ATP and Cellular Respiration

A. Metabolism Metabolism is all of the chemical reactions in the body. These reactions are either: Synthesis – combining small molecules to make complex molecules These reactions require energy ex: photosynthesis.

2. Decomposition reactions – breaking down molecules into simpler forms. These reactions release energy. This energy can be used to make ATP ATP is a small, useable packet of energy.

ATP (ENERGY) Adenosine triphosphate Adenosine – a nitrogen-containing compound and a five carbon sugar. 3 phosphate chain (tri= 3) High energy bonds ATP --> ADP + P + Energy Drawing of ATP (N compound and sugar + 3 phosphate) When ATP is involved in a chemical rxn that breaks one of the phosphate bonds, potential energy is released

Draw on board

ATP and Cellular Work ATP is used to make cells perform 3 main types of work Chemical work: Ex - work of building large molecules Mechanical work: Ex - moving a muscle Transport work: Ex - pumping solutes across a membrane

Cellular Respiration Cellular Respiration is a decomposition reaction that provides the energy cells need to function. In this series of reactions, sugars, proteins, and lipids are broken down (decomposed) and energy is released. Q: Since CR is a decomp rxn, what do we know about it? Sugars, proteins, and lipids are in food! (show food in ATP cycle)

Mitochondria Mitochondria are the energy factories of the cells. Most of cellular respiration occurs in the mitochondria

Cellular Respiration Overview Cellular Respiration Overall Equation O2 + C6H12O6  CO2 + H2O + Energy Three Stages Glycolysis Krebs Cycle Electron Transport Chain The Main form of Energy produced = ATP Review Photosynthesis overall reaction Then compare it to cell respiration

Types of Cellular Respiration There are two types of cell respiration – aerobic and anaerobic. Aerobic respiration occurs in the presence of oxygen. 2. Anaerobic respiration occurs in the absence of oxygen. ** both start with glycolysis reaction Relate to aerobic/anaerobic exercise

Glucose and Glycogen Glucose is the form in which animals transport carbohydrates through the blood stream. Glycogen is the form in which it is stored in animals. Glycogen is stored in the liver and muscles. All blood flows through liver- if blood sugar levels go down, liver will convert and release the storage. Muscles need constant glucose supply (need a lot of energy)

Step 1: Glycolysis -Takes place in cytoplasm -Splitting of glucose (has 6 Carbons) to produce 2 pyruvic acid molecules (has 3 Carbons) Glucose (C6H12O6) -- 2 PGAL 2PGAL - 2 Pyruvic Acid ** requires 2 ATP to produce PGAL, but releases 4 ATP (net gain of 2ATP) Draw glucose carbons and PA carbons PGAL reference from photosynthesis Demonstrate net: take 2 steps back and 4 steps forward (“how many steps have I moved forward from original position?”)

- These are combined with a molecule called NAD+ to produce NADH Glycolysis also produces Hydrogen ions (H+) and electrons that can later be used to produce energy. - These are combined with a molecule called NAD+ to produce NADH *** NAD+ + H+ + 2e- --- NADH - NAD+ are required in order for glycolysis to occur Write equation and balance charges

What Carries the Electrons? NAD+ (nicotinadenine dinucleotide) acts as the electron carrier NAD+ is a coenzyme It changes to NADH when it picks up two electrons and one hydrogen ion Copyright Cmassengale

Repetition!!! After split, explain one side and then have students double the products

HW- Write out question and answer in complete sentences! What process happens first in cell respiration and where does this occur? What three things need to be input in order for glycolysis to happen? Where is the energy stored in ATP?

(One option after glycolysis) Anaerobic Pathway (One option after glycolysis)

Fermentation Breakdown of Pyruvic acid w/out the use of O2 (anaerobic respiration) -Produces no additional ATP, but does regenerate NAD+ for glycolysis. Types: 1. Alcohol Fermentation Pyruvic acid + NADH  Ethyl alcohol + CO2 + NAD+ *Yeast and bacterial cells used to produce alcohol in industry.

2. Lactic Acid fermentation Pyruvic acid + NADH  Lactic acid + CO2 + NAD+ Occurs in most animals, some plants and bacteria Causes burning sensation during strenuous exercise Animals can change lactic acid back to pyruvic acid when O2 is available. (requires Energy) Used to produce cheese and yogurts.

Anaerobic Respiration Review - No O2 used - Glycolysis and fermentation - Takes place in the cytoplasm - Net gain of 2 ATP ( 2 from glycolysis and 0 from fermentation) - recycles NAD+ during fermentation - 3.5 % energy efficiency (-Of possible energy available in glucose, this pathway harnesses 3.5% of it) Steps to Anaerobic Respiration: Glycolysis Fermentation (alcoholic or lactic acid)

(Other option after glycolysis) Aerobic Pathway (Other option after glycolysis)

The “Mighty” Mitochondria The mitochondria is the organelle where the final stages of cellular respiration occurs. Kreb’s Cycle Electron Transport Chain Cells that use a lot of energy have high numbers of mitochondria. Example: Muscle cells in the heart!!

Aerobic Respiration Breakdown of glucose requiring O2 -produces CO2, H2O, and ATP. Overall equation for Aerobic Respiration: C6H12O6 + O2- CO2 + H2O + *38 ATP * max ATP produced - 66 % efficiency

**Intermediate step after glycolysis: Pyruvic acid produced by glycolysis is transferred to the mitochondria. Reactions take place on the internal membrane folds (cristae) or in the space inside the mitochondria (matrix). STEPS TO AEROBIC RESP: Glycolysis **Intermediate step after glycolysis: 1. Pyruvic acid(3C)  Acetic Acid(2C) + CO2 (released) 2. Acetic Acid +Coenzyme A(CoA)Acetyl CoA ** 2 NAD+  2 NADH 32 carbons; if o2 is also available, what is the c and o given off as?

Stage 2: Krebs Cycle (Citric Acid Cycle) Acetyl CoA (2C) combines with Oxaloacetic Acid (4C) to produce Citric Acid (6C). Citric Acid goes thru a series of reactions and is converted back into Oxaloacetic Acid. (CO2 is given off) Another Acetyl CoA join the Oxaloacetic acid to start the cycle again. ** 2 turns of the cycle for each glucose (because glucose makes 2 pyruvic acids/ 2 acetyl CoA) DRAW CARBONS ON BOARD What is given off when CA is converted back into OAA? How many turns of the cycle for each glucose? (How many acetyl CoAs does 1 glucose make?)

Point out where carbon is taken out!

Net results for citric acid cycle For each Acetyl CoA For each glucose 2 CO2 3 NADH 1 ATP 1 FADH2 4 CO2 6 NADH 2 ATP 2 FADH2 x2

HW on handout Look at the overall equation for cell respiration. What would be the only reactant in anaerobic respiration? Explain. What is the point of fermentation? (think about what it recycles) Fill in the boxes on this flow chart with the following terms: Fermentation Glycolysis Krebs Cycle Reword Question 1: How does the cell decide which pathway to use? Or What determines if the cell uses aerobic or anaerobic respiration? (hint: what does anaerobic mean) Anaerobic Aerobic

Stage 3: Electron Transport Chain Occurs in the folds of the Inner Membrane of the Mitochondria (Cristae) Uses high energy electrons to generate energy for ATP Electron/ energy carrier molecules produced during Glycolysis and the Krebs Cycle enter the ETC NADH FADH2

NADH carries high energy electrons and Hydrogen ions to a series of transport proteins on the cristae of the mitochondria The electrons are passed from protein to protein radiating energy as they move. This energy is used to create a concentration gradient of H+ ions across the mitochondrial membrane.

Electron Transport Chain

Electron Transport Chain The electrons are passed down until they reach the final electron acceptor…..oxygen, which then couples with hydrogen to make water. O2 + 4 e- + 4 H+ -- 2 H2O So this step is aerobic (requires oxygen) H+ flows thru ATP Synthase making ATP.

ATP Synthase It is a protein structure in cell mitochondria that uses energy from H+ ions produced by the ETC to convert ADP into ATP. This can generate 34 ATP per 1 glucose

Electron Transport Chain Animation http://www.nclark.net/ElectronTransportChain.mp3 ETC song Electron Transport Chain Animation

Aerobic Respiration Review - in the mitochondria - completely metabolizes C6H12O6 to CO2 and H2O. - Produces up to 38 ATP/Glucose 2 ATP – glycolysis 2 ATP – Krebs Cycle ETC: 30 ATP – NADH ( 10 made x 3 ATP/NADH ) 4 ATP - FADH2 ( 2 made x 2 ATP/FADH2 )

Cellular Respiration Flowchart Glycolysis Anaerobic (no O2 present) Aerobic (O2 present) Krebs Cycle Fermentation Electron Transport Chain

HW Handout Fill in the blanks on the flow chart for cell respiration: Fill in the boxes with a reaction name and location On the side of each box, list the things that go into each reaction and what things come out Things to include in chart: # ATP produced at each stage Locations of NADH & FADH2 production/regeneration Locations CO2 is produced Location of Glucose, pyruvate, lactic acid, Acetyl CoA, Oxaloacetic acid, Citric Acid, Water

HW Remake the flow chart for aerobic and anaerobic respiration using rxn names For each process, indicate: # ATP produced If NADH or FADH2 is produced/ NAD+ is regenerated if CO2 is produced If any of these terms are associated with the process: Glucose, pyruvate, lactic acid, Acetyl CoA, Oxaloacetic acid, Citric Acid, Water