Cellular Respiration Notes Biology - Ms. Spinale

Cellular Respiration Video Clip https://www.youtube.com/watch?v=4Eo7JtRA7lg

Cellular Respiration: Energy Transfer Photosynthesis: Light Energy → Chemical Energy Energy + 6CO2 + 6H2O → C6H12O6 + 6O2 Cellular Respiration: Chemical Energy → Usable Energy → Heat Energy C6H12O6 + 6O2 → 6CO2 + 6H2O + 38 ATPs

ATP - Adenosine Triphosphate How our cells get the energy the need to function. Energy carrier - stores/releases/converts to usable form for cells. Energy in bonds of phosphates.

ADP - Adenosine Diphosphate Last phosphate breaks free. Lots of energy is released and used in the cell to do work. To rebuild energy reserves, the body uses energy from food to put a “P” back onto ADP to reform ATP and the molecule is recycled.

ADP - Adenosine Diphosphate Cycle of bond-breaking and bond-making = storing and releasing. Breaking bonds takes energy. Making bonds releases energy.

Cellular Respiration Process by which enzymes convert energy stored in macromolecules (starch/glycogen) or small molecules (glucose) into a usable form of ATP. Potential energy in food molecules must be converted into a usable form.

Begins in the cytoplasm. Cellular Respiration Begins in the cytoplasm. Glycolysis = no O2 Continues in the mitochondria. Krebs cycle, electron transport system = both with O2

Cellular Respiration in 3 Stages: 1 - Glycolysis Sugar is broken down into 2 pyruvate molecules. Pyruvate - an organic molecule consisting of a 3-Carbon backbone. Glyco - sugar; lysis = split. 2 ATP of energy are made. 2 NADH are made and carried away.

Cellular Respiration in 3 Stages: 1 - Glycolysis NADH - a high energy molecule used by cells to generate ATP.

Cellular Respiration in 3 Stages: 1 - Glycolysis The Fate of Pyruvate Anaerobic respiration - without oxygen. Fermentation End of glycolysis - each glucose is broken down into two pyruvates. No oxygen for aerobic respiration - glycolysis continues.

Cellular Respiration in 3 Stages: 1 - Glycolysis Lactic Acid Fermentation During exercise, O2 is not supplied fast enough and pyruvic acid is converted to lactic acid. In muscles, lactic acid builds up and causes eventual fatigue.

Cellular Respiration in 3 Stages: 1 - Glycolysis Lactic Acid Fermentation After exercise, O2 is still needed to convert lactic acid back into pyruvic acid. Some organisms get energy from this process; we use lactic acid to make cheese, yogurt, and sour cream.

Cellular Respiration in 3 Stages: 1 - Glycolysis Alcoholic Fermentation Pyruvic acid is converted into ethyl alcohol and CO2. Used by yeasts to obtain energy (ATP) Humans use yeast to make bread and alcoholic beverages.

Fermentation Video Clip https://www.youtube.com/watch?v=hWKy8hpEjjc

Cellular Respiration in 3 Stages: 2 - Krebs Cycle Makes CO2 (carbon dioxide) 2 ATP of energy 10 NADH Aerobic respiration - requires oxygen Reactions release most of remaining energy in pyruvate

Cellular Respiration in 3 Stages: 2 - Krebs Cycle Enzymes convert pyruvate into a 2-C molecule by removing a molecule of CO2 - breathe out the waste.

Cellular Respiration in 3 Stages: 2 - Krebs Cycle Acetyl-CoA (from pyruvate) combines with a 4-C molecule. Forms a 6-C molecule (citric acid). Broken down to a 5-C molecule, then 4-C molecule. Releases CO2 at each step. 4-C molecule available to combine with new acetyl-CoA that enters cycle.

Krebs Cycle to Electron Transport System Energy from glucose has been converted to ATP molecules and NADH molecules. Energy stored in NADH is used to produce large amounts of ATP. 1 NADH = 3 ATP.

Cellular Respiration in 3 Stages: 1 - ETS Final step in aerobic respiration = transfer of electrons. H atoms (1e-, 1p+) carried by NADH are separated into electrons and protons (H+) Electrons join with oxygen and protons to form H2O. Flow of p+ (potential energy) makes ATP.

Cellular Respiration in 3 Stages: 1 - ETS End result = lots of ATP, H2O 34 ATP of energy are made from NADH in the inner membranes of mitochondria. Molecules of water are made.

Anaerobic Respiration Summary of Products Aerobic Respiration Anaerobic Respiration * Glycolysis * 2 pyruvate * 2 ATP * 2 NADH * Fermentation * Lactic acid / ethyl alcohol

Anaerobic Respiration Summary of Products Aerobic Respiration Anaerobic Respiration * Krebs Cycle * CO2 * 2 ATP * 10 NADH

Anaerobic Respiration Summary of Products Aerobic Respiration Anaerobic Respiration * Electron Transport System * 34 ATP * H2O

What controls how fast sugar is used in the body? Supply and Demand What controls how fast sugar is used in the body? High demand of energy needed: Sugar is rapidly absorbed from the blood into cells. The liver breaks down glycogen into sugar to restore the blood levels. Example: exercising

Low demand of energy needed: Supply and Demand Low demand of energy needed: Cells use excess sugar to make glycogen in the liver then convert to fat. Example: resting.

Energy Production - ATP: The Ultimate Source CO2 and H2O are by-products that we release as we exhale. ATP is the energetic push that starts reactions in the cell.

Energy Production - ATP: The Ultimate Source When the body needs more energy, mitochondria detect increased ADP levels, responding by increasing the rate of respiration. Presence or absence of oxygen in cells detects fate of pyruvate.

Energy Production - ATP: The Ultimate Source With oxygen: about 38 ATPs per molecule of sugar. Without oxygen: 2 ATPs are made with alcohol or lactic acid in muscles.