Cellular Metabolism ATP adenosine triphosphate ADP adenosine diphosphate

Cellular Metabolism

ATP: adenosine triphosphate ADP: adenosine diphosphate - product of ATP

• ADP + O + Energy = ATP Anabolism ATP = ADP + O + Energy Catabolism

• ATP is synthesized by adding a phosphate group (Pi), to ADP. Energy is required to form this high-energy bond. When ATP is used in a chemical reaction, the energy released and made available to cells to do work.

• ATP is a specific nucleotide. What makes ATP different from other nucleotides such as cytosine, thymine, guanine, and adenine, is that it is used widely as a carrier of chemical energy. ATP is adenine with three phosphate groups attached. The bond connecting the phosphate molecules to adenine are highly energetic bonds. • Locate this in your lab book.

• Two of the phosphate groups, which are easily broken down to release energy, are added in a covalent bond during processes such as respiration. ATP is used to drive active transport, and other chemical reactions such as photosynthesis, and cellular respiration.

• ATP is broken down by hydrolysis (reaction with water), which yields adenosine diphosphate (ADP), inorganic phosphorous, and energy.

ADP/ATP Cycle

Catabolic Processes • metabolic process that breaks down molecules into smaller units

Catabolic Processes • Glycolysis: the breakdown of glucose to pyruvic acid in the cytoplasm of the cell; it’s the oxidation of glucose. -anaerobic: does not require oxygen -this reaction provides: +2 ATP molecules +2 pyruvic acid molecules -not an efficient method

• This anaerobic process of glycolysis enables the cell to continue generating ATP when the mitochondrial activity alone cannot meet demand. • Not efficient because the mitochondria can produce 18 X more ATP per single glucose molecule. Lots of energy is still locked away inside the pyruvic acid molecules. The only way to get it is with the use of oxygen.

Glycolysis • http: //www. science. smith. edu/departments /Biology/Bio 231/glycolysis. html

Krebs Cycle • AKA: TCA Cycle, citric acid cycle • Occurs inside the mitochondria, removes hydrogen atoms from organic molecules and transfers them to coenzymes. • The electrons in these hydrogen atoms contain energy that can be used by the mitochondria to generate ATP.

• A complete revolution of the TCA cycle removes the two added carbon atoms, regenerating the four-carbon chain. The two removed carbon atoms generate two molecules of CO 2, a waste product. The hydrogen atoms are removed by coenzymes and delivered to the electron transport chain.

• Occurs in the mitochondria • Removes two carbon atoms due to coenzymes • Hydrogen atoms are delivered to the ETC to generate ATP

• The only immediate value of the TCA cycle is an immediate ATP molecule. The real value in this cycle is the fact they deliver H atoms to the ETC.

Electron Transport Chain Coenzymes in the mitochondria matrix deliver hydrogen atoms to the electron transport chain; the electrons are removed and passed from cytochrome to cytochrome, losing energy in a series of small steps. Most important mechanism for the generation of ATP (provides 95%)

• At the end of the ETS, an oxygen atom accepts the electrons, creating an oxygen ion (O 2 -). This ion is very active, and quickly combines with Hydrogen ions (H+) to form a water molecule. • Fore each glucose molecule broken down 32 molecules of ATP will be generated.