In the cytoplasm, one glucose is phosphorylated
into glucose diphosphate using 2 ATP
The glucose diphosphate splits into
two molecules of triose phosphate
The two triose phosphate molecules are dehydrogenated by
dehydrogenase, oxidising them into two pyruvate
Also, two NAD+ are reduced into NADH and four
ATP are formed by substrate-level phosphorylation
The two pyruvate accept the hydrogen from the
NADH, converting it into NAD+, this froms two lactate
Plants and Fungi
In the cytoplasm, one glucose is phosphorylated
into glucose diphosphate using 2 ATP
The glucose diphosphate splits into
two molecules of triose phosphate
The two triose phosphate molecules are dehydrogenated
by dehydrogenase, oxidising them into two pyruvate
Also, two NAD+ are reduced into NADH and four
ATP are formed by substrate-level phosphorylation
The two pyruvate is decarboxylated, releasing
carbon dioxide, forming two ethanal
The two ethanal accept the hydrogen from the NADH,
converting it into NAD+, this froms two ethanol
Aerobic Respiration
Glycolysis
In the cytoplasm, one glucose is phosphorylated
into glucose diphosphate using 2 ATP
The glucose diphosphate splits into
two molecules of triose phosphate
The two triose phosphate molecules are dehydrogenated
by dehydrogenase, oxidising them into two pyruvate
Also, two NAD+ are reduced into NADH and four
ATP are formed by substrate-level phosphorylation
Link Reaction
Pyruvate diffuses from the cytoplasm
into the mitochondrial matrix
The pyruvate is dehydrogenated with dehydrogenase
and the hydrogen is accepted by NAD+ to from NADH
The pyruvate is decarboxylated at the same
time by decarboxylase to form carbon dioxide
When the pyruvate is dehydrogenated
and decarboxylated it forms acetate
The acetate combine with coenzyme
A to form acetyl coenzyme A
Kreb's Cycle
Acetyl coenzyme A enter the Kreb's cycle by combing with a 4-carbon
acid, forming a 6-carbon acid and the coenzyme A is regenerated
The 6-carbon acid is dehydrogenated, making NADH and is
decarboxylated to make carbon dioxide, forming a 5-carbon acid
The 5-carbon acid is dehydrogenated, making NADH and FADH and is
decarboxylated to make carbon dioxide and to regenerate the 4-carbon acid
The 4-carbon acid can combine with more acetyl coenzyme A and repeat the cycle
Each cycle of the Kreb's cycle produces one ATP by substrate-level phosphorylation,
three molecules of NADH, one molecule of FADH and two molecules of carbon dioxide
Adenosine Triphosphate
What is ATP
ATP is the universal energy currency, meaning
it is used in all cells to drive their reactions
ATP is made up of three phosphate molecules, one
adenine molecule and one ribose molecule
ATP is inert, can pass out of mitochondria into the cytoplasm, releases energy efficiently, releases
energy in useable quantities, is easily hydrolysed and is readily reformed by phosphorylation
Proton Gradients
Photosynthesis
Electrons are excited by energy from light, these electrons
move through a series of carriers in the thylakoid membranes
Their energy pumps protons from the stroma into
the spaces between the thylakoid membranes
The energy is released in chemiosmosis, in which protons flow back down
an electrochemical gradient into the stroma, through ATP synthetase
The energy is incorporated into ATP, this ATP drives the light-dependent reactions of
photosynthesis and energy is incorporated into the macromolecules made by the cell
Respiration
Electrons are excited by energy derived from food molecules, their energy is made
available as they move through a series of carriers on the inner mitochondrial membrane
The energy pumps protons across the membrane, from the
matrix into the inter-membrane space, setting up a proton gadient
Energy is released in chemiosmosis, as the protons flow back into
the matrix through ATP synthetase, and is incorporated into ATP
The Electron Transport Chain
Respiration
Hydrogen atoms derived from the respiratory breakdown of glucose are transferred by dehydrogenase
enzymes to coenzymes NAD and FAD and carried to the inner membrane of the mitochondrian
The electrons and protons of the hydrogen atoms have different pathways
but because they both move through the electron transport chain.
For every two protons delivered by NADH, enough
energy is released to synthesise three molecules of ATP
When FADH delivers two protons, enough
energy is released for only two molecules of ATP
Photosynthesis
Groups of pigments and proteins, called photosystems, transfer excited electrons to electron
acceptors and, from there, to a series of proton carriers, all on the thylakoid membranes
Protons from the water and the electrons are transferred to the coenzymes NADP and
subsequently, to glycerate phosphate, in the pathway that synthesises carbohydrates
The energy that powers the proton pump and electron transport chain in the
chloroplast comes from light, so chloroplasts synthesise ATP by photophosphorylation