GLYCOLYSIS & CELLULAR RESPIRATION (OXIDATION RESPIRATION) Ch. 9 From Molecules to Organisms: Structures and Processes LS1-7-Create a model to illustrate that cellular respiration is a chemical process where by the bonds in food molecules & oxygen molecules are broken and the bonds in the new compound are formed resulting in a net transfer of energy

Big Ideas  Energy flows from the sun and through all life on earth.  Cellular Respiration converts food molecules into ATP (universal source of energy for living organisms)  There are alternative pathways to energy acquistion.

Feel the Burn  Do you like to run, bike, or swim? If none, what is your favorite outdoor activity?  These all are good ways to exercise. When you exercise, your body uses oxygen to get energy from glucose, a 6-carbon sugar.  On your notes answer the following questions:  How does your body feel at the start of exercise, such as a long, slow run? How do you feel 1 minute into the run; 10 minutes into the run?  What do you think is happening in your cells to cause the changes in how you feel?  Think about running as fast as you can for 100 meters. Could you keep up this pace for a much longer distance? Explain your answer.

Various types of fuel  Biofuels  Fuels produced from plant & animal products  Fossil fuels  Fuels produced from the decayed remains of plants & animals modified over millions of year

Production of Fossil Fuels

Metabolism  Metabolism = all of the chemical reactions in a cell  Catabolic- releases energy by breaking down LARGE molecules into smaller molecules (cellular respiration)  Anabolic-uses energy released by catabolic pathways to build LARGE molecules from smaller molecules. (photosynthesis)  Anabolic steroids

Forms of Energy  Potential-stored energy  Water in dam  Chemical bonds  Oxidative respiration (cellular respiration)  Kinetic-energy of moving objects  Concentration gradient  Heat  Photosynthesis

Transformation of Energy Law of Thermodynamics ◦ 1 st - energy can be converted from 1 form to another, but cannot be destroyed. ◦ 2 nd - energy cannot be converted without the loss of usable energy (heat-thermal heat) Autotrophs ◦ organisms that convert light energy into chemical energy (plants, cyanobacteria) Heterotroph ◦ organisms who need to ingest food to obtain energy (ladybug, grasshopper)

ATP-Adenosine Triphosphate  Considered a “rechargeable battery”  Composed of:  Ribose sugar, adenine (nitrogen base), 3 phosphate groups  Removal of 1 phosphate group = release of energy  Replace the 1 phosphate group = ?

Check for Understanding  What is the difference between kinetic and potential energy?  Give one example for each type.  What are the two types of metabolism?  Why is ATP considered a “rechargeable battery?”

How is Energy Used?  The chemical energy produced by respiration, ATP, is used by cells to undertake work.  Where might ATP be used?  Movement Enabling muscle contraction  Thermoregulation in mammals and birds  Biosynthesis – building new molecules, cells and tissues  Active transport – moving molecules against a concentration gradient.

Glucose Glycolysis Krebs cycle Electron transport Fermentation (without oxygen) Alcohol or lactic acid Chemical Pathways Go to Section:

Where does respiration take place? Mitochondria = organelles in which respiration takes place. Contains cellular DNA Enzymes convert the energy from glucose into ATP.

Mitochondria The inner membrane is coated in enzymes, which catalyze the reactions of aerobic respiration to produce ATP. It is surrounded by two membranes. The inner layer folds inwards to form the cristae. The cristae project into a liquid called the matrix. outer membrane matrix inner membrane cristae

Energy Carriers  What was the energy carrier in photosynthesis?  NADPH  Electrons require a carrier during oxidative respiration  NAD + is the energy carrier in glycolysis (Nicotinamide adenine dinucleotide- coenzyme)  NAD + + H +  NADH (electron carrier)  NAD+ Video NAD+ Video

1 st Step of Sugar breakdown Glycolysis  Where: Occurs in the cytoplasm  Who: All eukaryotes and some prokaryotes (bacteria)  What: Breaks glucose (C 6 H 12 O 6 ) in half  2 molecules of pyruvate/pyruvic acid ( C 3 H 4 O 3 )  Product: 2 NADH produced and 2 ATP (4 total but 2 used in reaction)  NAD+ (energy carrier) accepts a pair of electrons producing NADP

Glycolysis  Glycolysis can be followed by two types of pathways:  Oxidative Respiration (when O 2 is present-aerobic) OR  Fermentation (when O 2 not present-anaerobic)

Oxidative Respiration  Follows glycolysis if oxygen is present  What: Process that releases energy by breaking down food molecules  Where: Occurs in matrix of mitochondria  Who: Occurs in all eukaryotic organisms (plants and animals)  C 6 H 12 O 6 + 6O 2  6CO 2 + 6H 2 O  Product :sugar + oxygen  carbon dioxide + water  Total ATP molecules produced =

Kreb’s Cycle (Citric Acid Cycle) Han Kreb 1937  Who: Eukaryotes  Where: mitochondrial matrix  What: Pyruvic acid is broken down into CO 2 in a series of energy- extracting reactions  Involves enzymes which control reaction (coenzyme A)  Product = CO 2 (waste), 4 NADH, 1 FADH2, and 1 ATP 

Check for Understanding  What is the starting material for the Kreb Cycle?  What is the product of the Kreb cycle?  Where do the reactions of the Kreb cycle take place?

Electron Transport Chain  High energy electrons from Kreb are used to convert ADP to ATP  NADH and FADH 2 pass electrons along carrier proteins plasma membrane of mitochondrion (eukaryotes)  Energy is used to move H+ ions across membrane via ATP synthase.

ETC Continued  At the end of the chain, ATP synthase combines electrons with H + and O to form H 2 O.  Oxygen serves as the final hydrogen acceptor  Chemiosmosis  Inner membrane space becomes + charge  Outside membrane – charge  Final product = H 2 O produced as waste, 34 ATP

ETC

Check for understanding  When electrons join NAD+ and FAD during Kreb cycle, what do they form?  NADP and FADH 2  What molecule is the final electron acceptor in the etc?  Oxygen  How many molecules of ATP are produced from Kreb and ETC?  34

ETC video  ?v=xbJ0nbzt5Kw

Totals 38% of glucose used Remaining 62% released as heat

Glucose Glycolysis Cytoplasm Pyruvic acid Electrons carried in NADH Krebs Cycle Electrons carried in NADH and FADH 2 Electron Transport Chain Mitochondrion Respiration: An Overview Mitochondrion Section 9-1 Go to Section:

Cellular Respiration Flowchart Glucose (C 6 H ) + Oxygen (0 2 ) Glycolysis Krebs Cycle Electron Transport Chain Carbon Dioxide (CO 2 ) + Water (H 2 O)

Aerobic respiration

Cellular Respiration Energy Release Mitochondria C 6 H 12 O 6 & O 2 CO 2 & H 2 O 6O 2 + C 6 H 12 O 6 6CO 2 + 6H 2 O Function Location Reactants Products Equation

Comparing Photosynthesis & Cellular Respiration PhotosynthesisOxidative Respiration Alcoholic Fermentation Lactic Acid Fermentation Function Location Reactants Products Equation