Respiration Flashcards
(7 cards)
Glycolysis
-First, glucose enters the cell’s cytoplasm. Upon entry, an enzyme adds two phosphate groups to glucose in a process known as phosphorylation. These phosphate groups are available due to the breakdown of
2 ATP molecules. As a result, this produces a new molecule called glucose phosphate.
-Second, glucose phosphate breaks down into two molecules of triose phosphate.
-Third, triose phosphate is converted into pyruvate. In this step, 2 molecules of NADH and 4molecules of ATP are formed.
-The overall yield of ATP within glycolysis is 2 ATP.
Glycolysis
Glucose enters cell cytoplasm, upon entry 2 phosphate molecules bind to it, which are available from the hydrolysis of 2 ATP molecules. This is called glucose phosphate. Next this is converted into 2 triose phosphate molecules. these are then converted into 2 Pyruvate molecules, and in this step 4 ATP molecules are formed, and NAD is reduced to NADH. Overall yield of 2 ATP molecules in glycolysis.
Link reaction
Occurs in the matrix of mitochondria. Pyruvate converted to acetate. In this step, a CO2 molecule is formed and a NADH. Next, coenzymeA binds to acetate to form AcetylCoA. No ATP produced.
Krebs cycle
Acetyl CoA produced in the link reaction enters the Krebs cycle, where it reacts with a molecule containing 4 carbons to produce a new molecule containing 6 carbons. CoenzymeA is removed in this reaction. Then, in a series of oxidation and reduction reactions, the 6-carbon molecule is converted back into the 4-carbon molecule. Carbon dioxide is produced as two carbon atoms are lost. In addition, for every acetylCoA molecule that enters the Krebs cycle, one ATP molecule is produced as an ADP molecule reacts with a phosphate group. Also, intermediate molecules in the Krebs cycle lose hydrogen atoms, which reduces NAD and FAD to produce NADH and FADH2 respectively.
Oxidative phosphorylation
In oxidative phosphorylation, electrons supplied by reduced NAD and reduced FAD are transferred through the electron transfer chain via a series of oxidation-reduction reactions.
Next, these oxidation-reduction reactions provide energy to the electron transfer chain. As a result, protons move from the matrix to the intermembrane space via active transport. This ensures that a proton gradient is maintained across the inner membrane.
Additionally, the electrons in the final inner membrane protein react with oxygen and protons to form water. Through this reaction, oxygen is also known as the final electron acceptor.
Finally, chemiosmosis through ATP synthase results in the production of ATP.
Uses of triglycerides in respiration
Broken down into glycerol and 3 fatty acids. Glycerol can be used to make triose phosphate, which enters glycolysis. Each fatty acid can form acetyl-coA, which enters the Krebs cycle
Amino acids
Amino group first removed. Amino acids with 3 carbons form Pyruvate and enter the link reaction, while amino acids with 4 or 5 carbons act as intermediate molecules in Krebs cycle.
