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Glycolysis the first set up reactions in cellular respiration it involves many chemical steps to transform glucose the end result is two molecules of a three carbon molecule called Puruvic acid.

During glycolsis one molecule of glucose a six carbon compound is transformed into two molecules of pyruvic acid a three carbon compound.

ATP production glycolysis is an energy releasing process the cell needs to put in energy to get things going. Two ATP molecules are used up.
*Compared to withdraw from savings account. The two ATP molecules use at the onset of glycolysis is like an investment that pays back interest. In order to earn interest from a bank you have to put money into the account. Although the cell puts two ATP molecules into the account to get glycolysis going it produces for ATP molecules giving it again of two ATP molecules.

NADH production one of the reactions of glycolysis removes for electrons now in a high-energy state and passes them to electron carrier called NAD+ molecule accepts a pair of high-energy electrons in the molecule is now known as NADH.

The advantages of glycolysis 1. Speed 2. Does not require oxygen

  1. Speed : In the process of glycolysis for ATP are synthesized from for ADP molecules this is a net gain of just two ATP molecules because two are used to start the process. The energy is small the process is fast and can produce thousands of ATP molecules in a few milliseconds.
  2. Does not require oxygen: this means that glycolysis can quickly supplied chemical energy to cells when oxygen is not available.

The Krebs Cycle in the presence of oxygen pyruvic acid produced in the glycolysis passes the second stage of cellular respiration called the Krebs cycle.

During the cycle pyruvic acid is broken down into carbon dioxide and a series of energy extracting reactions. It is also known as the citric acid cycle


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Citric Acid Productionpyruvic acid passes through two membranes of the mitochondrion into the matrix. The matrix is the innermost compartment of the mitochondrion and the site of the Krebs cycle reactions.

Energy Extraction as a cycle continues citric acid is broken down into a for carbon molecule more carbon dioxide is released and electrons are transferred to energy carriers.

Krebs cycle products carbon dioxide ATP and electron carriers; carbon dioxide is not useful to the cell and is expelled every time you exhale. The ATP are very useful and become immediately available to power cellular activities and the carrier molecules like NADH in the presence of oxygen the electrons a hold are used to generate huge amounts of ATP.

Electron Transport and ATP Synthesis the electron transport chain uses the high-energy electrons from glycolysis and the Krebs cycle to convert ADP into ATP

Electron transport NADH and FADH2 pass their high-energy electrons to the electron transport chain. High-energy electrons from NADH and at a DH to our past from carrier to carrier down the electron transport chain. Water is formed when oxygen accepts the electrons in combination with hydrogen ions. Energy generated by the electron transport chain is used to move H+ ions across the inner mitochondrial membrane and into the inter membranes space.

ATP production H+ ions pass back across the mitochondrial membrane through ATP synthase causing the base of the synthase molecule to rotate. With each rotation driven by the movement of on H+ ion ATP synthase generate ATP from ADP

The totals how much ATP does cellular respiration generate? glycolysis and the Krebs cycle and the electron transport chain release about 36 molecules of ATP per molecule of glucose. Our diets contain more than glucose it is broken down into molecules that enter the Krebs cycle at one of several places.

The 36 ATP molecules generated represent 36% of the total energy of glucose. It is very efficient. The remaining 64% is released as heat. Which is the reason your body feels warmer after exercise.