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透過科學探究提升分析思維 Enhancement of Analytical Thinking thr

ough Scientific Investigations

Instructor: Ann S N Lau

Lesson 3

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Fermentation 發酵

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Fermentation

Make use of yeast metabolism

Conversion of carbohydrates into

carbon dioxide, alcohol

acid, water, energy

depending on the availability of oxygen

http://en.wikipedia.org/wiki/Yeast

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The life cycle of Yeast

6http://en.wikipedia.org/wiki/Image:Yeast_lifecycle.svg

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Availability of Oxygen

Aerobic respiration

Undergo respiration in the presence of oxygen

Anaerobic respiration

Undergo respiration in the absence of oxygen

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Aerobic respiration

In the presence of oxygen:

C6H12O6 (Sugar) + O2 Pyruvate

Pyruvate CO2 + Water + Energy (ATP)

Glycolysis + Pyruvate oxidation + Krebs cycle

Krebs cycle: a series of enzymatic reaction in living cells that make use of oxygen in cellular respiration

Aerobic respirationNucleus

Mitochondrion

Oxygen

Sugar

Pyruvate

PyruvateInside mitochondrion

CO2 + Water + Energy (ATP)

Yeast cell

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Anaerobic respiration

In the absence of oxygen:

C6H12O6 (Sugar) + O2 Pyruvate

Pyruvate CO2 + Ethanol

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The use of Fermentation in Daily Life

http://en.wikipedia.org/wiki/Image:Dry_yeast.jpg

www.bread.com.tw

http://en.wikipedia.org/wiki/Image:Slice_bread.jpghttp://en.wikipedia.org/wiki/Image:Pain_aux_noix.jpg

http://en.wikipedia.org/wiki/Image:Sourdoughbreadcrumb.jpg

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Beer

Water + Starch source (malted barley)

+ Yeast + flavoring

Carbon dioxide + Ethanol

Anaerobic respiration of yeast

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http://en.wikipedia.org/wiki/Image:Sjb_whiskey_malt.jpg

http://www.budweiser.com/

www.heinekenhongkong.com/

http://en.wikipedia.org/wiki/Image:Leffe_900px.jpg

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In biotechnology……

Yeast fermentation

Production of proteins, e.g. insulin, human growth hormone, etc.

Short-life cycle

Secrete into the culture medium OR

Stored inside the cellFrom Hong Kong Institute of Biotechnology Ltd.

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Think……

Design an experiment

to

investigate the effect of

yeast fermentation in bread dough

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Materials: flour and water, yeast, incubator

What are the factors necessary for yeast growth?

What are the products produced by yeast cells?

What parameters of bread dough you would like to measure with the effect of yeast metabolism?

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Try a different way to record your data!

Plot graph using the statistical data

Diameter of Bread Dough Treated by Different Conditions

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5

10

15

20

25

30

0 5 10 15 20 25 30 35

Time (min)

Dia

met

er (m

m)