Chapter 9 - Cellular Respiration

What is the relationship between Photosynthesis and Cellular Respiration? Role of the Sun? * atoms get rearranged during these processes Provide energy (sun light) which plants use to create glucose from water and CO2 Role of Glucose? Broken down by cells to create (ATP)

Cellular Respiration Overview C6H12O6 + 6O2  6CO2 + 6H2O + 38 ATP Cellular Respiration (process in which living things convert the chemical potential energy stored in glucose and other food into chemical potential energy in the form of ATP). This occurs in the presence of oxygen (aerobic process)

How do organisms harvest the energy stored in foods? Cellular Respiration: chemical process that uses oxygen to convert the chemical energy stored in organic molecules into another form of chemical energy (ATP) ATP (adenosine triphosphate) is a usable form of chemical energy Energy is stored in the bonds. http://www.nutridesk.com.au/simple-sugars.phtml

Stored Chemical Energy in food Energy in food can be measured in calories or Calories calorie: amount of energy needed to raise 1g of H20 by 1°C A Calorie is what they use on food labels and is actually a kilocalorie (1000 calories) Chemical energy from food is converted into ATP Labels on food packages are listed as calories but are actually kilocalories. So a 230 calorie snack has 230,000 calories. That’s enough energy to raise 1000 g of water by 230 degrees Celsius.

Exercise – Expended Energy Bicycling (Slowly) – 170 cal per hour Bicycling (Racing) – 514 Dancing (Slow) – 202 Dancing (Fast) – 599 Running – 865 Swimming – 535 Basal Metabolic Rate – 1,300 to 1,500 kcals per day. That is if you sedentary all day long and didn't’t even read. (Oh yes, reading does consume calories.) For Mr. LaBar – 5’10” 180 lbs – Sitting and reading a book or newspaper = 24 cal per hour.

ATP provides energy for cellular work. Phosphates are slightly negatively charged. They don’t like be near each other. When the bonds are broken they release energy. ATP Packs Potential Energy!!!! When a phosphate group is pulled away…energy is released. This Energy is used for Cellular Work

Varying energy in the bonds between phosphates

Mitochondria Outer Membrane Inner Membrane Space Matrix

There are 3 Stages of Cellular Respiration 1. Glycolysis 2. Krebs Cycle 3. Electron Transport Chain Location in Cell Cytoplasm Mitochondria What is Produced 2 Pyruvic Acid 4 ATP 4 CO2 2 ATP H2O 34 ATP

Equation for Cellular Respiration In cellular respiration, the atoms in glucose and oxygen are rearranged, forming carbon dioxide and water. The cell uses the energy released to produce ATP.

Cellular Respiration converts energy in food to energy in ATP Stages Include… Glycolysis The Krebs Cycle ETC What is produced?

Glycolysis (aka “splitting of sugar”) Occurs in the cytoplasm Glucose (6C) is broken down into 2 Pyruvic Acid (3C molecules) 2 ATP molecules used, 4 ATP molecules produced Net Gain of 2 ATP

Krebs (Citric Acid) Cycle Occurs in the mitochondrial matrix Pyruvic acid from glycolysis is used to produce NADH, ATP, and FADH2 The NADH and FADH2 feed into the last step of cellular respiration (the electron transport chain) During Krebs cycle 2 ATP produced and carbon dioxide produced

Electron Transport Chain Occurs in the mitochondrial inner membrane Uses the high energy electrons from glycolysis and the Krebs cycle to convert ADP into ATP High energy electrons are passed from one carrier to the next Oxygen serves as the final electron acceptor of the electron transport chain (this is why oxygen is a requirement of cellular respiration)

Oxygen and the Electron Transport Chain As electrons move down each step in the chain, a small amount of energy is released The energy is used to generate ATP molecules

The totals Cellular respiration (glycolysis, the Krebs cycle, and electron transport chain) release about 36 molecules of ATP per molecule of glucose. Q: How efficient is cellular respiration? A: converts about 36 percent of the total energy in glucose into ATP This is very efficient when compared to many human inventions. For example the gasoline engine in a car is only about 25% efficient.

Other food? The diets of humans (and many other organisms) that utilize cellular respiration contain more than just glucose. The cell can generate chemical energy in the form of ATP from just about any source To simplify things we focus on how it generates ATP from glucose