Chemical Energy and ATPSection 4.1Michael Slemp

Bell WORKWhy is ATP important? Give examples

List the three types of high energy rich molecules that make up our food. Which of the three has the most amount of energy?

ALL CELLS NEED ENERGY !You are made out of billions of cells so your body need energy too.So, what do you do when you are tired and hungry?YOU EATyour body is telling you that you need more energy

What do you EAT?

Food = high energy molecules Carbohydrates, lipids and proteins are organic molecules (not found in nature but made by organisms)

Energy MoleculesExamplesEnergy Content (calories)CarbohydratesSugar, bread, pasta, apples, carrots4 calories per mgLipidsOil, butter9 calories per mgProteinsChicken, fish, burger4 calories per mg

The easiest source of energy for cells are carbohydrates (sugars)However, sugar molecules are too HUGE and cannot be used directly by cells.Instead, sugars are broken down in mitochondria to smaller units via process called cellular respiration (covered in section 4.4)During cellular respiration, energy stored in bonds of sugar molecules are released and stored in bonds of another molecule called ATP

ATPAdenosine triphosphate (tri=three)Translation: Adenosine molecule with three phosphate groups123Majority of Energy is stored between P2 and P3

Use of ATP ATP made in mitochondriaTravels to various cell sites to supply energyEnergy is released from ATP molecule by breaking bond between P2 and P3ATP molecule ENERGY(used by cell)ADPAdenosine diphosphate (di=two)Free phosphate groupTransported back to mitochondria for more ATP production

ATP cycleATP Energy + ADP + PADP + P + Energy ATP

(released)(supplied)

Compare Energy rich moleculesSugar (glucose)Stores energy in the chemical bonds (chemical energy)Too large to be used by cellsADPATPEnergy rich moleculeUsable by cells, energy rich molecule Energy poor molecule1 glucose molecule = 36 ATPs

Where do sugars come from?Animals get energy from food that they eat(as we discussed above)However, some organisms are able to produce their own carbohydrates Plants are able to make their own sugars by a process called photosynthesis Remember chloroplasts?

Photosynthesis Plants do not need to feed on organic food like carbohydratesPlants harvest energy from sunlightIn process of photosynthesis, plants convert sunlight energy, carbon dioxide and water into energy rich carbohydratesWe will be covering photosynthesis next class session

Chemosynthesis Photosynthesis = uses sunlight energy to produce sugarsChemosynthesis = uses chemical energy (instead of light energy) to produce energy-rich molecules like sugarSunlight energy + Water+ Carbon Dioxide = Glucose + OxygenHydrogen Sulfate + Water+ Carbon Dioxide = Glucose + other products(chemical energy)

Chemosynthesis is used by some organisms that live deep down on ocean floor near hydrothermal vents. Because they never get sunlight here, they had to find alternative source of energyChemosynthesis