CELLULAR RESPIRATION CHAPTER 9

9-1 CHEMICAL PATHWAYS CHEMICAL ENERGY and FOOD 3811 calories of heat energy are produced per gram of glucose burned. This is quite a lot of energy. 1 CALORIE = amount of energy needed to raise the temperature of 1 gram of water by 1 degree C. 9-1 CHEMICAL PATHWAYS CHEMICAL ENERGY and FOOD

Chemical Energy and Food Food labels display the number of Calories and other nutritional information about a particular product. These Calories (CAPITAL C) are actually kilocalories. Chemical Energy and Food

9-1 How much energy is in food? when glucose is broken down completely in the presence of oxygen, then water and carbon dioxide are produced Glycolysis is a series of enzymes catalyzes chemical reactions that change glucose one step at a time into different molecules One molecule of glucose is broken in half producing two molecules of pyruvic acid Pyruvic Acid is a 3-C compound

Chemical Energy and Food Also called “sugar breaking” occurs in the cytoplasm and does not need oxygen Glycolysis only releases a small amount of energy. Let’s find out how our cells can produce the large amounts of energy we require to perform our everyday functions. Chemical Energy and Food

SECTION 9-1: AN OVERVIEW of Cellular Respiration When oxygen is present, the products of glycolysis enter the KREBS CYCLE and the ELECTRON TRANSPORT CHAIN. This process is called CELLULAR RESPIRATION SECTION 9-1: AN OVERVIEW of Cellular Respiration

GLYCOLYSIS Process in which one molecule of glucose is broken in half producing two molecules of pyruvic acid. Pyruvic Acid is a 3-C compund. Where does the need energy in Glycolysis? To split the Glucose molecule. Cell spends 2 ATP to begin process. Makes a TOTAL of 4 ATP  NET GAIN = 2 ATP What is the electron carrier in Glycolysis?

Glycolysis and NADH Production NAD+ is the electron carrier. Nicotinamide adenine dinucleotide 4 HEe- are removed and passed to NAD+ Each NAD+ accepts 2 HEe-  NADH NAD+ helps pass energy from glucose to other cellular pathways. Energy yield is only 2 ATP but the cell can make thousands of ATP in a short time.

FERMENTATION Why is this a problem for the cell? NAD+ is limited and they quickly fill up with e- NAD+ is required to continue Glycolysis. FERMENTATION releases energy from food molecules in the absence of oxygen. Cells convert NADH back to NAD+ Passes electrons back to Pyruvic Acid TWO TYPES Alcoholic and Lactic Acid What does anaerobic mean?

Question of the DAY NOV 12 What are the reactants of fermentation? A. ADP and NADH B. Glucose and NADH C. Pyruvic Acid and Carbon Dioxide D. Pyruvic Acid and NADH Question of the DAY NOV 12

Why is NAD+ essential to a cell’s ability to produce ATP? DO NOW Nov 12

It transports energy from glucose to other pathways. ANSWER

FERMENTATION ALCOHOLIC LACTIC ACID Yeast and microorganisms Pyruvic acid + NADH yields Ethyl Alcohol + Carbon Dioxide + NAD+ Why does bread dough rise? Performed in most cells Pyruvic acid + NADH yields Lactic Acid + NAD+ Why do your muscles burn when engaging in strenuous activity? FERMENTATION

REVIEW OF GLYCOLYSIS What are the advantages of GLYCOLYSIS? Are there any disadvantages to GLYCOLYSIS? REVIEW OF GLYCOLYSIS

9-2: KREBS CYCLE and ETC DRAW Figure 9-6 in your NOTES Label all the parts and write down the STEPS ANSWER the following Questions. Write down the question and the answer. 1. Where does the KREBS CYCLE take place? 2. How many ATP molecules are generated in one turn of the cycle? 3. How many ATP are generated per one molecule of glucose? 4. Where is most of the energy in pyruvic acid transferred to in this cycle? 5. What is FAD? What is its role in the cycle? 9-2: KREBS CYCLE and ETC

The Krebs Cycle 90% of energy in pyruvic acid still unused Locked in the HE electrons Discovered by Hans Krebs British Biochemist in 1937 Pyruvic acid from glycolysis travels into the mitochondrion KREBS CYCLE occurs here The Krebs Cycle

The Krebs Cycle Respiration is a synonym for breathing. Oxygen is the final electron acceptor. This is why organisms need to breathe in oxygen. The Krebs Cycle

Pyruvic Acid is broken down into carbon dioxide in a series of energy-extracting reactions. Second stage of cellular respiration. Also called the Citric Acid Cycle. Citric Acid is the first compound fromed in this process. The Krebs Cycle

The Krebs Cycle: STEP A 1. PA from Glycolysis enters mitochondria 2. One C from PA becomes part of CO2 Released into air 3. Remaining 2 C joined with Coenzyme A 4. Forms Acetyl Coenzyme A (CoA) 5. Acetyl CoA joins with 4 C molecule to produce Citric Acid The Krebs Cycle: STEP A

1. Citric Acid (6-C) broken down to a 4-C molecule 2 molecules of CO2 released 2. Electrons transferred to e- carriers. Occurs 5 times throughout cycle. NAD+  NADH FAD  FADH2 3. ADP molecule  ATP One turn produces 4 NADH, 1 FADH2, 1 ATP One turn = 1 Pyruvic acid How many turns are made for 1 molecule of glucose? The KREBS CYCLE: STEP B

PRODUCTS of KREBS CYCLE What are the products of the KREBS Cycle? ATP, NADH, FADH2, and Carbon Dioxide How are these products used? ATP for Cellular Activities Carbon Dioxide is exhaled NADH and FADH2 carry HEe- to ETC Used to make huge amounts of ATP

HOMEWORK REVIEW TEXTBOOK Page 237 and 238 Answer questions 20-24 and 29-30 TEXTBOOK Page 239 Answer questions 1-9 HOMEWORK REVIEW

Which of the following are electron carriers? A. NAD+ B. FAD C. NADH D. All of the above Question of the Day Nov 13

What are the products of the Krebs Cycle for 1 Molecule of glucose? DO NOW Nov 13

ANSWER The KREBS Cycle produces 8 NADH, 2 FADH2, and 2 ATP Per molecule of Glucose These products are from 2 turns of the KREBS Cycle. ANSWER

AGENDA NOV 13 BIG Question: How do organisms produce energy? 1. QotD and DO NOW 2. Chapter 9 3. Electron Transport Chain 4. STUDY GUIDES 5. Tomorrow – Review 6. TEST on FRIDAY – CHAPTER 9 AGENDA NOV 13

ELECTRON TRANSPORT CHAIN HEe- from KREBS are carried to ETC. Delivered by NADH and FADH2 STEP A: HEe- passed along the ETC Series of Carrier Proteins Inner membrane of Mitochondria Electrons lose a small amount of energy for each “jump” it they make along ETC. ELECTRON TRANSPORT CHAIN

Electron Transport Chain What happens to the electrons when they reach the end of ETC? Oxygen is the final electron acceptor. Enzymes combine these LEe- with H ions and Oxygen to form water.

ETC: ENERGY MAKING STEPS STEP B: For every 2 HEe- that pass along ETC, their energy is used to transport H+ ions from the matrix to the inner-membrane space. How many membranes does the mitochondria have? Concentration gradient is formed.

ETC: ENERGY MAKING STEPS STEP C: ATP SYNTHASE allows the movement of H+ ions back across the inner membrane. This movement produces energy used to make ADP + P  ATP Each pair of HEe- that “jump” along ETC produce enough energy to produce 3 ATP

TOTALS FOR 1 Molecule of GLUCOSE GLYCOLYSIS produces 2 NADH and 4 ATP (2 ATP SPENT) KREBS CYCLE produces (2 Turns) 8 NADH, 2 FADH2, and 2 ATP ETC produces 32 ATP TOTALS

The overall process of Cellular Respiration produces available to the cell. 38 ATP – 2 ATP SPENT = 36 ATP This is 38% of the energy available in Glucose. Where does the rest of the energy go? It is lost as heat. This is why we feel hot after strenuous activity. TOTALS

ENERGY and EXERCISE Short Term Energy Long Term Energy Small amounts of ATP in muscles Lactic Acid Fermentation takes over Enough energy to last approximately 90 seconds Long Term Energy Cellular respiration is needed Releases energy slower than fermentation Stored in the carbohydrate Glycogen 15 – 20 minutes of energy (then breaks down fats and other molecules) Even the most conditioned athletes must pace themselves. ENERGY and EXERCISE