- Information
- AI Chat
Respiration - Term 1 Human Body Notes
Term 1 Human Body Notes
Module
The Human Body (PY4010)
171 Documents
Students shared 171 documents in this course
University
Kingston University
Academic year: 2021/2022
Uploaded by:
Anonymous Student
This document has been uploaded by a student, just like you, who decided to remain anonymous.
Kingston UniversityRecommended for you
Preview text
Aerobic Respiration and the Mitochondrion
Metabolism is the set of life-sustaining chemical transformations within the cells of
organisms.
Three main purposes of metabolism:
• Catabolic for the conversion of fuel to energy
• Anabolic for the conversion of fuel to building blocks
• The elimination of nitrogenous wastes
ATP is a combination of adenine, ribose sugar and three phosphates.
ATP + H 2 O = ADP + Pi
The phosphorylation potential (delta G) is –30 kJ/mol
The phosphorylation potential (amount of energy released) is high because hydrolysis
releases a lot of free enthalpy.
Stages of catabolism:
• Bigger molecules broken down into smaller parts
• Small molecules converted into simple units that have a central role in
metabolism
• Production of ATP
The first 2 stages are anaerobic.
Glycolysis
First stage:
Glucose into fructose 1,6-bisphosphate, which can be kept easily in the cell. Consumes 2
molecules of ATP and is irreversible.
• Glucose to glucose 6-phosphate using hexokinase
• Glucose 6-phosphate to fructose 6-phosphate using phosphoglucose isomerase
• Fructose 6-phosphate to fructose 1,6-biphosphate using phosphofructokinase
2 nd Stage:
Splitting of 6 carbon molecules into two 3 carbon molecules. These are not identical, so
we isomerise the dihydroxyacetone phosphate into glyceraldehyde 3-phosphate using
triose phosphate isomerase. From this point onwards every reaction happens TWICE as
there are 2 copies of each molecule.
3 rd Stage:
• Glyceraldehyde 3-phosphate undergoes oxidation and phosphorylation to 1,3-
biphosphoglycerate using the addition of an inorganic phosphate and a co-factor.
This uses the enzyme glyceraldehyde phosphate dehydrogenase
• Substrate level phosphorylation of 1,3-biphosphoglycerate to 3-phospho-
glycerate using phosphoglycerate kinase and a phosphate is donated to form 1
molecule of ATP from ADP
• Intramolecular transfer of 3-phosphoglycerate to 2-phosphoglycerate using
phosphoglyceromutase
• Dehydration of 2-phosphoglycerate to phosphoenolpyruvate
• Substrate level phosphorylation of phosphoenolpyruvate to pyruvate, where 1
ATP is produced
So, in stage 3, 2 x 2 ATP are produced by substrate level phosphorylation. So, 4 ATP
produced but 2 used up.
Uses of pyruvate:
Middle and left involve anaerobic oxidation of NADH.
The Cori Cycle shows what happens under anaerobic conditions.
Glycolysis takes place in the cytoplasm; the second step takes place in the mitochondrion. This is
known as pyruvate oxidation, or the link reaction.
• Pyruvate enters the mitochondria via transport protein, and we lose Carbon dioxide,
which we breath out.
• NAD+ goes to NADH.
• Coenzyme A is used to produce Acetyl CoA
Stage 3 is known as the Krebs Cycle or Tricarboxylic acid cycle (TCA)
Overall, we produce 2 x 3 NADH, 2 x 1 FADH 2 and 2 x 1 GTP
Both NADH/FADH 2 and NAD/FAD are redox electron carriers, so they are easily reduced and
easily oxidised.
The final stage is oxidative phosphorylation.
Electrons of NADH/FADH 2 are used to slowly oxidise oxygen to water. The energy released is
used to pump H+ across the inner membrane, and this H+ gradient is used to form ATP.
2 ATP produced (per glucose).
Mitochondria has a bilayer.
• Electrons from NADH go into complex 1, which pumps 4 H+ across into intermembrane
space
• Electrons from FADH 2 go into complex 2, and associates with enzyme Q
• Electrons then transferred onto complex 3, and a further 4 H+ get pumped into the
intermembrane space. This lowers the pH of the intermembrane space.
• Electrons move from complex 3 and attach to cytochrome c, which then transfer the
Was this document helpful?
Respiration - Term 1 Human Body Notes
Module: The Human Body (PY4010)
171 Documents
Students shared 171 documents in this course
University: Kingston University
Was this document helpful?
Aerobic Respiration and the Mitochondrion
Metabolism is the set of life-sustaining chemical transformations within the cells of
organisms.
Three main purposes of metabolism:
•Catabolic for the conversion of fuel to energy
•Anabolic for the conversion of fuel to building blocks
•The elimination of nitrogenous wastes
ATP is a combination of adenine, ribose sugar and three phosphates.
ATP + H2O = ADP + Pi
The phosphorylation potential (delta G) is –30.5 kJ/mol
The phosphorylation potential (amount of energy released) is high because hydrolysis
releases a lot of free enthalpy.
Stages of catabolism:
•Bigger molecules broken down into smaller parts
•Small molecules converted into simple units that have a central role in
metabolism
•Production of ATP
The first 2 stages are anaerobic.
Glycolysis
First stage:
Glucose into fructose 1,6-bisphosphate, which can be kept easily in the cell. Consumes 2
molecules of ATP and is irreversible.
•Glucose to glucose 6-phosphate using hexokinase
•Glucose 6-phosphate to fructose 6-phosphate using phosphoglucose isomerase
•Fructose 6-phosphate to fructose 1,6-biphosphate using phosphofructokinase
2nd Stage:
Splitting of 6 carbon molecules into two 3 carbon molecules. These are not identical, so
we isomerise the dihydroxyacetone phosphate into glyceraldehyde 3-phosphate using
triose phosphate isomerase. From this point onwards every reaction happens TWICE as
there are 2 copies of each molecule.
3rd Stage:
•Glyceraldehyde 3-phosphate undergoes oxidation and phosphorylation to 1,3-
biphosphoglycerate using the addition of an inorganic phosphate and a co-factor.
This uses the enzyme glyceraldehyde phosphate dehydrogenase
