Information Don’t forget your Microworlds Project! – Protist cultures on back counter? – Yeast cells fr/ today’s lab (try methylene blue) – Catch fruit flies? (Eyes are easy to study) – You will have a lot of time to work on microworlds today & in lab 9 – Making an Informal Lab Report on an experiment you’re designing today! – Due at start of week 9 (Meiosis Lab)

INFORMAL LAB REPORT: See my web page for instructions. With your lab group: – From your observations, make a question about some aspect of fermentation. – Come up with a hypothesis to answer your question. – Design an experiment to test your hypothesis. – Perform the experiment, collect your results.

INFORMAL LAB REPORT: As an individual: – Fill in the Informal Lab Report Worksheet. All answers must be your own independent work! – Turn it in by week 9, normally in 2 weeks. For point totals, see the lab syllabus. – Pay attention to how to write up a scientific paper, how to make a scientific figure, and how to write a scientific reference, as these must be followed for full credit. – There are directions for all three of these in the appendix of the lab manual, although the guide for writing a scientific paper seems to apply more for a Formal lab report than an Informal one.

Lab 7: Fermentation & Cellular Respiration Cellular respiration is only covered in the reading today.

Part 1: Alcoholic Fermentation Glucose Alcohol + CO2 + ATP

Part 1: Alcohol Fermentation Yeast + corn syrup CO2

Ex. 1: Alcohol Fermentation Test the effect of different amounts of yeast suspensions on fermentation. I will demonstrate setting up the fermentation tubes. Note error in the lab manual, it tells you how many ml to add, but the tubes vary & you must fill the tubes to get all the bubbles out! Use bubble size to measure your fermentation. Take care to distinguish a bubble from an area where the yeast has settled out of solution. When done, clean WELL 4X or more with water.

Ex. 2: Alcohol Fermentation Design your own fermentation experiment Ask a question and make a hypothesis You can vary one independent variable: – Different sugar substrates & other substrates – pH buffers (do not use pH 11!) – Temperatures – Saline (salt) solutions Remember to keep constant all other variables!

Ex. 2: Alcohol Fermentation Think about what you are doing! If you add 1 ml of 10% NaCl to 10 mls, you have diluted it to 1% or nearly isotonic. If you add room temp yeast and sugar together and then put them on ice, it will ferment immediately and while the temp slowly cools. Do not use saccharin, it is a mixture of saccharin and D-glucose. Do not use pH 11 or we will all need goggles.