By Eric Savoie, Christian Bonzheim, Nick Aguayo, and Michael Arkwright

Cell RespirationCell Respiration is the controlled release of

energy within the cell of organic compounds to form ATP.

All living cells must carry out cellular respiration.

Cells use this energy for 3 main types of activity:1.Synthesizing Large Molecules2.Pumping ions or molecules across membranes by

active transport.3.Moving things, such as chromosomes and

vesicles, around in the cell.

GlycolysisIn cell respiration, glucose in the cytoplasm

is broken down by glycolysis into pyruvate with a small yield of ATP. This process of converting glucose into pyruvate is known as glycolysis.

The most significant product of glycolysis is the small amount of ATP produced without the use of oxygen.

Glycolysis can take place in two forms, aerobic and anaerobic.

Aerobic and Anaerobic RespirationAnaerobic Respiration- This type of respiration

takes place without the presence of oxygen. If no oxygen is available after glycolysis, than

the small amount of ATP that it produces without oxygen in this process is all that it will produce. No more ATP from this will be produced.

Therefore the pyruvate that is produced needs to go somehwere.

In humans and some bacteria- pyruvate is converted into lactate.

In yeast- Pyruvate is converted to ethanol and CO2.

Aerobic and Anaerobic RespirationAerobic Respiration- This type of respiration

occurs in the presence of oxygen. Pyruvate produced by glycolysis can use the

oxygen to be oxidised to release more energy.This process of oxidization takes place inside

the mitochondria, and yields more than 10 times more energy output than that of glycolysis.

The waste product of aerobic respiration is water and carbon dioxide.

Oxidation and ReductionOxidation involves the loss of electrons from an

element.Reduction involves a gain of electrons Oxidation frequently involves gaining oxygen or losing

hydrogen.Reduction frequently involves losing oxygen or

gaining hydrogen.

Steps of GlycolysisGlycolysis begins with the use of ATP to

phosphorylate the sugar.The purpose is to reduce activation energy for

the following reactionsThe fructose biphosphate produced is now split

to form two molecules of triose phosphate.Each of the triose is then oxidized to glycerate-

3-phosphate in a reaction that yields the energy to make ATP.Hydrogen atoms are removed.

Steps of GlycolysisThe hydrogen is now accepted by NAD+ to

become NADH + H+.The phosphate group is now transferred to

ADP to produce more ATP and pyruvate. This process occurs twice per glucose.

Structure of MitochondriaMany parts of aerobic cellular respiration

occur in different areas of the mitochondria. These are the parts of a mitochondria:

Aerobic Respiration- Krebs CycleTwo molecules of pyruvate are produced in

glycolysis per glucose molecule, and are absorbed into the mitochondrion where they can become fully oxidized.

The oxidation of pyruvate is done by the removal of pairs of hydrogen atoms.

Hydrogen carriers NAD+ and FAD accept these hydrogen atoms.

Decarboxylations occur to remove carbon and oxygen to form carbon dioxide.

Aerobic Respiration- Krebs CycleLink reaction- when pyruvate is decarboxylated

and oxidized to form the acetyl group.The link reaction involves one decarboxylation

and one oxidation.To complete the Krebs cycle, there are two

more decarboxylations and four more oxidations.

The energy produced is chemical energy that can now be passed to the final part of aerobic respiration called oxidative phosphorylation.

Krebs Cycle

Aerobic Respiration- Oxidative PhosphorylationADP is phosphorylated to produce ATP using

energy released by oxidation.NADH + H+ is the main substance oxidized.

The energy is released in small steps so more energy can be trapped in ATP.

The mechanism used to couple the release of energy by oxidation is known as chemiosmosis.H+ moves across a membrane, down the

concentration gradient. This releases the energy needed for ATP synthase to make ATP.

Aerobic Respiration- ChemiosmosisNADH + H+ supplies pairs of hydrogen atoms to

the first carrier in the chain, with the NAD+ returning to the matrix.

Hydrogen atoms split to release two electrons.Energy is released as the electons pass from carrier

to carrier, and three of these use this energy to transfer protons across the inner mitochondrial membrane, from the matrix to the intermembrane space.

As electrons continue to flow, a concentration gradient of protons builds up. This proton gradient is a store of potential energy.

Aerobic Respiration- Chemiosmosis

Chemiosmosis

Mitochondria FunctionsThe structures of mitochondria are adapted

to best help in the process of cellular respiration.

Cristae- Form a large surface area for the electron transport chain.

The inner-membrane space- accumulation of protons.

Fluid matrix- Contains enzymes of the Krebs cycle.

Overview

Work CitedPhotos

http://www.abe.ufl.edu/~chyn/age2062/OnLineBiology/OLBB/www.emc.maricopa.edu/faculty/farabee/BIOBK/redox.gif

http://library.thinkquest.org/27819/media/glycolysis.gifhttp://giantshoulders.files.wordpress.com/2007/10/

mitochondria.jpghttp://uwstudentweb.uwyo.edu/a/ateeter/krebs_cycle.gifhttp://archive.biosci.uga.edu/1996/spring_96/bio_104/

images/7_3.jpghttp://scienceblogs.com/worldsfair/Mitochondria.jpg

Work CitedInformation

Allot, A. & Mindorff, D. (2007). IB Diploma Programme Biology Course Companion. New York: Oxford University Programme.