Respiration

The Chemistry of Respiration energy and mitochondria clip

Adenosine triphosphate The energy released during respiration is not used directly by cells. Instead it is used to make a molecule called ATP which stores the energy until it is needed. ATP = Adenosine triphosphate

What does ATP do? ATP supplies energy for all the processes that need it. For example: movement chemical reactions growth. slow twitch/fast twitch investigation

Structure of ATP adenosine Pi

Formation of ATP ATP is made when another molecule called adenosine diphosphate (ADP) is bonded to a third inorganic phosphate (Pi) using the energy released from glucose.

adenosine + Pi adenosine Pi Enzymes Energy from respiration Energy Rich bond formed

Summarised as: ADP + Pi ATP The whole process is under the control of enzymes

The role of ATP ATP stores the energy in the third bond of the molecule The energy is released when that bond is broken to release the third inorganic phosphate (Pi) .

adenosine Pi ATP Enzymes Pi adenosine + ADP Energy released to do work

Summary ATP energy (out) cellular respiration cell activities ATP ADP + Pi energy (out) (in) cellular respiration cell activities The whole process is an enzyme controlled reaction.

Aerobic respiration = respiration with oxygen.

glucose + OXYGEN energy + carbon dioxide + water (to make ATP)

Mitochondria The matrix where 3-carbon pieces that came from carbohydrates are broken down to (CO2 and water) The cristae is where ATP is made

Cellular Respiration Is a series of reactions where fats, proteins, and carbohydrates, mostly glucose, are broken down to make CO2, water, and energy.

Cellular Respiration Cellular Respiration is a metabolic process like burning fuel Releases much of the energy in food to make ATP This ATP provides cells with the energy they need to carry out the activities of life. C6H12O6+O2 CO2 + H2O + ATP 1. g. Students know the role of the mitochondria in making stored chemical-bond energy available to cells by completing the breakdown of glucose to carbon dioxide. Mitochondria consist of a matrix where three-carbon fragments originating from carbohydrates are broken down (to CO2 and water) and of the cristae where ATP is produced. Cell respiration occurs in a series of reactions in which fats, proteins, and carbohydrates, mostly glucose, are broken down to produce carbon dioxide, water, and energy. Most of the energy from cell respiration is converted into ATP, a substance that powers most cell activities. 1. i.* Students know how chemiosmotic gradients in the mitochondria and chloroplast store energy for ATP production. Enzymes called ATP synthase, located within the thylakoid membranes in chloroplasts and cristae membranes in mitochondria, synthesize most ATP within cells. The thylakoid and cristae membranes are impermeable to protons except at pores that are coupled with the ATP synthase. The potential energy of the proton concentration gradient drives ATP synthesis as the protons move through the ATP synthase pores. The proton gradient is established by energy furnished by a flow of electrons passing through the electron transport system located within these membranes.

Vocabulary Cellular Respiration – the transfer of energy from an organic compound into ATP Fermentation – the breakdown of carbohydrates by enzymes, bacteria, yeasts, or mold in the absence of oxygen Pyruvate- an ion of a three-carbon organic acid called pyruvic acid.

Cellular Respiration Stage One: Breakdown of Glucose Glycolysis Glucose is broken down to pyruvate during glycolysis, making 2 ATP. 13

Aerobic respiration happens in 2 stages: Stage 1 – Glycolysis glyco lysis glucose splitting

Glycolysis

Cellular Respiration Stage Two: Production of ATP Krebs Cycle The Krebs cycle is a series of reactions that produce energy-storing molecules during aerobic respiration. 2 ATP are made. Electron Transport Chain During aerobic respiration, large amounts of ATP are made in an electron transport chain. Making about 34 ATP. 14

Kreb’s Cycle

Electon Transport Chain Uses FADH2 and NADH produced in kreb’s cycle to produce about 34 ATP.

Summary of ATP production Stage 1 and 2 release all the chemical energy in one molecule of glucose to make a total of 38 ATP molecules. 2 molecules ATP from glucose  pyruvic acid 36 molecules ATP from pyruvic acid  carbon- dioxide + water Total 38 molecules ATP

Cellular Respiration Fermentation in the Absence of Oxygen Fermentation When oxygen is not present, fermentation follows glycolysis, regenerating NAD+ needed for glycolysis to continue. Lactic Acid Fermentation In lactic acid fermentation, pyruvate is converted to lactate. 15

Anaerobic Respiration (in animals) anaerobic = in the absence of oxygen

In low oxygen conditions or during heavy exercise, when not enough oxygen can be supplied, muscle cells swap to anaerobic respiration

in absence of oxygen pyruvic acid is turned into lactic acid. glucose glycolysis still happens as it does not require oxygen 2 ADP + 2 Pi 2 ATP pyruvic acid in absence of oxygen pyruvic acid is turned into lactic acid. lactic acid

A build up of lactic acid produces muscle fatigue A build up of lactic acid produces muscle fatigue. Muscle fatigue makes muscles ache and contract less powerfully. A recovery period is needed. During this time more oxygen is taken in to convert the lactic acid back into pyruvic acid again. The volume of oxygen needed is called the oxygen debt.

Summary oxygen debt e.g. during hard exercise oxygen debt glucose pyruvic acid oxygen debt e.g. during hard exercise oxygen debt repaid during recovery time lactic acid

ethanol + carbon dioxide glucose pyruvic acid 2 ADP + 2 Pi 2 ATP glycolysis still happens, producing 2 ATP molecules This time in absence of oxygen, pyruvic acid is turned into carbon dioxide and ethanol This is irreversible ethanol + carbon dioxide

Comparison of aerobic and anaerobic respiration in animals in plants and yeast Oxygen required? yes no Glycolysis occurs ATP yield 38ATP 2ATP Glucose completely broke down? End products Carbon dioxide and water Lactic acid Ethanol and carbon dioxide