Cellular Respiration

Cellular Respiration and Breathing Aerobic process – requires oxygen. Cellular Respiration – exchange of oxygen and carbon dioxide between a cell and its environment Breathing – exchange of oxygen and carbon dioxide between your blood and the outside air.

Cellular Respiration Purpose: Generate ATP for cellular work 38 ATPs made per glucose molecule

Electron Transport Chain During Respiration glucose is broken down in several steps. Molecules (electron carriers) accept electrons from glucose and pass them to other carriers (electron transport chain). In each transfer the electrons release a little energy, which is trapped to make ATP.

Electron Transport Chain (cont’d) Oxygen is the final electron acceptor. It takes the electrons and joins them with hydrogen ions to form water.

Stage 3: Electron Transport Chain Cellular Respiration Stage 1: Glycolysis Stage 2: Kreb Cycle Stage 3: Electron Transport Chain

What type of process is glycolysis? A. aerobic B. anaerobic A by-product of cellular respiration is: A. Oxygen B. Carbon Dioxide C. Glucose

Structure of Mitochondria Double membrane envelope with space in between. Inner membrane is highly folded and encloses a fluid filled space called the Matrix. Complex folding allows for sites where reactions can occur to make ATP.

Mitochondria

Stage 1: Glycolysis Breaking down a glucose molecule Location: cytosol

Stage 1: Glycolysis Input: 2 ATP molecules, 1 Glucose, 2 NAD+ Output: 4 ATP molecules, 2 pyruvic acid molecules & 2 NADH molecules

When oxygen is not present Example: Sprinting Your lungs can’t supply oxygen fast enough to meet the need for ATP. Fermentation is used to make ATP.

Fermentation Regenerate NAD+ to keep glycolysis going. ATP made entirely from glycolysis.

Lactic Acid Fermentation In human muscle cells, making of cheese Pyruvic acid is converted into lactic acid. Lactic acid is converted back to pyruvic acid using oxygen.

Alcoholic Fermentation Yeast: Produces alcohol and carbon dioxide. Uses: alcohol, bread

What is the final net gain of ATP molecules in the first stage, glycolysis? Describe how glycolysis and Photosynthesis are dependent on one another.

Acetal CoA 2 Pyruvic Acids (from 1 glucose) converted into Acetal CoA – input for the Kreb Cycle 2 NADH’s produced as a result

Stage 2: The Krebs Cycle Finishes the breakdown of pyruvic acid to carbon dioxide, releasing more energy. Takes place in matrix of the mitochondria.

Stage 2: The Krebs Cycle Input: Acetyl CoA. Output: 2 ATP molecules, 4 carbon dioxide molecules, 6 NADH and 2 FADH2

Stage 3: Electron Transport Chain and ATP Synthase Action Occurs in the inner membrane of the mitochondria. 2 Part Process

Part 1 NADH transfers electrons from glucose to transports chain. Electrons move down the transport chain, releasing energy which is used to pump hydrogen atoms across the membrane from an area of low to high concentration.

Part 2 Hydrogen atoms flow back through ATP synthases (protein structures in mitochondria) to the outside of the mitochondria. ATP synthase uses the energy from the hydrogen flow to convert ADP to ATP. (34 ATPs/glucose molecule)

Electrons Flowing (e-) DO NOW: COPY THIS CHART!!!! From Kreb’s From Glycolysis From Acetyl Formation FADH2 NADH Electrons Flowing (e-) H2O (made) (2 electrons needed) O2 (consumed) H+ (pumped in) ATP (produced)

Notes For every 1 electron moving across a pump, one H+ ion is pumped in. For every NADH, 6 H+ ions are pumped into the mitochondria. For every FADH, 4 H+ ions are pumped in

Notes Total H+ = (# of electrons flowing) X (# of pumps) For every 2 H+ ions moving through ATP synthase, 1 ATP is formed.

COPY THIS SUMMARY For every 1 electron moving across a pump, one H+ ion is pumped in. Each NADH and FADH2 holds 2 electrons. Total H+ = (# of electrons flowing) X (# of pumps) For every 2 H+ ions moving through ATP synthase, 1 ATP is formed.

If 3 NADH’s flow across 3 pumps how many H+ ions enter the mitochondria? How many ATPs are formed?