2. By: Riley Thomas and Katie Tibus

3.  Food provides living things with chemical building blocks they need to grow and reproduce. › Serves as source of raw materials from which the cells of the body can synthesize new molecules. * Food serves as a source of energy

4.  Calorie- the amount of energy needed to raise the temperature of one gram of water, one Celsius degree › One gram of the sugar glucose (C 6 H 12 O 6 ) when burned in the presence of oxygen releases 3,811 calories of heat energy › Cells do not burn calories they gradually release the energy from glucose and other food compounds › The calorie used on food labels is the kilocalorie (1,000 calories)

5.  Cells do not release all of the energy from glucose all at once, instead it gradually releases the energy in the first process glycolysis.  Glycolysis only releases a small amount of energy, if not most of the energy would be lost in the form of heat and light.  If O 2 is present glycolysis is followed by the Krebs Cycle, Electron Transport Chain(ETC).  If O 2 is not present glycolysis is followed by fermentation.

6.  Glycolysis, the Krebs cycle(citric acid cycle), and the electron transport chain make up a process called cellular respiration.  Cellular respiration is the process that releases energy by breaking down food molecules in the presence of oxygen

7. Equation for Cellular Respiration

8.  Cellular respiration requires a food molecule such as glucose and oxygen and gives off carbon, water, and energy.  There are 3 stages in cellular respiration › Each of the stages captures some of the chemical energy available in food molecules and uses it to produce ATP

9.  Glycolysis is the process in which one molecule of glucose is broken in half, producing two molecules of pyruvic acid, a 3 carbon compound.  ATP Production. › 2 molecules of ATP are needed to begin glycolysis. › When glycolysis is complete 4 ATP is produced. That is a net gain of 2 ATP.

10.  One of the reactions of glycolsis removes four high energy electrons and passes them to an electron carries called NAD+  Like NADP+ in photosynthesis, each NAD+ accepts a pair of high energy electrons. This molecule known as NADH hold the electrons until they can be transferred to other molecules.

11.  By doing this NAD+ helps pass energy from glucose to other pathways in the cell  Glycolysis yields a small amount of energy, however the process is so fast that the cells can produce thousands of ATP molecules in milliseconds  Another advantage is that glycolysis does not require oxygen. This means glycolysis can supply chemical energy to cells when oxygen is not available

12.  When a cell generates large amounts of ATP from glycolysis it runs into a problem.  All of the cells available NAD+ molecules are filled up with electrons.  Without NAD+ the cell cannot keep glycolysis going, and ATP production stops.

13.  When oxygen is not present glycolysis is followed by a different pathway. (anaerobic conditions)  Cells convert NADH into NAD+ by passing the electrons back to pyruvic acid.  The process of this pathway and glycolysis is called fermentation  Fermentation releases energy from food molecules in the absence of oxygen

14.  The two main types of fermentation are alcoholic fermentation and lactic acid fermentation.

16.  Alcoholic Fermentation causes bread to rise. The alcohol bakes out of the bread.

17.  Pyruvic Acid that accumulates is converted into lactic acid.  This process regenerated NAD+ so that glycolosis can continue.  Equation for lactic fermentation is… pyruvic acid + NADH  lactic acid+ NAD+

18.  Lactic acid is produced when your body can not supply enough oxygen to the tissues(muscles) to produce all of the ATP that is required.  Without oxygen ATP cannot be produced without oxygen.  The muscle cells then begin to produce ATP via lactic acid fermentation.  Build up of lactic acid is what causes muscles to burn after vigorous activity.

19.  If pathways require oxygen for cellular respiration they are said the be aerobic Example: Richard Simmons’ pathways require oxygen For cellular respiration.

20.  During the Krebs cycle or the citric acid cycle pyruvic acid is broken down into CO 2 in a series of energy extracting reactions.  It takes place in the mitochondrion.  The Krebs Cycle begins when pyruvic acid ( from glycolysis) enters the mitochondrion. › One carbon atom from pyruvic acid becomes part of a molecule of CO 2

21.  The other two atoms of carbon from pyruvic acid are joined to a compound called coenzyme A to form acetyl- CoA.  Acetyl-CoA then adds the two 2 carbon acetyl group to a 4 carbon molecule, producing a 6- carbon molecule called citric acid.  As the cycle continues. Citric acid is broken down inot a 4 carbon molecule, more CO 2 is released and electrons are transferred to energy carriers.

22.  For every turn of the cycle one ATP is produced. › 5 pairs of electrons are captured by 5 carrier molecules, 4 NADH, and 1 FADH 2.

24.  During the Krebs Cycle, pyruvic acid from glycolysis is used to make: › carbon dioxide › NADH › ATP › FADH 2

25. 1. CO 2 is released into the ATP 2. ATP produced is used for cellular activities. 3. NADH and FADH can be used to generate huge amounts of ATP. 2 turns of the Krebs cycle is needed for one molecule or C 6 H 12 O 6

26.  The Krebs Cycle spins around and around generation high energy electrons that are passed to NADH, and FADH 2  The electron transport train uses the high energy electrons from the Krebs Cycle to convert ADP into ATP

28.  High energy electrons from NADH and FADH 2 are passed into and along the electron transport chain.  In eukaryotes the electron transport chain is composed of a series of carrier proteins that is located in the inner membrane of the mitochondrion › In prokaryotes the same chain is in the cell membrane

29.  NADH and FADH 2 are passed along the ETC. › The ETC is composed of a series of carrier proteins that’s is located in the inner membrane of the mitochondrion. › High energy electrons are passed from one carrier protein to the next At the end of the ETC is an enzyme that combines electrons from the ETC w/ Hydrogen and oxygen to form H 2 O. › Everytime 2 high energy electrons transport down the ETC their energy is used to transport H+ across the membrane.

30.  During the ETC H+ ions build up in the inner-membrane space, making it positively charged. The other side from which those H+ ions have been taken is now negatively charged.  The inner membrane contains protein spheres called ATP synthases. › As the H+ ions escape through the channels into these proteins, the ATP synthase spin. › Eaxh time it rotates the enzyme grabs a low energy ADP and attaches a phosphate to make ATP. › On average each pair of high energy electron that moves down the ETC provides enough energy to convert 3 ADP into 3 ATP.

31.  High energy electrons are passed from one carrier protein to the next  At the end of the electron transport chain is an enzyme that combines electrons from the electron chain with hydrogen ions and oxygen to form water  Oxygen serves as the final electron acceptor of the electron transport chain

32.  The Krebs Cycle and the electron transport enabled the cell to produce 34 more ATP molecules per glucose molecule in addition to the 2 ATP molecules obtained from glycolysis › 18 times as much ATP can be generated from glucose in the presence of oxygen. › For 1 glucose molecule › 2 ATP from Glycolysis and 34 from the Krebs Cycle and ETC. › Total of 36 ATP.

33.  Photosynthesis is the opposite of cellular respiration  Photosynthesis deposits energy, cellular respiration withdraws energy Boraphyll allows this tree to take in light, go through photosynthesis and “deposit” energy.

34. Comparing Photosynthesisand Cellular Respiration PhotosynthesisCellular Respiration FunctionEnergy StorageEnergy Release LocationChloroplastsMitochondria ReactantsCO 2 and H 2 OC 6 H 12 O 6 and O 2 ProductsC 6 H 12 O 6 and O 2 CO 2,H 2 O and energy (36 ATP molecules) Equation6CO 2 + 6H 2 O + Energy  C 6 H 12 O 6 + 6O 2 C 6 H 12 O 6 + 6O 2  6CO 2 + 6 H 2 O + 36 or 38 ATP