Download Photosynthesis (briefly) and Cellular Respiration (aerobic

Photosynthesis (briefly) and Cellular Respiration (aerobic respiration)
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Capturing Energy
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Sun is primary source of energy
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Energy flows through life systems
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Producers
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Primary consumers
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Secondary
consumers
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What this means…
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On Land, most energy needs come from the plant kingdom
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This energy originally comes from the sun
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Photosynthesis converts the energy in sunlight into chemical energy (sugar)
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Energy in the Cell
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Photosynthesis transforms kinetic energy (light) into potential energy (chemical bonds in glucose)
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Cellular respiration moves energy stored in glucose into ATP, which can be used for cellular work
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Cellular Respiration
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Think of what happens when you breathe – closely related to CR
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Cellular Respiration and Gasses
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Breathing brings O2 into the body
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O2 is distributed to cells by the blood
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In cellular respiration, mitochondria use O2 & glucose to generate ATP
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In converting E (sugar -> ATP), heat is generated (2nd Law of Thermodynamics)
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Breathing disposes of the waste product CO2 produced from cellular respiration
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ATP – An Energy Carrier
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Temporarily stores & transfers energy
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ATP stores energy in phosphate bonds
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Other Energy Carriers In Cells
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NADP+ & NAD+
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Pick up electrons
 NADPH and NADH
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Donate these electrons and energy
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NAD+ shown
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Aerobic respiration burns sugar
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Electrons move from carbon in glucose to oxygen in water
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Energy released rapidly as light and heat
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Cellular Respiration
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Electron movement is carefully controlled
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Energy is released in small amounts; stored in ATP
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Oxidation – Reduction Reactions
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Oxidation: loss of electrons from an atom (or loss of a H atom from a molecule)
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Reduction: addition of electrons to an atom (gain of a H atom to a molecule)
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Think: reduction in CHARGE due to more e-
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Always paired (one loses an e-, one gains)
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What molecule gets OXIDIZED (loses e-)?
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What molecule gets REDUCED (gains e-)?
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Redox Reactions in Cellular Respiration
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Glucose loses electrons (in H atoms) and becomes oxidized
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Redox Reactions Continued
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Glucose loses electrons (in H atoms) and becomes oxidized
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O2 gains electrons (in H atoms) and becomes reduced
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Along the way, energy is released
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Cellular Respiration
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Electrons are transferred to the coenzyme NAD+, which is converted to NADH
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Is this oxidation or reduction?
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NADH shuttles electrons in to another part of Cellular Respiration
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Cellular Respiration: Big Picture
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Electron transfer to NAD+ is the first step in an ELECTRON TRANSPORT CHAIN
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Series of redox reactions
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Pass from different carrier molecules eventually to O2
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Cellular Respiration
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STEP 0: Eat to get glucose
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Glucose is absorbed by cells in small intestine
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Glucose enters the bloodstream and is transported to all the cells in your body
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How is this different in a plant?
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Cellular Respiration: Inside a Cell
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STEP 1: Glycolysis
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STEP 2: Prep. Step & Citric Acid Cycle
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STEP 3: Oxidative Phosphorylation (Electron transfer chain)
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Cellular Respiration
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STEP 1: Glycolysis
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Occurs in CYTOPLASM
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Glucose is split into 2 molecules of pyruvate
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2 ATP and 2 NADH are made for each pyruvate
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STEP 1: Glycolysis
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STEP 1: Glycolysis Summary
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Glucose is split into 2 three-carbon molecules called pyruvate (pyruvic acid)
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2 net ATP molecules are generated
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Redox reaction generates 2 NADH
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So far…
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Glycolysis Prepatory Step Citric Acid (Krebs) Cycle
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Mitochondria Structure
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Two membranes
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Outer membrane
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Inner membrane
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Matrix inside the inner membrane
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Intermembrane space
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Folded into cristae
STEP 2: The Prepatory Step & the Citric Acid Cycle (TCA)
In the prepartory step, Pyruvate (x2) is prepared for TCA cycle:
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1 Carbon atom released as CO2
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1 NADH is made
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Coenzyme A joins 2C
which then enters TCA
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STEP 2: The Citric Acid Cycle
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Occurs inside matrix of MITOCHONDRIA
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Completes breakdown of glucose to CO2
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Makes 1 ATP per pyruvate
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Generates several NADH & FADH2
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STEP 2: Citric Acid Cycle
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Also called TCA (The Citric Acid cycle)
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Also called the Krebs Cycle
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Note: There’s TWO pyruvates, so the TCA runs 2x!!
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STEP 2: The Prep Step & TCA Summary
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Completes oxidation of glucose:
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Releases 3 CO2 molecules per pyruvate (1 fr/ Prep step)
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Net yield/pyruvate
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1 ATP,
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4 NADH (1 fr/ Prep step)
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1 FADH2
There are 2 pyruvates
per glucose!
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So far…
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TCA  Electron Transport Chain
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Step 3: Electron Transport Chain
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Complicated process,
see my html page.
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Step 3: Electron Transport Chain
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Electrons passed down from NADH to ETC
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H+ ions pumped inside inner mitochondrial membrane
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Electrons passed down ETC to O2 which accepts electrons & 4H+ to become 2 H2O (decreases H+ inside)
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So far…
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Cellular Respiration Review
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Occurs in all eukaryotes
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Generates ATP
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Involves oxidation – reduction reactions
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Oxidation = loss of electron / H atom; charge is more positive
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Reduction = gain of electron / H atom; charge is more negative
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STEP 3: ETC Summary
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Electons passed from NADH and FADH to proteins in ETC to O2
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Transports H+ into inner membrane space in mitochondria creating a gradient
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STEP 3: ETC Summary
Energy from H+ flowing downhill is stored in bond of ATP
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STEP 3: ETC Summary
CHEMIOSMOSIS: H+ flowing (downhill) from high to low concentration releases KINETIC energy
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STEP 3: ETC Summary
H+ gradient is POTENTIAL energy
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STEP 3: ETC Summary
STEP 3: CHEMIOSMOSIS
Generates majority of ATP (34)
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Cellular Respiration Organizer
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Cellular Respiration Animations
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Cellular Respiration
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Aerobic metabolism: three steps
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Glycolysis, Citric Acid Cycle, & Oxidative Phosphorylation
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Releases LOTS of energy – typically 36 ATP per molecule of glucose