Cellular Respiration Module

Cellular Respiration Module V. 1

Driving Questions:

Have you ever though about why we eat and breath?

How do our bodies use food and oxygen to get energy?

How does this happen within our cells?

Story:

Our bodies need food and oxygen to get energy. How do our cells get the energy from food and oxygen?

Eric and Roger are classmates and good friends. Both are 12 years old and exercise regularly. Their science assignment is to figure out how the human body uses food and oxygen to get energy. They were asked to run (as a form of exercise) and measure the following:

(1) the rate of muscle cell contractions;

(2) how much carbon dioxide (CO2) they exhaled (breathed out);

(3) their average body temperature; and

(4) how much oxygen (O2) they inhaled (breathed in).

Eric and Roger took note of what they ate before running. Then they went running together. They were each given the measurement instruments they needed. Here are their measurements and their body conditions:

The following table is a comparison of Eric and Roger’s physical condition.

Table (1) Physical Fitness

Eric / Roger
Height (cm.) / 158 / 161
Weight (kg.) / 52 / 50
Exercise / regularly / regularly

This study describes muscle contraction in the presence of varying levels of sugar and oxygen.

Figure (1) Muscle Cell Contraction during Exercise

Microscopic view of muscle cells

Note: when we use muscles, like doing exercise, the muscle cells in the muscle contract (tighten). The harder the exercise, the faster the muscles contract.

Rate of Muscle Cell Contractions

This figure compares the amount of carbon dioxide Eric and Roger exhale while exercising.

Figure (2) Exercise and CO2 Exhaled (breathed out)

This table is the comparison of body temperature for Eric and Roger as they run.

Table (2) Body Temperature during Run

10 min. / 20 min. / 30 min. / 40 min.
Eric / 36.7 / 36.9 / 37.4 / 38.0
Roger / 36.6 / 36.9 / 37.2 / 37.8

**Note: Body Temperature in Degree Celsius

This figure compares the amount of oxygen Eric and Roger inhaled while exercising.

Figure (3) Exercise and O2 Inhaled (breathed in)

However, for some reason Eric could not keep up with Roger’s running pace after a while. They are in similar physical condition, so what could be the reason? Eric thought that it might have to do with what they ate before running. Eric had a big steak beforehand, and Roger had pasta and a fruit cup instead. Below is the graph describing how long they ran based on different foods they ate.

Figure (4) Low-Carb Runner vs. High-Carb Runner

**Note- Remember Eric and Roger’s assignment was to link their measurements to how our bodies use food and oxygen to get energy and how this happen within our cells.

This figure compares the density (amount/cell)

of various organelles in Eric and Roger’s muscle cells.

Figure (5) Cellular organelles

Organelles / Eric / Roger
Nucleus / normal / normal
Mitochondria / normal / slightly high
Ribosomes / normal / normal
Endoplasmic reticulum / normal / normal

In your groups (pairs):

(1) Look at the data about Eric and Roger.

(2) Fill out the first column of the study worksheet and explain what each graph or table shows.

(3) Now look at the model worksheet and evaluate the three models. Give reasons to explain why you like or dislike each model.

(4) As you compare the models fill out column two of the study worksheet.

(5) Now take turns asking each other these questions:

(a) How does your model explain Table/ Graph_____?

(b) Does your model explain all these data?

(d) Is there any evidence that doesn’t fit your model?

(6) Chose the model you like best and revise it to make it better. Fill out column three in the study worksheet to help you revise the model.