Cellular Respiration

To grow, function, and reproduce, cells must: A. Create new cellular components such as cell walls, cell membranes, nucleic acids, ribosomes, proteins, etc… B. Collect energy and convert it into a form that is usable to do cellular work.

Cellular respiration is the process by which organisms obtain energy from food. A. Glucose is the most common source of energy 1. It comes from the breakdown of complex carbohydrates B. Making a bond stores energy (dehydration synthesis)

Energy corresponds to the electrons shared in a bond. Organic molecules store energy in shared electrons with CARBON. H H C H Energy stored

C C. Breaking a bond releases energy (hydrolysis) H H+ H H - - Bond breaks H is released along with an electron= energy

D. The breakdown of food/glucose releases electrons that are used to form chemical energy in the form of ATP 1. Adenosine triphosphate is a high energy molecule (ATP) 2. Adenosine diphosphate is a low energy molecule (ADP) 3. Phosphorylation is the transfer of energy caused by the addition of a phosphate molecule

ADP + P = ATP ( high energy) Adenosine P P P + = (ADP) Adenosine P P P High energy (ATP)

Cellular respiration begins in the cytoplasm of the cell and is completed in the mitochondria.

Mitochondria are present in living organisms; all cells plant and animal.

Mitochondria are “power houses” of the cell. ATP is formed here. ATP is used for all cellular processes. Energy is formed here and waste products produced from respiration are excreted.

The Energy Cycle in the Cell C6H12O6 Low Energy High Energy Phosphorylation

Types of Cellular Respiration A. Anaerobic respiration is respiration without oxygen 1. Results in little energy produced (2 ATP) 2. Takes place in the cytoplasm only 3. Organisms that use anaerobic respiration are yeast & bacteria

yeast are used to produce CO2 to make bread rise b. Yeast also makes alcohol

4. The equation for anaerobic respiration is:

5. Lactic acid is produced in. animal muscle cells when 5. Lactic acid is produced in animal muscle cells when there is not enough oxygen present. This causes muscle cramps.

B. Aerobic respiration is respiration with oxygen 1. Results in maximum energy produced (36 ATP) 2. Takes place in the cytoplasm and mitochondria 3. Most organisms use aerobic respiration

C6H12O6 + 6O2 4. The equation for aerobic respiration is: Glucose Oxygen 6CO2 + 6H2O + 36 ATP Carbon Dioxide Water energy

This reaction is actually the summary of many reactions. We will investigate the main reactions/steps of Aerobic respiration. These 4 steps summarize the electron movement from glucose to ATP and the waste products formed (C02 and H2O)

Step 1: Glycolysis Glucose is broken down into two molecules of Pyruvate. 2 Pyruvates 6C 8H 6O glucose Two electrons released 6C 12H 6O

Step 2 Pyruvate Conversion The 2 Pyruvates are converted to acetyl groups which combine with a protein to form 2 Acetyl CoA acetyl acetyl 2 AcetylCoA Release of 2 CO 2 and 2 Electrons

Step 3 Kreb’s Cycle The AcetylCoAs combines with an Organic molecule, OX.A to form Citric acid. Citric acid is converted to more OX.A that combines with more acetylCoA and the cycle continues.

OX.A Citric Acid Kreb’s Cycle AcetylCoA Release of electrons Total, 4 CO2 Citric Acid

Electron Transport Chain Step 4 Electron Transport Chain The electrons released during the breakdown of the molecules(pyruvate, citric acid and OX.A) are carried to the cristae of the mitochondria and transported through several proteins. The electrons finally combine with Oxygen to make water and initiate phosphorylation of ADP to form ATP.

Cristae Protein carrier Protein carrier ATPase Electron carrier electrons Oxygen (Water) Matrix Phosphorylation of ADP

The Ultimate goal of the mitochondria is to … …form ATP

V. Comparing Anaerobic and Aerobic Respiration Reaction Oxygen needed? Yes or No Location in the cell Reactants (starting materials) ATP formed products Lactic acid Alcohol CO2 H2O Anaerobic Respiration No Cytoplasm C6H12O6 2 CO2 H20 Aerobic Respiration Yes Cytoplasm and Mitochondria C6H12O6 36

Testing for Cellular Respiration In the lab, it is easy to test for the presence of cellular respiration. Cells give off water and CO2 as waste. This can be measured to quantify the rate of respiration. Amount of water may be difficult if testing cells in a water solution. It is easy to test for CO2.

Count bubbles to correspond to respiration rate. Yeast solution

What can be tested? Water at different temps Different food sources for the yeast

HW: separate sheet of paper Write a paragraph discussing the similarities and differences between aerobic and anaerobic respiration.