Cellular Respiration Flashcards
What is cellular respiration
A series of metabolic pathways which release energy from food and generate ATP
What is ATP composed of
One adenosine and three inorganic phosphate (Pi) groups
When is energy released from ATP
When the bond attached to the terminal phosphate is broken by enzyme action
What happens when ATP is broken down
It becomes ADP + Pi
What is phosphorylation
An enzyme controlled process by which a phosphate group is added to a molecule
e.g. ADP + Pi —> ATP
Why do humans not need a vast store of ATP
Because ATP is continuously being made at the same rate as it is being used up
What is glycolysis
The first stage in cellular respiration and occurs in the cytoplasm of a cell
What are the 2 phases of glycolysis
Energy investment phase (2 ATP are required for phosphorylation) & energy payoff phase (4 ATP are produced)
What do dehydrogenase enzymes do
Carry hydrogen ions and electrons from intermediates to NAD, forming NADH
What are hydrogen ions and electrons passed to
The coenzyme NAD, forming NADH
What is the citric acid cycle
The second stage of cellular respiration and occurs in the matrix of the mitochondria
Pyruvate is broken down to
Acetyl group that combines with CoA to form Acetyl CoA
Acetyl CoA is added to oxaloacetate to produce
Citrate
The citric acid cycle results in enzymes causing release of
CO2, generation of ATP, removal of H+ ions & electrons to regenerate oxaloacetate
What does the electron transport chain consist of
A series of carrier proteins attached to the inner membrane of the mitochondria
NADH from glycolysis and the citric acid cycle
Pass their H+ ions and electrons to the electron transport chain
What does the electrons from NADH provide the electron transport chain with
Energy to pump H+ ions across the membrane
The high concentration of H+ ions
Flow back through a membrane protein called ATP synthase, which rotates, providing energy to make ATP
What is the final electron acceptor
Oxygen
What does oxygen combine with
Hydrogen ions and electrons to form water H2O
