326 Lab summary table

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University of Michigan, Dearborn *

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326

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Biology

Date

Dec 6, 2023

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docx

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Uploaded by JusticeWorldLapwing30

La b Experimental Question Technique Purpose of technique Basic description of technique Biomolecule Cell type Data generated Example applications 1 What cellular structures are visible with a light microscope? Size of prokaryotic cells relative to eukaryotic? Compound light microscopy View things too small to see with naked eye Prepare slides of samples; view using microscope at 3 different powers of magnification ----- Lilium – eukaryotic E. coli - prokaryotic Observations about specimen Many! 2 Did (mock) patient sample contain antibodies to antigen (e.g. COVID-19)? Enzyme-linked immunosorbent assay (ELISA) Detect presence and/or amount of protein in a sample Use wells coated with antibodies which recognize and bind to the protein (antibody to COVID). Protein (antibodies) Human – eukaryotic (simulation) Color change Diagnostics; Food industry uses it to detect food allergens 3 What photosynthetic pigments are present in spinach leaves? Spectroscopy Paper chromatography Determine absorbance of sample Separate lipids by polarity Separate pigments using nonpolar solvent; extract pigment from chromatogram; measure absorbance Lipids (pigments) Spinach – eukaryotic Absorbance values Chromatogram with separated pigments Forensic science; DNA/RNA fingerprinting 4 What is the optimal sugar/temperature for fermentation? Measuring CO2 Measure fermentation Culture yeast in anaerobic conditions in presence of various sugars and at various temperatures; measure CO2 given off Carbohydrates Yeast – eukaryotic Measurements Brewing; baking 5 Was a water sample contaminated with microbes (part 1)? Polymerase chain reaction (PCR) Amplify target region of DNA Extract DNA from cells; amplify it with PCR DNA Bacteria – prokaryotic Nothing visible Paternity testing; identification of remains; forensics 6 Was a water sample contaminated with microbes (part 2)? Gel electrophoresis Separate DNA fragments by size Load DNA samples to individual wells of agarose gel; subject gel to electrical field which draws DNA to positive electrode DNA Bacteria – prokaryotic Bands on a gel Same as above 7 How to work with bacterial samples? Gram staining Streak plates Antibiotic disks Stain cell envelope Streak for isolation Determine susceptibility to antibiotic Crystal violet – iodine – decolorizer – safranin Drag bacteria from previous third of plate into next Plate lawn, add antibiotic discs Cell envelope – lipids and carbohydrates ---- ---- E. coli and S. saprophyticus - prokaryotic Color and shape of bacteria Individual colonies Zone of inhibition on plated lawn Any work with microbes uses these techniques (eg diagnostic testing for infection) 8 How are cells genetically modified? Transformation Transfer a trait to new cells Make cells competent, heat shock to expose to plasmid containing gene for new trait Plasmid DNA E. coli - prokaryotic Green glowing colonies Creating insulin for diabetics; genetically modifying foods to resist pests, etc 9 How do researchers work with eukaryotic cells? Cell culture techniques Cell counting Differential staining Maintain and count cells; determine cell structures Dislodge cells, add trypan blue, count with hemocytometer Fix and stain -------- Sf9 insect cells – eukaryotic Number of cells Stained cell structures Tell the effect of drug treatments/toxins Many other applications

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