Respiration What do you remember? Definition ...... occurs in ... 2 types ...... Equation? Equation? Reactants  Products Reactants  Products Extra Bonus Marks – Interestingly ..... What do you remember?

Learning Outcomes Define cellular respiration Identify the energy source in cells and within a molecule of ATP Understand the link of ATP between catabolic and anabolic reactions Explain the process of phosphrylation Potential for LO3

Cellular Respiration Definition – Biochemical process by which energy-rich substrate molecules (foodstuff) are progressively broken down in enzymatic pathways to form adenosine triphosphate (ATP, high energy compound) Foodstuff is usually glucose. Glucose is broken down in a series of enzyme controlled steps. Hydrogen and high energy electrons are removed by dehydrogenase enzymes and used to yield ATP.

What is ATP? Adenosine Triphosphate is a molecule composed of: 1 x Adenosine (adenosine) 3 x inorganic phosphate (Pi) Guess what it would be called with only 2 phosphates? 1 phosphate? Pi Pi Pi Adenosine 3 Inorganic Phosphate Groups Bonds contain energy How could it release energy?

Energy Release & ADP A Adenosine Triphosphate Adenosine Diphosphate When the terminal bond is broken energy is released. 1 Free Inorganic Phosphate Molecule Adenosine Triphosphate Adenosine Diphosphate A Pi Pi Pi 2 (di-) Inorganic Phosphate molecules Adenosine Molecule Energy released when bond breaks Inorganic Phosphate molecules 1 phosphate – adenosine monophosphate

Adenosine triphosphate (ATP) Main energy carrier molecule in the body (and all living things). ATP is used to transfer (links) the energy released (catabolic) from cellular respiration to synthetic pathways (anabolic) and other cellular processes where energy is required Which cells/processes need energy? Carbon dioxide and water ATP Amino acids energy energy CELLULAR RESPIRATION ENERGY TRANSFER SYNTHETIC PATHWAY energy energy Protein Glucose and oxygen ADP +Pi

Uses of ATP in cells are: Muscle cell Image source: http://www.agen.ufl.edu Image source: http://www.sccollege.edu Liver cell Muscle contraction Driving chemical reactions Active transport Synthesis of e.g. protein Transmission of nerve impulses Image source: http://www.dkimages.com Sperm cell Nerve cell Image source: http://www.dkimages.com

Bioluminescence Demonstration - Luminescence is emission of light by a substance not resulting from heat; it is thus a form of cold body radiation

ADD ATP

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ATP 2 million molecules of ATP per second is needed to satisfy energy requirements for an active cell (such as liver/muscle etc)! How and where is it stored?

Phosphorylation at step 3 catalysed by Not stored! Rapid turnover of ATP molecules occurs continuously in a cell. Remains quite constant as the same amount is made that is used up (~50g) Cell conserves resources by only producing ATP when needed – it is another example of feedback inhibition . ATP and citric acid inhibit phosphofructikinase ATP Glucose (6C) ATP Phosphorylation at step 1 ADP+ Pi ATP & citric acid inhibit phosphofructikinase! So go back to intermediate 2 Other metabolic pathways (eg. stored as glycogen) Intermediate 1 Intermediate 2 ATP Phosphorylation at step 3 catalysed by phosphofructokinase Irreversible step ADP+ Pi Intermediate 3 Citric Acid Cycle & Electron Transport Chain

Phosphorylation Phosphorylation is process which is enzyme controlled where a phosphate group (Pi) is added to a molecule. ATP ADP +Pi Build-up energy required Breakdown energy released

Phosphorylation Not only making ATP is called phophorylation (remember post translational modifiction of proteins), also when Pi from ATP given to another molecule in a metabolic pathway it makes them more reactive. For example glucose in glycolysis ...... The phosphorylation of molecules to alter their reactivity. ATP ADP +Pi Glucose Glucose-6-phosphate (high energy)

Advantages of ATP Instant source of energy in the cell Releases energy in small amounts as needed It is mobile and transports chemical energy to where it is needed IN the cell Universal energy carrier and can be used in many different chemical reactions

Complete your exit slip before you go ATP Exit cards Draw/label ATP Complete the following equation: ATP  _____ + ________ + _______ The process name of adding a phosphate? What happens to the molecules then? Name 3 process that need ATP;