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Unformatted text preview: Biology Lab Final Study Guide Chapter 1 – I ntroduction Scientific Method – observation, model, prediction, test- Hypothesis – a prediction that hasn’t been widely tested o Null Hypothesis – there will be no difference in the results between the control and the experimental group- Theory – hasn’t been disproven, widely tested, supported, not proven Pipettes and Pipetting- Mechanical Pipettes – used for small volume transfers (less than 1 mL) where a high degree of precision is required- Volumetric/Transfer Pipettes – designed to deliver a single volume precisely (only transfers 5 mL)- Mohr/Measuring Pipettes – graduated but stops at a baseline before the pipette tip begins to narrow o The meniscus must be precisely on a calibration mark both at the beginning and end of a transfer- Serological Pipettes – graduated to deliver (no base mark), the entire amount is transferred- Pi-Pump – a device designed to safely and easily draw fluid up into a pipette Spectrophotometry- Spectrophotometer – an instrument designed to detect the amount of radiant energy absorbed by the molecules o Light is diffracted to separate light into different wavelengths o A slit only allows a certain wavelength to pass through- T ransmittance – how much light passes through the liquid (%)- Absorbance – how much light does not pass through a liquid (odu) o The amount of light absorbed is proportional to the concentration of a compound- Blank – a solution containing everything that the test solutions contain except the compound that you are trying to measure 1. Adjust the wavelength on the top surface next to the sample holder 2. Set mode to TRANSMITTANCE 3. Adjust the LEFT knob until the Transmittance is 0 4. Insert the blank 5. Adjust the RIGHT knob until Transmittance is 100% 6. Remove the blank and place the treatment into the sample holder 7. Switch mode to ABSORBANCE and record 8. Always blank the spec to 100% Transmittance- Beer’s Law – As the concentration of a substance in solution increases, the amount of light absorbed by the solution increases (direct relationship)- Concentration is a function of absorbance and can be calculated using a Standard Curve Chapter 2 – Analyzing Enzymes and Enzyme Kinetics- Catalyst – increases the rate of chemical reaction without being consumed or changed during the process- Activation Energy – the energy needed to produce an activated complex needed for a reaction to occur o A catalyst lowers the activation energy resulting in a change in the rate of reaction o A catalyst allows an activated complex to form with less energy- Enzymes – highly specific organic catalysts o A single enzyme will only catalyze one chemical reaction o Most enzymes are proteins and have a complex 3 dimensional conformation Most enzymes can have multiple conformations ( isomers ) o The enzyme binds to the substrate forming an enzyme-substrate complex o The substrate is attracted to the active site interacting chemically with the amino...
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This note was uploaded on 07/02/2011 for the course POLI SCI 2051 taught by Professor Kevinmulcahy during the Spring '10 term at LSU.
- Spring '10