7.2 Glycolysis- Splitting Glucose
What happens to the pyruvate that is produced in glycolysis in respect to aerobic respiration and fermentation?
Aerobic respiration oxidizes pyruvate to produce acetyl coenzyme A (acetyl-CoA) which is then further oxidized in the Krebs Cycle. Fermentation uses pyruvate to oxidize NADH back to NAD+
What is the first half of glycolysis called?
It consists of 5 steps called Priming Reactions and Cleavage.
What does it mean when it is said that glycolysis is believed to have evolved backwards?
The ATP-yielding breakdown of glycolysis, the final step, is said to have been the original step in ancient times.
what are the priming reactions of glycolysis?
it is the first three steps. Glycolysis begins with the addition of energy. Two high energy phosphates from two molecules of ATP are added to the 6-carbon glucose. This results in a 6-carbon molecule with two phosphates.
Why must NADH be recycled back into NAD+?
the cell does not have many NAD+ molecules for glycolysis to continue.
Why does glycolysis still take place in organisms if the energy yield, two ATP molecules, is not a whole lot?
1. It is energetically efficient. it's a lot better than having no ATP. 2. It's an improvement on past successes. Only organisms that could do glycolysis were the ones that survived.
What is cleavage in glycolysis?
Cleavage is the part where the 6-carbon molecule with the two phosphates split into two 3-carbon sugar phosphates ALSO called gyceraldehyde 3-phosphate (G3P)
What happens in Oxidation and ATP formation in glycolysis?
Each G3P (3-carbon sugar phosphate) is oxidized and it transfer two electrons (+ 1 proton) to NAD+, which turns into NADH. Then, a molecule of Pi is added to each G3P which produces 2, 3-bisphosphoglycerate (BPG). Another 4 reactions convert the BPG into pyruvate. Meanwhile, the phosphates (the phosphate from the beginning and the Pi) are sent to ADP to yield two ATP per G3P. Overall, it produces 4 ATP molecules, 2 NADH molecules, and two pyruvate but since 2 ATP molecules were used in the beginning, the net yield for ATP is only 2 molecules.
Briefly describe glycolysis
Glycolysis is a glucose-catabolizing process that releases enough free energy to drive ATP synthesis. It converts glucose into two 3-carbon molecules of pyruvate and for each molecule that passes, two ATP molecules are made.
The second half of glycolysis is called?
Oxidation and ATP formation
How is NADH recycled back?
Through aerobic respiration and fermentation. The NADH is oxidized back to NAD+ by reducing another molecule.
In Aerobic respiration and fermentation, NADH is recycled back how?
aerobic respiration has the precense of oxygen and oxygen has a high affinity of electrons. The elctrons are transferred through a series of membrane carriers, which ultimately reduces oxygen and form water. In fermentation, an organic molecule can still accept electrons.
