Chapter 12: Energy And Respiration (Glycosis – Kreb’s cycle)
Introduction to glycolysis
Glycolysis is the first stage of aerobic respiration. It occurs in the cytoplasm of cells.
It breaks glucose, a six-carbon molecule, into two three-carbon pyruvate molecules.
Glycolysis does not require oxygen so it is an anaerobic process.
Reactants and products of glycolysis
The reactants required for glycolysis are:
One glucose molecule
Two ATP molecules
The products of glycolysis are:
Four ATP molecules
Two reduced NAD molecules
Two pyruvate molecules
The net energy gain from glycolysis is 2 ATP molecules and 2 reduced NAD molecules
per glucose molecule processed.
The products of glycolysis, namely pyruvate and reduced NAD, have roles in the
following stages of cellular respiration that generate a larger yield of energy.
, The process of glycolysis is divided into four distinct stages:
1. Phosphorylation - Two ATP molecules donate phosphate groups to glucose,
forming fructose 1,6 bisphosphate.
2. Lysis - The fructose 1,6 bisphosphate molecule is split into two molecules of
triose phosphate (TP).
3. Dehydrogenation - A hydrogen is removed from each TP molecule (they are
oxidised) and used to form two molecules of reduced NAD.
4. Production of ATP - The TP molecules are converted into two pyruvate
molecules, also producing four ATP molecules through substrate-linked
phosphorylation.
After glycolysis, if oxygen is available, pyruvate moves through mitochondrial
membranes by active transport.
Introduction to glycolysis
Glycolysis is the first stage of aerobic respiration. It occurs in the cytoplasm of cells.
It breaks glucose, a six-carbon molecule, into two three-carbon pyruvate molecules.
Glycolysis does not require oxygen so it is an anaerobic process.
Reactants and products of glycolysis
The reactants required for glycolysis are:
One glucose molecule
Two ATP molecules
The products of glycolysis are:
Four ATP molecules
Two reduced NAD molecules
Two pyruvate molecules
The net energy gain from glycolysis is 2 ATP molecules and 2 reduced NAD molecules
per glucose molecule processed.
The products of glycolysis, namely pyruvate and reduced NAD, have roles in the
following stages of cellular respiration that generate a larger yield of energy.
, The process of glycolysis is divided into four distinct stages:
1. Phosphorylation - Two ATP molecules donate phosphate groups to glucose,
forming fructose 1,6 bisphosphate.
2. Lysis - The fructose 1,6 bisphosphate molecule is split into two molecules of
triose phosphate (TP).
3. Dehydrogenation - A hydrogen is removed from each TP molecule (they are
oxidised) and used to form two molecules of reduced NAD.
4. Production of ATP - The TP molecules are converted into two pyruvate
molecules, also producing four ATP molecules through substrate-linked
phosphorylation.
After glycolysis, if oxygen is available, pyruvate moves through mitochondrial
membranes by active transport.
