Cells capture and release energy. Chapter 2 – Section 2 Notes

PHOTOSYNTHESIS “Photo-” = light “-syntesis” (synthesize) = to make something Definition – a step by step process that a plant uses to make GLUCOSE (sugar) from light Job is done in the CHLOROPLAST – specifically in the CHLOROPHYLL (light absorbing chemical inside the choloroplasts)

PHOTOSYNTHESIS Steps Step one Plants collect CO 2 (Carbon Dioxide) from the air and H 2 O from their roots to go inside the Chloroplasts Step Two Chloroplasts use sun / light and a Chemical Reaction takes place to change the molecules Step Three The elements rearrange and form GLUCOSE (sugar) and OXYGEN (waste for the plant)

PHOTOSYNTHESIS in Action (see page 49 in the book) “makes” 6H CO 2 + light C 6 H 12 O 6 + 6O 2 Chemical Equation for Photosynthesis It takes, 6 Carbon Dioxide molecules and 6 water molecules being exposed to light to make just one molecule of Glucose and 6 Oxygen molecules. ?id=none&mod=1# ?id=none&mod=1# BrainPop Video

Stop for now

All cells make and use energy Two Types of Energy Making and Releasing Cellular Respiration Fermentation Requires Oxygen NO Oxygen Required

CELLULAR RESPIRATION Uses Glucose = “Cell Food” Chemical Energy is stored in bonds between the elements It requires Oxygen in order to work and releases LOTS of usable energy

Cellular Respiration Steps Step one All cells collect “Carbohydrate” (Glucose) and Oxygen (leftovers from Photosynthesis in plants) and starts to break apart the “Carbohydrate”. Step Two Mitochondria takes the “carbo-chunks” and has the oxygen break them into separate elements to be rearranged. Step Three Chemical Energy gets released, and H 2 O and CO 2 are made from the rearranged elements.

CELLULAR RESPIRATION in Action (see page 51 in the book) “makes” C 6 H 12 O 6 + 6O 2 6H CO 2 + Energy Chemical Equation for Cellular Respiration It takes, just one molecule of Glucose and 6 Oxygen molecules to make 6 Carbon Dioxide molecules and 6 water molecules with lots of Energy released to the cell to be used.

Now Put them together…. Photosynthesis and Cellular Respiration Cycle

Not quite done…. Fermentation  Basically the same as Cellular Respiration…just different in that NO Oxygen is needed to get the Energy  It only releases a small amount of Energy  Does NOT happen in the Mitochondria, it happens in the Cytoplasm

Two Types of Fermentation… 1.Alcoholic Fermentation “Sugar” is changed into an alcohol and CO 2 without Oxygen being used Example: Bread (made with flour, milk and sugar and yeast) – They have a Chemical Reaction and the small amount of alcohol evaporates and the CO 2 makes the “bubbles” in the bread

Two Types of Fermentation… Type Two 2. Lactic Acid Fermentation “Carbohydrates” are broken apart releasing their Energy – without Oxygen- and an acid is left Examples: Yogurt (sits only a short time), Cheese (left to sit a long time) and Sourdough bread (made with milk) or the sugar “Lactose” as the “sugar / carb”. Human Example: Exercising for a long time / distance…you will use up your Oxygen supply in the muscle and have to do Fermentation to make a little emergency energy. You feel “sore / pain / burn” sensation – this is the Lactic Acid build up. See BrainPop video…