biology lab report
Lab Report is an individual research work (3-5 pages long) and may not be copied from Internet. Such copying is easy to detect and will result in disciplinary action by the Department.
Two options for your Lab Report are:
Lab 2. Chromatography. Describe the different types of chromatography: ion-exchange, gel filtration, reverse phase, hydrophobic, and the different formats of chromatography: gas, liquid, capillary, thin layer chromatography (including paper), analytical, and preparative. Describe the factors affecting chromatographical separation: temperature, pressure, molecular weight, charge, and shape of molecules. Give examples, including paper chromatography in Lab#2.
Lab 2. Chromatography. Describe the different types of chromatography: ion-exchange, gel filtration, reverse phase, hydrophobic, and the different formats of chromatography: gas, liquid, capillary, thin layer chromatography (including paper), analytical, and preparative. Describe the factors affecting chromatographical separation: temperature, pressure, molecular weight, charge, and shape of molecules. Give examples, including paper chromatography in Lab #2.
Lab 8. Energy and catalysts. Define enzymes, substrates, and the process of catalysis. Provide examples of enzymes and the reactions they catalyze. Use the attached data in an Excel spreadsheet on: 1) pH dependence of enzymatic reaction and the temperature dependence of the enzymatic reaction for turnip peroxidase.
Use the following format for your Lab Report:
Title
Abstract
Introduction
Materials and Methods
Results Skip this section for Lab 2. Chromatography ONLY, as you have no data for this experiment. But write this section for Lab8. Energy and catalysts.
Discussion
Literature References
Conclusion
The Metric System
The metric system is an internationally agreed upon measurement system based on
decimals or powers of 10. Scientists use a refined version called the International System of
Units (abbreviated SI). In biology, you will often find a need to describe measurements of
length, volume, mass, time, temperature or amount of substance.
International System of Units
Jeremy Seto [emailprotected]
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Metric Units:
length: meter (m)
volume: liter (L)
mass: gram (g)
time: second (s)
temperature: Celsius (C)
Kelvin (K) is a unit of thermodynamic temperature and is the SI unit. The Kelvin scale in
the same as the Celsius or centigrade scale but offset by 273.16
Biology uses Celsius predominantly because of the range in which organisms live.
amount of substance: mole (mol)
A mole is a number representing 6.022×1023 of something
Just as a pair of shoes equals 2 shoes, a mole of shoes is 6.022×1023 shoes
Just as a dozen eggs equals 12 eggs, a mole of eggs is 6.022×1023 eggs
Jeremy Seto [emailprotected]
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Strategy for conversions
1. What unit is being asked for?
500ml = ____L liters
2. What unit are you starting from?
500ml = ____L milliliters
3. Which unit is larger? By how much is that unit larger?
Liters are the larger unit. Liters are 1,000X (103) greater than milliliters.
4. Which direction are we moving?
Since we are moving to a larger unit, our value will be smaller. In this case, the
value is smaller by 1,000X
In other words, the value is 1/1000 or 0.001 the value.
So what is the answer?
Factoring Out
Using the idea of factors of ten, you can assess the difference of the two units and cancel out
the original unit algebraically to reach the desired final unit.
500ml=_____L
OR,
which states 1000 milliliter in every 1 liter
pay attention to the units and how we’ve canceled out the ml in the
numerator of 500ml and in the denominator in the conversion of 1L in
1000ml
Additional Resources
Jeremy Seto [emailprotected]
mailto:[emailprotected]
ACCURACY and PRECISION
Accuracy refers to how closely a measured value agrees with the correct or target value.
Precision refers to how closely individual measurements agree with each other and reflects a
repeatability in those measurements.
Instruments have a finite amount of accuracy and it is important to report measurements
within that level of accuracy. Significant figures, report the number of digits that are known
to some degree of confidence with the measuring device. With increased sensitivity of the
equipment , the number of significant figures increases.
Jeremy Seto [emailprotected]
This illustrates accuracy. Measurements
are on target.
This illustrates Accuracy AND Precision.
Each measurement is on target and also
highly repeatable.
This illustrates precision.
Measurements are very close to each
other and repeatable.
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https://commons.wikimedia.org/wiki/File%3AHigh_accuracy_Low_precision.svg
https://commons.wikimedia.org/wiki/File%3AHigh_precision_Low_accuracy.svg
Chromatography
Chromatography is a collective term for a set of analytical techniques used to separate mixtures.
Chroma means color and graph means to write or draw. Paper chromatography is an analytical
technique used to separate mixtures of chemicals (sometimes colored pigments) using a partitioning
method. The paper in this method is called the stationary phase because it does not move and
serves as a substrate or surface for the separation. Analytes (substances being analyzed) are
separated from each other based on a differential affinity to a solvent. The solvent dissolves and
carries the analytes along the matrix of the stationary phase. Since the solvent moves through a
wicking action, it is
called the mobile
phase.
The distance that the analyte migrates along the paper related to the total distance that the solvent
or mobile phase moves is called the Retention Factor or RF.
Are the food colorings used in colored candy the same as
the the FD&C approved chemicals?
How many colored spots do you expect to see for each reference standard?
1. Obtain a 25 cm square piece of chromatography paper that will fit into the beaker that will
serve as the chromatography chamber.
2. Draw a pencil line across the lower end of the chromatography paper about 2 cm from the
bottom.
3. Draw additional vertical tick marks along this line every 2 cm
4. Place colored candy in a flask with 2 ml ethanol until the color dissolves into the solution
5. Using an applicator, create a very small spot on a tick mark and allow to dry
6. repeat application on the spot to make a very small and dark spot
Jeremy Seto [emailprotected]
Credit: Theresa Knott [CC BY-SA 3.0 or GFDL]
Solvent
Front
Start Point
(analyte origin)
Solvent
Filter Paper
Lid
https://en.wikipedia.org/wiki/Federal_Food,_Drug,_and_Cosmetic_Act
https://commons.wikimedia.org/wiki/File:Chromatography_tank.svg
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https://github.com/jeremyseto/bio-oer/blob/master/figures/chromatography/chromatography-tank.png?raw=true
7. Continue to spot reference standards along other tick marks. These reference standards are
food coloring.
8. Place approximately 1 cm of mobile phase solution (a very polar salt water solution) into the
beaker
9. Roll the filter paper into a cylinder and fix with staples
10. place cylinder into the beaker and cover for 20 minutes or until the mobile phase reaches 2 cm
from the top of the paper.
11. Mark the final distance of the mobile phase and dry the filter
12. Measure the distance of each spot from the starting point
1. Each spot is a separate analyte.
2. Some spots separate into multiple analytes.
3. Measure EACH one
13.Measure the distance from the starting point to the final point that the solvent reached.
14.Calculate RF values and tabulate results.
Jeremy Seto [emailprotected]
mailto:[emailprotected]
Table of Reference Standards Table of Unknowns
Reflect
1. Compare and average the RF values of each analyte across the entire class
2. Did you predict the number of spots that would appear from each analyte (reference or
candy)?
3. Assuming all the dye molecules are of the same mass, what influenced the migration patterns
of each spot?
4. Were the colors used in the candy the same as the references?
5. What does it mean if the candy color didn’t match anything from the food colors from the cake
decorating set used as references?
Jeremy Seto [emailprotected]
mailto:[emailprotected]
The Metric System
International System of Units
Metric Units:
Strategy for conversions
Factoring Out
Additional Resources
ACCURACY and PRECISION
Chromatography
Are the food colorings used in colored candy the same as the the FD&C approved chemicals?
Table of Reference Standards Table of Unknowns
Reflect
