CELLULAR RESPIRATION Living things get the ENERGY they need from the breakdown of glucose (sugar)

It all happens in what organelle? ______________ ____

summary All our cells need energy ATP is the energy that the cells use for all life processes. The cell makes ATP by breaking down a sugar called glucose. Glucose is the energy of the body. ATP is the energy of the cell

How does glucose get into the body? Through the foods you eat. You eat a piece of bread which is made of large carbohydrate molecules. Your body breaks the large carbs into tiny sugars during digestion. It starts with the saliva in the mouth, then in the stomach and finally the food passes through intestines.

When the carbs reach the large intestines, they are broken down so small that they get absorbed in the blood. The small sugars are monosaccharides Glucose is one of these monosaccharides. The red blood cells then carry the small sugars to the cells that need them.

When the sugars reach the cells, they cant pass through the cell membrane because of the lipid bilayer. However, a protein channel recognizes then and lets them in.

The small 6-carbon sugar is now in the cell Its brought to the mitochondria to be further broken down into ATP CO2 is one waste product of these process. AS you exhale now, you are releasing CO2 into the classroom from your mitochondria by the process of cellular respiration. You need food, oxygen and water for this process. All of your trillions of cells are doing this Each cell can have hundreds of mitochondria, all making ATP.

Lets review this process a little better. Cellular respiration

Key ideas behind cellular respiration Organic sugar (glucose) is converted to inorganic gas Carbon dioxide. ATP or cell energy is made in the process Cell respiration occurs in the mitochondria of all cells. It occurs 24/7. The diagram at the bottom shows a six carbon glucose being broken down into six molecules of CO2 in a series of steps

What is a calorie? Calorie: amount of energy needed to raise the temperature of one gram on water by one degree Celsius. It is how we measure the energy levels; One gram of glucose releases 3811 calories of energy. cellular respiration: process of breaking down food for energy.

From food to ATP (energy)

Steps in cellular respiration Step one is always Glycolysis: Step two: depends on whether oxygen is present or not.

if oxygen is not present, the pyruvic acid either enters fermentation. In this process, alcohol or an acid is a waste product as small amounts of ATP are made from the sugar. If oxygen is present, step two is the Krebs cycle. This is true for human muscle cells. This will be explained better later.

Step One: Glycolysis Step 1 in cellular respiration is always glycolysis. Glyco means sugar; glucose Lysis means to split. Glycolysis mean to split glucose. Glucose is a sugar made of six carbons.

glycolysis Glycolysis is the process in which one molecule of glucose (6 Carbons) is broken “in half”, producing two molecules of pyruvic acid, a 3- carbon compound. Occurs in CYTOPLASM of cell.

Glycolysis Summary (step one) 2 ATP needed to begin glycolysis. 4 ATP produced when its done. NET gain 2 ATP. (4 – 2 = 2) NADH is an electron carrier. Glycolysis starts w/ ONE GLUCOSE Ends with TWO PYRUVIC ACID

Glycolysis and cellular respiration

What next? The next step after glycolysis depends on whether oxygen is present or not. If oxygen is not present (anaerobic) Step two is Fermentation Anaerobic means without oxygen. Fermentation is a type of anaerobic respiration. If Oxygen is PRESENT (aerobic) step two is the Krebs Cycle & Electron Transport Chain Aerobic means with oxygen as in aerobic respiration

Glucose Glycolysis Krebs cycle Electron transport Fermentation (without oxygen) Alcohol or lactic acid Chemical Pathways Go to Section:

Fermentation: occurs only when oxygen is not present. Two types of fermentation 1. Alcoholic Fermentation – Used by Yeast and a few other microorganisms. – Produces alcohol and carbon dioxide from the three carbon pyruvic acid. 2. Lactic Acid Fermentation – Used by Bacteria and human muscle cells. – Produces lactic acid from the three carbon pyruvic acid..

Glucose Pyruvic acid Lactic acid Lactic Acid Fermentation Go to Section: In your own words, explain this diagram:______________________________ ______________________________________________________________

Step 2: Krebs Cycle (oxygen) When oxygen is present such as in muscles, step two in cellular respiration is the Krebs Cycle Occurs in mitochondria (matrix). Pyruvic acid is changed (modified) in a series of reactions. these reactions produce high-energy electron carriers to be used in the electron transport chainelectron transport chain NAD + and FAD + are the high energy electron carriers H + is the electron that needs to be carried. They turn into NADH and FADH 2 when carrying electrons and provide the energy to drive the Electron Transport Chain. 2 molecules of ATP is generated per glucose. CO 2 is produced and released.

Step 3:Electron Transport Chain (oxygen) Takes place in mitochondria (inner membrane). Series of proteins accept high energy electron pairs from NADH and FADH 2. – NADH and FADH 2 (Energy taxi dropping off energy) – Oxygen bonds with 2 hydrogens (final electron acceptor) to form H molecules of ATP are produced per glucose molecule.

Summary Step one is always glycolysis. Step two depends on whether or not oxygen is present If it is not, then step two is fermentation, (anaerobic respiration) If it is, then step two is the Krebs Cycle and step 3 is the electron transport chain. In the process, organic glucose is converted to inorganic CO 2

If oxygen is present, its called Aerobic respiration, and 36 ATP are created. During anaerobic respiration or fermentation, 2 ATP are created. ATP is the universal energy molecule, meaning that all living organism use it as an energy source. Notice that much more ATP is made when oxygen is present.

Flowchart Section 9-2 Carbon Dioxide (CO2) + Water (H2O) Glucose (C 6 H ) + Oxygen (0 2 ) Glycolysis Krebs Cycle Electron Transport Chain Go to Section: Aerobic Respiration

Summary of photosynthesis Solar energy is converted to chemical energy. Solar energy is converted to chemical energy. The chemical energy is stored in the form of glucose (sugar). The chemical energy is stored in the form of glucose (sugar). Carbon dioxide, water, and sunlight are used to produce glucose, oxygen, and water. Carbon dioxide, water, and sunlight are used to produce glucose, oxygen, and water. Chemical equation for this process is: 6CO 2 + 6H 2 O + light → C 6 H 12 O 6 + 6O 2 + 6H 2 O Chemical equation for this process is: 6CO 2 + 6H 2 O + light → C 6 H 12 O 6 + 6O 2 + 6H 2 O 6 molecules of carbon dioxide (6CO2) and 6 molecules of carbon dioxide (6CO2) and 6 molecules of water (6H2O) are consumed in the process, 6 molecules of water (6H2O) are consumed in the process, 1 molecule of glucose (C6H12O6) 1 molecule of glucose (C6H12O6) six molecules of oxygen (6O2) six molecules of oxygen (6O2) and six molecules of water (6H2O) are produced. and six molecules of water (6H2O) are produced.

Summary of cellular respiration Organic sugar (glucose) is converted to inorganic gas Carbon dioxide. Organic sugar (glucose) is converted to inorganic gas Carbon dioxide. Chemical equation for cellular respiration that occurs in the mitochondria Chemical equation for cellular respiration that occurs in the mitochondria 1)C 6 H 12 O 6 + 6O 2  6CO 2 + 6H 2 O + 38ATP

Looking at the equation, why are cellular respiration and photosynthesis sometimes considered to be opposites? Looking at the equation, why are cellular respiration and photosynthesis sometimes considered to be opposites? 1)C 6 H 12 O 6 + 6O 2  6CO H 2 O ~ 38 ATP 2)6CO H 2 O + light → C 6 H 12 O 6 + 6O 2 + 6H 2 O ________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

Cellular Respiration Summary