bioed online food and fitness virtual workshop activity one: energy for life by nancy moreno, phd,...

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Food and Fitness Virtual Workshop

Activity One: Energy for Life

by Nancy Moreno, PhD, and Paula Cutler, BS

Baylor College of Medicine

www.BioEdOnline.orgBioEd Online

Energy for Living Organisms

All living things require a source of energy.

Producers make sugars and other carbohydrates (“food”) from water and carbon dioxide in the presence of light energy (photosynthesis).

Consumers (listed below) rely on producers, such as green plants, for food.

Animals Fungi Other non-photosynthetic

organisms

Sugars are small molecules made of carbon, hydrogen and oxygen. Energy in sugar is trapped in the chemical bonds between atoms. Glucose, the sugar molecule depicted above, is the initial product of photosynthesis.

H O

H C OH C H

C

OH

H C OH

H C OH

CH2OH

H

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Activity One: Predict

What do you think will happen when:

Yeast is combined with water? Yeast is combined with water

and sugar?

Saccharomyces cerevisiae

Common baking and brewing yeast

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Set Up the Experiment

Label two 250 mL containers: “Sugar” and “No Sugar.”

Measure 50 mL water into each container.

Add 1 packet of rapid rising yeast to each container.

Add 2 teaspoons of sugar to the container labeled “Sugar.”

Use separate spoons or stirrers to mix the contents of each container.

Each group of students also will need:

• small metric ruler;

• sheet of graph paper; and

• copy of “Is It Alive?” student sheet.

• OPTIONAL thermometer or temperature probe

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Make Observations

Record the starting and ending temperatures (degrees C).

Observe the following characteristics of each mixture at five-minute intervals.

Appearance Height of the liquid plus foam, if present (measure from

bottom of container to top of foam)

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0

1

2

3

4

5

6

7

8

9

Water

WaterandSugar

Height in cm (from bottom of beaker)

Height of FoamSample Graph

Activity One: Yeast Growth

Yeast cells broke down sugar molecules to obtain energy.

Carbon dioxide gas was released as waste (created foam at top of mixture).

Changes in height of CO2 foam reflect growth and resource use by yeast cells.

Yeast without an energy source grew very little.

Heat also was released. Mixture with sugar may

become warmer by 1–3 degrees C.

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bioed online food and fitness virtual workshop activity one: energy for life by nancy moreno, phd,...

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