Metabolism Photosynthesis Cellular Respiration Chapters 8 10 Metabolism

Metabolism Photosynthesis Cellular Respiration Chapters 8 -10

Metabolism and Energy Metabolism Catabolism Anabolism Bioenergetics Energy Kinetic Heat/Thermal Light Energy Potential Chemical Organisms are energy transformers!

Metabolism and Energy Metabolism Organisms are energy transformers! Metabolic pathway begins with a specific molecule, which is then altered in a series of defined steps leading to a specific product Each step is catalyzed by a specific enzyme

Metabolism and Energy Organisms are energy transformers! Metabolism Catabolism Energy released (helps to drive anabolic pathways). Ex: cellular respiration sugar put in to the body is broken down to do work in the cell (movement, active transport, etc).

Metabolism and Energy Organisms are energy transformers! Metabolism Catabolism Anabolism sometimes called biosynthetic pathways- Ex: synthesis of a protein from amino acids. Energy required/absorbed.

Metabolism and Energy Metabolism Catabolism Organisms are energy transformers! Anabolism Bioenergetics the study of how energy flows through living systems.

Metabolism and Energy Metabolism Catabolism Anabolism Organisms are energy transformers! Bioenergetics Energy the capacity to cause change. Some forms of energy can be used to do work- or move matter against opposing forces Ex: (friction and gravity) Ability to rearrange a collection of matter

Metabolism and Energy Kinetic Organisms are energy transformers! Relative motion of objects moving objects can perform work by imparting motion to other matter. Ex: Moving water through a dam turns turbines, moving bowling ball knocks over pins

Metabolism and Energy Kinetic Organisms are energy transformers! Heat/Thermal comes from the movement of atoms or molecules associated with kinetic energy

Metabolism and Energy Kinetic Organisms are energy transformers! Heat/Thermal Light Energy Type of energy that can be harnessed to perform work Ex. Powering Photosynthesis

Metabolism and Energy Kinetic Organisms are energy transformers! Heat/Thermal Light Energy Potential Non-kinetic energy because of location or structure, height, chemical bonds, etc.

Metabolism and Energy Kinetic Heat/Thermal Light Energy Organisms are energy transformers! Potential Chemical the potential energy available for release by a reaction. Ex: Glucose is high in chemical energy and the process of glycolysis breaks it down. As bonds are broken, energy is released, but bonds also reform to make new molecules, thus it uses some energy.

Metabolism and Energy Organisms are energy transformers! All original energy comes from light. (photosynthesisprimary producerconsumer- who changes it from chemical to kinetic and releases thermal.

Thermodynamics What is Thermodynamics?

Thermodynamics The energy transformations that occur in a collection of matter

Thermodynamics System vs. Surroundings Isolated System vs. Open System First Law of Thermodynamics

Thermodynamics Two Laws of Thermodynamics govern energy exchange: First Law of Thermodynamics Second Law of Thermodynamics

Thermodynamics Two Laws of Thermodynamics govern energy exchange: First Law of Thermodynamics energy cannot be created or destroy Only transferred or transformed Known as Principle of conservation of energy

Thermodynamics Second Law of Thermodynamics During energy transfer, some energy become unusable energy (unavailable to do work) Entropy (S) – Measure of disorder or randomness

Thermodynamics So, What is the Second Law of Thermodynamics? Every energy transfer or transformation increases the entropy of the universe

Thermodynamics Spontaneous (Energetically Favorable) vs. Nonspontaneous Processes Leads to the second way we state the 2 nd Law of Thermodynamics: For a process to occur spontaneously, it must increase the entropy of the universe

Think-Pair-Share How does the second law of thermodynamics help explain the diffusion of a substance across a membrane? If you place a teaspoon of sugar in the bottom of a glass of water, it will dissolve completely over time. Left longer, eventually the water will disappear and the sugar crystals will reappear. Explain these observations in terms of entropy.

Gibbs Free Energy Portion of system’s energy that can perform work when temp and pressure are uniform throughout system ΔG = free energy of a system -ΔG = spontaneous reaction +ΔG = nonspontaneous reaction ΔG = 0 = Dead Cell (can do no work) ΔG = ΔH – TΔS ΔG = ΔGfinal – ΔGinitial Enthalpy

Gibbs Free Energy ΔG = ΔH – TΔS ΔG = ΔGfinal – ΔGinitial ΔH = he change in the system’s enthalpy What is enthalpy? Total energy ΔS = change in system’s entropy T = absolute Temperature in Kelvin

Gibbs Free Energy Endergonic vs. Exergonic Reactions +ΔG Non-Spontaneous -ΔG Spontaneous

Warm Up Exercise Glow in the dark necklaces are snapped in a way that allows two chemicals to mix and they glow. Is this an endergonic or exergonic reaction? Explain. In simple diffusion, H+ ions move to an equal concentration on both sides of a cell membrane. In cotransport, H+ ions are pumped across a membrane to create a concentration gradient. Which situation allows the H+ ions to perform work in the system?

ATP and Cellular Work Three Types of Work Chemical Transport Mechanical Energy Coupling Phosphorylated Intermediate

ATP Hydrolysis kh

ATP and Cellular Work

ATP Cycle The body regenerates 10 million molecules of ATP per second per cell!

Flashback Name the four major macromolecules and their monomers.

Enzymes Enzymes- biological catalyst Substrates

Enzymes Activation Energy (EA)

Enzymes catalyze reactions by lowering the activation energy.

Enzymes Enzyme + Substrate = Enzyme-Substrate Complex Enzyme + Substrate(s) Enzyme. Substrate Complex Enzyme + Product(s)

Enzymes Active Site Induced Fit

Warm Up Exercise Explain the affect that enzymes have on activation energy. What is a substrate? Describe what is meant by induced fit.

Effects of Environment Temperature p. H Concentration of Enzyme Concentration of Substrate

Enzymes Cofactors Coenzyme

Enzyme Action Competitive Inhibitors Noncompetitive Inhibitors

Allosteric Regulation

Cooperativity

Feedback Inhibition

Warm Up Exercise Explain the difference between competitive and noncompetitive inhibitors Describe the negative feedback demonstrated by ATP/ADP.

Cellular Respiration

Cellular Respiration Cell respiration is a catabolic pathway. Aerobic Cellular Respiration Anaerobic Cellular Respiration (aka: Fermentation)

Redox Reactions Reduction vs. Oxidation Why are carbs and fats the best molecules for energy? Why must glucose be broken down in a series of steps rather than one quick reaction?

Electron Transport Dehydrogenase- removes electrons from glucose (or other substrate) transferring them to its coenzyme (NAD+) which is reduced to NADH. (NADH = potential energy) NAD+ (nicotinamide adenine dinucleotide)- an electron carrier. Cycles between NAD+ and NADH

NAD to NADH

Electron Transport As glucose is broken down (in many small reactions) electrons are shuttled (by NADH) down the Electron Transport Chain (ETC). Ultimately, oxygen is the final electron acceptor.

Warm Up Exercise What is the function of NAD+? Explain the terms oxidation and reduction. What is the difference between aerobic and anaerobic respiration?

Stages of Respiration Glycolysis (in cytoplasm)- can occur with our without oxygen. Pyruvate Oxidation (in mitochondria) Citric Acid Cycle (in mitochondria) Oxidative Phosphorylation: Electron Transport Chain and Chemiosmosis (in the outer membrane of the mitochondria)

Stages of Respiration asdklf

ADP to ATP Oxidative Phosphorylation- inorganic phosphate is added to ADP to produce ATP. Occurs in ETC and chemiosmosis. Substrate-Level Phosphorylation- an enzyme transfers a phosphate group from a substrate molecule to ADP to form ATP. Occurs in glycolysis and citric acid cycle. Substrate = an organic molecule generated as an intermediate in glycolysis.

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Warm Up Exercise Without using your notes, name the four major processes of cellular respiration and where in the cell they occur. Explain the difference between oxidative and substrate-level phosphorylation.

Oxidative Phosphorylation Pyruvate enters mitochondria (via active transport) and is converted to Acetyl Co. A

Citric Acid/ Kreb’s Cycle

Citric Acid/Kreb’s Cycle Acetyl Co. A (from oxidative phosphorylation) enters the Citric Acid cycle and combines with oxaloacetate to form citrate, the ionized form of citric acid.

Warm Up Exercise Walk through the Kreb’s cycle, stating the reactants and the products and where they came from, or go to

ETC Cytochromes- electron carriers in ETC. They are proteins with a Heme group attached. Represent a series of redox reactions.

Chemiosmosis Chemiosmosis- energy coupling mechanism that uses H+ gradient to drive cellular work. ATP Synthase- enzyme that makes ATP from ADP in the inner membrane of mitochondria.

Chemiosmosis Proton Motive Force- the H+ gradient that results from the pumping of H+ ions from the matrix of the mitochondria to the intermembrane space.

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Energy Totals Kh;

Warm Up -Cell Resp Challenge Why does NADH have more energy than FADH 2? Explain the idea of energy coupling that occurs in chemiosmosis. What element (atom) helps to pull electrons down the ETC? How many total ATPs are produced per molecule of glucose in aerobic respiration?

Alternatives to Aerobic Respiration Anaerobic Respiration- uses ETC with a different final electron receptor (besides oxygen) Fermentation- no ETC. Glycolysis followed by a fermentation process. Two main types: Alcoholic and Lactic Acid

Fermentation Alcoholic Fermentation- pyruvate is converted to acetaldehyde then to ethanol (ethyl alcohol). CO 2 byproduct.

Fermentation Lactic Acid Fermentation- pyruvate is reduced by NADH to form lactate, with no release of CO 2.

Aerobic vs. Anaerobic Obligate Anaerobes- organisms that cannot survive in the presence of oxygen. Carry out only fermentation or anaerobic respiration. Facultative Anaerobes- organisms that can survive using fermentation or respiration.

Warm Up Exercise A glucose-fed yeast cell is moved from an aerobic environment to an anaerobic one. How would its rate of glucose consumption change if ATP were to be generated at the same rate?

Photosynthesis Mesophyll- tissue in the interior of the leaf. Where chloroplasts are found. Stomata- microscopic pores in the leaf that allow CO 2 and O 2 enter and exit.

Photosynthesis The O 2 given off in photosynthesis comes from H 2 O, not CO 2.

Photosynthesis Light Reactions- solar energy is captured (by chlorophyll in the thylakoids) and converted into chemical energy (ATP and NADPH). Photophosphorylation- creates ATP through the use of the ETC in the light reactions. Dark Reactions/Calvin Cycle- chemical energy is used to make organic compounds of food. (ie: glucose) Occurs in stroma. Carbon Fixation- CO 2 (from air) is combined with molecules present in chloroplast to form organic molecules that are reduced to carbohydrates. (w/NADPH)

Warm Up Exercise

Light Energy Photons- packets of light energy. Pigments- substances that absorb visible light. Chlorophyll a, chlorophyll b, carotenoids. Spectrophotometer- instrument that measures the ability of a pigment to absorb various wavelengths of light.

Absorption Spectrum and Action Spectrum

Photosystems Photosystems- a reaction center complex surrounded by light harvesting complexes (pigment molecules + proteins). PS II (P 680) and PS I (P 700)

The Light Reactions Photon of light is absorbed by pigment molecule in PS II exciting electrons. Electrons are passed along pigment molecules in the light-harvesting complex, to the reaction center complex, and ultimately to the primary electron acceptor. Water molecule is split into 2 e-, 2 H+ and O. These e- are transferred back to P 680 and H+ is released to lumen of thylakoid. O combines with O from previous water splitting to release O 2.

The Light Reactions Electrons are passed from primary electron acceptor in PS II down the ETC to PS I. As electrons pass through the ETC, ATP is generated. Meanwhile, PS I has absorbed light, excited electrons, that are assed on to P 700 and to primary electron acceptor, leaving p 700 without electrons. P 700 accepts electrons from ETC (that came from PS II).

The Light Reactions Excited electrons are passed from primary electron acceptor of PS I through a second ETC. Electrons move through a protein called ferredoxin and to NADP+ reductase, where they are accepted by NADPH. This stores the energy of the electrons into a form that can be transferred to the Calvin Cycle. (No chemiosmosis, thus no ATP in this ETC)

The Light Reactions j

Warm Up Exercise What are the main pigments in chloroplasts?

Cyclic Electron Flow Cyclic Electron Flow- electrons take an alternative pathway that uses PS I but not PS II.

Differences in ETC Type of phosphorylation Where electrons come from Where energy comes from Direction/location of H+ pumping

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Calvin Cycle CO 2 enters the Calvin Cycle from the light reactions and exits as sugar. The carbohydrate produced in the Calvin Cycle is not actually glucose, but a 3 -carbon sugar called G 3 P. To synthesize 1 molecule of G 3 P, the process has to happen 3 x fixing 3 molecules of CO 2. Expends 9 ATP and 6 NADH.

Calvin Cycle 1: Carbon Fixation- CO 2 is attached to 5 -C molecule (ribulose bisphosphate- Ru. BP) to form a 6 -C molecule. Enzyme: Rubisco. 2: Reduction- molecule from phase 1 is reduced (by NADPH) to become 6 molecules of glyceraldehyde 3 phosphate (G 3 P). One G 3 P is released. 3: Regeneration of CO 2 Acceptor (Ru. BP)- other 5 molecules of G 3 P are rearranged to create 3 more CO 2 acceptors (Ru. BP)