Worksheet

Checkup on a Treadmill: Food, Oxygen and Energy

Grade 7 life science: analyze a teen's treadmill breath test and blood glucose data to model how food is broken down and rearranged to release energy.

Grade 7ScienceInteractive · Printable

Aligned toMS-LS1-7

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Single worksheet
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1 NGSS standard
Printable answer key
10 questions
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Details

Format: Interactive · Printable
Grade: Grade 7
Subject: Science
Question types: Fill in the blank, Multiple choice, Sorting, Short answer

About this worksheet

What students practice

Students use oxygen and carbon dioxide data to show that cells release more energy from food during exercise.
Students model how food molecules are broken down and rearranged to build new molecules or release energy.

How to use

Read the passage together and have students mark the respiration model in paragraph 2. The last question works well as a written explanation.

Curriculum

NGSS standard covered

MS-LS1-7

Model how food is broken down and rearranged in cellular respiration to release energy and build new molecules.

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Name Date

Checkup on a Treadmill: Food, Oxygen and Energy

Use a hospital breath test and blood sugar data to model cellular respiration.

The treadmill breath test

Read the passage and study Table 1. Then answer the questions.

A Visit to the Sports Medicine Clinic

1Rosalind Tanaka, a 13-year-old soccer player, had been feeling out of breath at practice, so her family took her to the sports medicine clinic at Riverside Hospital. Her doctor, Dr. Felix Amankwah, explained that he wanted to see how her body uses food and oxygen. He ordered two tests: a blood glucose test after breakfast and a breath test on a treadmill.

2Dr. Amankwah described a model of what happens to food. In the digestive system, large food molecules are broken down into smaller ones. Starch becomes glucose, a sugar, and proteins become amino acids. The blood carries these small molecules to cells all over the body. Cells can rearrange them to build new large molecules, such as proteins for muscle or glycogen, a stored form of glucose in the liver and muscles. Cells also release energy from glucose through cellular respiration: glucose + oxygen → carbon dioxide + water, releasing energy.

3For the blood test, Rosalind ate nothing overnight. A nurse measured her blood glucose in milligrams per deciliter (mg/dL), and then Rosalind ate toast and a banana. The nurse measured again 30, 60 and 120 minutes later while Rosalind sat and read. Table 2 shows the results.

4For the breath test, Rosalind wore a soft mask connected to a machine that measures how much oxygen she takes in and how much carbon dioxide she breathes out each minute, in liters per minute (L/min). She stood still, then walked, jogged and ran on the treadmill for 4 minutes at each speed, with a short rest between stages. A heart monitor recorded her heart rate. The results for the last minute of each stage are in Table 1.

5Dr. Amankwah told Rosalind that her results were in a healthy range. He suggested that she warm up longer before practice and build up her running time slowly.

Table 1. Treadmill Breath Test
Stage	Speed (km/h)	Heart rate (beats/min)	Oxygen used (L/min)	CO₂ breathed out (L/min)
Standing	0	80	0.25	0.2
Walking	5	110	0.8	0.7
Jogging	8	150	1.4	1.25
Running	11	180	1.9	1.8

How much more oxygen per minute did Rosalind use while jogging than while standing? L/min

Which pattern does Table 1 show as the treadmill speed increased?

A. Oxygen used and carbon dioxide breathed out both went up.
B. Oxygen used went up, while carbon dioxide breathed out stayed the same.
C. Oxygen used went up, but the carbon dioxide breathed out went down.
D. Heart rate went up, but oxygen used stayed about the same.

Which explanation best fits the data for the running stage?

A. Her lungs turned the extra oxygen directly into carbon dioxide.
B. Her muscle cells carried out more cellular respiration to release more energy.
C. She breathed in extra carbon dioxide from the air in the clinic.
D. Her muscle cells made new carbon atoms to build more carbon dioxide.

Use the model in paragraph 2. Where do the carbon atoms in the carbon dioxide Rosalind breathes out come from?

A. From glucose and other food molecules broken down in her cells
B. From her lungs, which make carbon atoms while she exercises
C. From the air in the room, which she breathes in and back out
D. From the oxygen molecules she breathes in with each breath

Suppose Rosalind kept jogging at the same rate for 10 minutes.

About how much oxygen would she use in that time? L

Building up and breaking down

Use paragraphs 2 and 3 and Table 2 to answer the questions.

Table 2. Rosalind's Blood Glucose
Time	Blood glucose (mg/dL)
Before breakfast	85
30 min after	135
60 min after	120
120 min after	95

By how much did Rosalind's blood glucose rise from before breakfast to 30 minutes after? mg/dL

Why did Rosalind's blood glucose rise after breakfast?

A. Her cells made glucose out of the oxygen she breathed in as she sat.
B. Sugar from the banana went from her mouth to her blood without digestion.
C. Digestion broke the starch in her breakfast into glucose that entered her blood.
D. Her muscles sent their stored glycogen into the blood the moment she ate.

From 30 to 120 minutes after breakfast, Rosalind sat still, but her blood glucose fell. Which explanation fits the model best?

A. Glucose stops being useful after one hour, so it left her body as waste.
B. Glucose turned into energy and its atoms disappeared from her body.
C. Her blood broke the glucose back down into starch for later.
D. Her cells took glucose from the blood to use for energy or to store as glycogen.

Sort each process in Rosalind's body.

Digesting the starch in a slice of toastJoining amino acids into new muscle proteins after soccer practiceLinking glucose molecules into glycogen in the liverDigesting the proteins in an egg into amino acidsBreaking stored glycogen into glucose in the muscles during a soccer game

Large molecules broken into smaller ones	Small molecules rearranged into larger ones

10.

Rosalind asks, “When I breathe in oxygen and breathe out carbon dioxide, is my body just turning oxygen into carbon dioxide?” Answer her. Write a claim, use evidence from Table 1, and use the model in paragraph 2 to explain what happens to the food molecules and where the energy comes from.