Journal  What do all living things need?

Journal  How do living things acquire energy?

: Cellular Respiration

 Everything that is alive needs energy.  Energy is the ability to do work  Without the ability to produce & use energy living things would cease to exist.

Adenosine Triphosphate  ATP  One of the most important compounds that cells use to store and release energy  ATP can easily release and store energy by breaking and making the bonds between its phosphate groups  The currency of the cell  An efficient way to temporarily store energy that can be quickly released by one reaction

ATP  Stores its energy in its chemical bonds  Energy can be converted into electrical energy, into other chemical bonds, or into power

ATP  Drives ion pumps to restore an electrical potential  powers movement  Used for just about every process in the body that requires energy

Composition of ATP  Adenine  Ribose (5-C Sugar)  3 Phosphate Groups Adenine + Ribose = Adenosine

ADP  Adenosine diphosphate  looks almost like ATP, except that it has two phosphate groups instead of three.  Adenonine  Ribose  2 Phosphate Groups  ADP contains some energy, but not as much as ATP.

 When a cell has energy available, it can store small amounts of it by adding phosphate groups to ADP, producing ATP.  ADP is like a rechargeable battery that powers the machinery of the cell.

AMP  Adenosine monophosphate  Adenine  Ribose  1 Phosphate Group  Like an uncharged battery  Stores the least amount of energy

Production of ATP from ADP & AMP  Cells can release the energy stored in ATP by breaking the bonds between phosphate groups  Because a cell can add or subtract these phosphate groups, it has an efficient way of storing and releasing energy as needed.

 Animal & Plant cells produce their own ATP through chemical reactions

 ATP can be produced from ADP  ADP + P + Energy  ATP

 ATP can be produced from AMP  AMP + P + P + Energy  ATP

 Animal & Plant Cells can use ATP through the following reaction  ATP  ADP + P + Energy

Where do we get ATP?  Adenosine  The cell gets adenosine either by absorbing food which contains adenosine or by making adenosine through a series of reactions  All cells have the capability of producing this important compound

 Phosphate Groups  Plant cells get their phosphate groups from the soil  Animal cells get their phosphate groups from absorbed food

 Cells break down food molecules gradually and use the energy stored in the chemical bonds to produce compounds such as ATP that power the activities of the cell.

ATP & Long-Term Storage  ATP is not a good molecule for storing large amounts of energy over the long term.  It is more efficient for cells to keep only a small supply of ATP on hand. Cells can regenerate ATP from ADP as needed by using the energy in foods like glucose.  Why?  A single molecule of glucose stores more than 90 times the chemical energy of a molecules of ATP.

 When your body needs to use energy, you break down ATP to ADP to AMP.  When your body is making energy you are building AMP to ADP to ATP

Journal:  What do cells use ATP for?

Examples of Using & Storing ATP

 1. Your body is requesting energy in order to allow your muscles to lift a box. How will ATP be used in this situation?  ATP  ADP + P + Energy  Energy is made available for use.

 2. You eat dinner. In doing this, you are producing energy. How will ATP be used in this situation?  ADP + P + Energy  ATP  Energy is stored for later usage

Journal  Define the following terms in your own words: respiration, aerobic, anaerobic

Cellular Respiration

 Process by which the chemical energy of “food” molecules is released & partially captured in the form of ATP

 Carbohydrates, fats, and proteins can all be used as fuels for cellular respiration

Cellular Respiration can be divided into 3 processes  1. Glycolysis  2. Krebs Cycle  3. Electron Transport Chain (ETC)

Where does this happen?  1. Glycolysis  cytoplasm  2. Krebs Cycle  in mitochondrial matrix  3. Electron Transport Chain  Inner membrane of the mitochondria

Review of Mitochondria Structure  Smooth outer Membrane  Folded inner membrane  Folds called Cristae  Space inside cristae called the Matrix

 Each molecule of glucose  can generate a total of 36 ATP molecules during cellular respiration  only 2 ATP molecules through glycolysis (fermentation).

Glycolysis  Breakdown of glucose inside the cell; “sugar breaking”  Process in which glucose is broken down in order to utilize Potential Energy stored in this molecule

Glucose  Chemical formula of glucose  C 6 H 12 O 6

Gylcolysis  Net gain of 2 ATP & 2 NADH  Glucose is broken down into pyruvate (Pyruvic acid)  Glycolysis – does not require oxygen

Steps to Glycolysis  1. 2ATP molecules convert glucose into a high energy 6-C sugar with 2 phosphates  2. 6-C sugar broken down to two-3C molecules called PGAL

 3. 2 PGAL go to chemical reactions to make pyruvic acid (pyruvate)  Producing 4ATP molecules for each molecule of glucose  2 pair of high energy e- are produced & carried by NADH  Net gain of 2 ATP & 2 NADH

Why is there only a net gain of 2 ATP?  Glycolysis produces 4 ATP, but 2 ATP molecules are used to start the process therefore yielding a net gain of 2 ATP

If oxygen is present after glycolysis:  Pyruvate will move to the Krebs cycle when oxygen is present (aerobic respiration)

If no oxygen is present after glycolysis: oxygen is not fermentation.  If oxygen is not present ( anerobic respiration ) then pyruvate will go through the process of fermentation.

 Anaerobic  “without air”

Lactic Acid Fermentation  In the absence of oxygen  In most animals pyruvic acid is converted to lactic acid when it accepts electrons from NAD+  Lactic acid Fermentation occurs during vigorous exercise

 When you cannot supply enough oxygen to your muscles, lactic acid forms to help produce ATP  Causes a painful burning sensation in muscles

Lactic Acid Fermentation Chemical Reaction Pyruvic Acid + NADH  Lactic acid + NAD+

Alcoholic Fermentation yeast  Only occurs in yeast  Pyruvic acid alcohol & CO 2  Pyruvic acid is broken down into alcohol & CO 2

rise bubbles  Causes bread dough to rise, produces tiny bubbles in beer & sparkling wine as well as the alcohol content  Anaerobic  Anaerobic process

Alcoholic Fermentation Reaction Pyruvic Acid + NADH  Alcohol + CO 2 + NAD+

Kreb’s Cycle Citric Acid Cycle  Another name is Citric Acid Cycle mitochondria  Takes place in the mitochondria ATP, NADH, FADH 2  Generates a pool of energy ( ATP, NADH, FADH 2 ) from the oxidation of pyruvate (glycolysis)

pyruvic acid ( which is broken down by glycolysis) and converts it into  takes pyruvic acid ( which is broken down by glycolysis) and converts it into ATP which the body can use as energy  CO 2 released  CO 2 is released in this process  This is why we breathe out CO 2

 Pyruvate is transported to the mitochondria & loses CO 2 to form acetyl-CoA (a 2-C molecule)  Chemical energy is released and captured in the form of NADH, FADH 2, & ATP

glucose pyruvic acid two  Remember! Each molecule of glucose results in 2 molecules of pyruvic acid, which enter the Krebs cycle. So each molecule of glucose results in two complete “turns” of the Krebs cycle.

Kreb’s Cycle Products Per Glucose Molecule 6 CO 2 2 ATP 8 NADH 2 FADH 2  Therefore, for each glucose molecule, 6 CO 2 molecules, 2 ATP molecules, 8 NADH molecules, and 2 FADH 2 molecules are produced.

The Krebs Cycle  During the Krebs cycle, the second stage of cellular respiration, pyruvic acid produced in glycolysis is broken down into carbon dioxide in a series of energy-extracting reactions.  The Krebs cycle is also known as the citric acid cycle because citric acid is the first compound formed in this series of reactions.

Citric Acid Production  Pyruvic acid from glycolysis enters the matrix, the innermost compartment of the mitochondrion.

Citric Acid Production   Once pyruvic acid is in the mitochondrial matrix, NAD + accepts 2 high-energy electrons to form NADH. One molecule of CO 2 is also produced.  The remaining 2 carbon atoms react to form acetyl- CoA.

Citric Acid Production   Acetyl-CoA combines with a 4-carbon molecule to produce citric acid.

Energy Extraction   Citric acid is broken down into a 5-carbon compound and then a 4-carbon compound. Two molecules of CO 2 are released. The 4-carbon compound can then start the cycle again by combining with acetyl- CoA.

Energy Extraction   Energy released by the breaking and rearranging of carbon bonds is captured in the forms of ATP, NADH, and FADH 2.

Energy Extraction   For each turn of the cycle, one ADP molecule is converted into ATP. ATP can directly power the cell’s activities.

Energy Extraction   The electron carriers NAD + and FAD each accept pairs of high-energy electrons to form NADH and FADH 2. NADH and FADH 2 are used in the electron transport chain to generate ATP.

Energy Extraction  Remember! Each molecule of glucose results in 2 molecules of pyruvic acid, which enter the Krebs cycle. So each molecule of glucose results in two complete “turns” of the Krebs cycle.  Therefore, for each glucose molecule, 6 CO 2 molecules, 2 ATP molecules, 8 NADH molecules, and 2 FADH 2 molecules are produced.

Electron Transport  NADH and FADH 2 pass their high-energy electrons to electron carrier proteins in the electron transport chain.

 At the end of the electron transport chain, the electrons combine with H + ions and oxygen to form water.

 Energy generated by the electron transport chain is used to move H+ ions against a concentration gradient across the inner mitochondrial membrane and into the intermembrane space.

ATP Production  H+ ions pass back across the mitochondrial membrane through the ATP synthase, causing the ATP synthase molecule to spin. With each rotation, the ATP synthase attaches a phosphate to ADP to produce ATP.

Total Breakdown of Glucose  Glycolysis  2 ATP  Kreb’s Cycle  2 ATP  ETC  32 ATP  Total  36 ATP from aerobic cellular respiration