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 onePlants collect CO2 (Carbon Dioxide) from the air

and H2O from their roots to go inside the Chloroplasts

Step TwoChloroplasts 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”

6H20 + 6CO2 + light C6H12O6 + 6O2

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.

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BrainPop Video

Stop for now

All cells make and use energy

Two Types of EnergyMaking and Releasing

Cellular Respiration Fermentation

Requires OxygenNO 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 oneAll cells collect “Carbohydrate” (Glucose) and

Oxygen (leftovers from Photosynthesis in plants) and starts to break apart the “Carbohydrate”.

Step TwoMitochondria takes the “carbo-chunks” and has

the oxygen break them into separate elements to be rearranged.

Step ThreeChemical Energy gets released, and H2O and

CO2 are made from the rearranged elements.

CELLULAR RESPIRATION in Action

(see page 51 in the book)“makes”

C6H12O6 + 6O2 6H20 + 6CO2 + 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….

FermentationBasically 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 CO2

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 CO2 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…