MRs. Jackie

2.7 Cell respiration

Define cell respirationIs 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 ATPCell respiration can be divided in several

stagesFirst stage is glycolysisGlycolysis= breakdown of one molecule of

glucose into two molecules of pyruvate with a small yield of ATPTakes 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 ATPIf there is no oxygen present the cell will

used ANAEROBIC respirationIt will carry out glycolisys and used pyruvate

to convert it into something elseYeast 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 ATPIF 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 micrographsBe sure to identify

ATP synthetaseCristaInner membraneMatrixCircular DNAInter membrane spaceRibosomeOuter membranes

Define oxidation and reductionOxidation

Involves loss of electrons from an elementFrequently involve gaining oxygen or losing

hydrogen Reduction

Involves gain of electronsFrequently involves loss of oxygen and

gaining hydrogen

OIL RIGOxidation is loss reduction is gain

Outline the process of glycolysis including phophorilation, lysis, oxidation and ATP formationGlycolysis

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+HLink reaction- form the link between

glycolysis and the Krebs cycle. This process is known as oxidative

decarboxilation of pyruvate

Krebs cycleOccurs in the matrix of the mitochondria

and produces CO2, NADH+H, FADH2 and ATP

Oxaloacetate1 x 4C

Acetyl CoACoA

Citrate1x6C

CO2 NAD

NADHKetoglutarate5C

ATPADP +P

2NADH +2H +FADH2

2NAD + FAD

CO2

Krebs CycleYield

2CO23 NADH+H1 FADH21 ATP

Remember the roles of NAD and FAD is to collect and remove H

Electron transport chainLast step of aerobic respirationThe electron transport chain passes two hydrogen

from NADH or FADH2 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 reactionsThe final acceptor is oxygenThe process produces 3 ATP for every 2 hydrogen

from NADH +H and 2ATP for every hydrogen from FADH2

See diagram given by the teacher

Explain oxidative phosphorilation in terms of chemiosmosis Occur in the inner membrane of the

mitochondriaAs 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 theoryAs 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 metabolismLinks Krebs cycle to glycolysisAlso involved in the metabolism of fatsFats contain more energy than proteins

and can be used in cell respirationThe 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