Cellular Respiration

Energy from Food

Cellular Respiration: the process of

releasing energy stored in food for

use in cells.

Our goal is to find out the inputs and outputs of

cellular respiration

Please read pp. 288-289, “A Matter of Explosions” and

answer the questions on your

activity sheet.

Questions:

Where did the energy for the grain explosion come from?

How can energy be stored in grain?

What started the explosion that released the energy?

How do you explain the fact that you do not explode when you eat grain products such as cereal or bread?

So, what is our first IMPUT of cellular

respiration: FOOD! But not just food, GLUCOSE!

It’s chemical composition looks like this: C6H12O2

Glucose is a sugar (and a carbohydrate). Remember: Carbo=carbon,

Hydrate=hydrogen+oxygen

Chemical energy is stored in food. Our digestive system is able to break down food into smaller parts like lipids, proteins, and carbohydrates that our cells can use to create energy.

Glycolysis

Glycolysis is the first step of cellular respiration. It releases some energy, but also creates the ingredients for the later steps to use.

Glycolysis means SUGAR SPLITTING Glyco = sugar -lysis = splitting

So far…

Candle Demonstration

What made the candles go out? Why did the top candle go out first?

How can you explain the change in water level inside the beaker?

What does this tell you about the requirements for burning (releasing) energy?

Can you guess what our next input will be?

http://www.youtube.com/watch?v=x-stLxqPt6E

Oxygen is needed for cellular respiration

You can not light a fire without enough oxygen

Similarly, if you don’t have enough oxygen (O2) during cellular respiration than FERMENTATION occurs. This creates Lactic Acid in your muscles This is also the process that creates alcohol in

beer and wine. This process is called Anaerobic respiration.

When there is Oxygen present, we say it is AEROBIC RESPIRATION

Now, we have our inputs…

Bromothymol Blue Demo

Why did the water turn clear?

What does this tell us about the gasses that come out when we breathe?

If you were to exercise heavily first and then exhale through the solution, would it change color faster or slower? Why?

Can you guess what our next output will be?

Carbon Dioxide

Carbon Dioxide is one byproduct of cellular respiration

It’s chemical composition looks like this: CO2

CO2 is also emitted into the atmosphere by cars, boats, factories, and power plants when they burn fuel for energy (in MUCH bigger amounts).

Now we have this…What goes last?

And, there we have it!

Final reflection questions:

What form does the water produced by cellular respiration take?

Explain why when you exercise you breathe harder and sweat more (at least 3 sentences).

Draw your own diagram representing cellular respiration. Be as creative as you like.