1. Utilizing Spectrophotometry in Life Science Date: Subject:

2. Why do we see colors? ___________________of Color – This is the radiation that can be seen with the naked eye Radiation moving within a frequency of ___________ nm is viewed as visible light. Colors differ due to light particles moving at different ________________. ___________________ – Particles that absorb certain frequencies of colors of light but reflect others. The apple’s pigments absorb most colors but reflect red’s frequency. ds

3. Spectrophotometer – 1. Spectrometer – 2. Photometer Made of two instruments: – Used to _____________any frequency of light – Used to _____________ the intensity of light

4. How is window tint like spectrophotometry?

5. Measuring Light and Color Light is quantified by two methods: The significance of measuring light 1. _______________ – the amount of light that is absorbed – Measuring units are in ___________________(O.D.) 2.__________________ – amount of light that passes through – Measured in % The amount of light indicates the _______________ of the colored substance. – Allows for detection of very small quantities.

6. Colorimetric Assays Assays are test that can be used to detect the presence of ____________ ______________in the body.

7. Calibrating a Spectrophotometer Reference Tube Range of Concentrations This is also known as “_______________” – Contains everything except the ___________ __________ which absorbs light. – Set the absorbance to zero Insures the absorbance is due to compound of interest only. Prepare standard samples that have been _________________. – Start with concentrated solution then pipette small amounts out.

8. Seeing the Substance ________________ Examples: Biuret Solution Benedicts Solution These are reagents that ___________________in the presence of specific substance: – Indicate presence and relative concentration Turns purple with protein Turns orange/red with simple sugars

9. Using Standards Standards Simple _________________ These are substances with a _______________of the measured substance. – Substances that have unknown quantities are compared to the standards. The absorption data is usually organized onto a _____________. – A __________________may then utilized to determine the general trend of the data.

10. Elements of a Scatter Plot Axes – Equal ___________ (2,4,6,8…) – Each axis is labeled Measurement (length, mass, volume…) Units (in, cm, mi…) – _________ to include all data Avoid values on axis beyond range of data Easily viewed (not too small) Line of Best Fit – Equal number of points _________ and ___________ – Drawn with ruler (or computer generated)

11. Predicting with Linear Models Graphs can be used as a tool for prediction. – __________________ – prediction within data – __________________ – prediction outside of data A relationship between x and y is established. – This may be linear (straight) y = mx + b – m = slope of line – b = y intercept

12. Why do the two bottom graphs have similar lines as the top graph? The ___________ (data point not trending with other points) shifts the slopes of the lines.