Respiration Flashcards
Describe the role of oxygen in aerobic cell respiration
oxygen is the final electron acceptor at the end of the electron transport chain.
Oxygen accepts protons/hydrogen ions and water is produced, 1/2O2 + 2 electrons + 2H+ –> 2H2O.
Oxygen helps to maintain the proton gradient across the inner mitochondrial membrane by removal of protons from the stroma.
Oxygen is highly electronegative
Oxygen prevents anerobic respiration and the production of lactic acid
Oxygen allows NAD, FAD to be regenerated
Explain the stages of aerobic respiration that occur in the mitochondria of eukaryotes
cellular respiration is the controlled released of energy from organic compounds to produce ATP, it involves the oxidation and reduction of electron carriers.
In link reaction, pyruvate is converted into acetyl coenzyme A, CO2 is released and NAD is reduced
In Kreb cycle, a 4C molecule oxaloacetate combines with acetyl CoA. Decarboxylation (6C to 5C and 5C to 4C) releases 2 CO2 molecules for each pyruvate. A total of 3 reduced NAD and 1 reduced FAD produced. ATP is also generated
The reduced molecules (FAD and NAD) are carried to the cristae.
There is then transfer of electrons between carriers in the electron transport chain in the membrane of the cristae, which is coupled to proton pumping
Protons accumulate in the intermembrane space and are diffused through ATP synthase. Chemiosmosis is known as the use of a proton gradient to generate ATP
oxygen is the final electron acceptor
Explain how chemical energy for use in the cell is generated by electron transport chain through chemiosmosis
Electron transport chain performs chemiosmosis and produces ATP, occurs in the mitochondrial inner membrane/cristae.
NAD and FAD carriers are reduced by gaining electrons. Reduced NAD produced in glycolysis, link reaction, Kreb cycle. These electron carriers deliver electrons to ETC.
Electrons release energy as they flow along the chain, from carrier to carrier
Electrons from ETC are accepted by oxygen, the final electron acceptor
proteins in the inner mitochondrial membrane act as proton pumps. Protons are pumped into intermembrane space, the proton concentration is higher in intermembrane space than matrix, creating a proton gradient.
ATP synthase is in inner mitochondrial membrane and energy is released as protons pass down the gradient through ATP synthase.
ATP synthase converts ADP into ATP.
Explain the processes involved in the Krebs cycle
Krebs cycle only occurs in aerobic conditions and in the matrix of the mitochondria.
Acetyl CoA from the link reaction releases an acetyl group. reduced NAD and CO2 are produced with each decarboxylation.
Acetyl group joined to oxaloacetate to form 6C molecule, citrate.
Decarboxylation changes citrate into 5C molecule. Decarboxylation changes 5C molecule into oxaloacetate and the cycle repeats
One molecule of ATP is made during this step. NADH, FADH2 and carbon dioxide are the end-products of Krebs cycle
Outline the process of glycolysis
Glycolysis occurs in the cytoplasm.
Hexose is phosphorylated by ATP into hexose diphosphate. Hexose diphosphtate is split into two triose phosphate by oxidation, removal of hydrogen.
Glycolysis has a net gain of 2 ATP (2 used and 4 produced), there is conversion of NAD to NADH. Pyruvate is the end-product of glycolysis
