Cellular Respiration The organic compounds that animals eat

Cellular Respiration Ø The organic compounds that animals eat and plants produce are converted to ATP through Cellular Respiration. Ø Oxygen makes the production of ATP more efficient. Ø Metabolic processes that use oxygen are called aerobic. Ø Metabolic processes that do not use oxygen are called anaerobic.

Cellular Respiration Overview C 6 H 12 O 6 + 6 O 2 6 CO 2 + 6 H 2 O + 36 -38 ATP Ø Plants and Animals both undergo cellular respiration. Ø Aerobic Respiration takes place in the mitochondria of plants and animals. Ø

Cellular Respiration Overview Ø Stage 1 - Glycolysis: Glucose is broken down into pyruvate, producing NADH and ATP in the cytoplasm of cells. Ø Stage 2 (Aerobic)-Krebs Cycle: With O 2, pyruvate and NADH are used to make a large amount of ATP in the mitochondria of plant and animal cells. Ø Stage 2 (Anaerobic)- Fermentation: Without oxygen, pyruvate is converted into lactate or ethyl alcohol in the cytoplasm of cells.

Cellular Respiration

Stage One: Glycolysis Ø Glycolysis: Glucose from food, is broken down in the cytoplasm of cells. Ø Step 1: Phosphate groups from 2 ATPs are transferred to a glucose molecule. Ø Step 2: The six carbon compound is broken into two 3 -carbon compounds with a phosphate group.

Stage One Glycolysis Ø Step 3: Two NADH molecules are produced another phosphate group is added to each of the 3 -carbon compounds. Ø Step 4: Each of the 3 -carbon compound is converted to pyruvate and each molecule produces 2 ATP Ø Used: Glucose, 2 ATP Ø Produced: 2 pyruvate, 4 ATP, 2 NADH

Chapter 5

Cellular Respiration

Stage 2: Krebs Cycle Ø Krebs Cycle: The pyruvate molecule enters the mitochondrion and are broken down into a 2 carbon compound and release CO 2 Ø Step 1 - The 2 -carbon compound is combined with a 4 -carbon compound to make a 6 -carbon compound Ø Step 2 - CO 2 is released from 6 - carbon compound to form a 5 -carbon compound. Electrons are transferred to NAD+ to make NADH

Stage 2: Krebs Cycle Ø Step 3 - CO 2 is released from the 5 -carbon compound making a four carbon compound. A molecule of ATP and NADH are made. Ø Step 4 - The 4 -carbon compound is converted and electrons are transferred to an electron acceptor-FAD which makes the electron carrier FADH 2. Ø Step 5 - The new four carbon compound is converted to the 4 -carbon compound to begin the cycle. NADH is produced.

Krebs Cycle Review Ø Aerobic cellular respiration that takes place in the mitochondria of cells. Ø Also called the Citric Acid Cycle Ø Used: pyruvate Ø Produced: CO 2, NADH, FADH 2, ATP

Krebs Cycle

Electron Transport Chain Ø The electrons carried by NADH and FADH 2 enter an electron transport chain of the inner membrane of the mitochondria. Ø The energy in the electrons allow proteins to pump (actively transport) H+ ions out of the inner compartment to the outer compartment of the mitochondria.

Electron Transport Chain Ø A concentration gradient of H+ ions will be produced and the H+ will flow by facilitated diffusion through a ATP that will make ATP. Ø Used H+ ions and electrons will combine with O 2 to produce water.

Electron Transport Chain

Electron Transport Chain of Aerobic Respiration

Aerobic Respiration Review Ø Glycolysis l l Used: 1 Glucose, 2 ATP Produced: 2 pyruvate, 2 NADH, 4 ATP Ø Krebs Cycle l l Used: 2 pyruvate Produced: 2 FADH 2, 8 NADH, 2 ATP, 6 CO 2 Ø Electron Transport l l Used: 8 NADH, 2 FADH 2, 6 O 2 Produced: 32 -34 ATP, 6 H 2 O

Net Results of Respiration Ø Used: 1 Glucose, 6 O 2 Ø Produce: 6 H 2 O, 6 CO 2, 36 -38 ATP Ø 1 C 6 H 12 O 6 38 ATP + 6 O 2 6 CO 2 + 6 H 2 O + 36 -

Anaerobic Respiration Ø When no oxygen is available, fermentation is an anaerobic process that can produce ATP Ø Two main types of anaerobic respiration are Lactic Acid and Ethyl Alcohol Fermentation Ø Without oxygen NAD+ needs another way to cycle into NADH

Lactic Acid Fermentation Ø In Lactic Acid fermentation, glucose is still broken down to pyruvate through glycolysis Ø Using NADH, the pyruvate is converted into another 3 -carbon compound called lactate and ATP is produced. Ø During exercise, without oxygen, cells in muscles break down pyruvate to lactate to produce ATP

Ethyl Alcohol Fermentation Ø In Alcohol Fermentation, glucose is broken down into pyruvate through glycolysis. Ø The pyruvate is broken down into a 2 carbon compound releasing CO 2. Ø Using NADH the 2 -carbon compound is converted to ethyl alcohol (ethanol). Ø Alcoholic beverages and bread us alcoholic fermentation.

Lactic Acid and Alcoholic Fermentation Ø When oxygen is not present, cells recycle NAD+ through fermentation.

Respiration in the Absence of Oxygen Ø When oxygen is present, aerobic respiration occurs to produce ATP. When oxygen is not present, fermentation occurs instead.

Cellular Respiration vs. Fermentation