Updates: Last week’s quiz average: 78% Pediducer grades are posted We will try to finish up...
-
Upload
percival-melton -
Category
Documents
-
view
212 -
download
0
Transcript of Updates: Last week’s quiz average: 78% Pediducer grades are posted We will try to finish up...
Updates:
• Last week’s quiz average: 78%
• Pediducer grades are posted
• We will try to finish up genetic disease presentations today. Those who have already presented, I need you all to individually send me emails detailing the amount of work put into your project by each group member (See RUBRIC!)
• At the end of class, if we have time, I want to touch base with everyone on Semester Projects
Light and Colors
•Building and confirming tools for inquiry
Reminder…• OIL RIG:
–Oxidation Is Loss (of electrons)–Reduction Is Gain (of electrons)
• Whenever something is reduced, something else is oxidized! These do not happen alone!
What is ‘color’
•Is there a difference between your
•shirt and a neon light?
Some Dye Structures
Crystal Violet
Yellow Napthol Green
FDC Blue1
FDC Red 3
FDC Yellow5
What do you know about…
Think With Me…• Why do you see (different) colors when • chemicals are flamed?
• Why different colors?
• Assertion I – unlike planets, electrons are • only allowed discrete energies
• Assertion II – energies that don’t take • electrons to an “allowed” place are ignored
Hydrogen Atom Simulator
•http://chemsite.lsrhs.net/FlashMedia/html/flashEMR.htm
•Also in Further Explorations
•Predict what happens to an arbitrary energy photon
•Predict what happens to one that matches a difference between current and potential orbital
Think With Me…• Why do you see (different) colors when • chemicals are flamed?
• Why different colors?
• Assertion I – unlike planets, electrons are • only allowed discrete energies
• Assertion II – energies that don’t take • electrons to an “allowed” place are ignored
Types of evidence/arguments
• Empirical--you saw it, touched it, etc.
• Reasoned argument from documented/identified assumptions & previous knowledge
• Repeatedly established by others
• Never: Assertions by authority regardless of the nature (or volume) of that authority
How are these different?
• Using a thermometer to test temperature
• Pointing a stick, say magic words, wait for rain
• Using pH paper to count protons
• Using Ba(OH)2 ‘test’ for CO2
• Counting ‘geigs’ with a Geiger counter
Principles ofspectrophotometry
• Absorption?
• Re-emitted?
• What will density do to readings?
The Parts
Set for infinite absorbance
(blocked path)
Set wavelength
Set zero absorbance
Tool using
• We have chalk at each station
• Place these in the specs (IN THE TUBE!)
• Look at the beam inside!
• Slowly (and carefully) move the wavelength • selector
• What do you see?
• Reset spec to ‘correct’ wavelength
Calibrating your eye
• Graph paper page I-9
• Predict: how will a blue liquid absorb? A green one?
Do it• Tubes in the rack
• Find the absorbance of each color at each wavelength
• MOVE to the next wavelength
Data350 430 500 590 630 660
Violet
Blue
Green
Yellow
Red
Chlorophyll
Page I-1 in lab manual
Do it• Tubes in the rack
• Find the absorbance of each color at each wavelength
• MOVE to the next wavelength
•Protocol for chlorophyll on 11-3 (Exercise 2) Make absorption closer to 1, not 2 (page 11-4)
Remember ‘density’?• What would you have to do to make a dye so
that there were half as many collisions between dye molecules and the beam of light?
• Build a solution with ¼ absorbance of the stock solutions
• Confirm
• Is it consistent with all wavelengths?
Photosynthesis
• 6CO2 + 6H2O C6H12O6 + 6O2
Light
Photosynthesis: Intro
Photosynthesis: Intro
Photosynthesis: Intro
Flight of the
electron
Photosynthesis: Intro
Fashioning an Assay• How can you tell if photosynthesis is
happening?
• What are the inputs? The products?
– How can you test for these?
• Protocol on 11-4; Exercise 4
• More information on 12-2
Next week!• You’ll take the data you
have from this week to create a red-passing, blue-passing or green-passing solution
• This will be used to test whether different portions of the visible spectrum are equally potent for photosynthesis
Sadava, Life, Fig. 8-6
Homework
•Table & Graph of absorbance data
•including your ‘predictions’
•Dilution worksheet (fine to do in-class)
What’s in a leaf
• Predict: what will we find when we grind up a leaf?
• Protocol: p. 11-3– Graph absorption of spinach extract– ‘ultra’-violet light it (high or low energy)?– Note!! These wavelengths re-do your DNA!!
Thinking it through
• Is the reddish light emitted being used for photosynthesis?
• What would happen if we applied a drug that BLOCKED electron transport?
Graphing
• Create a graph, table for HW• See rubric!!!
The Joy of Dilution• What fraction of molecules
would you have to remove for there to be 1/2 as many collisions between beam & dye?
• OK, build a solution with 1/4 absorbance of stock; confirm
• Tubes will be covered