Exam 3 Flashcards
Restriction Endonucleases (enzymes)
- origination in bacterial cells
- Protect organism (bacteria) from foreign DNA (bacteriophage)
- Cleaves DNA at phospate-sugar bonds
- Recognizes palindromes of 4-10 base pairs where it cleaves DNA
Sticky Ends
Unpaired bases that are left where restriction endonucleas cleaved at DNA palindrome
Ligase
DNA ligase, rejoins base pairs
Reverse Transcriptase
Converts RNA to DNA
Four DNA analysis techniques
- electrophoresis
- hybridization and probes
- Sequencing
- PCR
Electrophorsis
- DNA is cut with restriction endonucleauses to specific gene sequences
- put in gel at (-) end and phosphates (base pairs) move towards the (+) end
- Smaller sequences move farther
Probes
- Small sequences of single stranded nucleic acids (olionucleotides)
- Used to identify complementary sequences on single stranded DNA
Southern Blot
- Method for detecting unknown DNA sequences
- electrophesis seperates DNA, denatured and transfered to filter paper, probes to visualize hybridization
DNA/RNA hybridization
-Degree of similarity between two different strands
Sequencing
Identify and order nucleotides
-Sanger Method
Polymerase Chain Reaction
- amplifiy’s DNA
- Can be used to detect diseases/infectious agents
Recombinant DNA
-DNA genetically manufactured to possess genetic material from multiple sources
Cloning Vectors
- Carry significant piece of donor DNA readily accepted by cloning host
- ex. plasmids, phages
Cloning Host
Bacteria (prokaryote) -E. coli -will NOT excess introns from eukaryotic DNA Yeast -S. cerevisae -will excess introns
Gene Therapy
Used to repair genetic defects such as: immunodeficiency diseases, cycstic fibrosis, Sickle Cell Anemia
In vivo Strategy
- Gene therapy technique
- Done inside a live organism (rat, gerbil, human, etc.)
Ex vivo strategy
- Gene Theraoy technique
- Done with living cells but not in an organism
Antisense DNA/RNA
- Gene therapy technique
- A oligonucleotide (single stranded DNA/RNA) that binds to mRNA to prevent specific protein synthesis
Triplex DNA
-Targets double stranded DNA and prevents transcription
Three types of Genome Analysis
Maps
fingerprints
family trees
3 types of Genome Maps
- Linkage - relative proximity and locus of genes
- Physical- proximity and size of genes
- Sequence - exact order of bases
Genome Maps
-Determine locus (location) and alleles
Fingerprinting
Emphasizes differences in genome -techniques endonucleases PCR Southern Blot -Uses forensics hereditary diseases
Family Trees
- Determine genetic tree for diseases
- Animal pedigrees
- genetic diversity in animals
Ideal Antimicrobic
-Soluble in body fluids selectively toxic nonallergenic reasonable half life unlikely to elecit resistance long shelf life good priced.
Chemotherapy
Use of any chemical agent for disease treatment
antibiotic
chemical substance made by microbe
antimicrobic
synthetic version of a antibiotic
Sources of antibiotics (3)
- mold type fungi (Penicillium, Cephalosporium)
- Bacillus strains (bacitracin)
- Actinomycetes (soil bacteria)
Broad Spectrum Antibiotic
treatment is effect against wide variety of microbes
Narrow Spectrum Antibiotic
Treatment is effective against a limited number of similar microbes
Kirby-Bauer Disk Diffusion Test
-Antibiotic placed on plate with lawn of targeted bacteria, clear zones around antibiotic indicate effectiveness
Minimum Inhibitory Concentration
-lowest concentration that will inhibit growth
5 Mechanisms of Action for Antibiotics
- Inhibition of cell wall synthesis
- disruption of cell membrane function
- inhibition of nucleic acid synthesis
- anti-metabolic activity
Cell Wall antibiotics
- Penicillin, Cephalosporins
- block transpeptididation (required in cell walls to cross link peptidoglycan)
- Bacitracin utilizes different method due to topical application only
Penicillins
- 1945 (1st drug)
- Sir Alexander Flemming
- beta-lactam ring w/ variable R group
- Targets transpeptidation
- Also triggers autolysin (digests cell wall)
