KREBS CYCLE & ELECTRON TRANSPORT Chapter 5.3 Continued http://www.clickatutor.com/mitochondria.jpg http://www.therunningdoctor.com/runinjuries.htm

REMEMBER: The “fork in the road” happens following glycolysis REMEMBER: The “fork in the road” happens following glycolysis. The presence or absence of _______________ decides which path it takes next. OXYGEN

Flowchart Section 9-2 Cellular Respiration Glucose (C6H1206) + Oxygen (02) Glycolysis Krebs Cycle We will next focus on the Krebs Cycle. This is the path that is taken when oxygen is present.

Image from BIOLOGY Miller and Levine; Prentice Hall Publishing _______________ follows glycolysis if oxygen is present KREBS CYCLE

REMEMBER: Glycolysis happens in the ________________ outside the mitochondria. Krebs cycle happens in _____________ inside the mitochondria CYTOPLASM MATRIX

(also called pyruvate) enters the _________________ PYRUVIC ACID _______________ (also called pyruvate) enters the _________________ Pyruvic acid joins with _______________ to form ________________ MITOCHONDRION COENZYME A ACETYL - CoA Diagram by Riedell

Carbon dioxide is released into the ________________ WHERE DO THESE GO? Carbon dioxide is released into the ________________ High energy electron carriers move into the ____________________ atmosphere ELECTRON TRANSPORT CHAIN, ETC (We will come back to this later)

Citric Acid Formation: Krebs Cycle Animation 2 carbon ACETYL-COA combines with a 4 carbon molecule to form a 6-carbon molecule called _______________ . citric acid

WHERE DO THESE GO? Coenzyme A goes back to pick up another ________________ Citric acid completes the ____________ Pyruvic acid KREBS CYCLE

KREBS CYCLE KREBS CYCLE PRODUCES ____ ___ 3 1 1 4 Krebs Cycle Animation KREBS CYCLE PRODUCES ____ ___ 3 1 1 4

WHERE DOES IT GO? → 6 carbons in original glucose are lost as ________________ to atmosphere Carbon dioxide

WHERE DO THESE GO? ATP can be used directly to supply __________ for the cell. High energy electron carriers move into the ____________________ energy ELECTRON TRANSPORT CHAIN

WHERE DOES IT HAPPEN? Glycolysis Glycolysis ____________ Cytosol KREBS Glycolysis ____________ Krebs Cycle ____________ Cytosol Matrix

Electron Transport Chain Flowchart Section 9-2 Cellular Respiration Glucose (C6H1206) + Oxygen (02) Glycolysis Krebs Cycle Electron Transport Chain We will next focus on the Electron Transport Chain.

WHERE DOES IT HAPPEN? ET Glycolysis KREBS Enzymes for ELECTRON TRANSPORT CHAIN are located in the ___________________________ Inner mitochondrial membrane (cristae)

ELECTRON TRANSPORT CHAIN INTERMEMBRANE SPACE CRISTAE Energy Carrying Protein MATRIX Image from: BIOLOGY by Miller and Levine; Prentice Hall Publishing©2006

Electron Transport Chain: Electron Transport Chain Animation electrons High-energy _____________ from __________ and __________ are passed along the electron transport chain. Energy from passing electrons is used to transport _____________________ across the membrane. NADH FADH2 Hydrogen ions (H+)

Electron Transport Chain: Electron Transport Chain Animation The pumping of H+ ions into the _______________________ represents potential energy that is harnessed to make ATP. As H+ ions escape through ion channels back into the matrix, ________________ spins and adds a phosphate to ADP to form _______ INTERMEMBRANE SPACE ATP SYNTHASE ATP

Electron Transport Chain: ________________ serves as the final electron acceptor of the electron transport chain. These electrons are at their lowest energy level. At the end of the electron transport chain, an enzyme combines the electrons with the hydrogen ions and oxygen to form ______________ For every two high energy electrons one _____ is transported to the intermembrane space of the mitochondria. OXYGEN water (H2O) H+

NADH FADH2 ATP Synthase _ _ _ _ _ Electron Transport Chain Animation NADH High-energy electrons from ________ come in at beginning but electrons from _________ come in farther down the chain. FADH2 ATP Synthase Intermembrane Space _ Matrix _ _ _ _

NADH → _____ FADH2 → _____ 3 ATP’s SO: Two high energy electrons produce 1 ATP NADH → _____ FADH2 → _____ 3 ATP’s 2 ATP’s

SO:

Figure 9–2 Cellular Respiration: An Overview WHATS THE BIG PICTURE? Electrons carried in NADH Electrons carried in NADH and FADH2 Pyruvic acid Electron Transport Chain Krebs Cycle Glucose Glycolysis Cytoplasm Mitochondrion H2O CO2 Heat

CELLULAR RESPIRATION includes: ______________________ _______________________ GLYCOLYSIS KREBS CYCLE ELECTRON TRANSPORT CHAIN

GLYCOLYSIS Happens in ______________ Breaks down ____________ into ________________ Produces _______ __________ CYTOPLASM outside mitochondria 1 glucose 2 pyruvic acid (pyruvate) 2 2

KREBS CYCLE happens in ________________ Breaks down _________________ Produces: ____ ____ ____ ____ MATRIX inside mitochondria 2 pyruvic acid 2 6 8 2

ELECTRON TRANSPORT Enzymes found in _____________ Uses high energy electrons and H+ ions donated by _______ and _______ Makes ___________ ________ acts a final electron acceptor to produce ________ cristae inner membrane of mitochondria NADH FADH2 32 (net) ATP OXYGEN H2O

Image from BIOLOGY Miller and Levine; Prentice Hall Publishing

CELLULAR RESPIRATION (aerobic/ with oxygen): 1 glucose → _______________ FERMENTATION (anaerobic/ without oxygen): 1 glucose → ________________ 36 ATP 2 ATP

CARBOHYDRATES SUPPLY ENERGY Remember ! CARBOHYDRATES SUPPLY ENERGY Cells burn GLUCOSE for their energy needs Images from: http://www.miranda.com/library.en/Images/Pictures/girls-runners.jpg http://www.estrellamountain.edu/faculty/farabee/biobk/BioBookCHEM2.html

EXERCISE and ENERGY (Short term energy) SMALL GLYCOLYSIS http://www.therunningdoctor.com/runinjuries.htm EXERCISE and ENERGY (Short term energy) Cells normally contain _________ amounts of ATP produced by _______________ & __________________________ (only enough for a few seconds of activity) Once this ATP is used up_____________ fermentation can provide enough ATP to last about ___________________. SMALL GLYCOLYSIS CELLULAR RESPIRATION LACTIC ACID 90 seconds

EXERCISE and ENERGY (Short term energy) Once race is over, _______________ must be broken down using oxygen. Well __________ athletes burn lactic acid more efficiently. Lactic acid trained Image from: http://www.miranda.com/library.en/Images/Pictures/girls-runners.jpg

EXERCISE and ENERGY (LONGER term energy) For exercise longer than 90 seconds _____________________ is the only way to make enough ATP. Cellular respiration releases energy _____________ than fermentation. Well conditioned athletes must pace themselves during a long race. Cellular respiration more slowly

GLYCOGEN What happens in a long race when the body’s glucose all is used up? Animal cells store GLUCOSE as _____________ to use later. GLYCOGEN REMEMBER Image from: http://www.msu.edu/course/lbs/145/smith/s02/graphics/campbell_5.6.gif

MUSCLES glycogen EXERCISE and ENERGY (LONGER term energy) ________________ store glucose as ________________ which can be broken down into glucose to supply energy for_______________ of activity. MUSCLES glycogen 15-20 minutes

That’s why aerobic exercise must continue for longer than EXERCISE and ENERGY (LONGER term energy) After glycogen stores are used up the body begins to break down ________ That’s why aerobic exercise must continue for longer than 20 minutes if you want to lose weight! FAT Image from: http://blackmovie.us/movie/Fat.Albert/fat.albert.movie.jpg

ALL CELLS NEED ENERGY All __________________ (including plant and animal cells) have _______________ for cellular respiration All __________________ (bacteria) have their electron transport enzymes attached to their _____________________ Remember: No membrane bound organelles! Eukaryotes mitochondria Prokaryotes Cell membranes