Biological Oxidation and Respiration Flashcards
Biological oxidation stages and aim
glycolysis
decarboxylation of pyruvate Krebs cycle
electron transport chain
aim is to generate Adenosine
triphosphate (ATP)
oxidation and reduction
oxidation is the loss of electrons
reduction is the gain of electrons
oxidoreductases
Enzymes involved in oxidation and reduction reactions
oxidases
dehydrogenases
oxygenases
hydroxylases
hydroperoxidases
reductases
oxidases
O2 as the H or e- acceptor
dehydrogenases
oxidise substrates by transferring one or more hydride ions
reductases
catalyses reduction
peroxidases
reduction of H peroxide and hydroperoxides
oxygenases
incorporate O2 into organic substrates
hydroxylases
add hydroxyl group to substrates
Large DNA viruses replicate + transcript
bigger genomes = encode their own replication and transcription factors
RNA viruses replicate + transcript
require RNA polymerase for transcription and these enzymes are not present in the host cell thus must be encoded by the virus
Retroviruses
RNA viruses which utilize RNA-dependent DNA polymerase to replicate the RNA genome through a DNA intermediate (reverse transcription)
Cellular respiration
form of biological oxidation which involves a series of redox reactions, the three stages of cellular respiration are glycolysis, Krebs cycle and oxidative phosphorylation (electron transport chain-ETC)
Glycolysis, Krebs cycle and ETC occurs in
cytosol of a cell
mitochondria matrix
mitochondria matrix
Glycolysis
anaerobic process
glucose is broken down to form pyruvate and minimal energy in the form of ATP is released.
2 ATP molecules used (stage 1 and 3)
produce 2ATP molecules (stages 7 and 10 each)
Energy is required in the form of ATP to split glucose intermediate (6 carbons) into
2 (3 carbon) intermediates. Thus the net gains of ATP from glycolysis are 2 ATP molecules. 2 pyruvate and NADH molecules also obtained from glycolysis.
NADH
energy carrying molecule which is used as a cofactor in the electron transport chain to yield more ATP
Decarboxylation of Pyruvate
Takes place between glycolysis and the Krebs cycle
pyruvate is decarboxylated coenzyme A is attached to it. The final product acetyl CoA is the molecule + enters the Krebs cycle
Krebs Cycle
2 molecules of pyruvate generated by glycolysis are transported into the matrix
of the mitochondria.
Energy within pyruvate in the form of acetyl CoA is used to make 2 ATP, 6 NADH and 2 FADH2 via the Krebs cycle.
Oxidative phosphorylation (ETC)
aerobic reaction
energy from 6 NADH and 2 FADH2 are converted into ATP with the help of 4 complexes.
NADH and FADH2 release
high energy electrons when they are transported.
Some of this energy is used to
pump hydrogen ions across the membrane which creates a chemiosmotic gradient.
ATP synthase is a channel protein that allows hydrogen ions to cross the membrane
and in the process it synthesises ATP and water. Without o2 this process cannot occur.
Total ATP molecules made from cellular respiration
30-32 from glycolysis to ETC
Metabolism
chemical reactions that place in a cell
3 aims of metabolism is to convert food/fuel to energy sources, utilize these energy sources to make macromolecules like proteins, nucleic acids and lastly the elimination of waste generated from these numerous reactions and processes
2 types of metabolic reactions
Anabolism and Catabolism
Catabolism
breaking down of molecules
Anabolism
synthesis of compounds and molecules
