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Unformatted text preview: Living Factories
Unit 7 Biotechnology Saccharomyces cerevisiae Saccharomyces cerevisiae YEAST!!! Yeast
Yeast Single celled microorganism Type of fungus Exist on all living matter 16 chromosomes Hundreds of different species! Did you know?
Did you know? We may not look much like yeast or they like us, but many of the 6,000 genes in yeast have counterparts in humans! Looking at Yeast
Looking at Yeast Yeast as a Living Organism
Yeast as a Living Organism As a living organism, just like us, yeast needs the following to survive and flourish:
warmth Respiration is the process by which a living organism releases energy from its food Do you remember the difference Do you remember the difference between aerobic and anaerobic respiration? Aerobic Respiration
Aerobic Respiration Humans produce energy through aerobic respiration In aerobic respiration glucose reacts with oxygen in the mitochondria of the cells to release energy. Carbon dioxide and water are byproducts of the reaction. Aerobic Respiration
Aerobic Respiration Glucose + oxygen carbon dioxide + water + energy Anaerobic Respiration
Anaerobic Respiration Anaerobic respiration occurs when oxygen is not available. In anaerobic respiration the glucose is only partially broken down, and lactic acid is produced Fermentation
Fermentation Living yeast cells in the absence of oxygen are still able to use sugar as their source of food to make energy This is known as fermentation In this case ethanol (alcohol) is produced instead of lactic acid Anaerobic Respiration
(Fermentation) Glucose carbon dioxide + ethanol
+ energy Aerobic Vs. Anaerobic Aerobic Vs. Anaerobic Respiration Aerobic oxygen always required
efficient method of respiration
sugar completely broken down to carbon dioxide and water Aerobic Vs. Anaerobic Aerobic Vs. Anaerobic Respiration Anaerobic oxygen never required
inefficient method of respiration
releases a small amount of energy
much of the energy remains locked up in the molecules of the end product (e.g. the alcohol) Quick Quiz
Quick Quiz Can you sort out the following statements into aerobic or anaerobic respiration? Just fill them into your table! Glucose + oxygen Much of the
locked up in the
molecules of the
Only releases a
required carbon dioxide
of respiration Glucose reacts in
the mitochondra of
cells Sugar completely broken
down to carbon dioxide
required carbon dioxide
Efficient method of
respiration Breadmaking Bread Basics!
Bread Basics! Bakers use two simple facts of life to create soft, spongy, moist bread: 1. First, they use the fact that yeast (a singlecell fungi) will eat sugar: from the sugar yeast creates alcohol and carbon dioxide gas as waste products the carbon dioxide gas created by yeast is what gives bread its airy texture, and the alcohol, which burns off during baking, leaves behind an important component of bread's flavor. Bread Basics!
2. Second, wheat flour, if mixed with water and kneaded, becomes very elastic. the flourandwater mixture in bread becomes stretchy like a balloon because of a protein in wheat known as gluten gluten gives bread dough the ability to capture the carbon dioxide produced by yeast in tiny flour balloons. Gluten
Gluten http://www.exploratorium.edu/cooking/brea d/bread_science.html How to make bread….
How to make bread….
You will need:
1. 2. 3. Flour with added salt and lard rubbed in to make dough
Yeast added to warm sugar solution and allowed to grow to produce bubbles
Mix the yeast and the flour together in a bowl 4. Kneading the dough
4. 5. Leaving the mixture to rise
5. Mixture left in warm place covered by damp cloth 6. Proving the dough
6. Yeast releases CO2 bubbles making dough rise 7. Baking bread
7. After dough rises a couple of hours in a warm place, it's ready to go into the oven. There, heat causes pockets of gas in the dough to expand This powerpoint was kindly donated to
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- Winter '08