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 s 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 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 CO 2 Counting ‘geigs’ with a Geiger counter

Principles of spectrophotometry 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

Data 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 6CO 2 + 6H 2 O C 6 H 12 O 6 + 6O 2 Light

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 –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