Energy in Living Organisms How is energy created in the cells/body?

Metabolism all the chemical reactions that occur within a cell to keep it living. includes the building up and the breaking down of substances. a cell’s metabolism relies on chemical energy created by cellular respiration

Cellular Respiration a series of chemical reactions needed to break down carbohydrates and other molecules in order to release the energy they contain. when chemical bonds are broken energy is released. when bonds are broken the energy released and is temporarily stored in a compound called adenosine triphosphate (ATP).

Cellular Respiration ATP is the currency cells use for processes like muscle contraction, sending nerve impulses or pumping substances across the cell membrane. ATP is made up of 3 phosphate molecules. When one phosphate is removed, the energy is released and a new substance adenosine diphosphate (ADP) is made.

ATP  ADP + Phosphate + Energy

How is ATP made? Energy has to be converted to usable forms to have the desired effect.

How is ATP made? There are two types of cellular respiration. Aerobic Respiration Anaerobic Respiration

Aerobic Respiration Energy uses oxygen and produces large amounts of ATP. consists of two stages: A. Glycolysis happens in the cytoplasm converts glucose into a molecule called pyruvate makes only 2 ATP C6H12O6  2 C3H6O3 + 2 ATP (glucose) (pyruvate) Energy

Aerobic Respiration Lots of Energy B. Kreb’s Cycle (Oxidative respiration) if oxygen is available pyruvate is transported into the mitochondria converts pyruvate into water and carbon dioxide makes 34 ATP 2 C3H6O3  6CO2 + 6H2O + 34 ATP (pyruvate) Lots of Energy

Aerobic Respiration Summary C6H12O6 + O2  CO2 + H20 + 36 ATP Water Carbon Dioxoide Water Energy Sugar Oxygen

What now? Text page 72 #19-21 Write out a word equation or chemical equation showing aerobic cellular respiration? What are the 2 different stages of aerobic respiration? Where do they occur?

2. Anaerobic Respiration does not use oxygen and produces small amounts of ATP. this method is referred to as fermentation. there are two types: Alcoholic (Ethanol) Fermentation Lactic Acid Fermentation

Anaerobic Respiration 1. Alcoholic Fermentation Glycolysis breaks down glucose to produce pyruvate + 2 ATP Pyruvate is converted to ethanol and carbon dioxide *This process is only used by plants, some bacteria, yeast Uses? baking, alcoholic beverages

Alcoholic Fermentation

Anaerobic Respiration Lactic Acid Fermentation Glycolysis breaks down glucose to produce Pyruvate + 2 ATP Pyruvate breaks down to form lactic acid Advantages? While only producing small amounts of ATP the process is very fast! (Doesn’t last long though)

Cellular Respiraton Summary Glucose 2 ATP (through Glycolysis) 2 Pyruvate Oxygen No Oxygen Aerobic Respiration 34 more ATP! Fermentation (Anaerobic Respiration) Alcohol + CO2 (yeast, plants) Lactic acid (animals)

What now? Text page 77 #22-24 Page 77 Mini Activity 2-5 – Lactic Acid Friend or Foe Research online to find out how scientists used to explain muscle fatigue as a by-product of lactic acid fermentation. Describe your findings. What is the most current explanation for muscle fatigue?