biology cell respiration - aerobic and anaerobic respiration

glycolysis, link reaction, oxidation

glycolysis

• the metabolic pathway that occurs in the cytoplasm of cells and converts glucose into pyruvate, does not require oxygen in the process

phosphorylation

attachment of a phosphate group to a molecule or anion

what is the role of phosphorylation in glycolysis?

makes the glucose unstable and more reactive, attaches two phosphate molecules on the glucose, converts 2 ATP into 2 ADP

lysis

breaks down the glucose into 2 three carbons and one phosphate

what is the role of oxidation in glycolysis?

a hydrogen is removed from each 3 carbon compound, and the hydrogens are added to NAD molecules to form reduced NAD/NADH

what is the role of reduction in glycolysis?

• is to convert NAD+ to NADH.

• NAD+ is reduced to NADH

• NADH can then be used in later stages of cellular respiration to generate ATP.

what occurs after the reduction of NAD+?

2 pyruvates are formed

how many products are produced at the end of glycolysis?

• 2 NADH

• 4 ATP molecules (net gain of 2 ATP molecules)

• 2 pyruvate

describe the process in glycolysis

• glucose is phosphorylated, 2 ATP becomes into 2 ADP, phosphate groups attach to the glucose molecule, this is the energy investment stage

• phosphorylated glucose goes through lysis and breaks down into a three carbon and phosphorus molecule

• redox reactions occur, 2 molecules of NADH are reduced, 2 molecules of NAD+ are oxidised, 2ADP becomes into 2 ATP

  • 2 3-carbon and phosphorus molecules create 4 ATP molecules

• 2 molecules of pyruvate are created at the end

link reaction

• the process that occurs in the mitochondrial matrix during cellular respiration and requires oxygen

what occurs in link reaction?

• pyruvate decarboxylation occurs, occurs in the mitochondria, 2 CO2 molecules are removed

• co-enzyme is added in this reaction

• NAD+ is oxidised to form NADH, 2 molecules of NADH are produced at the end

• pyruvate molecules produced in glycolysis are converted into acetyl-CoA

how many products are made in link reaction?

• 2 molecules of acetyl co-enzyme

• 2 molecules of NADH

kreb’s cycle

• acetyl CoA transfers its acetyl group to a 4-carbon compound (oxaloacetate) to make a 6-carbon compound (citrate)

• co-enzyme is released and it can return to the link reaction to form another molecule of acetyl CoA

• 2 reactions oxidative decarboxylation occur: removes 2 molecules of carbon dioxide and reducing NAD+ to NADH (changes 6-carbon into 4-carbon)

• one atp is generated through substrate-level phosphorylation

• FAD+ is reduced to FADH, FAD carries one more H+ than NAD when it is reduced

• reduced NAD and reduced FAD will deliver the required electrons and hydrogen to the electron transport chain