LABS REVIEW
 State Labs
New York State requires that four labs be performed prior to the exam. Part D of the NYS Living Environment Regents Exam will test the students' knowledge of these labs and comprises about 15% of the exam. The labs are: 1. Diffusion Through a Membrane 2. Making Connections 3. Beaks of Finches 4. Relationships and Biodiversity
Laboratory Skills
In order to really study the world around us, scientists use all kinds of tools and need all kind of skills to successfully carry out observations, data collection and experimentation. Knowing what to use, when to use it and how to use it safely in the laboratory is key to the workings of every scientist- and that means YOU! Common tools of measurement
In order to observe our environment, with any accuracy, we need to use tools. What tools are used in science? Read on... Compound Microscope A compound microscope is probably going to be the microscope that you use most often in your science class. What makes it a compound microscope? A compound microscope has two lenses. One lens is called an occular lens and the other lens is the objective lens. The magnification of these lenses will be found right on the lens. Simple Microscope A simple microscope has only one lens. You probably know it best as a magnifying glass. Phase-Contrast Microscope This microscope will allow a scientist to view a specimen without staining the specimen (and killing it). Light will pass through different regions of a cell and will allow you to see more than if you simply used a compound microscope. Stereomicroscope This microscope has two eyepieces. Although the magnifying power is low, you are able to put a specimen on the stage and manipulate it. Many scientists will use this to dissect a specimen. For this reason, the stereomicroscope is often referred to as a dissecting microscope. Chromatography Chromatography allows substances to be separated out based on either physical or chemical properties. Chromatography paper will be placed in a liquid, to which a solvent has been added. The liquid will then separate out, as it travels up the chromatography paper. Bands will appear, and conclusions can be drawn from the banding patterns. Electrophoresis Gel electrophoresis is used to make a "blue print" of DNA. An enzyme will be added to the DNA, to cut it at specific sites. The DNA will then be placed in the gel electrophoresis, so that the bands can be separated out by size. The smaller bands will travel further through the gel, and the larger bands will remain closer to the wells. An electrical current is the energy that is added to cause the DNA to move. Once the bands have been separated out, a "blue print" has been made. It can be used to compare the DNA of a variety of organisms. Finding total magnification
Total Magnification Total magnification can be found my multiplying the ocular lens magnification by the objective lens magnification. For example, if the ocular lens is 10x and the objective lens is 40x, then the total magnification would be... 400x The Metric System
The Basic Units of Measurement The basic unit of length is the meter (m); the unit of mass is the gram (g);and the unit of volume is the liter (L). Scientists will usually use Celsius (C) or Kelvin (K) as the units for temperature, and will measure time in seconds (s).
Common Metric System Prefixes: Prefix Symbol Meaning kilo- K 1,000 deci- d 0.10 centi- c 0.01 milli- m 0.001 micro- u 0.000 0001
Measuring Cells: Cells, as I'm sure you know, are very, very small, and need to be measured in micrometers. It is important to know that scientists will use the term, "micron," when they are talking about micrometers. They are synonyms!
Converting You will most likely be converting between a millimeter and a micrometer. There are two "steps" between these two measurements: milli X X micro If you want to go from a millimeter to a micrometer, you will move the decimal point over to the right three spaces. For example, 3.0 millimeters = 3000 micrometers (or 3000 microns) If you want to go from a micrometer to a millimeter, you will move the decimal point over to the left three spaces. For example, 265 micrometers= .0265 millimeters
 DIFFUSION LAB NOTES
(ppt file - 725kb)
DIFFUSION LAB PART 2
(ppt file - 1,055kb)
BIODIVERSITY LAB NOTES
(ppt file - 1,363kb)
BEAKS OF FINCHES REVIEW
(ppt file - 502kb)
 Review sheet Biodiversity lab
(doc file - 27kb)
Review Sheet Beaks of Finches
(doc file - 663kb)
Review Sheet Making Connections
(doc file - 84kb)
Review Sheet Diffusion
(doc file - 1,732kb)
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What you need to know from lab
Ms. CRISPIN's BioWorld
McKinley High School
1500 Elmwood Ave
Buffalo, NY 14213
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