All organisms obtain & use energy Cellular Energy All organisms obtain & use energy

Thermodynamics = study of energy flow & transformation Therm = heat Dynamics = motion 1st Law = conservation of Energy Energy can not be created or destroyed 2nd Law = disorder increases naturally… energy is needed to hold things together

Metabolic Pathways: sets of related chemical reactions 1) Anabolic pathways: Use energy to put molecules together increasing order 2) Catabolic pathways: Break apart large molecules Releasing Energy & increasing disorder

Which type of reaction is spontaneous? Consider the 2nd law….

Cellular Energy = ATP energy given off by catabolic reactions is stored in a molecule called ATP ATP is used to transport Energy around the cell Adenosine TriPhosphate Has 3 phosphates Attached in a row

To use the energy stored in the ATP one phosphate is broken off. Removing the last phosphate releases energy that the cell can use for: 1) motor proteins 2) protein pumps 3) anabolic rxns.

To store energy in ATP, cells add a phosphate to ADP (Adenosine Diphosphate) The energy is stored in the bond that holds the last phosphate on

Cellular Respiration Chemical energy in glucose is converted into chemical Energy in ATP Reactants Products C6H12O6 + O2  CO2 + H2O+ 36ATP (glucose)

3 Steps to Cellular Resp. 1) Glycolysis – in cytoplasm (sugar breaking) 2) Krebs Cycle – in mitochondria - gives off CO2 3) Electron transport chain – in mitochondria - uses Oxygen - makes 32 ATP

Glycolysis Glucose in cytoplasm broken in ½ Each ½ of a glucose is a pyruvic acid The pyruvic acids move into the mitochondria to the Kreb cycle Glycolysis makes 2 ATP

Kreb Cycle Pyruvic acids enter the mitochondria The Kreb Cycle pulls them apart Carbon dioxide is given off Hydrogens from the Pyruvic acid fuel the electron transport chain Kreb Cycle makes 2 ATP

Electron transport chain Hydrogens give electrons to electron transport chain Electron transport chain and ATPase make 32 ATP. Oxygen is needed to keep the electron transport chain running.

When there is no oxygen Anaerobic = no oxygen Electron transport chain and kreb cycle stop working Only glycolysis still works (2 ATP/glucose) The pyruvic acid made by glycolysis gets converted to lactic acid

Anaerobic bacteria/yeast Do not have mitochondria so Only run glycolysis They give off CO2 and alcohol when they do glycolysis Any anaerobic glycolysis = Fermentation

Photosynthesis * Uses light energy to build sugar * Anabolic * Converts light energy into chemical energy in the bonds of sugar molecules * Takes place in plant leaves … * Leaves have large surface area to gather light energy

Chloroplasts Not found in Animal cells Photosynthesis takes place inside the chloroplast in disk like structures called thylakoids (stacks of thylakoids = grana)

Photosynthesis Reactants Products CO2 + H2O  Glucose + O2 (chemical energy)

Photosynthesis – 2 parts 1) Light Energy converted to ATP energy -called the light reaction 2) ATP Energy used to build glucose (chemical energy) -called the dark reaction or Calvin cycle

Light Reaction - happens in thylakoids 1) Light absorbed by chlorophyll 2) excited electron jumps out of chlorophyll and is passed down the electron transport chain 3) electron transport chain makes ATP 4) ATP flows out into the chloroplast 5) Water is used & Oxygen is released

Calvin Cycle Carbon dioxide is taken in from the air ATP from light reaction used to put Carbons from CO2 together with H and O to make Glucose. (chemical energy)