Respiration

The oxidation of glucose into carbon dioxide and water with release of energy

Glucose + oxygen -> carbon dioxide + water (+energy)

It is released or transferred, not produced

Enzyme controlled steps - this means the release of energy is controlled

Adenosine Triphosphate

3 phosphate groups combined with adenine and pentose sugar, ribose

The immediate, but short term energy store of cells

ADP (adenosine diphosphate) and inorganic phosphate (Pi) during phosphorylation

ATP has a high free energy of hydrolysis meaning when it is hydrolysed a relatively large amount of energy is released

Conversion yields energy. Conversions carried out my enzyme ATPases

• hydrolysis of ATP molecules releases a small amount of energy so energy can be released in small manageable steps • ATP hydrolysis is a single reaction releasing immediate energy and providing cell with control over energy • ATP is small and soluble so can be transported around cell easily. Enables it to be transported from mitochondria to any part of cell

• energy for metabolic processes including synthesis of larger molecules • movement • active transport • activates molecules via phosphorylation

• surrounded by a double membrane separated by intermembrane space • outer membrane is permeable to most small molecules involved in cellular respiration • inner membrane is highly folded forming cristae inc SA enabling more ATP to be produced. • matrix contains many chemical compounds and some respiration reactions occur here

• substrate Level phosphorylation: direct transfer of a phosphorylated substance to ADP • Oxidative phosphorylation: ATP is produced from ADP and Pi as electrons are transferred along a series of carriers

1 glycolysis 2 pyruvate oxidation (link reaction) 3 Krebs cycle 4 electron transport chain

The splitting of the hexose sugar (glucose) into two 3-carbon pyruvate molecules

Glycolysis

In fluid part of cytoplasm

1) activation of glucose by phosphorylating it. Makes glucose more reactive and uses up ATP as 2 phosphates come from hydrolysis of 2 atp molecules. Resulting molecule is fructose 1,6 bisphosphate 2) that then splits into two 3 carbon molecules of trios-phosphate, which is then oxidised through loss of hydrogen to form pyruvate with the production of 2 ATP molecules. The hydrogen atoms are collected by NAD which is reduced to form NADH. 3) overall the process from glucose to 2x pyruvate molecules results in the formation of 4 ATP and 2 NADH + H+, but the 2 ATP are used up in the process of glucose activation, so the net gain of ATP is only 2

Dehydrogenase enzymes in a process called dehydrogenation

Form a molecule called acetyl coenzyme A (acetyl CoA). This is necessary to allow the entry of a 2 carbon molecule into mitochondrial matrix

Removal of a carbonyl group

The removal of hydrogen atoms

1) pyruvate is decarboxylated with the removal of one CO2 2) dehydrogenations occur with the removal of hydrogen leading to formation of NADH 3) The resulting 2 carbon (acetyl) group then combines with coenzyme A forming acetyl CoA