In the presence of Oxygen, Cells convert energy stored in Glucose into ATP 1

Flow of Energy 2

3 All living things must be able to convert glucose into ATP.

Adenosine Triphosphate 4

5

Energy is released from Glucose through “burning” with oxygen. 6

Energy (in the form of glucose) is supplied by the foods you eat. 7

8 Oxygen is supplied by the air you breathe, and Carbon dioxide is released into the atmosphere. O2O2

Plants make their own glucose through Photosynthesis

10 Inside your cells, mitochondria use oxygen to release energy from glucose.

11 Specific chemical reactions occur in each compartment of the mitochondrion.

12 The most efficient release of energy occurs in three main stages of Cellular Respiration. Glucose Pyruvic acid O2O2 O2O2 H2OH2O H2OH2O CO 2

13 The three stages of cellular respiration are glycolysis, the Krebs cycle and the electron transport chain.

Glycolysis takes place in the cytoplasm of the cell The Krebs cycle takes place in the matrix of the mitochondrion Electron transport chain take place on the inner membrane of the mitochondrion 14

15 Glycolysis splits glucose into 2 pyruvic acid molecules

Glycolysis Occurs in the cytoplasm of the cell. All cells go through glycolysis. can occur whether or not oxygen is present. The main purpose of glycolysis is to split glucose into 2 pyruvic acid molecules. –It also extracts energy in the form of NADH and ATP. 16

When glucose enters the cytoplasm, enzymes invest 2 ATP molecules to begin the process. Then other enzymes produce 2 NADH molecules and 4 ATP molecules from the rest of glucose. The resulting molecules are 2 pyruvic acid molecules. 17

NAD + NADH An electron carrier Empty: no electrons Carrying electrons 18 NADH is an electron carrier (much like NADPH from photosynthesis). It carries electrons from glycolysis to the electron transport chain (like a taxi or a vesicle)

Products from Glycolysis: 2 Pyruvic Acid Molecules 2 NADH 2 ATP – Although you made 4 ATP, 2 ATP are used in the beginning so the net production of ATP in Glycolysis is only 2 ATP 19

20 The Krebs Cycle releases energy from Pyruvic acid and produces CO 2

Krebs Cycle The Krebs cycle only occurs if oxygen is present. –If conditions are anaerobic (without oxygen), then fermentation will occur (We’ll talk about this tomorrow) Occurs in the matrix of the mitochondrion. –The matrix is like a soup of chemical necessary for the chemical reactions. 21

The purpose: break pyruvic acid down even further to extract even more energy. Enzymes first must convert pyruvic acid into another molecule called Acetyl CoA. –CO2 is released, and NADH is made. Then, Acetyl CoA enters the matrix and is processed by even more enzymes. One Pyruvic acid molecule makes: –2 more CO2 are released –ATP is made –FADH2 is made –3 NADH are made. 22

Remember that glycolysis produces 2 pyruvic acid molecules from each glucose molecule. –This means that the Krebs cycle has to “turn” two times to process each glucose molecule Product totals in Krebs cycle with two turns: –6 NADH –2 FADH2 –2 ATP 23

24 Electron carriers (NADH & FADH 2 ) generate even more ATP in the Electron Transport Chain.

ETC Occurs in the inner membrane of the mitochondrion. There are membrane phospholipids, protein pumps that use electron energy to pump H+ ions into the intermembrane space. There is a protein channel called ATP synthase which allows the H+ ions to diffuse into the matrix which generates energy to make ATP. (Just like light reactions for photosynthesis) 25

Step 1. NADH and FADH2 carry electrons from glycolysis and the Krebs cycle to a protein in the inner membrane. (FADH2 carries its electrons to a protein further along the chain) Step 2. The electrons travel through the membrane from one protein to the next and the energy from the electrons help the proteins to pump H+ into the intermembrane space (between the inner membrane and the outer membrane)—this builds up the concentration of H+ in the space. 26

Step 3. As the electrons reach the end of the chain of proteins, they are out of energy and used by oxygen to make water—oxygen is the “final electron acceptor” (Oxygen makes this reaction aerobic, and water is a waste product) Step 4. The H+ ions have build up in the intermembrane space. They diffuse through ATP synthase back into the matrix. Their flow generates energy to produce 6 ATP. 27

Oxidative Phosphorylation Detail (ETC) 28 AB_Yc

ATP Synthase Detail 29 _kKds&feature=related Watch the youtube video to learn how ATP Synthase works.

ATP Tally 30 Part of CR# NADH Produced # FADH2 produced # ATP produced Glycolysis Krebs Cycle ETC

Check for Understanding: 1.Explain why plants must do both, photosynthesis and cellular respiration? 2.Where in the cell does glycolysis, the Krebs cycle and the electron transport take place? 3.What is the final electron acceptor in Oxidative Phosphorylation (ETC)? 4.Which parts of the mitochondria are analogous to the parts of the chloroplast? Explain how they are alike.

Textbook Artist: You have been assigned to illustrate the biochemical pathways involved in cellular respiration. You should include the processes of glycolysis, the Krebs cycle and the Electron Transport Chain You should indicate the reactants and products of each phase You should include the total energy products for each phase Finally, indicate where in the cell each phase occurs.

Create an amusement park ride using one of the Cell Respiration processes as your inspiration. 1.Create an analogy for your starting material (glucose, or pyruvic acid) 2.Show how it will change throughout the ride 3.Show how energy molecules are produced (what will be the ATP released? Or NADH?) 4.Describe your ride, and how it relates to the CR process. 33

Create an amusement park using Cell Respiration as your inspiration. Use analogies for the starting materials, process and products of each process (like glucose might be 6 people on a ride together) 34