MRs. Jackie 2.7 Cell respiration

Define cell respiration Is the controlled release of energy in the form of ATP from organic compounds in cells

State that in cell respiration glucose in the cytoplasm is broken down into pyruvate with a small yield of ATP Cell respiration can be divided in several stages First stage is glycolysis Glycolysis= breakdown of one molecule of glucose into two molecules of pyruvate with a small yield of ATP Takes places in the cytoplasm and does not require oxygen

Explain that in anaerobic respiration pyruvate is converted into lactate or ethanol and CO2 in the cytoplasm with no further yield of ATP If there is no oxygen present the cell will used ANAEROBIC respiration It will carry out glycolisys and used pyruvate to convert it into something else Yeast cells will convert pyruvate into ethanol Human cells will change pyruvate into lactate The body can only supply a limited amount of oxygen to the muscles Muscles can not produce energy at the rate required Production of lactic acid occurs and most time produced cramps

Explain that in aerobic respiration pyruvate is broken down into CO2 with a large yield of ATP IF oxygen is present, the pyruvate produced in the cytoplasm during glycolisis will move into the mitochondria Inside the mitochondria,pyruvate will be broken down to carbon dioxide and water. This process yield much more ATP than glycolysis.

Draw the structure of a mitochondrion as seen in electron micrographs Be sure to identify ATP synthetase Crista Inner membrane Matrix Circular DNA Inter membrane space Ribosome Outer membranes

Define oxidation and reduction Oxidation Involves loss of electrons from an element Frequently involve gaining oxygen or losing hydrogen Reduction Involves gain of electrons Frequently involves loss of oxygen and gaining hydrogen OIL RIG Oxidation is lossreduction is gain

Outline the process of glycolysis including phophorilation, lysis, oxidation and ATP formation Glycolysis Take place in the cytoplasm and produces 2 pyruvate molecules from every glucose One glucose molecule is converted into two 3 carbon molecule called pyruvate with a net gain of 2ATP + 2NADH +H To achieve this it is necessary to convert glucose into fructose 1,6 diphosphate whicg is then split (lysis) into two 3 carbon compound (pyruvate) Phosphorilation- is the process of making ATP in vivo

Explain aerobic respiration including oxidative decarboxilation of pyruvate, krebs cycle, NADH+H,the ETC and the role of Oxygen If oxygen is present puryvate is transported into the mitochondrial matrix and the reaction continues as (link reaction) Pyruvate + CoA + NAD  Acetyl CoA+ CO2 + NADH+H Link reaction- form the link between glycolysis and the Krebs cycle. This process is known as oxidative decarboxilation of pyruvate

Krebs cycle Occurs in the matrix of the mitochondria and produces CO2, NADH+H, FADH2 and ATP Oxaloacetate 1 x 4C Acetyl CoA CoA Citrate 1x6C CO2NAD NADH Ketoglutarate 5C ATP ADP +P 2NADH +2H +FADH2 2NAD + FAD CO2

Krebs Cycle Yield 2CO2 3 NADH+H 1 FADH2 1 ATP Remember the roles of NAD and FAD is to collect and remove H

Electron transport chain Last step of aerobic respiration The electron transport chain passes two hydrogen from NADH or FADH 2 from one electron carrier to the other Electron carriers are found in the inner membrane of the mitochondria Electron are passed by a series of redox reactions The final acceptor is oxygen The process produces 3 ATP for every 2 hydrogen from NADH +H and 2ATP for every hydrogen from FADH 2 See diagram given by the teacher

Explain oxidative phosphorilation in terms of chemiosmosis Occur in the inner membrane of the mitochondria As the electron passed down the electron transport chain, protons are being pumped across the membrane The resulting proton gradient drives the production of ATP by ATP syntethase THIS is the CHEMIOSMOTIC theory As the H ions go through the ATP syntethase molecule, the energy they possess will be used to drive ATP synthesis.

Explain the relation between the structure of the mitochondria and its functions Outer membrane- separates the mitochondria from the cytoplasm of the cell. Permeable to Hydrogen ions Intermembranal space- has a high concentration of H+ because of the electron transport chain. Its pH is lower Inner membrane- folded into cristae to provide space for the electron transport chain. Impermeable to H ions. Contain the ATP synthethase Matrix- contain enzymes for Kreb cycle to proceed

Acetyl CoA and its role in carbohydrate and fat metabolism Links Krebs cycle to glycolysis Also involved in the metabolism of fats Fats contain more energy than proteins and can be used in cell respiration The long chains of fatty acids are oxidized breaking sections of the molecules containing 2 C atoms These are change into Acetyl CoA and enter the Krebs Cycle