ch 8-10 smartbook
When UAA, UAG, or UGA is encountered on the mRNA transcript, translation ______
ends
Which of the following antibiotics inhibits translocation of the ribosomal subunit during translation?
erythomycin
A gas that is valuable for sterilization of heat-sensitive objects, such as plastics, surgical and diagnostic appliances, and spices, is _________ oxide. Other related gases are available that are less toxic.
ethylene
Which chemical is valuable for sterilization of heat-sensitive objects such as plastics, surgical and diagnostic appliances, and spices, but is more toxic than other available related gases?
ethylene oxide
Antifungal agents are often toxic to host cells because the fungal and the host cells are both
eukaryotic
Straining of air or fluid through a membrane with openings too small for microorganisms to pass through is called ______.
filtration
A _______ mutation results from an insertion or deletion of nucleotides in multiples of 1 or 2, and always leads to a change in the "reading" of the codons in mRNA.
frameshift
Which type of mutation is generally most harmful to cells?
frameshift
A method for separating DNA fragments of different lengths is ______.
gel electrophoresis
A(n) ______ is a sequence of DNA nucleotides that codes for a group of related proteins.
gene
Summarize the problems that have led to the worldwide problem of managing antimicrobial drugs.
increase in superinfections development of resistance in "bystander" microbes physicians use a "shotgun" approach to treat minor infections
In some fungi, a small RNA known as _____ binds a genetic sequence to silence a gene. This can provide a temporary resistance to the antibiotic.
interfering RNA
A sequence of DNA in a eukaryotic gene that does not code for protein is called a(n)
intron
Found interspersed between portions of the coding region within a eukaryotic gene, one to several sequences that do not code for protein are called ______.
introns
A combination of iodine and an organic carrier (such as alcohol) that serves as a moderate-level disinfectant and antiseptic is a(n)
iodophor
Which term describes a complex of iodine and alcohol?
iodophors
Taq polymerase is used in PCR because it ______.
is stable at high temps
Which enzyme seals the sticky ends of DNA pieces when splicing genes into plasmids or chromosomes?
ligase
Quats are rated as _______ disinfectants in the clinical setting.
low-level
a freeze-drying method to preserve microbes.
lyophilization
Which type of RNA is a copy of a structural gene that codes for a protein?
mRNA
Quinine is a drug used to treat
malaria
The CDC is monitoring the spread of the ______ gene among bacterial species because it makes cells resistant to polymyxin, an antibiotic used to treat infections by bacteria that are resistant to multiple drugs.
mcr-1
An agent's effect on cells is known as its ____ of action
mechanism
Cationic detergents disrupt the cell
membrane
Three factors that should be considered before beginning antimicrobial therapy are: the nature of the _____ causing the infection, its degree of _____ to various drugs, and the overall medical condition of the patient.
microbe susceptibility
Drugs that are selectively toxic should kill which cells?
microbial cells
Higher temperatures are usually ______, whereas lower temperatures are usually ______.
microbicidal; microbistatic
The smallest concentration of a drug that visibly inhibits the growth of a microorganism is called the ______ concentration. Multiple choice question.
minimum inhibitory
Any genetic change that leads to the placement of a different amino acid in a protein is called a(n) ____ mutation
missense
A change in the gene that encodes the lac repressor was detected such that the amino acid alanine was inserted into the polypeptide instead of the amino acid glycine. This mutation can be described by which two of the following?
missense & point
An antimicrobial agent's adverse effect on cells is known as its ______.
mode of action
A ______ mutation results in early termination of the protein.
nonsense
A point mutation that changes a normal codon into a stop codon is called a _____ mutation
nonsense
Which of the following are some of the desirable qualities in a germicide?
not corrosive and nonstaining broad-spectrum action rapid action solubility in a solvent
Eukaryotic chromosomes are located in the ______, while prokaryotic chromosomes are found in the ______.
nucleus nucleoid
Heavy metal germicides come in which of the following forms?
ointments aqueous solutions
Bacterial and archaeal genes are arranged into
operons
A sequence that is identical when read from the 5' to 3' direction on one strand and the 5' to 3' direction on the other strand is called a(n)
palindrome
Restriction enzymes recognize and clip at sequences called
palindromes
Items are classified as critical, semicritical, or noncritical based on ______.
parts of the body contacted by them
Which of the following antibiotics is an inhibitor of cell wall synthesis?
penicillin
Which class of enzymes destroys the beta-lactam ring in some antibiotics?
penicillinase
An enzyme that hydrolyzes penicillin and is found in penicillin-resistant strains of bacteria is called
penicillinase or beta-lactamase
Cloxacillin and nafcillin are useful in treating infections caused by _____-producing bacteria
penicillinase or beta-lactamase
Which term refers to bacteria that slow or stop their metabolism so that they cannot be harmed by an antibiotic?
persisters
Biofilm bacteria are not affected in the same way as their free-living counterparts by antibiotics because biofilm bacteria express different ____ and therefore have different antibiotic sensitivities.
phenotypes
Which two components of a nucleotide are bound to form the backbone of a DNA strand?
phosphate and deoxyribose sugar
Which type of chemical bonds in DNA are broken by restriction endonucleases?
phosphodiester
Donor and recipient bacterial cells are connected by the sex ____- during conjugation
pilus
An R factor is a type of___ that confers antibiotic resistance.
plasmid
Any substitution of a single nucleotide that does not change the DNA reading frame is called a(n) ________ mutation.
point
The lowest temperature required to kill all microbes in a sample in 10 minutes is the thermal death ______.
point
A method for making billions of copies of a specific DNA sequence is ______.
polymerase chain reaction
A concerning development is the identification of the mcr-1 gene which renders bacteria resistant to the last-resort antibiotic ______.
polymyxin
This image shows a _____ complex, which includes multiple ribosomes on a single transcript.
polyribosomal
The term describing the point at which some infections are untreatable due to the prevalence of antibiotic resistance is ______. Multiple choice question.
post-antibitoic era
Which disease-causing agent is resistant to both heat and chemicals?
prions
Preparations of live microorganisms that are fed to animals and humans to improve the intestinal biota are called ______.
probiotics
Which are preparations of live microbes used as a preventive or therapeutic measure to displace or compete with potential pathogens?
probiotics
Hydrogen peroxide typically kills microbes by ______.
producing toxic free radicals
Which term refers to the use of a drug to prevent imminent infection of a person at risk?.
prophylaxis
In translation, all of the elements needed to synthesize a _____, from the mRNA to the amino acids, are brought together on the ribosome.
protein
Tetracycline inhibits _____ synthesis by blocking the attachment of _____ on the A acceptor site.
protein tRNA
Tetracyclines inhibit ______.
protein synthesis
Glutaraldehyde affects what type of macromolecules?
proteins
Which of the following describes the study of an organism's complement of proteins and their functions?
proteomics
Which of the following drugs was the principal treatment once used for malaria?
quinine
Energy emitted from atomic activities and dispersed at high velocity through matter or space is called
radiation
The combination of genetic material from two different organisms is the primary intent of ______ DNA technology.
recombinant
An event in which one bacterium donates DNA to another bacterium, resulting in a strain that differs from both donor and recipient, is a type of genetic transfer called
recombination
An adaptive response in which microorganisms begin to tolerate an amount of drug that would ordinarily be inhibitory is called drug ______.
resistance
Plasmids called ______ factors confer antibiotic resistance through horizontal transfer.
resistance
An enzyme that creates breaks in the double helix by severing the phosphodiester bonds between adjacent nucleotides on both strands of DNA is a(n) ______.
restriction endonuclease
Which enzyme cleaves specific locations on DNA and is used to splice genes in genetic engineering?
restriction endonuclease
How does DNA polymerase I differ from DNA polymerase III?
DNA pol III is the primary replication enzyme, whereas DNA pol I removes the primer and closes gaps.
Which enzyme builds the new DNA strands in PCR?
DNA polymerase
The central theme of biology indicates that genetic information flows from ______.
DNA to RNA to protein
Which is true regarding DNA semiconservative replication?
Each new DNA helix contains one parent strand and one newly synthesized strand
In which of the following ways do the chromosomes of bacteria and eukaryotes differ?
Eukaryotic chromosomes are located in the nucleus and bacterial chromosomes are not in a membrane-bound organelle. Eukaryotes have histones but bacteria have histone-like proteins that are not true histones.
After conjugation, the recipient cell will be
F+
A(n) ______ cell has a separate fertility plasmid, whereas a(n) _____ cell has the F factor incorporated into its chromosome.
F+; Hfr
Which of the following is a palindrome sequence of DNA?
GAATTC
How does RNA differ from DNA?
In RNA, uracil replaces thymine. RNA is usually single-stranded.
What is the importance of PCR?
Increases the amount of DNA in a sample
Which of the following is NOT a general mechanism of antimicrobial drug actions?
Inhibiting electron transport systems
Which of the following are general mechanisms of antimicrobial drug actions?
Interference of cell membrane structure and function Inhibiting cell wall synthesis Inhibiting nucleic acid structure or function Inhibiting protein synthesis
Which of the following are newer antihelminthic drugs for use in humans?
Ivermectin Praziquantel
Which is true regarding bacterial chromosomes?
Located in the nucleoid region of the cytoplasm
What amino acid sequence is encoded by the DNA template sequence 3'-TACCGCGCTCTACCG-5'?
Methionine-Alanine-Arginine-Aspartic Acid-Glycine
Drugs that work for viral infections will target the virus in which of the following ways?
Prevents entry of the virus into host cells Do not allow the virus to reproduce inside the cell Prevents the assembly of new viral particles
What events initiate translation?
Ribosome scans to find AUG on the mRNA transcript Assembly of the ribosomal subunits
Which of the following are primary sites for action of antimicrobial drugs in bacteria?
Ribosomes Cell wall Nucleic acids Cell membrane
Soaps and quats are commonly used for ______.
Sanitization of food preparation equipment Sanitization of the home Skin cleansing Disinfection of restrooms
What is the role of reverse transcriptase?
Synthesizes DNA from RNA
The enzyme responsible for building the new strands of DNA in PCR is called ___ ___
Taq/DNA polymerase
How do an Hfr cell and an F+ cell differ?
The plasmid is integrated into the chromosome of an Hfr cell but not in an F+ cell.
Which of the following are the three factors that should be known before selecting an antimicrobial drug?
The sensitivity of the infecting agent The nature of the infecting agent The overall health of the patient
What is the thermal death time?
The shortest length of time required to kill all test microbes at a specified temperature
What is filtration?
The straining of a fluid or air through a membrane to trap microorganisms
Antimicrobial Chemotherapy
The use of drugs to control infection
The currently used antiviral drugs were developed to target specific points in the infectious cycle of viruses. Three major modes of action are as follows:
barring penetration of the virus into the host cell, blocking the transcription and translation of viral molecules, and preventing the maturation of viral particles.
Which enzyme catalyzes a reaction that hydrolyzes the beta-lactam ring structure to inactivate some penicillins and cephalosporins?
beta-lactamse
Antimicrobial drugs often cannot penetrate the sticky extracellular material surrounding organisms in a
biofilm
The normal colonists of the human body, mostly harmless or beneficial bacteria, are called the ______.
biota
Restriction enzymes create breaks in which part of a DNA molecule? Multiple choice question.
bonds of the backbone
One consequence of widespread use of ______-spectrum antibiotics is the development of resistance in ______ microbes that are part of the normal biota.
broad; bystander
Which type of detergents are more effective?
cationic
Which of the following antibiotics is an inhibitor of cell wall synthesis?
cephalosporin
Gases that are commonly used as sterilants or disinfectants are ethylene oxide and _____ dioxide.
chlorine
A discrete cellular structure composed of a neatly packaged DNA molecule is called a(n)
chromosome
Which of the following semisynthetic penicillins are useful in treating infections caused by penicillinase-producing bacteria?
cloxacillin nafcillin
The specific sequence of 3 mRNA nucleotides, based on a DNA triplet, that encodes a particular amino acid is a(n)
codon
In bacteria, horizontal gene transmission through a pilus is called
conjugation
Which of the following are methods of gene transfer in bacteria?
conjugation, transduction, transformation
After conjugation, the donor bacterium generally retains a copy of the genetic material that has been transferred, making conjugation a(n) _____ process
conservative
In the laboratory, the method that scientists use to renature DNA into its normal double-stranded form is
cooling
In the bacterium Escherichia coli, where is the chromosome located?
cytoplasm
Which bases can be found in both DNA and RNA?
cytosine guanine adenine
The lowest temperature that achieves sterilization in a given quantity of broth culture upon a 10-minute exposure is referred to as the thermal ____- _____
death point
Vegetative cells directly exposed to normal room air gradually become dehydrated or ______.
dessicated
The dehydration of microorganisms to inhibit or preserve them is called
dessication
Glutaraldehyde typically kills microbes by ______.
disrupting enzyme function disrupting protein activity
Cationic detergents typically work by ______.
disrupting the cell membrane
Alcohols usually affect microbes by ______.
disrupting the cell membrane disrupting cell surface tension
Higher concentrations of alcohols usually affect microbes by ______.
dissolving membrane lipids
synthetic drugs
drugs produced entirely by chemical reactions
semisynthetic drugs
drugs that are chemically modified in the lab after being isolated from natural sources
Glycylcyclines are __________ against bacteria that have become resistant to tetracyclines.
effective
Most drugs that inhibit protein synthesis or translation block the action of the
ribosome
The site of protein synthesis is the
ribosome
The property of an antimicrobial agent to be highly toxic against its target microbe while being far less toxic to the cells of the host organism is called _____ toxicity.
selective
A drug that kills or inhibits microbial cells without simultaneously damaging host tissues is called ______ toxic.
selectively
Devices that come into contact with mucosal membranes are called ______.
semi-critical
Newly made double helices are composed of one parent template and one newly synthesized strand as a result of _____ DNA replication.
semiconservative
In some fungi, a small regulatory RNA known as interfering RNA can temporarily silence a gene. When this gene encodes _____, the fungus is transiently resistant to the antibiotic.
the target of the antibiotic
The ratio of the dose of a drug that is toxic to humans compared to its minimum effective dose is called the ______.
theraputic index
The ratio of the toxic dose to the effective dose that is used to assess the safety and reliability of a drug is called the .
theraputic index
Dissolving a solid or gaseous antimicrobial chemical in pure alcohol or an alcohol-water mixture produces a(n) ______.
tincture
Antimicrobial solutions with alcohol or water-alcohol mixtures as the solvent are called
tinctures
The therapeutic index is the ratio of the ______ dose to the ______ dose that is used to assess the safety and reliability of the drug.
toxic; therapuetic
Which two types of horizontal gene transfer do NOT require direct contact between the donor and the recipient cells?
transduction translation
Which of the following are the three major types of RNA?
transfer (tRNA) messenger (mRNA) - a copy of the DNA template corresponding to a protein-encoding gene ribosomal (rRNA)
Horizontal gene transfer
transfer of DNA from a source other than the parent organisms
Vertical gene transfer
transfer of genes from an organism to its offspring
The uptake of free DNA by competent bacterial cells is called
transformation
The assembly of the ribosome and the locating of the AUG start codon are events that initiate the process of
translation
True or false: Heavy metals may be used for topical germicides and ointments.
true
The pyrimidine nitrogenous bases found in RNA are cytosine and
uracil
Which template DNA sequence encodes the peptide sequence phenylalanine-leucine-aspartic acid-valine?
3'-AAAAACCTACAT-5'
Which describes a plasmid?
A small circular piece of DNA that replicates its nonessential genes independently of the chromosome
To treat Pneumocystis infections in ____, ______ is used in combination with sulfamethoxazole
AIDS or HIV trimethoprim
Which of the following describe the origin of replication?
AT - rich located on chromosome
start codon
AUG
broad-spectrum (extended spectrum)
Antimicrobials effective against a wide variety of microbial types—for example, a drug effective against both gram-positive and gram-negative bacteria
What are biota?
Beneficial or harmless microbial residents of the human body
Identify the three major modes of action of antiviral drugs.
Blocking virus transcription and translation Preventing virus maturation Barring virus penetration into host cell
_______ involves the use of a connecting bridge, _______ requires a bacterial virus vector, and ______ entails transfer of naked DNA.
Conjugation; transduction; transformation
Ethylene oxide typically kills microbes by blocking _____ replication and enzymatic actions.
DNA
What is cDNA?
DNA made from RNA
True or false: A point mutation involves any substitution of a single nucleotide.
True
True or false: Tinctures and ointments are two types of heavy metal germicides.
True
RNA contains ______ that pairs with _____.
U, A
stop codon
UAA, UAG, UGA
The start codon AUG is associated with the tRNA anticodon _____ and the amino acid _______.
UAC; fMet
An organic substance that contains a -CHO functional group on a terminal carbon is a(n
aldehyde
antimicrobials
all-inclusive term for any antimicrobial drug, regardless of its origin
A drug reaction that occurs because the drug stimulates the immune system is known as a(n) _____.
allergy
Which antibiotic specifically inserts on sites of the 30S subunit of prokaryotic ribosomes causing the misreading of mRNA and thus inhibit translation?
aminoglycosides
Drug resistance arises when ______.
an organism gains the genetic information for resistance from another organism a spontaneous mutation occurs in the organism's DNA code
narrow-spectrum (limited spectrum)
antimicrobials effective against a limited array of microbial types- for example, a drug effective mainly on gram-positive bacteria
Alcohols are commonly used for ______.
antiseptic preparation for skin degermation of skin
A laboratory instrument that achieves the appropriate pressure and temperature combinations to sterilize materials is called a(n) ______.
autoclav
A ______ agent will inhibit the growth of bacteria, whereas a ______ agent will kill bacteria.
bacteristatic; bactericidal
The replacement of a faulty gene responsible for a disease with the wild type gene is termed ______.
gene therapy
The genetic makeup of an organism that is ultimately responsible for an organism's expressed characteristics is called the ______. Multiple choice question.
genotype
Which of the following describes the systematic study of an organism's genes and their functions?
geomics
Which of the following are NOT primary sites for action of antimicrobial drugs in bacteria?
golgi apparatus and mitochondria
Which two variables contribute to the thermal death time?
heat and time
The most common physical agent used to control microbes is
heat/temp
Which of the following is used in the laboratory to separate strands of DNA?
heating
_____ breaks the hydrogen bonds holding the two strands of DNA together, resulting in two separate strands.
helicase
In DNA replication, ______ unwinds the double helix, primase synthesizes the short RNA primer, and DNA ______ adds nucleotides to the new chain.
helicase DNA poly III
match each enzyme with its role in DNA replication
helicase - unzips the DNA helix primase - synthesizes an RNA primer DNA poly I - removes the primer, closes gaps and repairs mismatches DNA poly III - adds bases to the growing DNA chain, proofreads topoisomerase - untangles newly replicated strands ligase - seals nicks in DNA
Ivermectin and praziquantel are newer drugs used for the treatment of _____.
helminth infections
Transfer of DNA that results in organisms acquiring new genes that did not come directly from parent organisms is called ______ gene transfer.
horizontal
Dry heat occurs in the forms of ______ and ______.
hot air oven open flame
Plasmolysis of bacteria in foods occurs when high concentrations of salt or sugar are added to the foods creating a _____ environment.
hypertonic
The use of sugar or salt to preserve food creates a ______ environment for the bacteria in the foods.
hypertonic
Where are the chromosomes of yeast cells located?
in the nucleus
Heavy metals typically kill microbes by ______.
inactivating proteins
The destruction of microbes by subjecting them to extremes of dry heat, reducing them to ashes and gas, is called
incineration
Which type of mutation alters the DNA sequence of a gene, but does not change the amino acid sequence of the protein that is encoded by the gene?
silent mutation
Which of the following heavy metals are still used in germicidal preparations?
silver and mercury
Hydrogen peroxide is commonly used for ______. Multiple select question.
skin and wound cleansing sterilization of diagnostic instruments
Although they do have some drawbacks, heavy metals are used for ____
skin cleansing controlling microbial growth on objects preservatives prevention of infection
Bacterial cells described as persisters are resistant to antibiotics because they ______.
slow/stop their metabolism in the presence of the drug
Which compounds are commonly used for sanitation of the home and food preparation areas/utensils?
soaps and quats
Drug resistance occurs with spontaneous ____ or gene transfer from another species.
spontaneous
_______ mutations occur when errors are made in DNA replication whereas _____ mutations are caused by exposure to radiation or chemical agents.
spontaneous induced
Moist heat occurs in the forms of ______ and _____
steam and boiling water
A process that completely removes or destroys all viable microorganisms, including viruses, from an object or habitat is referred to as
sterilization
Of the following, which antibiotic is an inhibitor of protein synthesis?
streptomycin
antibiotics
substances produced by the natural metabolic processes of some microorganisms that can inhibit or destroy other microorganisms; genrally, the term is used for drugs targeting bacteria and not other types of microbes
The nucleotides in a DNA strand are linked by a covalent bond between the ______ of one nucleotide and the ______ of the next nucleotide.
sugar; phosphate
By blocking enzymes required for the synthesis of tetrahydrofolate, _____ interfere with folate metabolism.
sulfonamides
Trimethoprim and sulfamethoxazole are often given in combination because of the effect of the two drugs.
synergistic
Which of the following antibiotics is an inhibitor of protein synthesis?
tetracycline
Glycylcyclines are newer derivatives of _______.
tetracyclines
Sulfonamides interfere with folate metabolism by blocking enzymes required for the synthesis of ______.
tetrahydofolate
CRISPR has been used to treat antibiotic-resistant infections by directing specific gene cuts to _____. Multiple choice question.
the antibitoic resistance genes