Recap:

What is energy?

What do living things use energy for?

Brainstorm Question:

If energy cannot be created… then how do

organisms acquire energy?

How much energy is in a

Snickers bar?

Energy is measured in calories.

1 Calorie = the amount of heat required to raise the temperature

of 1g of water by 1ºC

Q: How do they figure this out for each food?

Q: Energy is not listed in the ingredients…

PEANUTS:

-high in plant oils

(lipis)

-high in starch

(carbs.)

PEANUT BUTTER

NOUGAT:

-high in oils (lipids)

-protein rich (egg

whites)

-high in sucrose (carbs)

CHOCOLATE:

-high in saturated

animal fats (lipids)

-high in fructose

(carbs)

-protein rich (milk)

CARAMEL:

-high in sucrose

(carbs)

…so where is it?

Energy is stored in the chemical bonds

of organic molecules.

The highest energy yield comes from

fats, carbs and proteins:

Carbohydrates 57%

Fats 30%

Protein13%

"Fuel Blend" Required by Humans

How does the body extract the

energy from the chocolate bar?

COMBUSTION

Combustion reaction

takes place in the

body to extract

energy from the fuel.

Same reaction that

happens in a car

engine or a burning

candle.

Q: Fuel does not spontaneously combust, what else is

needed?

Potential energy is stored in the bonds

between the atoms.

Breaking these bonds is exergonic, it

gives off energy.

The combustion reaction in the body=

CELLULAR RESPIRATION

Cellular respiration takes place in every

cell in the body.

A closer look…

Fuel alone does not combust (think of a lump of sugar on a plate).

Q: What does an engine need to start?

Q: What does a match need to burn?

Q: What does cellular respiration require other than fuel?

A few different enzymes involved to help extract the most energy from the bonds.

a spark + oxygen

friction/ heat + oxygen

enzymes + oxygen

The Reaction:

Reactants?

Products?

If energy is not tangible, how

can it be stored?

We don’t use all energy right away

Stored in the body as chemical energy

Cell batteries= molecules

ADP= uncharged ATP=

CHARGED

ATP

ATP molecules are synthesized during cellular respiration.

ATP then used to provide energy for other reactions through out the body.

When charge is drained, ADP is recycled in cells, gets charged again.

Produced in exergonic reactions, used in endergonic reactions.

Q: Example of an endergonic reaction where it may be used?

Back to our Snickers bar…

Let’s harvest the energy from a glucose molecule in it…

(remember the body will also get energy from the fats and proteins in it, but we will use glucose as an example since it’s body’s main fuel)

Q: Glucose does not show up in the ingredients either, where is it?

TEM micrograph of mitochondria in human lung tissue cell

Where the respiration process takes

place

STEP 1:

GLYCOLI

SIS

STEP 3:

ELECTRON

TRANSPORT

CHAIN

STEP 2:

KREBS

CYCLE

Cytosol

Introducing the main players…

Glucose

Oxygen

NAD+/ NAHD

FADH/FADH2

ADP/ATP

ATPase

1. Who will play what molecule

2. Read the handout with the player info

3. Familiarize yourself with your role

4. Get up and find your position around or

inside the mitochondria

Basic steps

1. GLYCOLYSIS (in cytoplasm)

Glucose broken up into 2 3-C molecules

(pyruvate)

Some ATP made

H+s and E-s given off from broken bonds

loaded onto coenzymes (NAD+ and FADH)

Loaded coenzymes “shuttle” E-s and H+s to

mitochondria.

2. KREBS CYCLE (in mitochondrial

matrix)

Atoms in the pyruvate molecules go through

several rearrangements

Pyruvate molecules get broken down further

More H+s and E-s get loaded onto

coenzymes and shuttled away

By product of Cycle is CO2, waste gas

3. ELECTRON TRANSPORT CHAIN (across mitochondrial intermembrane space)

NADH and FADH2 unload electrons into inner mitochondrial membrane

Carrier proteins pass electrons along membrane, creating gradient

H+s get unloaded into inter membrane space

ATPase uses gradient to pump hydrogen atoms across the inner membrane into matrix

ATP Synthase (ATPase)

Acts like a windmill

The movement of

protons creates the

energy for ATPase to

make ATP from ADP+P

More detailed ATP Synthase animation

ATPase dance (too funny!)

Oxygen then combines with H+s and E-s to

create water (byproduct of respiration)

Overview of Respiration video

Lab: Calorimeter

To determine how much energy is in

food.

Next up…

Can you respire without breathing?

What is more important for life- oxygen

or the sun?

This special edition Snickers bar is extra “charged”- it

contains caffeine, taurine and B-vitamins. How do these

ingredients contribute to the energy content of this

chocolate bar?

FOOD FOR

THOUGHT

Image Credits

Snickers bar (slide 5)- Flickr (Got Jenna)

Calories graphic (slide 6)- www.deo.ucsf.edu

Respiration graphic (slide 12)-http://bioweb.wku.edu/courses/BIOL115/Wyatt/Metabolism/Respiration.gif

Mitochondria (slide 17)- Public domain (tinojasontran)

TEM human lung tissue (slide 16)- Public domain (Louisa Howard)

Cell (slide 16)- European Bioinformatics Institute

Calorimeter (slide 26)- www.sciencebuddies.com

ATP synthase animation (slide 24)- Dr. Kaiser http://student.ccbcmd.edu/~gkaiser/biotutorials/energy/atpsynthase_an.html permission pending

Snickers Charged (slide 28)- Flickr (the futuristics)

Snickers bar info (slides 4 +15)- www.snickers.com

Clipart (slides 3+26)- Discovery School Clipart gallery