Microbiology Midterm (Ch.6,8-10)
Which biosafety level features open laboratory bench tops, gloves, lab coat, and face and eye protection?
BSL-2
Which level of biosafety (BSL) is appropriate for handling organisms that present the highest risk level for infection and the lowest success rate for prevention and treatment?
BSL-4
For the introduction of a genetically modified plasmid into E. coli, __________.
Calcium chloride and heat shock can be used
If a single bacterium replicated every 30 minutes, how many bacteria would be present in 2 hours?
16; One cell's division produces two cells, two cells' divisions produce four cells, and so on. If a single bacterium replicated every 30 minutes, they would reproduce 4 times—starting with one cell, dividing into two, then 4, then 8, and finally 16 cells.
If 52 bacterial colonies grow on a nutrient agar plate inoculated with 1 ml of a 1:1000 dilution of hamburger, how many bacteria are in the original hamburger sample?
52,000 bacteria per gram; If 52 bacterial colonies grow on a nutrient agar plate with 1 ml of a 1:1000 dilution of a hamburger, 52,000 bacteria per gram would have been present in the original hamburger sample. In order to solve this problem, you would multiply the sample count with the dilution factor - 52 x 1000 = 52,000 bacteria per gram.
Which one of the following is a method of vertical gene transfer?
Cell division
An organism that grows both in the presence and the absence of oxygen and uses oxygen when it is available is called a(n) __________.
Facultative anaerobe
An organism that grows in the presence and absence of oxygen & uses oxygen when available is called a(n):
Facultative anaerobe
You are testing the number of coliforms in a drinking water source. Which of the following test methods would be best to use?
Filtration
The ability of microbes to utilize N2 as a nitrogen source is called __________.
Nitrogen fixation
__________ can be used to silence a gene, and it holds promise for treating certain genetic disorders and viral infections.
RNAi
Recombinant DNA can be introduced into a host cell by any of the following methods EXCEPT __________. a. Polymerase chain reaction b. Electroporation c. Transformation d. Protoplast fusion e. Microinjection
a. Polymerase chain reaction
Which of these statements is NOT true of translation? a. The "language" of nucleotides is changed to the "language" of amino acids. b. A molecule of tRNA can bind to both an mRNA molecule and an amino acid. c. Three different nonsense codons code for termination of protein synthesis. d. Each amino acid is coded for by a single codon. e. A single mRNA may have several ribosomes attached.
d. Each amino acid is coded for by a single codon.
Which of these methods is NOT used to identify bacteria? a. DNA probes b. Biochemical tests c. Serology d. G + C composition analysis
d. G + C composition analysis
6. Which of the following terms are mismatched?? a. Psychrophiles; 0°C b. Extreme halophiles; 30% salt c. Acidophiles; low pH d. Hyperthermophiles; 0°C e. Extreme thermophiles; 100°C
d. Hyperthermophiles; 0°C
Which of the following statements is NOT true of dichotomous keys? a. They use characteristics such as staining reactions and sugar-fermentation patterns. b. They ask a series of questions, with each question in the series having two possible answers. c. They can be used in identification of organisms. d. They always show evolutionary relationships of organisms. e. They do not require rRNA sequence information.
d. They always show evolutionary relationships of organisms.
Which of the following is NOT a purpose of genetic modification? a. To create multiple copies of a gene of interest b. To create hormones such as insulin or human growth hormone c. To create proteins used in vaccines (e.g., hepatitis B vaccine) d. To remove antibiotic resistant plasmids from bacteria e. To modify the characteristics of an organism
d. To remove antibiotic resistant plasmids from bacteria
The basic steps to genetically modify a cell are listed below. Which step would come LAST? a. Restriction digestion of vector b. Ligation c. Restriction digestion of gene d. Transformation
d. Transformation
Which of the following is NOT a method used for the direct measurement of microbial growth? a. The most probable number (MPN) method b. Serial dilutions c. Spread plates d. Turbidity e. Filtration
d. Turbidity
All of the following are characteristics of prokaryotes EXCEPT __________. a. Possess 70S ribosomes b. Possess circular DNA c. Use binary fission d. Use mitosis
d. Use mitosis
Which of these statements is true about transduction? a. Segments of DNA move from one region of DNA to another b. Genetic recombination does not occur. c. Bacteria-bacteria contact is required. d. Naked DNA is passed from bacterium to bacterium. e. A virus is required for transfer of genetic material.
e. A virus is required for transfer of genetic material.
Which of the following is NOT a step in Southern blotting? a. Digestion of sample DNA with restriction enzyme b. Transfer of DNA fragments to filters c. Separation of DNA fragments by gel electrophoresis d. Addition of radioactive probe made from the gene of interest e. Addition of heat-stable DNA polymerase
e. Addition of heat-stable DNA polymerase
Which of the following is NOT a characteristic of members of the domain Archaea? a. May be hyperthermophiles or extreme halophiles b. Lack peptidoglycan in cell walls c. Carry out unusual metabolic processes d. Found in extreme environments e. Cause disease in humans
e. Cause disease in humans
Which of these methods can identify bacteria in a sample without culturing the bacteria? a. Flow cytometry b. Phage typing c. Biochemical testing d. Fluorescent in situ hybridization (FISH) e. Flow cytometry and FISH
e. Flow cytometry and FISH
A plasmid that has been cleaved with EcoRI can recombine with another plasmid that has been __________.
digested with EcoRI
During log phase, bacteria are:
dividing at the fastest possible rate
Southern blotting is used to ______.
identify particular sequences of DNA
Enzymes that are produced only when needed in the cell are called __________ enzymes.
inducible
Clostridium can be cultured in an anaerobic incubator or in the presence of atmospheric oxygen if thioglycolate is added to the nutrient broth. The addition of thioglycolate makes the medium __________.
reduced
The tryptophan operon contains genes that encode the enzymes involved in tryptophan biosynthesis. An abundance of tryptophan will turn off the operon. This operon is an example of a(n) __________.
repressible operon
What is quorum sensing?
the ability of bacteria in a biofilm to communicate with each other and coordinate their activities
Which of the following methods exploits the double stranded feature of DNA and complementary sequences? a. DNA-DNA hybridization b. Serology c. Phage typing d. FAME
a. DNA-DNA hybridization
Assume a cell is grown in a culture medium containing radioactively labeled thymidine. After three cell divisions, what percentage of the cells would contain the radioactive label?
100%; Cells must replicate their DNA before dividing. As DNA is replicated, radioactively labeled thymidine will be incorporated into the new DNA, thus 100% would contain the radioactive label.
What can cause changes in a sequence of several amino acids?
A frameshift mutation
The process of making multiple copies of a DNA molecule is referred to as __________.
Amplification
A unicellular microorganism has been isolated from an acidic sulfur-rich hot spring in Yellowstone Park. Its cell wall lacks peptidoglycan and has no nucleus or other membranous organelles. What is the most likely classification of this microorganism?
Archaea
Bergey's Manual includes information on two domains: Bacteria and __________.
Archaea
If you put the gene for Bt toxin from Bacillus thuringiensis into a tomato plant, the resulting plants will __________.
Be toxic to insects that eat them
The use of microorganisms, cells, or cell components to make products such as hormones, antibiotics, food, or vaccines is known as __________.
Biotechnology
Members of the genus Clostridium display the following properties: -Gram-positive bacilli -Endospore formation -Anaerobic growth Which of the following would be appropriate for the culture of members of this genus?
Both a blood agar plate in an anaerobe jar and sodium thioglycolate broth
A culture of identical cells, each derived from a single "parental cell," is referred to as a(n) __________.
Clone
Genes whose products are produced constantly are known as __________ genes.
Constitutive
Two bacteria with the same percentage of guanine plus cytosine __________.
Could be related
The process of using restriction enzymes to create DNA fragments that can be separated by electrophoresis and compared is known as __________.
DNA fingerprinting
DNA fingerprints are actually ______.
DNA fragments
Blood agar used to observe hemolysis or clearing around Streptococcus pyogenes colonies is an example of a(n) __________.
Differential medium
Members of the Kingdom Fungi are __________.
Either unicellular or multicellular
Special considerations must be taken when using bacteria to produce a eukaryotic protein. What is the cause for this additional difficulty?
Eukaryotic genes contain introns, which prokaryotic cells cannot remove.
You have found an organism that is eukaryotic and multicellular. It obtains nutrients by absorbing dissolved organic matter across its cell membrane. To which kingdom does it belong?
Fungi
__________ cells transfer genes to recipient cells in a particular order.
HFR
The transfer of genetic information between organisms through processes such as transduction or conjugation is called __________ gene transfer.
Horizontal
Describe the difference between classification and identification.
Identification is more practical in its purpose. For example, it is used to diagnose infection.
The following steps occur during binary fission. What is the third step?
Inward growth of the membrane
In which phase of the growth curve is the population-doubling time fastest?
Log phase
Bacteria growing in and on the human body, including normal microbiota as well as pathogens, are classified as
Mesophilic and heterotrophic
Which domain includes viruses?
None; viruses aren't part of any of the 3 domains because they are considered nonliving
FISH is used to identify a bacterium by __________.
Nucleic acid hybridization
A number of skin infections caused by MRSA (methicillin-resistant Staphylococcus aureus) were detected among members of the wrestling teams of several local high schools. Which of the following methods might demonstrate whether these infections are caused by the same bacterial strain?
Phage typing
A test that determines which phages a bacterium is susceptible to is called __________.
Phage typing
Describe phage typing
Phage typing helps identify bacterial species and strains, based on the type of bacteriophage to which they are susceptible.
If two organisms are in the same taxonomic class, then they must also be in the same __________.
Phylum
Which kingdom includes multicellular organisms with organelles containing a single circular chromosome, 70S ribosomes, and chlorophyll?
Plantae
__________ is a technique used to quickly amplify specific sequences of DNA.
Polymerase Chain Reaction (PCR)
In a(n) __________, cells are added to melted agar and poured into a Petri dish.
Pour plate
To begin transcription, the RNA polymerase binds a region on DNA known as the __________.
Promoter
__________, useful in recombinant DNA technology, are bacterial enzymes that recognize and cut specific sequences of DNA. (2 words)
Restriction enzymes
Martin Lewis agar is an enriched media (containing heated blood) designed for the growth of Neisseria gonorrhea. Antibiotics are added to suppress the growth of normal microbiota that may be found in patient specimens, yet permit the growth of Neisseria gonorrhea. This medium would best be described as __
Selective media
Plasmids that can exist in disparate species such as a bacterium and a plant cell are called __________ vectors, and they can be used to transfer cloned DNA from one type of organism to another.
Shuttle
Which one of the following is a biochemical test used to identify microorganisms? a. Agglutination test b. DNA-DNA hybridization c. Gram stain d. Sorbitol fermentation
Sorbitol fermentation
A novel restriction enzyme makes staggered cuts in the two strands of DNA. The staggered cuts are called __________.
Sticky ends
Before bacteria can be identified, mixed cultures must be separated. What technique is used to separate bacteria and get individual colonies?
Streak plate
Both transcription and DNA replication involve __________.
Synthesis using a DNA template
Small stretches of DNA that can move within a genome are referred to as __________.
Transposons
What do all of these bacteria have in common? • Bacteria in the rumen of cattle and sheep • Bacteria in a sewage treatment plant • Bacteria growing in the middle ear in chronic otitis media • Bacteria growing on the teeth in dental plaque
The bacteria are most likely growing in biofilms.
Which of the following statements regarding biofilms is true? ____ The microbes in biofilms can work cooperatively to carry out complex tasks. ____ Fortunately, biofilms are not an issue that impacts human health. ____ The close proximity of microbes within a biofilm probably inhibits conjugation. ____ Biofilms occur in nature but rarely occur in human infections.
The microbes in biofilms can work cooperatively to carry out complex tasks
The introduction of external pieces of "naked" DNA from solution into a cell is referred to as __________.
Transformation
During the Southern blotting technique, what is the purpose of transferring the DNA fragments from the gel to a nitrocellulose filter?
This step attaches the DNA fragments to a permanent substrate, which then can be probed.
What is the purpose of DNA replication?
To make an identical copy of DNA
Which means of genetic transfer among bacteria involves a virus?
Transduction
11. Your lab partner has mixed a dead tryptophan+ strain of Bacillus subtilis with a live tryptophan- strain and observes that her B. subtilis culture is now tryptophan+. The most likely explanation for this is __________.
Transformation
If a recombinant plasmid is put in solution with E. coli, the bacteria may pick up the plasmid by __________.
Transformation
Which method(s) can be used to diagnose infections by detecting specific antibodies in a patient's serum?
Western blotting and ELISA
You are analyzing a segment of DNA and observe an area of sequence that appears to act as a promoter element. Based on this, what can you conclude?
You have found the beginning of a gene
Campylobacter bacteria are grown with a CampyPak that produces 5% carbon dioxide and 15% oxygen. This bacterium is __________.
a Microaerophile
Which of the following could be a choice to track the source of hospital-acquired infections? a. DNA fingerprinting b. Determination of sugar-fermentation patterns c. Gram stain d. Morphology determination e. Acid-fast stain
a. DNA fingerprinting
A mutation occurs that results in a codon change from UGU to UGA. UGU encodes a cysteine amino acid, and UGA is a stop codon. Therefore, this is an example of
a nonsense mutation
Of the choices below, which is the LAST to happen during DNA replication? a. DNA ligase joins all the new pieces together. b. Primers are removed and replaced with DNA. c. Primase synthesizes primers for each strand. d. The two template strands of DNA are unwound
a. DNA ligase joins all the new pieces together.
Which of the following can be used as vectors to genetically modify cells? a. All of these b. Plasmids c. Viruses d. Shuttle vectors
a. All of these
Which of the following is a safety issue related to the use of recombinant DNA? a. All of these b. Spread if bioengineered traits, such as herbicide resistance, into related weed species c. None of these d. Reduction in populations of "desirable" insects due to the use of Bt insecticide
a. All of these
Which of the following is (are) part of an operon? a. All of these are part of an operon b. Promoter c. Structural genes d. Operator
a. All of these are part of an operon
Recombinant DNA technology is used for all of the following EXCEPT __________. a. Culturing unknown organisms b. Insertion of genes from humans or plants into bacteria or viruses c. Human-insulin production by bacterial cells d. Amplification of DNA for microbe identification e. Hepatitis-B-vaccine production using yeast cells
a. Culturing unknown organisms
You've discovered a multicellular organism that is photosynthetic. Which of the following taxonomic groups could it belong to? a. Plantae b. Bacteria c. Fungi d. Animalia
a. Plantae
Which of the following is an example of a cloning vector? a. Plasmid b. Tick c. Human growth hormone d. Mosquito e. Ribosomal RNA
a. Plasmid
6. Which of the following might specifically be used as part of a reverse-genetics approach to studying a gene? a. RNA interference b. Southern blotting c. PCR d. Ti plasmid e. Reverse transcriptase
a. RNA interface
Which of these statements is true for restriction enzymes? a. Restriction enzymes are useful in genetic engineering when they make staggered cuts in DNA. b. Any restriction enzyme can cut any piece of DNA. c. A different restriction enzyme must be used to open the vector DNA than to excise the gene sequence to be cloned. d. A given restriction enzyme will always recognize the same DNA sequence, but it will cut differently depending on the species of origin of the DNA.
a. Restriction enzymes are useful in genetic engineering when they make staggered cuts in DNA.
Which of the following is NOT true for the slide agglutination test? a. The absence of agglutination indicates that the antibody reacted with the antigen. b. The test is carries out on a microscope slide c. This test can be used to determine bacterial identity. d. Bacteria or other cells are mixed together with the antibody on a slide. e. Agglutination indicates that the antibody recognizes, and thus binds, to the antigens on the cell surface.
a. The absence of agglutination indicates that the antibody reacted with the antigen.
Which statement is NOT true of cladograms? a. They make dichotomous keys useless b. They show percent similarity among organisms c. They can be based on the fossil record d. They show evolutionary relationships among organisms and they can be based on the fossil record. e. They show evolutionary relationships among organisms
a. They make dichotomous keys useless
Which of the following is NOT true of the Western blot? a. This technique identifies signature rRNA sequences of microbes. b. Proteins from a known bacterium or virus are separated by electrophoresis in this assay. c. It is an important test for diagnosis of both HIV infection and Lyme disease. d. After electrophoresis of serum proteins, the separated proteins are blotted onto a filter e. After electrophoresis and transfer of proteins to a filter, specific proteins can be identified with a patient's antibodies and an enzyme linked to anti-human serum.
a. This technique identifies signature rRNA sequences of microbes.
All of the following are true of the plate count method EXCEPT that it __________. a. takes less than 12 hours to complete b. is the most commonly used method for assay of bacterial cell number c. measures number of viable cells d. involves cell plating and growth e. is dependable
a. takes less than 12 hours to complete
In genetic engineering, antibiotic-resistance genes are usually cloned into vectors to __________.
allow selection for bacteria containing the vector
Assume you insert a specific gene into a plasmid and use blue-white screening. You plate the transformed E. coli cells on an ampicillin X-gal medium. Cells that produce blue colonies are __________.
ampicillin resistant but do not contain the new gene
cDNA is made from ________.
an mRNA template
DNA probes _________
are DNA fragments
When two DNA pieces cut with the same restriction enzyme are combined, sticky ends will __________.
associate by complementary base pairing and hydrogen bonds
Which of the following statements correctly differentiates a genomic library from a cDNA library? a. Genomic libraries contain only those genes that a cell is currently expressing, whereas cDNA libraries contain all of the cell's genes, whether expressed or not. b. A genomic library contains fragments of the entire DNA in an organism's genome. A cDNA library contains the coding sequences of eukaryotic genes (minus the introns). c. cDNA libraries can be used for sequencing, but they cannot be transcribed and translated. Genomic libraries can be used for sequencing and for production of the desired protein product. d. A genomic library contains only noncoding DNA sequences, whereas a cDNA library contains only coding sequences. e. Genomic libraries are prepared from eukaryotes, and cDNA libraries are prepared from prokaryotes.
b. A genomic library contains fragments of the entire DNA in an organism's genome. A cDNA library contains the coding sequences of eukaryotic genes (minus the introns).
You have isolated a bacterium from a patient. Which of the following methods would NOT be sufficient for species identification? a. A series of rapid biochemical tests in the numerical identification format b. A gram stain c. Phage typing d. A slide agglutination test
b. A gram stain
7. Eukaryotic organisms can be found in which of the following kingdoms? a. Fungi b. All of these c. Animalia d. Plantae
b. All of these
Which of the following are common ways to introduce DNA into cells? a. Electroporation b. All of these c. Transformation d. Microinjection
b. All of these
Which of the following is/are NOT used in DNA fingerprinting? a. Electrophoresis b. Antibodies c. DNA d. Agarose gel e. Restriction enzymes
b. Antibodies
Which of the following is NOT a characteristic of members of the domain Archaea? a. Found in extreme environments b. Cause disease in humans c. Carry out unusual metabolic processes d. Lack peptidoglycan in cell walls e. May be hyperthermophiles or extreme halophiles
b. Cause disease in humans
Which of the following hypotheses was developed following Griffith's 1928 experiment? a. Dead encapsulated bacteria can cause disease. b. DNA from dead encapsulated bacteria can transform living nonencapsulated bacteria into living encapsulated bacteria. c. Some pathogenic bacteria cannot be heat-killed. Bacterial virulence is related to temperature resistance. d. Streptococcus pneumoniae causes disease.
b. DNA from dead encapsulated bacteria can transform living nonencapsulated bacteria into living encapsulated bacteria.
You have isolated a gram-negative bacterium that ferments both lactose and sucrose and CANNOT use citric acid as its sole carbon source. Which of the following organisms could it be? a. Citrobacter b. E. coli O157:H7 c. Escherichia d. Shigella
b. E. coli O157:H7
Which of the following is NOT a step in translation? a. Initiation at the AUG start codon b. Joining of the Okazaki fragments c. Transport of amino acids by tRNAs d. Pairing of codons with anticodons e. Peptide bond formation
b. Joining of the Okazaki fragments
Which of the following is NOT true of the polymerase chain reaction (PCR)? a. A heat-stable DNA polymerase is used in the reaction process. b. Large amounts of DNA must be isolated from the source organism c. Short pieces of DNA called primers are added to the reaction mixtures. d. Billions of copies of a DNA sequence are made in a few hours. e. An automated thermocycler is used to heat and cool the reaction samples.
b. Large amounts of DNA must be isolated from the source organism
Which of the following is NOT an advantage of obtaining the protein product called human growth hormone by recombinant DNA technology rather than extraction from cadavers? a. Speed b. Production of endotoxins c. Cost-effectiveness d. Cross contamination e. Purity
b. Production of endotoxins
Which of the following methods does NOT use antibodies? a. ELISA test b. Southern blot c. Western blot d. Agglutination test
b. Southern blot
12. Which of the following processes is involved in the production of diphtheria toxin by C. diphtheria or erythrogenic toxin by Streptococcus pyogenes? a. Mutation b. Specialized transduction c. Conjugation d. Transformation e. Generalized transduction
b. Specialized transduction
The following steps are necessary to clone eukaryotic genes in bacteria. What is the third step? a. Remove introns b. Splice exons together c. Transcription d. Reverse transcription of mRNA
b. Splice exons together
All of the following can be used to preserve bacterial cultures EXCEPT __________. a. Lyophilization (freeze-drying) b. Storing cultures at room temperature (25°C) c. freezing quickly and storing at -70°C d. refrigeration
b. Storing cultures at room temperature (25°C)
Which of the following statements concerning translation is correct? a. tRNAs enter the ribosome at the E site and leave from the A site. b. The ribosome stops protein synthesis when it reaches a nonsense codon in the mRNA. c. Each set of three nucleotides in the mRNA is called an anticodon. d. Amino acids are brought to the ribosome by the mRNA.
b. The ribosome stops protein synthesis when it reaches a nonsense codon in the mRNA.
Which of the following statements in NOT true of plasmids? a. They can be transferred between bacteria during conjugation. b. They are essential for survival of the organism in most situations. c. They may contain antibiotic resistance genes. d. They are small, circular molecules of DNA that can carry genes for heavy metal resistance. e. They may encode genes that enhance the pathogenicity of an organism.
b. They are essential for survival of the organism in most situations.
Which of the following is NOT a domain? a. Eukaryotes b. Viruses c. Archaea d. Bacteria
b. Viruses
Which of the following can be used to diagnose infections by detecting specific antibodies in a patient's serum? a. Western blotting b. Western blotting and ELISA c. PCR d. Differential staining e. DNA fingerprinting f. ELISA
b. Western blotting and ELISA
If DNA ligase were NOT used in the creation of a recombinant plasmid, __________.
base-pairing would occur but the sugar phosphate backbone would not be connected
When a bacterial cell reproduces by splitting into two daughter cells, the process is called __________.
binary fission
A bacterial medium contains chemicals that inhibit gram-positive bacteria and indicators so that bacteria that ferment lactose produce red colonies, and bacteria that do not ferment lactose produce colorless colonies. Such a medium is called __________.
both selective and differential
Through metabolism, pathogens often produce acids that interfere with their own growth. __________ are/is added to media to control pH changes.
buffers
Which of the following statements correctly differentiates biotechnology from rDNA technology? a. Biotechnology includes genetic modification of eukaryotic cells and prokaryotic cells, whereas rDNA technology exclusively involves the genetic modification of bacteria. b. Biotechnology is concerned only with the production of recombinant proteins, whereas rDNA technology is concerned exclusively with DNA. c. Biotechnology involves any use of microorganisms or cells to make products, regardless of the means used. Recombinant DNA technology involves methods for handling and modifying DNA and inserting it into different types of cells. d. Biotechnology includes techniques for gene amplification, whereas rDNA technology includes techniques for altering the nucleotide sequence of an organism's DNA.
c. Biotechnology involves any use of microorganisms or cells to make products, regardless of the means used. Recombinant DNA technology involves methods for handling and modifying DNA and inserting it into different types of cells.
Which of the following requires cell-to-cell contact? a. Transduction b. Transformation c. Conjugation d. Mutation
c. Conjugation
The following sequential steps are used to make a recombinant cell. Which of these steps occurs LAST? a. Isolate gene of interest b. Vector is taken up by cell c. Grow cells containing vector with gene d. Insert gene into a vector
c. Grow cells containing vector with gene
Which of the following correctly describes the lac operon? a. It is a constitutive operon that is unaffected by the presence of lactose. b. It is repressible operon that is turned on in the presence of lactose. c. It is an inducible operon that is turned on if lactose is present and glucose is absent. d. It is an inducible operon that is turned on in the presence of glucose.
c. It is an inducible operon that is turned on if lactose is present and glucose is absent.
Which of the following is NOT a step in binary fission? a. Cell elongation b. Cross-wall formation c. Lysis of the existing cell wall d. Replication of chromosomal DNA e. Invagination of the plasma membrane
c. Lysis of the existing cell wall
Which of the following statements about culture media is FALSE? a. A chemically defined medium is specifically formulated, and each ingredient is known. b. Complex media are formulated from nutrient-rich whole food sources whose exact ingredients may not be known. c. Nutrient agar contains ingredients that combine with oxygen and remove it. d. Reducing media are complex media containing chemicals, such as thioglycolate, that combine with oxygen, creating an anaerobic environment.
c. Nutrient agar contains ingredients that combine with oxygen and remove it.
Which of the following statements about DNA replication is FALSE? a. Primase synthesizes the primers b. DNA polymerase is required to add new nucleotides to the growing ends of the DNA strands. c. Only one strand of the parent DNA serves as a template for a newly synthesized complementary strand. d. DNA ligase joins the small DNA fragments of the lagging strand.
c. Only one strand of the parent DNA serves as a template for a newly synthesized complementary strand.
Which of the following is most often used in constructing cladograms for microorganisms? a. Cell morphology b. Characteristics of the cell wall c. Ribosomal RNA sequences d. Fossils
c. Ribosomal RNA sequences
Which of the following are examples of nucleic acid hybridization techniques? a. Western blotting b. ELISA c. Southern Blotting d. Slide agglutination test
c. Southern Blotting
Genetic technology has enabled screening for a variety of genetic conditions, and use of this technology is becoming more widely available. Which of the following is likely to become an important issue that will need to be addressed? a. The use of DNA analysis in criminal investigations b. The use of DNA analysis in anthropological studies c. The need for legislation to protect the privacy of individuals' genetic information d. The alteration of human phenotypes to prevent early disease
c. The need for legislation to protect the privacy of individuals' genetic information
Which of these answers is NOT true for positive (direct) selection? a. An example would be the detection of bacteria resistant to ampicillin by incorporation of ampicillin into the plating medium. b. It enables detection of a rare mutant from a population containing an extremely large number of bacteria. c. The procedure detects altered genotypes regardless of the phenotype. d. The selective medium is designed so that only the mutant cells grow on that medium. e. The mutant will grow on the selective medium, so there is no need for replica plating.
c. The procedure detects altered genotypes regardless of the phenotype.
All of the following are benefits and improvements made possible by recombinant DNA technology EXCEPT __________. a. Development of genetic screening procedures for early detection of genetic diseases b. Improved weed and pest control c. Use of baker's yeast to produce bread d. Development of new, safer vaccines
c. Use of baker's yeast to produce bread
In E. coli, Hfr cells __________.
can pass main chromosome genes to a recipient cell
The sequencing of rRNA __________.
can yield information about evolutionary relatedness
To express a human gene in a bacterium, cDNA must be made because bacteria __________.
cannot remove introns
During the lag phase, __________.
cells are engaged in intense enzymatic activity
A map that shows the evolutionary relationships of organisms among organisms is the __________.
cladogram
To look for bacteria that degrade petroleum, a culture medium containing crude oil, sodium nitrate, phosphate buffer, and magnesium sulfate is inoculated with soil. This medium is
complex
A culture medium consisting of agar, peptone, and beef-heart extract is a(n) __________.
complex medium
Non-regulated genes are also known as __________ genes.
constitutive
Which pair includes organisms that are the most closely related? a. A fungus and a bacterium b. A bacterium and an archaeon c. A fungus and an archaeon d. A fungus and a human e. A bacterium and a dog
d. A fungus and a human
Which of the following is NOT included in Domain Eukarya? a. A yeast b. A human c. A fern d. A photosynthetic bacterium e. A slime mold
d. A photosynthetic bacterium
Which of the following is an appropriate definition for prokaryotic species? a. Closely related organisms that can interbreed and produce fertile offspring b. Closely related organisms that appear identical when visualized using a microscope c. A population of cells with identical DNA sequences d. A population of cells with similar characteristics including morphology, biochemical reactions, and DNA sequences
d. A population of cells with similar characteristics including morphology, biochemical reactions, and DNA sequences
Which of these statements correctly describes RNA processing in eukaryotic cells? a. Introns are removed and the remaining exons are spliced together. b. mRNA is processed before is leaves the nucleus. c. Processing involves snRNPs. d. All of these statements
d. All of these statements
Which of the following is NOT a step in identification of bacteria by DNA probes? a. Making the bacterial DNA single-stranded b. Cloning and labeling of the probe (or obtaining a labeled probe) c. Lysis of the bacteria collected d. Making the probe double-stranded e. Isolating the bacteria to be tested by filtration
d. Making the probe double-stranded
Which of the following statements is NOT true of base substitutions? a. A base substitution may cause no change in the protein encoded by the affected gene. b. Base substitutions may be caused by radiation or chemical mutagens. c. A base substitution may be beneficial if the affected gene encodes an enzyme with enhanced activity. d. Mutations rarely involve base substitutions. e. A base substitution can result in the production of a shortened protein.
d. Mutations rarely involve base substitutions.
During conjugation, DNA is transferred from one bacterium to another. Often, it is plasmid DNA that is transferred. Which of the following plasmid names correctly matches the information that it carries? a. R factor - fertility factor b. F factor - plasmids that carry antibiotic resistance c. Dissimilation factors - antibiotic-resistance genes d. R factors - antibiotic resistance genes
d. R factors - antibiotic resistance genes
Which of the following enzymes and their function are MISMATCHED? a. DNA polymerase—synthesizes DNA and proofreads b. DNA ligase—joins pieces of DNA together c. DNA helicase—unwinds two strands of DNA d. RNA polymerase—makes DNA
d. RNA polymerase—makes DNA
Most amino acids are encoded by several different codons. This is referred to as the __________ of the genetic code.
degeneracy
In nature, the function of restriction enzymes is to __________.
destroy bacteriophage DNA
A key difference between classification methods and identification methods is that classification methods are designed to __________.
determine evolutionary relationships of organisms
For Agrobacterium tumefaciens to be used to introduce foreign DNA into a plant cell, that DNA must first be __________.
inserted into the T-DNA region of the Ti plasmid of A. tumefaciens
The chemical 5-bromouracil is a mutagen because it ___
is similar to thymine in structure but not base-pairing ability
PCR __________.
is useful as a step that may precede DNA fingerprinting or DNA sequencing
Which of the following is NOT a chemical requirement of all bacteria?
molecular oxygen
The major source of the genetic diversity among microorganisms upon which natural selection operates is __________.
mutation
Bacterial growth refers to an increase in the __________ of bacterial cells.
number
An unknown organism grows at the top of a tube of thioglycolate broth. This organism is best described as a(n) __________ for its oxygen requirements.
obligate anaerobe
Bacteria that CANNOT grow in the presence of oxygen (O2) are called __________.
obligate anaerobes
Instead of oxygen, __________ may utilize nitrate or sulfate as their final electron acceptors.
obligate anaerobes
An ampicillin-sensitive culture of E. coli is transformed with a plasmid that contains the gene of interest plus an ampicillin-resistant gene. If it is then plated on an ampicillin-containing growth medium, __________.
only the bacteria with the plasmid will grow
Martian soil is inoculated into a glucose-containing medium. The radioactive form of carbon, 14C, is used in the glucose. After incubation for five days, which of the following would provide evidence suggesting that there is life on Mars?
radioactive carbon dioxide
Niacin, when added to a medium, would be considered a(n) __
organic growth factor
The evolutionary history of a group of organisms is called __________.
phylogeny
When the antibiotic chloramphenicol binds to the 50S portion of the ribosome, the effect is to __________.
prevent the ribosome from moving along the mRNA strand
In the blue-white screening procedure, bacteria that are transformed with recombinant plasmid and cultured in media containing ampicillin and X-gal will __________.
produce white colonies
The three-domain system organizes all living organisms into two broad categories. Two of these include __________ organisms, and the third category is made up of __________ organisms.
prokaryotic; eukaryotic
The antibiotic kasugamycin blocks binding of bacterial tRNA that carries formylmethionine to a ribosome. From this information, you can conclude that kasugamycin prevents __________.
protein synthesis
Bacteria require nitrogen for the synthesis of __________.
proteins
An organism displays some growth at 4°C and at 25°C. However, it grows best at 20°C. This organism would be classified as a __________.
psychotroph
Bacteria that spoil food in the refrigerator are most likely __________.
psychotrophs
A frameshift mutation in a gene encoding a protein usually __________.
results in the production of a nonfunctional peptide
A medium containing chemicals to inhibit the growth of gram-positive bacteria would be called __________.
selective
A medium containing lauryl sulfate inhibits the growth of gram-positive bacteria. This medium is __________.
selective
Salt agar tends to inhibit the growth of most organisms, except Staphylococci. This is an example of a(n) __________ medium.
selective
The shotgun sequencing technique is used to __________.
sequence entire genomes
A good cloning vector __________.
should have a gene or genes that allows for selection of transformed host cells
During which phase of the cell cycle are bacteria dividing equal to bacteria dying?
stationary phase
Sequencing a genome provides __________.
the order of nucleotides in a genome
In the lac operon of E. coli, __________.
the repressor protein binds to the operator in the absence of lactose; In the lac operon of E. coli, the repressor protein binds to the operator in the absence of lactose. Regulation of the lactose operon also depends on the level of glucose in the medium, which in turn controls the intracellular level of the small molecule cyclic AMP (cAMP), a substance derived from ATP that serves as a cellular alarm signal.
You inoculate two tubes of liquid culture medium with 100 bacterial cells and incubate one tube at 37°C and the other at 55°C. After 48 hours, there are 20,000 bacteria per milliliter in the 37°C tube and 1,568,000 bacteria per milliliter in the 55°C tube. You conclude that this species is a
thermophile
The Ames test is used __________.
to determine if a chemical is mutagenic and possibly carcinogenic
Auxotrophs ___________.
will not grow on a plate that lacks the growth factor, but will grow on a complete medium that contains the growth factor
