Metabolism, Lesson 3.3

Metabolism
Lesson 3.3
Cellular Respiration, Growth & Repair

​Cellular Respiration

​Cellular respiration takes place in parts of the cell called mitochondria.

Multiple Choice

Where does cellular respiration happen?

• In the part of a cell called mitochondria.

• In the air.

• In the part of a cell called the nucleus.

​Cellular Respiration

You may have heard the word respiration to refer to breathing air: taking oxygen into your lungs and releasing carbon dioxide through your mouth and nose. What is cellular respiration, then? Cellular means “having to do with cells”—so do cells breathe, too? In a certain way, yes. Individual cells do take in oxygen and produce carbon dioxide. But cellular respiration is more than that: it’s a chemical reaction that releases energy to power everything that cells, and your body as a whole, need to function.

Multiple Choice

What is true about cellular respiration?

• Cellular respiration releases energy to power everything that cells, and your body as a whole, need to function.

• Cellular respiration needs oxygen molecules.

• Cellular respiration needs glucose molecules.

• All of these are true statements about cellular respiration.

How Cellular Respiration Works

Cells take in oxygen and glucose molecules. These molecules are the inputs needed for cellular respiration. In tiny cell parts called mitochondria, the oxygen and glucose combine in a chemical reaction. The outputs of cellular respiration are carbon dioxide molecules, water molecules, and energy. The cell uses the energy, stores the water or sends it out to be used somewhere else in the body, and gets rid of the carbon dioxide. Every time you breathe out, you release the carbon dioxide produced by cellular respiration in your cells. Cellular respiration is always happening in your body, whether you are exercising, sitting still, or sleeping.

Multiple Choice

True or False?

Cellular respiration is always happening in your body.

• False, cellular respiration does not happen when you are sleeping because you do not need energy.

• False, cellular respiration only happens when you are exercising because you need energy.

• True, cellular respiration is always happening in your body.

​Cellular Respiration

In the parts of cells called mitochondria, glucose plus oxygen combine to make carbon dioxide plus water, releasing energy. This is called cellular respiration.

Labelling

Identify the parts of cellular respiration.

Drag labels to their correct position on the image

energy

mitochondria

carbon dioxide

oxygen

glucose

water

Multiple Choice

What are the outputs of cellular respiration?

(What does the process create?)

• glucose and oxygen molecules

• water molecules, carbon dioxide molecules and energy

Multiple Choice

What are the inputs of cellular respiration?

(What is needed for it to happen?)

• glucose and oxygen molecules

• water molecules, carbon dioxide molecules and energy

Drag and Drop

Because of her diabetes, Elisa had lower numbers of glucose molecules getting to her cells. Why did this cause her to feel so tired?
You need ​glucose and ​

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to release ​

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. If one of those is missing, like ​

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in Elisa's cells, you will not release as much energy and feel ​

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.​

Drag these tiles and drop them in the correct blank above

oxygen

energy

glucose

tired

amino acids

water

energetic

Notebook Page 70
Watch the video on the next page and record your observations on page 70 of your notebook.

Multiple Choice

In the cell, amino acid molecules combine to form

• fiber molecules

• protein molecules

• starch molecules

• water molecules

Growth and Repair

When the body grows or repairs itself, cells divide into more cells.

​Cellular Growth

What does it mean to grow? For a body to grow, its systems and organs need to grow, too—and that growth all happens on a tiny scale at the cellular level. Cells are always making new proteins, growing, and dividing to make more cells. This is what makes bodies grow over time. You may not be able to watch a person getting taller, but through a microscope, you could watch his or her cells dividing to make more cells. When millions of healthy cells grow and divide to make millions more cells, the whole body grows.

Repair Is Really Growth

When you’re recovering from an injury or just healing from a cut, you’re actually growing—at least on a cellular level. The body repairs itself by growing the new cells and cell parts needed to fix damaged ones. Individual cells get old and die, and need to be replaced by new cells. Cellular growth is always happening, even in adults—who may not be getting taller anymore, but still need to grow new cells to replace old ones and repair damaged ones.

What Cells Need for Growth and Repair

To grow and repair themselves, cells combine amino acid molecules to form larger protein molecules. Those new proteins build new cells and cell parts. Growth and repair also require energy, so cells also need glucose and oxygen to release energy for these important functions

Multiple Choice

Your digestive system breaks down proteins into amino acids. What do your cells do with amino acids?

• Cells combine amino acids into larger protein molecules to build new cells and cell parts.

• Cells use amino acids for cellular respiration.

• Cells break down amino acids into glucose.

• Cells break combine amino acids to make oxygen.

Drag and Drop

How could Elisa's diabetes also affect her body’s ability to grow and repair cells?

Answer:

Your body needs ​ ​

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n order to grow and repair cells. In a healthy body, ​

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and oxygen combine in cells to release energy that can be used for ​

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and repair. Diabetes could affect how well Elisa's cells can grow and repair themselves because she doesn't have enough glucose entering her ​

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. Without glucose her cells are releasing less energy which leads to less growth and ​

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.

Drag these tiles and drop them in the correct blank above

energy

glucose

cells

growth

repair

amino acids

mitochondria

oxygen