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Terms in this set (67)
transfer pipettes are designed to deliver a single volume precisely (the volume will be indicated near the top of the pipet (i.e., 2 mL).
Above the bulb in the tube is an engraved ring. Fluid must be drawn up the pipet to above the ring and then released slowly until the bottom of the meniscus is exactly at the ring (the tip of the pipet should be touching the wall of the sample vessel as fluid is released). To transfer this volume to a second container, touch the pipette tip to the inside of the new container and allow the liquid to drain out.
measuring pipets are graduated but stop at a baseline before the pipet begins to narrow. (i.e., 10 mL in 1/10, the total volume of the pipet is 10 mL, and it is graduated in 1/10 mL increments)
To accurately transfer fluid with this type of pipet, the meniscus must be precisely on a calibration mark both at the beginning and at the end of a transfer.Near the top of this type of pipet you will find the total volume indicated and the size of the smallest gradations. In this type of pipet the marking near the tip of the pipet should be the same as the total volume listed near the top of the pipet.
pipets are graduated to deliver (there is no base mark).
The appropriate amount of fluid is drawn into the pipet (with the meniscus precisely on the correct mark) and the entire amount is transferred. You will find the total volume indicated and the size of the smallest gradations. There are two types. Those with a single painted or frosted ring at the top should be allowed to simply drain with the tip placed against the side of the receiving vessel. Those with double rings are designed to be "blown out" by pushing a small amount of air out of the pipet, completely emptying it.are labeled with the zero mark at the top of the pipet you will need to subtract the amount you are going to pipet from the total volume of the pipet to determine the exact mark to fill the pipet to. For example if you are going to pipet 6.5 mL using a 10 mL pipet you would fill the pipet to the 3.5 mL mark. To determine the total volume of the pipet look near the top of this type of pipet.
Mechanical Pipet or micropipettes
Mechanical Pipet or micropipettes
Are used for small volume transfers where a high degree of precision is required. Can be set to draw and dispense different volumes. (i.e., less than 1mL).
Mechanical Pipet or micropipettes
They are usually set by turn the knurled knob near the top. The volume is read in the window. Operated by depressing the plunger. On the downward stroke of the plunger there are two stops. The first offers firm resistance, and the second is a hard stop. To take up a volume in the pipet, place a tip on the end of the pipet. Depress the plunger to the first stop and insert into the sample to be transferred. Draw the liquid into the pipet by slowly releasing the plunger. To dispense the liquid from the pipet, place the tip of the pipet into the opening of the well and slowly depress the plunger all the way to the second stop. When the liquid has been dispensed withdraw the pipet tip from the well before releasing the plunger.
A. After selecting the appropriate sized pipet choose the proper pi-pump. The small (blue) pi-pumps are to be used with pipets up to 2.0 mL in volume. The large (green) pi-pumps are to be used with pipets greater than 3.0 mL in volume.
B. Gently push the top (the end cut off flat) of the pipet into the pi-pump.
C. Rotate the wheeled knob with your thumb moving the pi-pump plunger up. This should pull the solution up into the pipet.
D. Once the correct volume has been pulled up into the pipet place the tip of the pipet against the side of the new container and depress the plunger. This should empty the contents of the pipet into the new container.
E. If you are using a blow-out pipet you will need to move the plunger up slightly before filling the pipet. This will allow you to completely blow out the pipet.
A. Turn on the spectrophotometer (left-hand knob on the front of the instrument (A)) and allow it to warm up for at least 15 min.
B. Adjust the wavelength to the appropriate value. The knob on the right top (C)of the instrument controls the wavelength, which is indicated at the left of the digital display.
C. With the sample holder empty and the lid closed, adjust the Zero Adjust Knob (A) until the instrument reads 0% on the transmittance scale. Be sure that the display function is set to transmittance, if not push the "Mode" button until the display is set to transmittance.
D. Carefully insert the appropriate blank tube (cuvette) into the sample holder (E) and close the cover. Be sure you are using a cuvette with white markings. The cuvette's outside surface must be dry and clean, including free of fingerprints!! Use a Kimwipe to clean the cuvette before inserting. The white markings should line up with the notch on the sample holder. It is important to line up the markings. The cuvettes will be scratched otherwise.
E. Adjust the 100% Adjust Knob (B), on the right front of the instrument, until the display reads 100% on the transmittance scale.
F. Remove the blank cuvette and immediately insert the sample cuvette as described in step d above. Do not change any instrument setting! Switch the display to read absorbance by pushing the "Mode"(D) button.
G. Record the value indicated on the absorbance scale.
H. Repeat this procedure for additional cuvettes or wavelengths as required. Always adjust the blank transmittance to 100% before inserting and reading a new set of cuvettes.
an instrument designed to detect the amount of radiant light energy absorbed by molecules. To do this, the instrument must have five basic components: a light source; a prism or diffraction grating; an aperture or slit; a detector (a photoelectric tube); and a digital meter to display the output of the phototube.
When light is reflected from a diffraction grating, it is split into its component colors or wavelengths, which then diverge. Sections of the projected spectrum can be either blocked or allowed to pass through the slit so that only one wavelength will pass to the other sections. (The position of the grating is adjustable so that the region of the spectrum projected on the slit can be changed.). Light that passes through the slit travels to the phototube, where it creates an electric current proportional to the number of photons striking the phototube. If a digital meter is attached to the phototube, the electric current output can be measured and recorded. The scale is usually calibrated in two ways: percent transmittance, which runs on a scale from 0 to 100; and absorbance, or optical density units, which runs from 0 to 2.
As concentration ___________ the absorbance also__________. This relationship allows one to convert an absorbance value into a concentration.
explains the relationship between absorbance, at a given wavelength and concentration.
technique used to observe individual pigments by separating them. This process can separate complex mixtures into their component parts.
mobile phase and stationary phase
All chromatographic systems consists of
mobile phase; inhibited from moving
Molecules with a strong attraction for the mobile phase move with the _____________; those with a strong attraction for the stationary are ______________ in the mobile phase.
The technique of _________________ is based on the relative solubility of the molecules in the mixture to various kinds of solvents and their affinity or attraction.
capillary; equally soluble; attracted; cellulose
As the solvent moves up the paper by ____________ action, it carries pigments dissolved in it. The pigments move at different rates because they are not _____________ in the solvent and they are not ______________ to different degrees, to the _____________ in the paper.
Qubit CO2 system
measures CO2 levels in a flowing gas stream and may be used to measure photosynthesis, respiration, and photorespiration
infrared gas analyzer (IRGA); photosynthetic rate
initially, the CO2 concentration in the gas is pumped through the chamber at a known flow rate. The concentration in the effluent gas from the chamber is measured using the ___________, and the difference between this and the input gas is used to measure _____________ (or respiration rate if a greater CO2 concentration is measured in the effluent gas stream).
air bag, pump, infiltrator (flow meter), leaf chamber, desiccant, IRGA (CO2 analyzer), interface, and computer
List the components of the Qubit system:
Pump of the Qubit system
samples air from the lab, or from a gas bag, and pushes this through the gas exchange system at a measured flow rate
Infiltrator (flow meter) of the Qubit system
______________ is lessened by a needle valve on it attatched to the pump's outlet because the pump is too great for direct use with the IRGA.
Air bag of the Qubit system
provides air to the pump
Desiccant of the Qubit system
dries the gases thoroughly before they enter the IRGA by using drierite (turns blue or pink to indicate its functioning or spent)
Interface of the Qubit system
connects the CO2 analyzer (IRGA) to a computer to allow for computer assisted data acquisition.
involved in the manipulation of DNA fragments and involves the separation of charged molecules using an electric field.
Molecules are attracted to the electrode that has the charge which is ___________to the charge on the molecule (i.e., negativley charged molecules will move to the ___________ electrode).
The charge of nucleic acid is ____________ due to the presence of phosphate groups in the backbone of the molecule.
In gel electrophoresis the DNA molecules move through a semisolid matrix (______________).
positive; larger; slower
The matrix of long molecules acts like a 3-D sieve which the DNA has to move through as it travels to the _____________ electrode. As a DNA molecule moves through the matrix it undergoes random collisions with the molecules of the matrix. The _____________ the DNA molecue is, the more collisions with the matrix.Each collision effectively slows the DNA molecule in its journey. The end result is the larger the DNA molecule is, the ___________ it moves through the gel.
inversely proportional; greater; faster; small
The distance a fragment of DNA moves in the gel would be ________________ to the size (or length) of the DNA molecule. The closer two oppositely charged objects are the ____________ the attraction between them. The closer a DNA molecule gets to the positive electrode, _________ the DNA molecule moves. The _________ DNA molecules that experience few collisions with the matrix begin moving faster the farther into the gel they migrate.
The distance a DNA molecule migrates in the gel matrix is ________________ to the log10 of the size (or length) of the DNA molecule.
process in which external DNA is transferred to or taken up by an organism
closed-toe shoes, no sandals
What type of footwear must be worn in the lab at all times in the lab?
absorbance and transmittance
Broken glass container
Where should broken glass be discarded in the lab?
An enzyme ___________a reaction.
We used an instrument named _____________ to detect the absorbance of a solution, in order to determine the ________________ of this solution to Beer's Law.
mean; standard deviation
The most basic way to describe your data sets is the _________ which describe the center of your data and the ______________ which tells you how far from the center the data spread.
Can you reject one hypothesis after the experiment?
Can you judge if there is a difference between the control and experimental groups by the mean of these two data sheets?
the experiment will show no difference in the results between the control group and the experimental or treatment group; treatment will have no effect on the process being studied
the experiment will show a difference in the results between the control and the experimental groups; will be some affect based on the treatment involved
water molecules across a membrane from an area of high water concentration to an area of lower concentration
contains a lesser concentration of impermeable solutes than the solution on the other side of the membrane; RBC's will quickly swell and rupture
contains a greater concentration of impermeable solutes than the solution on the other side of the membrane; cells shrink and crenate (cell losing water)
contain equal concentrations of impermeable solutes on either side of the membrane; RBCs do not swell or shrink
During the process of ___________ atmospheric carbon dioxide is fixed to produce organic biomolecules.
A-2 B-3 C-1
Molecular weight of A is 64.5; molecular weight of B is 130.7; Molecular weight of C is 35.7. Order their speed at which they will hemolysis by putting one as the fastest.
Does a red t-shirt look red because it absorbs red color?
the color who has the highest absorption of light
In order to achieve maximum photosynthesis, what color of light should be given to plants?
In _____________ light is re-emitted and the red has the longest wavelength.
Light reaction & Calvin cycle
Name 2 stages of phtosynthesis: ______________, during light energy is absorbed and is converted to the form of ATP and NADPH, and the other is ____________, during which the energy is used to produce carbohydrates.
mobile phase & stationary phases
In the process of pigment separation, what are the 2 phases: ___________ phase is polar and ________ phase is nonpolar.
Carbon dioxide molecules are utilized in ______________.
How do you measure the rate of fermentation?
Does fermentation occur without oxygen?
Lactate & Alcohol fermentation
2 Forms of fermentation:
How do we measure the rate of photosynthesis?
glucose; 2 pyruvic acids
Starting material and final production of glycolysis:
2 pyruvate; 2 lactate acid or 2 ethanol
Starting material and final production of fermentation:
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