Exam Review Flashcards
What is a missense mutation?
A single nucleotide change results in a different amino acid.
What is a nonsense mutation?
A mutation that creates a stop codon, terminating translation early.
What occurs during an insertion mutation?
Addition of one or more nucleotides, potentially causing a frameshift.
What is a deletion mutation?
Removal of one or more nucleotides, potentially causing a frameshift.
Define a silent mutation.
A mutation that does not change the amino acid sequence.
How does PCR affect the number of DNA fragments?
The number of DNA fragments doubles each cycle.
What is a similarity between DNA and RNA?
Both synthesized in the 5’ to 3’ direction.
What are recombinant organisms?
Have foreign DNA integrated into their genome.
List the methods through which recombinant organisms can acquire genes.
- Conjugation
- Transduction
- Transformation
What are Single Nucleotide Polymorphisms (SNPs)?
Variations in a single DNA base.
What is the purpose of CRISPR-Cas9 in bacteria?
adaptive immunity
What is the application of CRISPR-Cas9 in science?
Used for gene editing by guiding nucleases to specific DNA locations.
What is gene therapy?
Inserts functional genes to correct genetic disorders.
Does gene therapy pass changes to offspring?
Does not necessarily pass changes to offspring.
What characterizes eukaryotic chromosomes?
Have histone proteins, multiple linear chromosomes, and a nucleus.
Describe the DNA antiparallel structure.
One strand runs 5’ to 3’, while the complementary strand runs 3’ to 5’.
What causes frameshift mutations?
Caused by insertions or deletions.
What is transduction?
Transfer of bacterial genes via bacteriophages.
What are transposons?
Mobile genetic elements that can alter DNA.
What is the function of gel electrophoresis?
Separates DNA by size using an electric current.
What is the start codon for translation initiation?
AUG.
What are sterilization methods?
Requires agents like sporicides.
List factors affecting antimicrobial agents.
- Microbial type
- Number
- Environment (pH, temperature)
- Dosage
What halogen is widely used in water treatment?
Chlorine.
What is the role of alcohols in disinfection?
Disrupt membrane lipids.
What does antimicrobial action on cell walls do?
Blocks synthesis or digests peptidoglycan.
What sterilization methods achieve complete sterilization?
- Autoclaving
- Ionizing radiation
Define thermal death time (TDT).
Time required to kill at a given temperature.
What is the thermal death point (TDP)?
Minimum temperature needed to kill in 10 minutes.
Disinfectants are used on _______.
surfaces.
Antiseptics are used on _______.
living tissue.
Cold & desiccation are considered _______.
bacteriostatic, not bactericidal.
What does physical removal of microbes involve?
Filtration removes microbes without killing them.
What is the therapeutic index (TI)?
Higher TI values (e.g., 100) are safer.
What is a characteristic of biofilm infections?
Biofilm bacteria express different genes, altering antibiotic susceptibility.
How do you choose antibiotics?
Choose the antibiotic with the highest therapeutic index.
What is a superinfection?
Overgrowth of resistant microbes after antibiotic therapy.
List mechanisms of antimicrobial resistance.
- Enzymes inactivate drugs (e.g., beta-lactamase)
- Decreased drug uptake
- Drug elimination via pumps
- Altered drug binding site
- Alternative metabolic pathways
What is conjugation in horizontal gene transfer?
DNA transfer via pili.
What is transformation in horizontal gene transfer?
Uptake of free DNA.
Example of antibiotics that inhibit cell wall synthesis?
penicillin.
antibiotics that inhibit protein synthesis?
tetracyclines.
