d. C-C-C-A-C-C-T-C-C - CORRECT ANSWER b. U-U-U-G-U-U-G-A-A If one strand of DNA has the base sequence AAGCAA, the complentary strand has which of the following sequences? a. UUCGUU b. TTCGTT c. AAGCAA d. UTCGTU e. TTCGTG - CORRECT ANSWER b. TTCGTT Which is the process that synthesizes mRNA, tRNA, or rRNA? a. translation b. transcription c. transposition d. transformation - CORRECT ANSWER b. transcription Which of the following nucleotide bases is found only in RNA, not in DNA?

a. guanine b. adenine c. thymine d. uracil e. cytosine - CORRECT ANSWER d. uracil Which of the following nucleotide bases is found only in DNA, not in RNA? a. guanine b. adenine c. thymine d. uracil e. cytosine - CORRECT ANSWER c. thymine Which of the process by which a protein is constructed? a. translation b. transcription c. transposition d. transformation - CORRECT ANSWER a. translation Which of the following are involved in protein synthesis? a. ribosomes b. mRNA c. tRNA d. rRNA e. all of the above - CORRECT ANSWER e. all of the above Which compound is added to solidify bacteria growth media? a. agar b. gelatine c. broth d. blood - CORRECT ANSWER a. agar

The destruction of all forms of microbial life is called? a. disinfection b. sterilization c. degermenation d. sanitization - CORRECT ANSWER b. sterilization Lysol contains? a. phenol b. alcohol c. cloroz d. halogens - CORRECT ANSWER a. phenol T or F - Mixing chlorine with ammonia compounds can release toxic gas - CORRECT ANSWER False Which of the following is NOT true about anaerobic respiration? a. it generates ATP b. it involves the Krebs cycle c. it requires cytochromes d. it involves glycolysis only e. it involves the reduction of nitrate - CORRECT ANSWER d. it involves glycolysis only