WARM UP Take today’s handout. Get out your journal. If you do not have a journal, you will need a sheet of lined paper. Turn to page 37 of your journal, which is the table of contents for the Biochemistry Unit. Add the following two entries: Grain Elevators48Cellular Respiration Notes 49

Grain Elevators We are going to do a writing assignment on Journal page 48. Turn to Page 48 of your journal. Title the Page “Grain Elevators” If you don’t have your journal, do this on a separate sheet of paper!

Grain Elevators (information – not notes) A grain elevator is a huge group of buildings used to store grains like wheat, oats, and barley, after it is harvested. We are about to see two movies. One shows a truck driving in to deliver wheat to a grain elevator. The second is a news report about a problem at a grain elevator.

Grain Elevator Delivery

Grain Elevator News Report

Grain Elevator QUESTIONS TO ANSWER in your journal on page 48: In your own opinion, why would a building full of wheat explode? Where does the energy for the fire come from? EXPECTATION: a paragraph of at least 5 sentences.

Cellular Respiration Notes As we go through this, complete your handout for page 49.

Heterotrophs If you cannot do photosynthesis like all plants, some protists, and some prokaryotes, you must collect your energy in another way. All animals, all fungi, some protists, and some prokaryotes are heterotrophs, or “other makers,” which means they consume calories.

We get your energy from food Carbohydrates, proteins, and fats are reservoirs of energy A series of chemical reactions known as cellular respiration makes that energy can become available to cells.

The process starts in your digestive system The large molecules in food are broken down into small molecules. Proteins become amino acids.

The process starts in your digestive system The large molecules in food are broken down into small molecules. Starches become sugars.

The process starts in your digestive system The large molecules in food are broken down into small molecules. Lipids break down into glycerol and fatty acids.

The one most important molecule for making energy is a specific sugar, glucose. Your body can change fats or proteins into glucose, if necessary.

Energy = Calories. One physics calorie will increase the temperature of 1 g water by 1 C. A biology Calorie is equal to 1000 physics calories. A biology Calorie is equal to 1000 physics calories. One gram of fat produces about 9 Calories; a gram of carbohydrate or of protein produces about 4 Calories.

Glucose is Best! When you need to burn lipids or amino acids, the process is less efficient, since it takes energy to convert them into glucose before you can use them for cellular respiration. When you convert amino acids into glucose, you also have to remove the nitrogen (“deamination”) – this waste is removed in your urine.

The most important organelle in each cell is your mitochondria. Every eukaryotic cell has mitochondria

The more active the cell is, the more mitochondria it has. Which type of cell has more mitochondria: liver or fat?

Origin of Mitochondria Scientists believe that mitochondria were once bacteria, and are now symbiotic with eukaryotic cells. One piece of evidence for this theory is that mitochondria have their own DNA. Endosymbiosis

The Structure of the Mitochondria Outer Membrane A lipid bilayer, the outside layer of the cell. CristaeFolds made of the inner membrane. MatrixThe cytosol fluid inside the mitochondrion.

Three Steps of Cellular Respiration 1. Glycolysis 2. The Krebs Cycle 3. The Electron Transport Chain

Homework Update your journal: On page 49: summarize all of today’s notes and thinking in a paragraph. Then write four study questions for yourself. Did you finish your paragraph on page 48 about Grain Elevators? If not, you can do that now. You have until 12/21 to finish the five coloring pages

THE STEPS OF CELLULAR RESPIRATION There are a few other steps, but you are only responsible for these three. You can fill in the graphic organizer as we go….

Glycolysis Where it happens: Glycolysis occurs in the cytoplasm of the cell. It is the only step that does not occur in the mitochondria.

Glycolysis Summary of what happens: Glycolysis means “break sugar” Glucose is broken in half.

Glycolysis The reactant is a molecule of glucose. NOTE: Oxygen is not needed for this step.

Glycolysis The products are two “half-glucose” molecules, called pyruvate and a small amount of ATP.

Step 2: The Krebs Cycle This cycle is also called the Citric Acid Cycle or tricarboxylic cycle or TCA. You should know all three names, since a test might use any of them, even though your book only uses “the Krebs cycle”

The Krebs Cycle… occurs in the matrix of the mitochondria.

The Krebs Cycle… is a whole long series of complicated chemical reactions ….

…involving all sorts of chemicals – pyruvate, pyruvic acid, Acetyl Co-A, acetate, and many enzymes

The Krebs Cycle The process starts where glycolysis ends, with pyruvate turned into a new molecule called “Acetyl Co-A’ Oxygen is also required.

The Krebs Cycle The products include carbon dioxide, a small amount of ATP and a lot of electrons. The carbon dioxide is waste. The electrons are needed for the next step

Electron Transport Chain This step happens in the inner membranes (cristae) of the mitochondria. Like the Krebs Cycle, it has many smaller steps. This is the part of cellular respiration which releases the most energy.

Electron Transport Chain This process starts with the electrons released by the Krebs cycle. Oxygen is also required. A chemical called ADP is also a reactant.

Electron Transport Chain The products of the electron transport chain are water and a large amount of ATP.

Oopsies! If there is no oxygen, the Krebs Cycle and Electron Transport Chain can’t happen. Some cells stop with glycolysis. Some cells perform anaerobic (without oxygen) fermentation.

Fermentation Fermentation creates poisons, like methane gas, lactic acid and alcohol. Some humans make a lot of money by fermenting compost or alcoholic drinks. Making wine or beer involves fermentation, and eventually kills the yeast.

Lactic Acid? Remember: lactic acid does not cause muscle soreness! It is caused by microscopic tears in the muscle.

HOMEWORK: Summarize today’s notes, and write at least four study questions for yourself.