Do now – make sure the following terms are in your glossary Turgid Flaccid Facilitated diffusion Vesicle Endocytosis Exocytosis

Cellular Respiration

Introduction to Respiration SLOs Describe the key component/ terminology used in respiration what each molecule does ATP – energy carrier (analogy with money) NADH – carries hydrogen atoms Glucose Acetyl CoA Pyruvate Krebs Cycle Electron transport system Give the overall word and chemical equation for the respiration reaction State the reactants and products in respiration

Respiration Respiration = conversion of chemical energy in organic compounds into energy that can be used by the cell. Large food molecules are broken down to release energy. I.e. Glucose is broken down via a series of enzyme reactions. ATP (Adenosine triphosphate) is the end- product of cellular respiration

Respiration Equation Glucose + oxygenenergy + carbon dioxide + water C 6 H 12 O 6 + O 2 CO 2 + H 2 O + energy

ATP (Adenosine triphosphate) ATP is the energy carrier in cells. It diffuses through cells and is used for all energy- consuming processes in the cell ATP exists in three forms, you only need to know two of these forms: - ATP = high energy form, energy carrier - ADP (adenosine diphosphate) = the “empty” energy carrier Role-playing demo

ATP (continued) ATP ↔ ADP + Phosphate + energy OR Adenosine-P-P-P  Adenosine-P-P + energy + P

ATP (continued) ATP loses a phosphate when it gives up its energy, and becomes ADP ADP has to return to the cytoplasm and the mitochondria to be recharged with energy by the process of respiration The conversion of ATP to ADP + P i and the reverse reaction is called the ATP/ADP cycle. The ATP/ADP cycle provides cells with energy for cellular activity.

The ATP/ADP cycle

Overall equation for Respiration 6O 2 + C 6 H 12 O ADP + 38 P  enzymes 6CO 2 + 6H 2 O + 38 ATP

ATP song (to the tune of the Beatles "Yesterday") ATP, active transport needs you, can't you see? Sodium pumps require energy to go against the gradient. Cilia and flagella depend on you, not to mention pinocytosis to internalize small molecules. Sometimes when water needs to be pumped out of a cell, That's when contractile vacuoles make it seem more iso-to-o-o-nic. ATP, the triphosphate of adenosine; ribose has five carbons in between. Three phosphates and an adenosine. Glucose finds its way through the carrier molecules; Those are proteins which are embedded in the cell membrane. Suddenly, turgor pressure builds up in a leaf When water rushes into the hypertonic plant cells Without the help of ATP.

Types of Respiration Aerobic respiration: respiration occur in presence of oxygen Anaerobic respiration: respiration occur in absence of oxygen (anaerobic = “without air”) Burning paper demo

NAD – the hydrogen carrier Hydrogen contains most of the energy that charges up ADP to ATP. The hydrogen comes from the breakdown of glucose during respiration. The hydrogen is carried around by the carrier nicotinamide adenine dinucleotide (NAD) When it is ‘full’ it is NADH 2

Do Now – try to do this without looking at your notes! 1. Give the word and symbol equations for cellular respiration Glucose + oxygen  energy + carbon dioxide + water C 6 H 12 O 6 + O 2  CO 2 + H 2 O + energy 2. Name the two forms of ATP – which is the high energy form? ATP – adenosine triphosphate (high energy form) ADP – adenosine diphosphate (energy carrier)

3 Stages of respiration 1. Glycolysis 2. The Krebs cycle (citric acid cycle) 3. The respiratory chain (electron transport system) [Sometimes the formation of acetyl coenzyme A is included a separate step – see p68]

1. Glycolysis Glycolysis = “glucose-splitting” Both aerobic and anaerobic respiration begin with glycolysis Takes place in the cytoplasm Glucose (6C) is broken down into pyruvate (3C) molecules and 2ATP (net gain) 2 NADH 2 carry hydrogen to the electron transport chain

The Krebs cycle Can only occur in the presence of O 2 (aerobic only) The pyruvate produced from glycolysis diffuses into the matrix of the mitochondria [matrix = space enclosed by the inner mem.], where they enter the Krebs cycle. Pyruvate reacts with a molecule called coenzyme A, and forms acetyl coenzyme A Pyruvate  acetyl coenzyme A (acetyl coA) + CO 2

The Krebs Cycle (continued) Acetyl group in acetyl coA is broken down to CO 2, H atoms, and ATP in the Krebs cycle. Coenzyme A is not broken down and return to pick up another acetyl group i.e. Pyruvate  Acetyl CoA  Acetyl group  ATP + CO 2 (waste) + H +

The Krebs cycle (continued)

The Respiratory Chain Most of the ATP is made in this step Takes place on the inner membrane of the mitochondrion (cristae) Also aerobic (needed to oxidise hydrogen to water) Uses the hydrogen produced in the Krebs cycle. A chain of reaction results in the release of ATP. High energy electrons are produced by the hydrogen (from Krebs cycle)

The Respiratory Chain (continued) – Advance The electrons are passed along the respiratory chain, losing their energy to H+ pumps across the cristae (folding of the inner mito. mem.) The H + ions move back across the cristae after the electron has passed along the respiratory chain, providing energy for ATP production. Oxygen is used to oxidise hydrogen to water

Yield of energy: Glycolysis = 2 ATP Krebs Cycle = 2ATP Electron transport = 34 ATP Total = 34 ATP

Summary

Brainpop Cellular respiration genetics/cellularrespiration/ 321 REQ

Anaerobic respiration If oxygen is absent, pyruvate remain in the cytoplasm and is broken down into:  Lactic acid + energy in animals  Ethyl alcohol + carbon dioxide + energy in plants (fermentation) Lactic acid = poison (but can be take away when oxygen is available) Fermentation: only 2 ATP is produced (vs. 38 ATP in aerobic respiration)

Factors Affecting the rate of respiration Rate of respiration = how rapidly glucose is broken down to produce energy Rate of respiration depends on: 1. The amount of oxygen present in cells 2. The amount of glucose or fat present in the cell 3. The cell or body’s demand for energy 4. Temperature – higher the temp., the greater the rate of respiration