A Closer Look at Converting Food Energy into Cell Energy

All living things require a source of energy for survival

Movement: Muscle contraction Synthesis of new molecules cells and other

structures Tissue Repair Growth

It must be converted to a usable form

These processes are very similar in all living organisms

Bacteria and humans have similar ways of producing ATP

This means the processes evolved very long ago before simple organisms became more complex

It has six carbon atoms The atoms are held together with strong

bonds Cells must use energy to begin the

reactions Energy is stored in ATP

A P P P

ADENOSINE MONOPHOSPHATE

ADENOSINE DIPHOSPHATE

Breaks glucose down Enzymes rearrange the pieces Two molecules of Pyruvate are formed There is still a lot of energy that has not

been released in these two molecules Muscles that don’t get enough oxygen use

glycolysis for energy

NADH stands for Nicotinamide adenine dinucleotide with a Hydrogen atom.

The energy from the glucose is stored in these molecules

This energy will be transferred to ATP in The Electron Transport Chain

The Krebs cycle happens in the mitochondria

It requires oxygen – so it’s Aerobic Enzymes convert pyruvate to a two carbon

molecule by removing a molecule of Carbon dioxide

The two carbon molecule enters the Krebs cycle

Aerobic Requires enzymes Rearranges molecules Energy is completely released from

Pyruvate Produces ATP Produces NADH – A Hydrogen carrier

molecule

Carbon Dioxide which travels to lungs to be exhaled as waste

An energy carrier and a hydrogen carrier Energy in each NADH will be used to make

3 more ATP This will happen in the electron transport

chain This is how large amounts of ATP are

generated This is how you get most of your energy

Happens in the inner membrane of the mitochondrion

There is a series of electron carrier molecules here

Hydrogen atoms in NADH are separated into protons and electrons

As the electrons move from one carrier to the next they release energy

The energy release from the electrons as the bounce is used to pump protons (H+) across the inner membrane of the mitochondrion

The protons build up in the outer compartment of the mitochondrion

There is a difference in the number (concentration) of protons between the inside and outside of the inner compartment of the mitochondrion

Is a concentration gradient (like the difference in energy between the top and bottom of a waterfall)

This is the source of potential energy The protons diffuse from high

concentrations outside to the inner compartment where their concentration is lower.

This flow of protons is used to make ATP from ADP and phosphate

This is where the energy from NADH is transferred to ATP

The transferred electrons combine with protons (H+) and molecular oxygen O2 to form water H2O

It completes the electron transport system Carbon dioxide and water are the by

products of cellular respiration