CHAPTER 7 Cellular Respiration

7.1 SUNLIGHT POWERS LIFE AUTOTROPHS Makes its own food Also called PRODUCERS - produce organic molecules to serve as food for their ecosystem Ex: plants/algae transform sun’s energy to sugar – PHOTOSYNTHESIS

can’t make their own food HETEROTROPHS can’t make their own food Also called CONSUMERS- consumes other organisms, depend on producers for food

Many organisms harvest energy stored in foods through. . . CELLULAR RESPIRATION – chemical process uses O2 to convert energy in food into ATP ATP-main energy supply for plants and animals

7.2 FOOD STORES CHEMICAL ENERGY ENERGY- ability to perform work 3 types of energy: KINETIC- energy of motion Ex: climbing up stairs

2. POTENTIAL-energy that is stored due to objects position/arrangement Ex: the motion of climbing stairs is kinetic energy-once you reach the top of a slide the energy becomes potential- when you slide down a slide, the energy becomes kinetic

O2 converts molecules such as fats, carbohydrates, proteins into ATP 3. CHEMICAL Potential to perform work based on the arrangement of atoms within molecules O2 converts molecules such as fats, carbohydrates, proteins into ATP Releases potential energy

Different forms of energy may be interconverted, as in this example of the conversion of potential energy into kinetic energy And finally into heat (thermal energy)

7.3 PROVIDES ENERGY FOR CELLULAR WORK ATP (Adenosine triphosphate) - “adenosine”- made of adenine and ribose “triphosphate”– three phosphate groups

When ATP is involved in a chemical reaction phosphate bonds are broken releasing energy When one phosphate group is removed, ATP becomes ADP

ATP CYCLE ATP continually converted to ADP ATP is “recyclable” – can be restored by adding a phosphate group

REVIEW Which type of organism can make its own food? Which type cannot make its own food? When you walk up stairs you are using this type of energy? When you are at the top of the stairs you have this type of energy. What is the main energy supply for plants and animals?

ATP is produced through this process. Explain how humans get energy from the sun. What does ATP stand for? How does ATP release energy? ATP is continually converted into what molecule?

Overall Equation for Cellular Respiration Cellular respiration’s main function is to generate ATP for cellular work

Structure of the Mitochondria

A Road Map for Cellular Respiration Cellular Respiration consists of a series of reactions. A specific enzyme catalyzes each reaction. The three reactions that take place are: Stage 1: Glycolysis Stage 2: The Krebs Cycle Stage 3: Electron Transport Chain

Stage 1:Glycolysis Occurs in the cytoplasm of the cell Reaction: Sugar (6C)  2 Pyruvates (3C) Produces: 2 ATP molecules 2 NADH2 How does the Pyruvic Acid get into the Mitochondrion? Pyruvate is converted to Acetyl CoA! Transition Reaction - Let’s take a look!

Stage 2: Krebs Cycle Occurs in the mitochondria Cyclical series of reactions which breaks down acetyls releasing CO2 Produces: 2 ATP’s 6 NADH2 2 FADH2

Only 4 ATP’s have been formed during: Up to this point, the molecule of glucose has been broken down to form 4 CO2’s Only 4 ATP’s have been formed during: Glycolysis & Krebs Cycle Potential energy of NADH2 and FADH2 can be released in Electron Transport Chain

Stage 3:Electron Transport Chain Occurs along inner membrane of mitochondrion

Electron Transport Chain Hydrogen ions are stripped of their energy, and large amounts of ATP are formed. Takes place in the inner membrane of the mitochondrion. The used ions and Hydronium are combined with oxygen to form H2O. Produces: 34 ATP

Adding Up the ATP Molecules Electron transport chain 34 ATP

7.6 Some Cells can produce ATP without oxygen being present If oxygen is not present, fermentation allows cells to make ATP

Fermentation In Human Muscles Fermentation produces 2 ATP’s per molecule of glucose broken down Fermentation can make enough ATP for short bursts of activity such as a sprint to catch the bus!

Exercise and Lactic Acid Fermentation If muscles use oxygen faster than it can be delivered by the lungs, then they switch to anaerobic respiration. Fermentation in muscle cells produces Lactic Acid This causes fatigue, pain, & cramps. This is the burn you feel when you exercise!

Fermentation in Microorganisms Yeast, when in an anaerobic environment, ferment sugar and other foods This produces ALCOHOL! Thus, it is called alcoholic fermentation CO2 is released Yeast are used in the making of bread, wine, and beer making Fungi and bacteria produce lactic acid during fermentation and are used to produce cheese products

Review of Cellular Respiration Glycolysis Lactic Acid Fermentation Alcoholic Fermentation Krebs Cycle Electron Transport Chain

REVIEW What does ATP stand for? Why is ATP recyclable? What are the products of cellular respiration? Why is mitochondria folded? What are the three stages of cellular respiration? Where does glycolysis occur?

8. What is produced from glycolysis? Where does the Kreb’s cycle occur? What is produced from the Kreb’s cycle? Where does electron transport occur? What is formed from electron transport? When does fermentation occur? What is produced from fermentation in muscles? What is produced from fermentation in microorganisms?