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Energy in Cells. Objectives:. SWBAT: Describe low of energy through living systems Compare chemical processes of autotrophs and heterotrophs Describe role of ATP in metabolism Describe how energy released. Metabolic activities alter molecules in a series of steps
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Objectives: SWBAT: Describe low of energy through living systems Compare chemical processes of autotrophs and heterotrophs Describe role of ATP in metabolism Describe how energy released.
Metabolic activities alter molecules in a series of steps Enzymes (proteins) accelerate each step Enzymes regulated to maintain a balance of supply and demand Metabolism- All the Chemical Reactions in organisms
SWBAT: • Describe low of energy through living systems • Compare chemical processes of autotrophs and heterotrophs • Describe role of ATP in metabolism • Describe how energy released. Catabolic and Anabolic Reactions Catabolic-give off energy by breaking down molecules Anabolic—use energy to build molecules Energy released by catabolic pathways used to drive anabolic pathways
Autotrophs vs Heterotrophs Autotrophs-Make own food through anabolic reactions Many autotrophs carry out photosynthesis Utilize cellular respiration Heterotrophs-Can not make own food Must eat other organisms to obtain energy from food through catabolic reactions Utilize cellular respiration
Energy Ability to do work
Thermodynamics Study of the flow and transformation of energy in the universe.
1st Law of Thermodynamics Law of conservation of energy Energy can be converted but not created nor destroyed. Example:Energy stored in food converted to chemical energy when we eat and mechanical energy when you run.
2nd Law of Thermodynamics. Energy cannot be converted without the loss of usable energy. (Energy “lost” is converted to thermal energy)
Entropy • Measure of disorder, or usable energy, in a closed system (not available for useful work) • 2nd Law AKA “Entropy Increases” • Food Chain –Useful energy available to next level decreases
Cell Energy All living organisms must • produce from environment • store for future use • Use in a controlled manner
Where does Cell Energy Come From? Sun → Autotrophs → Food → ATP
Types of Energy Cells Use Mechanical Work-moving cilia, contraction of muscle cells, movement of chromosomes Transport Work-Pumping substances Chemical Work-Synthesis of polymers, Bioluminescence
Adenosine Triphosphate (ATP) Multipurpose chemical energy storage molecule POWERS CELLULAR WORK
Objects compressed-store energy compressed object released- energy is released.Chemical bonds store energy, when bonds break energy is released.
ATP (Adenosine Triphosphate) Adenine molecule Ribose sugar three phosphate groups
Forming and Breaking Down ATP Law of electrical charges Bonding phosphate groups to adenosine required considerable energy.
3rd Phos + ADP ATP, Phos so eager to get away, bond is broken a great amount of energy is release. Energy available when ATP loses phos
ATP Cycle Doesn’t exist all the time as ATP. Phosphate available--cell has an unlimited supply of energy.
Energy from Fuels Digest large molecules into smaller ones break bonds & move electrons from one molecule to another as electrons move they “carry energy” with them that energy is stored in another bond, released as heat or harvested to make ATP
Photosynthesis We can write the overall reaction of this process as: 6H2O + 6CO2 ----------> C6H12O6+ 6O2six molecules of water plus six molecules of carbon dioxide produce one molecule of sugar plus six molecules of oxygenBasically Opposite of Cellular Respiration
Two Reactions of Photosynthesis Light Reaction ☼ – Light energy (sun) into chemical energy. Thylakoid Disk Produces ATP to power Light Independent Reaction. Oxygen Released Light Independent Reaction/Dark Reaction (Calvin Cycle) – Uses chemical energy to “Fix” Carbon dioxide into sugar. Uses ATP and Electrons from Light Reaction Stroma
Mesophyll Cells Specialized cells in the middle of the leaf that contain a lot of chloroplast for photosynthesis
Chloroplast: Organelle where photosynthesis occursThylakoids-Site of light dependent reactionsGrana: Stack of Thylakoids Chloroplasts
Stomata (stoma)Pores in plant’s cuticles through which water vapor and gases are exchanged between the plant and atmosphere (underside of leaves)
Pigments: Molecules that absorb specific wavelengths of light (Plants: Chlorophyll-absorbs and transfers light energy) **Chlorophyll forms a and b absorb most wavelengths except green. Because it doesn’t absorb it, it reflects it, hence green appearance.
Fall Colors Pigments other then chlorophyll Chlorophyll reduced revealing other pigments (carotenoids that are red, orange or yellow)
Light Dependent Reaction —“photo” of photosynthesis 1.)The light absorbed by chlorophyll causes a transfer of electrons and H+ from H20 molecules already present. This causes the H20 to split into molecular 0xygen (02) and a H+ ion (photolysis). 2.) The O2 is released (we breathe it) and the H+ bonds to NADP+ creating NADPH3.)ATP is formed through photophosphorylation. (ADP gets a phosphate group added to it creating ATP)4.) The NADPH and the ATP created here go on to fuel the reactions in the second part of photosynthesis - The Calvin Cycle
Photolysis: light causes water molecule split. Hydrogen to bind to an acceptor, subsequently releasing the oxygen. • Equation: H2O > 2H + O • Function: • Release O2 gas to the atmosphere • Replaces lost electrons
Calvin Cycle/Light Independent • “synthesis” of photosynthesis, making food, trapping CO2. • Rubisco (enzyme) brings together CO2 and sugar, carbon fixation • 3 CO2 (atmosphere) and 3, 5-carbon sugars (RuBP). • PGA Formation-Six-carbon product is unstable and splits into 3-carbon products (PGA). • ATP places a phosphate group on each PGA: NADPH donates a pair of electrons, yielding a high energy food, PGAL.
Calvin Cycle Completes Glucose Production-After several rounds 2 PGAL leave to form glucose Replenish RuBP (Ribose Biphosphate) Some PGAL reform 5-C Sugar-begin process again
Cellular Respiration Mitochondria break down glucose to produce energy (ATP)
Overview Every cell (plants and animals) Exergonic Reaction(produces energy) Equation- C6H12O6 + ADP 6CO2 + 6H2O + ATP
oxidation C6H12O6 + 6O2 6CO2 + 6H2O + ATP reduction Oxidation/Reduction Reactions • Oxidation • adding O • removing H • loss of electrons • releases energy • exergonic • Reduction • removing O • adding H • gain of electrons • stores energy • endergonic