Cellular Respiration Is a series of reactions where fats, proteins, and carbohydrates, mostly glucose, are broken down to make CO 2, water, and energy. Occurs in the mitochondria

Cellular Respiration: (2 kinds—Aerobic and Anaerobic) The energy produced is released in the cell to be used for life processes (movement, breathing, blood circulation, etc…)

Cells require a constant source of energy for life processes but keep only a small amount of ATP on hand. Cells can regenerate ATP as needed by using the energy stored in foods like glucose. The energy stored in glucose by photosynthesis is released by cellular respiration and repackaged into the energy of ATP.

Respiration occurs in ALL cells and can take place either with or without oxygen present.

Aerobic Respiration: requires oxygen Occurs in the mitochondria of the cell Total of 36 ATP molecules produced General formula for aerobic respiration: C 6 H 12 O 6 + 6O 2 6 CO 2 + 6H 2 O + 36 ATP glucose + oxygen carbon dioxide + water + energy Human cells contain a specialized structure – the mitochondrion – that generates energy.

Cellular Respiration Stage One: Breakdown of Glucose Glycolysis Glucose is broken down to pyruvate (3 carbon molecule) during glycolysis, making some ATP. NADH-carriers for energy and electrons during glycolysis Produces 2 ATP

Cellular Respiration Stage Two (2 steps): Production of ATP Krebs Cycle The Krebs cycle is a series of reactions that produce energy-storing molecules during aerobic respiration. Electron Transport Chain During aerobic respiration, large amounts of ATP are made in an electron transport chain.

Preparation for the Citric Acid Cycle The pyruvate loses a carbon leaving the 2 carbon molecule Acetyl CoA CC CO 2 products: CO 2, Acetyl CoA and NADH

The Krebs Cycle (Citric Acid ) Occurs in the matrix of the mitochondrion Aerobic phase (requires oxygen) 2-carbon acetyl CoA (formed from pyruvate) joins with a 4-carbon compound to form a 6- carbon compound called Citric acid

The Citric Acid Cycle Products: CO 2 ATP, NADH, FADH

Electron Transport Chain The mitochondria has two membranes--the outer one and the inner membrane which is convoluted. The H+ which are brought to mitochondria accumulate between these two membranes.

The electrons are passed back and forth across the membrane where their energy is gradually decreased and used to transport H + through the membrane. Oxygen is the final electron acceptor and it joins with the H + to produce H 2 O. If there is no oxygen, the electron chain cannot continue. because there is no way to release electrons. electrons

Diagram Glucose Glycolysis Electron Transport Chain 2 Krebs Cycle Mitochondria In Cytoplasm 232 Electrons carried in NADH Electrons carried in NADH and FADH 2

Anaerobic Respiration: occurs when no oxygen is available to the cell (2 kinds: Alcoholic and Lactic Acid) Also called fermentation-the breakdown of carbohydrates by enzymes, bacteria, yeasts, or mold in the absence of oxygen Fermentation regenerates the NAD+ needed for glycolysis to continue Much less ATP produced than in aerobic respiration

Alcoholic fermentation—occurs in bacteria and yeast Process used in the baking and brewing industry—yeast produces CO 2 gas during fermentation to make dough rise and give bread its holes glucose ethyl alcohol + carbon dioxide + 2 ATP

Lactic acid fermentation—occurs in muscle cells Lactic acid is produced in the muscles during rapid exercise when the body cannot supply enough oxygen to the tissues—causes burning sensation in muscles glucose lactic acid + carbon dioxide + 2 ATP

glycolysis Anaerobic Respiration Alcoholic fermentation Bacteria, Yeast 2 ATP Lactic acid fermentation Muscle cells 2 ATP Aerobic Respiration 36 ATP ETC Mitochondria Krebs Cycle Cytoplasm First step in anaerobic respiration is also glycolysis Diagram C 6 H 12 O 6 glucose