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229 Cards in this Set
- Front
- Back
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Microbes are present everywhere or ( )
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Ubiquitous
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Infectious microorganisms are those capable of what
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causing disease (also known as pathogens or potential pathogens)
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What are microbes present at a given place and time that are undersirable or unwanted
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contaminant (vegetative cells, endospores, cysts)
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What are infections that develop during the course of a hospital stay and not present at the time of admission. Limit such infections by adhering to good infection control practices
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Nosocomial infection
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What are free of all microorganisms and their spores; microbes have been destroyed or removed
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sterile
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What is use of physical procedures or chemical agents to destroy, inhibit, neutralize, or remove at least most potentially infectious microorganisms on an object or surface. Does not imply sterility
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Disinfect/ Decontaminate
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What is the order of microbial population composition
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1-bacterial endospores
2-mycobacterium 3-Protozoan cysts 4-non-enveloped small viruses 5-vegetative bacteria 6-Fungi 7-Enveloped viruses |
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Are younger cells more easily destroyed than mature cells
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Yes
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What are the factors of microbial death
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Population size, concentration/intensity of antimicrobial, duration of exposure, temperature and pH, Presence of protective or neutralizing matter, physical nature of materials being treated
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What are the modes of action of microbial control methods
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Damage to cell wall, disrupt cytoplasmic membrane, inhibit synthesis of proteins and nucleic acids, alter function of proteins & nucleic acids
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Explain damage to cell wall
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blocks its synthesis, digest it, or break down its surface Examples: antibiotics, lysozyme, detergents
Explain disrupt cytoplasmic membrane |
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Explain disrupt cytoplasmic membrane
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cause loss of membrane integrity and selective permeability Example: detergents (surfactants), heat
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Explain inhibit synthesis of proteins and nucleic acids
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interference with gene translation, thus preventing protein synthesis Examples: antibiotics, radiation, formaldehyde
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Explain alter function of proteins & nucleic acids
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alter bonds that determine secondary and tertiary structure. Altered structure inactivates or denatures functions of enzymes and nucleic acids. Examples: heat, strong organic solvents, phenolics, metallic ions, antibiotics
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What is a chemical substance of natural, semisynthetic, or synthetic origin that inhibits or kills microorganisms and which can be used to treat or control infection.
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Antibiotic/ antimicrobic agent (antimicrobic)
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What is the antibiotic will affect only the target organism (microbe) without harming the host (patient) [although mild toxicity or side effects are considered acceptable]
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selective toxicity
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The antibiotic activity of these compounds depends on the integrity of the beta-lactam ring (O--C-N). By altering the nature of the side chains (R), differences in antimicrobic properties can be obtained.
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Beta-lactam antibiotics
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What is a suffix that indicates that the chemical or process is destructive to (kills) the microbe (e.g. bacteria, fungi, viruses), although it does not necessarily kill spores.
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cide, cidal
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( ) chemicals destroy spores as well as vegetative cells
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sporicidal
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What is the principle of action of beta-lactam antibiotics
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inhibits peptidoglycan synthesis by inhibiting the formation of cross links between the polymers of the bacterial cell wall
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how many steps in peptidoglycan synthesis
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30 enzymatic steps
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What are cell-membrane enzymes (proteins) responsible for synthesizing peptidoglycan
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Penicillin binding proteins (PBP
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What are the results of Beta-lactam antibiotics binding to PBPs
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Inhibition of peptidoglycan synthesis; degradation of formed cell wall through the release of autolytic enzymes; weakened cell wall loses integrity and can no longer preserve osmotic pressure. Results in cell death and increased phagocytosis
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is most effective against gram-positive bacteria because the outer membrane of gram-negatives prevents some degree of antibiotic entrance
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Beta-lactams
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How can resistance occur with beta-lactams
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development of changes to pores thus preventing entrance of antibiotic; evention of binding of antibiotic to PBP due to modified PBP structure; hydrolysis of antibiotic by beta-lactamases (penicillinase, cephalosporinase)
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What binds onto the cross-link peptide, so that the link cannot be completed and peptidoglycan polymer cannot elongate.
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Vancomycin
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What blocks phospholipid carrier that helps carry subunits of peptidoglycan across membrane to cell wall
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Bacitracin
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What inhibits formation of mycolic acid in cell walls of mycobacterium (tuberculosis organism)
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Isoniazid (INH)
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What inhibit translation by binding to 30S ribosomal protein causing misreading of mRNA and incomplete synthesis of protein molecules
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Amino glycosides
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What inhibits translation into polypeptides (proteins) by blocking binding of tRNA to the 30S ribosome-mRNA complex.
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Tetracycline’s
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What inhibits the polypeptide elongation steps in translation by binding to 50S ribosome subunit. Is Bacteristatic, Is Broad-spectrum. Resistance is primarily due to chemical alteration of either the antibiotic or the ribosomal molecule, thus preventing binding.
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Chloramphenicol, clindamycin, and macrolides (e.g. erythromycin) [different classes but similar mechanism]
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What is the principle of inhibitors of cell membrane function
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disrupts functional integrity of cytoplasmic membrane, allowing nucleotides and proteins to escape
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What are active against gram-negatives, but nephrotoxicity limits them to external use
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Polymyxins
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hat are antifungal; binds with ergosterol in fungal membranes; somewhat toxic
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Amphotericin B (a polyene)
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What is the principle behind inhibitors of nucleic acid synthesis
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competitive inhibition of essential nucleic acid precursor or binds essential enzyme (e.g. DNA gyrase)
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What inhibit bacterial DNA gyrase (the enzyme that controls DNA coiling -- if DNA is not tightly coiled, it will not fit into the bacterial cell)
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Quinolones (e.g. nalidixic acid) and Fluoroquinolones (e.g. ciprofloxacin
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What inhibits transcription by binding to RNA polymerase and inhibiting initiation of mRNA synthesis
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Rifampin
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What causes breakage of microbial DNA (bacterial and parasitic DNA)
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Metronidazole
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What are antiviral antimicrobics (fake nucleotides that completely insert into viral DNA & viral RNA). They inhibit DNA or RNA synthesis by altering their composition using nucleic acid analogues
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Nucleoside analogues
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What are some examples of Nucleoside analogues
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Acyclovir, Ribavirin, Zidovudine
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What incorporates into fungal RNA and interferes with DNA and protein synthesis
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Flucytosine, 5-fluorocytosine (5FC)
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Flucytosine, 5-fluorocytosine (5FC)
What inhibits folic acid synthesis by competing for precursor molecules (inhibitors of bacterial metabolism) |
Sulfonamides (sulfamethoxazole)
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What competitively interferes with folic acid production by inhibiting a metabolic enzyme (inhibitors of bacterial metabolism)
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Trimethoprim
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What are antifungal and inhibits synthesis of ergosterol, a key structural molecule of fungal cell membranes. (inhibitors of bacterial metabolism
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Azoles (fluconazole)
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Is Bacteristatic. Is Broad-spectrum. Resistance most commonly results from active efflux of the antibiotic out of the cell or the production of proteins that protect the 30S ribosome
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Tetracyclines
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Are bactericidal, broad-spectrum, although predominately used against various systemic gram-negative infections. Resistance most commonly results from enzymatic modification of the antibiotic.
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Aminoglycosides
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. Resistance is primarily due to chemical alteration of either the antibiotic or the ribosomal molecule, thus preventing binding.
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Chloramphenicol, clindamycin, and macrolides (e.g. erythromycin) [different classes but similar mechanism]
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What is the entire complement of genes on all chromosomes normally found in an organism; the hereditary information
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Genome
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What is a segment of DNA that contains the genetic code (blueprint) for a functional product (e.g. code for a specific protein)
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Gene
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The genetic code is translated into proteins for structural, catalytic, or regulatory functions within the cell with the aid of ( ) and ( )
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messenger RNA, ribosomes
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Genetic code for each protein is carried as a sequence of nucleotide molecules in the ( )
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nucleic acid macromolecule
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E. coli DNA contains about ( ) genes
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4000
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What is the total genetic makeup of an organism (potential properties of the cell)
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Genotype
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What is the actual, expressed properties of an organism. Almost all of a cell's properties derive from the structures and functions of its proteins
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Phenotype
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What does a nucleotide consist of
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5-carbon sugar (ribose or deoxyribose),
a phosphate group (bound to the fifth carbon of the sugar molecule), a nitrogenous base (bound to the first carbon position of the 5-carbon sugar. |
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Adenine binds to what
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Thymine or Uracil
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What are paired nucleotides (adenine paired to thymine and guanine paired to cytosine ) attached to the deoxyribose
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double helix
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What is it called when the two strands run in opposite directions; i.e. the nucleotide of the 3' end o fone strand pairs up with the nucleotide of the 5' end of the adjacent strand. Strands are not identical, but are complementary.
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The strands are antiparallel
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What forms where short lengths of double-stranded DNA helix unwind
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Replication forks
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What is unwinding due to
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the action of enzymes such as helicase and DNA gyrase which break the hydrogen bonds between bases
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If the separated parent strand exposes bases TGCCAT, the newly forming strand will have bases in the order ACGGTA which is the ( ) of the original strand
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complement
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( ) are always added to the exposed 3' end of the growing strand, thus the strand grows in the 5' to 3' direction (extends the length of the 3' end)
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Nucleotides
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( ) edits for errors with accuracy of about 1 error in a billion base pairs replicated
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DNA polymerase
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What is the newly growing strand having the 3' end of the exposed nucleotide "facing toward" the replication fork
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Leading strand
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The newly developing strand grows toward the ( ), and "leads into" the fork
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replication fork
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The leading strand is ( ) because of enzymatic simplicity and ease of access to the molecule
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continuously replicated
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What is the strand having the 5' end of the exposed nucleotide facing toward the replication fork
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Lagging strand
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The newly developing lagging strand grows away fromt he replication fork, which is accomplished by ( ), then commecting them together to form a new complementary strand.
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replicating short fragments
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( ) and RNA polymerase are needed to initiate strand growth in the absence of a nucleotide having a 3' binding site
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RNA primer
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After RNA primer is in place, thus providing a 3' site, then ( ) takes over the replication and continuew to within one nucleotide of the existing, previously generated strand.
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DNA polymerase
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Why can't DNA polymerase join the final nucleotide of the new fragment to the existing strand
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because it cannot facilitate linking to both 3' and 5' binding sites.
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( ), which can facilitate linkage of a nucleotide to both 3' and 5' binding sites simultaneously, inserts a nucleotide to join the newly replicated fragment with the existing strand
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DNA ligase
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The replication of the lagging strand is ( ) because of this process of producing short fragments and joining them to the existing strand. A new fragment is generated each time the replication fork advances a short distance. This process continues throughout the entire replication process until the entire DNA has been replicated
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discontinuous
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The new double-stranded ( ) into a helix as the parental DNA unwinds exposing more nucleotides to be replicated
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DNA re-winds
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E. coli can replicate about ( )
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1000 nucleotides per second
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What is it when the entire chromosome is copied, each double helix consists of one newly synthesized strand of DNA bound to one original parent strand
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Semiconservative replication
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What is large, single stranded molecule of nucleotides attached to the sugar, ribose
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Ribonucleic acid (RNA)
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What carries the genetic code from the DNA to the ribosome
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mRNA
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What are three nucleotides on the mRNA that specify the amino acid to be placed in a polypeptide
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Codon
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What is another name for Genetic Code
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Triplet Code
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What transports and then transfers the amino acid to the developing peptide chain
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tRNA
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what assists protein synthesis by serving as a facilitator for the mRNA and tRNA functions
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rRNA
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What is the transfer of the genetic code on DNA gene into a messenger RNA (mRNA) strand by means of DNA-dependent RNA polymerase
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Transcription
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What is steps 1 of transcription
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1 DNA double-helix unwinds a portion and strands separate thus exposing nucleotides of a gene
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What is steps 2 of transcription
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(2) RNA polymerase binds to the DNA at the promoter site (beginning of the gene)
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What is steps 3 of transcription
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(3) Complementary RNA nucleotides are joined together in sequence by the RNA polymerase
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What is steps 4 of transcription
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(4) Transcription ends when the RNA polymerse reaches the termination region of the gene, and the new single-stranded mRNA is released (the DNA re-winds)
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What is the synthesis of a polypeptide at the ribosome through linkage of amino acids in a sequence specified by a mRNA molecule
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Translation
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What is steps 1 to translation
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(1) mRNA attaches to the ribosome with the "start" in place
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What is steps 2 to translation
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(2) A tRNA with the complimentary anticodon matches to the codon on the mRNA, thus bringing the first amino acid into place
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What is steps 3 to translation
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(3) As the mRNA codons are matched with complimentary tRNA anticodons, the amino acids arelinked together and the tRNA released
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What is steps 4 to translation
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(4) Polypeptide chain is released when the reading frame reaches the "stop" codon
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What are constantly expressed (transcribed and translated inot functional products) (60-80% of genes are in this category)
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Constituitive genes
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What are related genes that are regulated as a group/series (e.g. genes which code for the enzymes of a single metabolic pathway
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Operon
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what is located in another portion of the chromosome than the operon and codes for a repressor protein which can bind to the operator region
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repressor gene
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What is the region of the chromosome to which the RNA polymerase binds during transcription
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Promoter site
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What is the region of the chromosome which controls (either permits or blocks) access of the RNA polymerase to the structural genes of the operon; site to which the repressor protein binds (or fails to bind)
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Operator site
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What are adjacent genes of the operon which direct the synthesis of proteins with related functions and which are regulated as a unit
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Structural genes
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What is it when genes are expressed only when certain environmental conditions are present (e.g. genes for enzymes of a biosynthetic pathway are expressed only when the appropriate substrate is present
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Inducible operon
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What are changes in the sequence of DNA bases, thus changing the genetic code
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mutation
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What is a single base is replaced with another, thus changing the codon. May result in an improper amino acid in the protein- usually not highly significant.
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Substitution
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What is insertion or deletion of bases may shift the codon reading frame of the mRNA in the ribosome -- often results in significantly different or nonfunctional protein
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Frameshift mutation
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What is gain or loss of entire gene segment or inversions or transpositions of gene sequences. results in major change or non-functional cell.
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Gross mutations
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Spontaneous mutatoin typically occurs about once in a ( ) replicated genes.
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million
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Mutation is caused by what
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chemical mutagens, e.g. nitrous acid, base analogs (do not pair properly), Radiation - X-ray, gamma rays, ultraviolet light
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What are exchange of genes between two DNA molecules to form new combinations of genes
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Genetic recombination
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what is a small, circular, self-replicating piece of DNA in bacteria
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Plasmid
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Plasmid is separate from the normal ( )
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chromosomal DNA
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Genes are usually not essential for growth of ( )
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bacterium
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Genes often code for antibiotic resistance or ( )
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diesease-causing factors
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A plasmid can be used in the ( ) -- recombinant plasmid inserted into a new host bacterium, e.g. HeptaVax
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genetic engineering process
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What is integration of the DNA of a temperate bacteriophage (virus) into the bacaterial chromosome where it replicates along with the bacterial chromosome
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Lysogeny
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What is the transfer of genetic material between donow and recipient cells involving direct cell-to-cell contact
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Conjugation
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What is a hollow tube extending from one bacterium to another that is used to transfer DNA from one cell to another
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Sex pilus
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During Conjugation a copy of DNA strand or ( ) is transferred to the recipient cell
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plasmid
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What is the direct transfer of genes from one bacterium to another as "naked" DNA in solution (free DNA from one cell is incorporated into the DNA of another; usually folows cell breakdown and release of DNA after bacterial death
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Transformation
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What is the transfer of DNA from donor bacterium to recipient bacterium by using a bacterial virus as the vehicle (host DNA or plasmid is accidently enclosed in a bacterial virus during exit of the virus from the bacterium)
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Transduction
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What is it when genes are expressed except when certain environmental conditions are present (e.g. presence of certain metabolic products causes genes for metabolic enzymes to be repressed, thus slowing down metabolism)
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Repressible operon
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are the close associatoin and interaction of two dissimilar organisms living together
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Symbiosis
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What are those microorganisms which are normally and consistently found in or on the body in the absence of disease
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Normal flora
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Nature and variety of normal flora microbes are often distinctive for different ( )
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regions of the body
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Resident vs. transient flora are part of what
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normal flora
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Normal flora of one area may cause infection when
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in another region of the body
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What is association between organisms in which one is benefitted and the other is neither benefitted nor harmed
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Commensalism
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What is it called whe What is association between organisms in which one is benefitted and the other is neither benefitted nor harmed n both the microbe and host derive benefits from the relationship
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Mutualism
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What is it called when disease traits of the resident flora are demonstrated only when mormal host-microbe relationship is altered (e.g. injury, surgery, immunological compromise, other debilitation)
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Opportunism
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What are symbiotic relationship in which a microorganism lives in or on a host at the expense of the host
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Parasitism
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What are a carrier of microbes from one host to another (insects and other animals and inanimate articles, personal items, eating utensils, tools)
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Vector
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What are the growth and spread of a pathogen in or on a host resulting in injury to the host tissue.
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infectious disease
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What is it called when a microbe is capable of causing disease by invading tissues, producing toxins. or both
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Pathogen
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What is the degree of pathogenicity (infectivity--how easily the microbe survives the normal host defenses and establishes infection and Severity of the damage it causes the infected host)
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Virulence
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Direct contact with the skin or mucous membranes of a diseased person (or carrier) with or without active penetration of the microbe through the skin or mucous membranes
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direct
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Indirectly through the air on droplets or dust
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inhalation
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Indirect contamination of food and water, fecal material, dead or live animals, soil, and other source
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ingestion
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Blood contamination indirectly by arthropod and other animal vectors and by nonsterile syringes and needles
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`
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Attachment/Establishment Factors are what
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things that enable the establishment of infection
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What attach to specific receptor sites on specific tissue
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Fimbriae
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What dissolve covering or cells and aid chemical attachment
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Surface chemicals
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The organism must enter what in order to overcome local defenses and find right/best environment
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correct portion of the body
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What is the action of Antiphagocytic factors
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prevent microbe from being englufed and/or destroyed by white blood cell (physical protection or chemical poison)
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What are factors that promote the invasion and spread of a pathogen in/on the tissue
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Invasive Enzymes
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What is the action of Invasive Enzymes
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enable the pathogen to invade the tissue or the site of infection to spread
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What breaks down collagen fibers thus destroying tissue integrity (example of Invasive Enzyme)
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Collagenase
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What are destructive to cell membranes of red blood cells and other tissue cells (example of Invasive Enzyme)
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Lecithinase
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What breaks down hyaluronic acid in cell membranes (example of Invasive Enzyme
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Hyaluronidase (Staphylococcus, Streptococcus, Clostridium perfringens)
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What lyses fibrin in blood clots thus preventing isolation of the infection (example of Invasive Enzyme)
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Fibrinolysin & Streptokinase
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What dissolves red blood cell membranes (example of Invasive Enzyme)
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Hemolysins
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Proteins excreted from the cell Cause specific and widespread effects on the body Highly potent Elicit good, protective antibodies This describes what
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Exotoxins
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Exotoxins
What attacks motor nerves, triggers involuntary muscle contractions (example of Exotoxins) |
Tetanus neurotoxin
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What causes diarrhea, vomiting (example of Exotoxins)
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Staphylococcal enterotoxin
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What causes just diarrhea (example of Exotoxins)
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Cholera toxin
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What interferes with protein production in bronchial epithelial cells causing the production of a mucous, fibrous blockage of the respiratory tract; also affects heart muscle (example of Exotoxins)
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Diphtheria toxin
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What causes scarlet fever rash (example of Exotoxins)
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Streptococcal erythrogenic toxin
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What component of gram-negative cell walls is released upon disintegration of the cell
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Lipid A
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What triggers white blood cells to discharge chemicals which induce fever, pain, hemorrhage, blood pressure drop, etc.
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Endotoxins
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Endotoxins are not very ( ) per unit weight
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potent
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Endotoxins do not elicit very good or ( )
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protective antibodies
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gram-negative bacillus cell wall sloughs off or disintegrates- example of what
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Endotoxins
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( )-DNA code is translated into intended enzymes and proteins (some of which are antigens)
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Normal genetic operation
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What is extrachromosomal DNA in bacteria
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Plasmid
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What do plasmids code for
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exotoxins, antibiotic resistance, invasive enzymes
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Plasmid are transmitted to ( ) during cell division
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daughter cells
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Plasmids are passed to another ( ) during conjugation
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bacterium
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What is it called when viral DNA is incorporated into bacterial DNA
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Lysogeny
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Lysogeny codes for some ( ) and ( )
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exotoxins, invasive enzymes
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Lysogeny is introduced by viral infection of the bacteria and transmitted to ( ) during cell division
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daughter bacterial cells
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What are pieces of genetic material from one organism are incorporated into the genetic material of another organism.
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Gene recombination
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Gene recombination results in what
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different antigens are produced and causes increased resistance to antibiotics
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What are some chemical barriers
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Acid pH, bile salts, lysozyme, antimicrobial chemicals from normal flora, and interferon
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What does lysozyme digest
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gram-positive cell walls
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What is a human host cell that is produced in response to invasion by certain viruses. It acts as a local defense against certain viruses by producing inhibitin substances that "interfere" with viral reproduction
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Interferon ( a type of lymphokine
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What develops after mechanical injury or exposure to certain chemicals
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inflammation
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What are three nucleotides on the mRNA that specify the amino acid to be placed in a polypeptide
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Codon
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Culture and biochemical tests: Type of culture and testing depends on ( ) and ( )
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anticipated pathogen and testing conditions
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What are screening/presumptive tests
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rapid, sensitive but possibly less specific, less expensive
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What are definitive/confirmatory tests
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less rapid, more specific, more expensive
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What do immunodiagnostic tests test for
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antibody in patient's serum, and antigen in patient's specimen
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Are cellular morphology and staining characteristics useful for a microscopic exam
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Yes
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How long to complete an identification of most bacteria as well as mycobacteria (tuberculosis
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1 to 2 days, 2 to 6 weeks
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Cultivation -- grows on blood agar plate and other special media similar to bacteria, 2-7 days Identification -- presumptive by microscopy; biochemical tests; antigen tests
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Yeasts
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Cultivation -- frow on media with antibiotics which inhibit the growth of bacteria. Colonies will be visible in 1 to 4 weeks. Identification -- direct microscopic exam of specimen; microscopic exam of culture; few biochemical tests; few antigen detection tests
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Moulds
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Cultivation -- grow in livin tissue culture cells -- 2 to 21 days to grow Identification -- antibody detection; antigen detection; gene probes
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Viruses and some atypical bacteria
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Are all epitopes on the antigen useful in laboratory diagnosis
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NO. only certain ones are
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What is it called when some Fab sites will bind with very similar, but incorrect antigens
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cross-reactive
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what is the ability of the test to detect very low levels of antigen (or antibody) when it is present
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sensitivity
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A test might be developed to be overly-sensitive to ensure that all ( ) are detected, even if that means a low percentage of ( ) are included
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true-positives, false-positives
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Tests with high sensitivity may be used as ( ) or ( )
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initial screening or presumptive tests
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What is the ability of the test to accurately detect only the correct antigen
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Specificity
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Tests with high specificity are used to eliminate cross-reactive and ( ) results from ( )
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false-positive, true positive
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Tests with high specificity may be used as ( )
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follow-up confirmatory tests
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The overall degree of accuracy of the immunological test depends on
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quantity of antigen or antibody, exposure of antigen, and any cross-reactivity between non-matching antigen and antibody
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From lab or specimen either the ( ) or the ( ) can be the unknown
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antigen or antibody
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Specimen: What tests for presence of antibodies in the patient blood
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usually test serum
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Specimen: what tests for presence of antigen
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microorganism in lab culture or body specimen
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What increase the number of copies of significant microbial gene sequences so they can be detected, e.g. polymerase chain reaction (PCR)
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Gene amplification
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What test kits used to detect the presence of significant gene sequences
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Gene probes
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What uses iol immersion high power
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gram stain of bacteria
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KOH preparation for moulds uses low or high power
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low
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Other wet mount preparations use what type of power
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low or high dry power (not oil immersion because that would press on the fluid specimen)
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What is the purpose of Gram Stain
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staining enables bacterial cells to be seen using brightfield mocroscopy (unstained cells are invisible) Enables bacterial differentiation based on morphologic and staining differences (different cell wall composition)
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What is the principle of Gram Stain
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Bacteria stain either gram positive or gram negative on the basis of differences in their cell wall composition
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What are the smear preparation steps
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smear the specimen onto a clean glass microscope slide Allow the smear to dry in the air without heating Fix the smear to the slide by flooding the dry smear with methanol for about 1 minute (less favorable aternate: heat the dried smear slightly to fix the bacteria to the slide)
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What are the staining steps
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(a) primary stain (crystal violet) : 1 minute
(b) mordant (gram's iodine): 1 minute (c) Decolorizer (Acetone & alcohol): 2 to 5 seconds (d) Conterstain (Safranin): 30 to 60 seconds |
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What are the examination steps to Gram Stain
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1 Allow dry w/out heating
2 Focus on objects using the low power and low light; use coarse focus adjustment 3 Change to oil immersion lens to observe details of bacteria |
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How long does it take to interpretate Gram Stain
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30-60 min if necessary
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In the principle of Wet mount microscopic examinations, direct examination of certain ( ) (i.e. ) specimens to permit examination of cells in their ( ) state
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unfixed, wet, natural
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Place a portion of the specimen and any reagents required on a clean slide and cover with a thin coverglass and observe using low and/or high-dry power objectives and using reduced light intensity. These are general procedures of what
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Wet Mount Microscopic Examinations
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What is 10% KOH dissolves (clears) epithelial cells permitting visualizatoin of fungal mycelial fragments in skin scrapings; performed by the clinician without about 10 minutes after specimen is collected.
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Potassium Hydroxide Wet Preparation (KOH)
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Yeast Cells with capsules in cerebrospinal fluid (CSF) are revealed by the addition of what
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india ink to the CSF
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Saline wet preparation of vaginal exudate reveals yeast cells and motile ( ) organisms
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Trichomonas
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How are the beta-lactam antibiotics further broken down?
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Penicillins, cephalosporin
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How do the DNA helicase and DNA gyrase unwind the DNA strands?
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they break the hydrogen bonds between the nitrogenous bases
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To which carbon is the phosphate group bound to within the nucleotide?
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the 5-p they break the hydrogen bonds between the nitrogenous bases rime carbon of the sugar molecule
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To which end are nucleotides added to the new DNA strand during replication
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to the 3' end
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True/False: The 3' end of the DNA strand is designated as such because of the phosphate group bound to the 3' carbon.
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False. The 3' end is the end where no carbon is bound to the 3' carbon of the sugar.
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True/False: The lagging strand grows away from the replication fork
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True
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True/False: The strands of DNA are identical to each other.
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False: the strands of DNA are complementary to each other, but not identical.
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What 5-carbon sugar is found in RNA?
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ribose
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What are changes, such as substitutions or deletions, in the sequence of DNA bases that change the genetic code?
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mutations
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What are constituitve genes?
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genes that are constantly expressed
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What are genes that are expressed except when certain environmental conditions are present?
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repressible operon
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What are the 4 classes of cell wall synthesis inhibiting antibiotics
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Beta-lactam, Vancomycin, Bacitracin, Isoniazid
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What are the 5 types of nucleic acid inhibiting antibiotics?
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Quinolones, Rifampin, Metronidazole, nucleoside analogues, and flucytosine
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What are the causes of gross mutations?
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gain or loss of entire gene segments, inversions or transpositions of gene sequences
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What are the enzymes that unwind the DNA?
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DNA helicase and DNA gyrase
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What are the three classes of antimetabolite antibiotics
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Sulfonamides, Trimethorpin, and Azoles
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What are the three types of mutations?
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substitution, frameshift mutation, and gross mutation
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What are the two categories of nitrogenous bases found within the nucleotide
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purines and pyrimidines
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What are the two most common events that can cause mutations, aside from completely natural causes?
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chemical mutagens, and radiation
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