Equipment Monday April 28 2014 5 17 PM Mechanical Pipettes Mechanical pipettes or micropipettes are used for very small volume transfers i e less than 1 mL where a high degree of precision is required Volumetric Pipettes Volumetric or transfer pipettes are designed to deliver a single volume precisely the volume will be indicated near the top of the pipette i e 5 mL These pipettes do not have gradation markings and only have a single mark or engraved ring above the bulb in the pipette indicating the volume the pipette is designed to contain Graduated Pipettes There are two general types of graduated pipettes Mohr and serological Mohr pipettes are designed to transfer a volume by moving the meniscus of the liquid between two gradation marks on the pipette Serological pipettes are graduated to deliver there is no base mark Pi pump A device designed to safely and easily draw fluid up into a pipette Study Guid for Final Page 1 Spectrophotometer One of the most widely used lab instruments How it works A beam of is separated into its different wavelengths Each wavelength passes through the sample individually The transmittance and absorbance are measured Transmittance the amount of light that passes completely through the sample Absorbance measurement of light that is absorbed by the sample How to use it Use bottom left knob to turn on then wait 15 minutes for it to warm up Then set the wavelength using nob on top Then set the right most number to 0 0using the nob on the bottom left Then wipe your blank clean and insert into spectrophotometer making sure the lines on the test tube align with the lines on the spectrophotometer Now set the rightmost number to 100 using the nob on the bottom right Remove blank Change mode to absorbance Wipe sample test tube and insert it insuring lines are aligned Allow number to stabilize before taking it as your reading Study Guid for Final Page 2 Scientific Method Monday April 28 2014 5 56 PM The scientific method is a way to logically answer questions 2 kinds of Hypothesis Null states that your treatment will have no effect on the process being studied no meaningful difference between control and experimental groups Alternative states that there will be some effect based on the treatment involved meaningful difference between control and experimental groups Study Guid for Final Page 3 Analyzing Enzymes and Enzyme Kinetics Monday April 28 2014 4 47 PM Chemical reactions are the basis of most biological processes Enzymes act as the needed catalysts in most biological reactions Catalyst Decreases the activation energy of the reaction Activation energy is the energy that needs to be added to the system for the reaction to begin Enzymes Enzymes are highly specific One enzyme will catalyze only one type of reaction Most enzymes are proteins Enzyme reactions To determine the rate of a reaction you must be able to observe 1 of 2 things Disappearance of reactant Appearance of product Study Guid for Final Page 4 Movement of Materials Across the Cell Membrane Monday April 28 2014 6 07 PM Cell membranes are composed of phospholipid bilayers The movement of molecules through the membrane is controlled giving the cell control over its chemical environment The cell controls the movement of molecules through proteins imbedded in the membrane Some molecules can pass through the phospholipid bilayer Small non polar molecules Water The movement of molecules across the semi permeable membrane from areas of higher concentration to areas of lower concentration Diffusion Osmosis The diffusion of water molecules Tonicity these terms are relative Ex A is hypotonic to B and B is hypertonic A Hypertonic less water and more solute than the other side of the membrane water will flow towards this side of the membrane Isotonic equal water and solute concentration to the other side of the membrane no net movement of water Hypotonic more water and less solute than the other side of the membrane water will flow away from this side of the membrane Study Guid for Final Page 5 away from this side of the membrane Study Guid for Final Page 6 Photosynthesis Monday April 28 2014 8 32 PM Photosynthesis Respiration Atmospheric CO2 is fixed producing organic biomolecules and oxygen Carbon based molecules are used to produce cellular ATP CO2 and water Photosynthesis has 2 phases light reactions and Calvin cycle dark reactions Light reactions Light energy absorbed by pigments in chloroplasts and converted to chemical energy in the form of ATP and NADPH Oxygen is produced as a byproduct and released into the atmosphere Study Guid for Final Page 7 Oxygen is produced as a byproduct and released into the atmosphere Calvin cycle Uses ATP and NADPH from light reactions and CO2 from atmosphere to produce carbohydrates Study Guid for Final Page 8 Fermentation Monday April 28 2014 8 51 PM Fermentation provides the cell with the ability to metabolize organic nutrients and produce ATP in the absence of oxygen Glycolysis converts glucose to pyruvic acid Fermentation uses this pyruvic acid to regenerate NAD from NADH which is essential to ATP production Study Guid for Final Page 9