BIO 101, 102 ENERGY & METABOLISM

BIO 101, 102ENERGY & METABOLISM

Dr. Michael C. PotterPaul VI Catholic High School

Fairfax, Virginia


ENERGY: Ability to do work States of Energy

PotentialKinetic

Forms of Energy MechanicalHeatAtomic, etc.

BIO 101, 102ENERGY &

METABOLISM

Potential Energy Kinetic Energy


METABOLISMMEASUREMENT OF ENERGY Calorie: Amount of heat needed

to raise 1.0 Gm. H2O 1.0 Co

Kcal (kilocalorie) Joule: SI unit of work (energy)

Energy needed to raise 1.0 Kg.1.0 meter

1.0 Kcal. = 4.184 kilojoules


ALL Energy obtained from Sun 13X1023 calories per year…or 40 million billion calories/sec.

Sun energy stored as potentialenergy in chemical cmpds.


Oxidation Reduction Reactions


METABOLISMOXIDATION/REDUCTION REACTION OXIDATION: Molecule LOSES

electron REDUCTION: Molecule GAINS

electron REDOX REACTIONS i.e. “coupled”

reactions


OXIDIZING AGENT: Causes oxidation in molecule therefore is reducedREDUCING AGENT Causes reduction in molecule

therefore is oxidized“LEO the lion says GER!”


FIRST LAW OF THERMODYNAMICS Energy can neither be made nor

destroyed; only changed fromone form to another

The TOTAL AMOUNT of energy inthe universe remains constant


SECOND LAW OF THERMODYNAMICS

ENTROPY is increasing, i.e. disorder is more likely than order Entropy is the measure of

disorder in a system


METABOLISM

Second Law of Thermodynamics


FREE ENERGY: That energy in a system that is available to dowork

Free Energy equals ENTHALPYminus ENTROPY times Ko


Josiah Willard GibbsProfessor of Mathematics Yale University


METABOLISMGIBBS FREE ENERGY: Josiah Willard Gibbs ΔG = CHANGE in Free Energy

Negative value - exothermicPositive value – endothermic

ACTIVATION ENERGY:Energy required to initiate a chemical reaction


METABOLISMCATALYSTS: Lower Activation nrg.ENZYMES:

Protein catalystsMechanisms of Action (4)Factors Affecting Activity: Inhibition

Competitive Inhibition Non-Competitive Inhibition


METABOLISM


METABOLISM

Copyright © 2005 Brooks/Cole — Thomson Learning

Biology, Seventh Edition CHAPTER 6 Energy and Metabolism

Competitive and noncompetitive inhibition


ENZYMES:

Factors Affecting Activity:Activation “Activators” Maintain “active

configuration”


ENZYME COFACTORS: Usually inorganic substances e.g. ions

COENZYMES: Nonprotein organicmolecules (vitamins)

NADH (reduced form)FADH2 (reduced form)


Biological Redox

Often a PAIR of H atoms are removed, & one proton and 2 electrons are then transferred to NAD+


COENZYME NADH


ADENOSINE TRIPHOSPHATE (ATP)Nucleotide consisting of:

RiboseAdenine (N-containing base)Three PO4 groups

Transient Existence (Use it orlose it)


METABOLISM

Phosphate groups

Adenine

Ribose


Energy (Potential) stored in bondYields 7.3 kcal/mol when

ATPADPProvides energy for most

endergonic reactionsCoupled Reactions


EVOLUTION OF METABOLISM 1. Degradation 2. Glycolysis 3. Anaerobic Photosynthesis 4. Nitrogen Fixation 5. O2 Forming Photosynthesis 6. Aerobic Respiration


GLUCOSE CATABOLISM

A.STAGE I: GLYCOLYSISB.STAGE II: PYRUVATE OXIDATIONC.STAGE III: KREBS CYCLED.STAGE IV: ELECTRON TRANSPORT


METABOLISM


METABOLISMA.GLYCOLYSIS: A process that occursin the cytoplasm of every living cell

1. Glucose Priming: This changes glucose into a molecule that can be“cleaved”.Requires 2 molecules of ATPPhosphofructokinase: commits glucose to glycolysis


METABOLISM


METABOLISMA.GLYCOLYSIS:2. Splitting & Rearrangement:

Six carbon compound splits to (2) 3 carbon cmpds.

Fructose 1,6, Diphosphate into(2) Glyceraldehyde 3 PO4

“Substrate Level Phosphorylation” Making ATP (4 molecules/glucose)


METABOLISM


METABOLISMGLYCOLYSIS: 3. Oxidation: Removal of electrons

(energy) & capturing in NADHfrom NAD+.

4. ATP Generation: 4 reactions thatconvert G-3-PO4 to PyruvateGenerates 2 ATP per Pyruvate


METABOLISM


GLYCOLYSIS RESULTS IN: Glucose → 2 molecules Pyruvate 2 molecules ADP → ATP for each

molecule of pyruvate 2 molecules NAD+ → NADH from

oxidation of glyceraldehyde-3-PO4


B. Oxidation of Pyruvate: Occursin mitochondrion

1. Aerobic conditions Pyruvate OXIDIZED to Acetyl CoA

2. Anaerobic conditions result in FERMENTATION REACTIONS


METABOLISMMetabolism of

Pyruvate


METABOLISM


METABOLISMFERMENTATION REACTIONS: 1.Lactic Acid Fermentation:

Pyruvate REDUCED to LactateNo CO2 removalNADH → NAD+

2. Alcohol Fermentation:Fungal (Yeast) CellsPyruvate REDUCED to AlcoholCO2 Removed; NADH → NAD+


METABOLISM

Cytosol


METABOLISM

BIO 101. 102ENERGY & METABOLISM

C. KREBS CYCLE: 1. “Priming” Reactions

Prepares the molecule for energy extraction Acetyl CoA (2C) joins oxaloacetate (4C) to form Citrate (6C)Citrate isomerizes to Isocitrate


METABOLISM


C. KREBS CYCLE: 2. “Energy Extraction”- oxidation

reactions disassembling the molecule Decarboxylation Reactions Reduction NAD+→ NADH Reduction FAD+ → FADH2

Regeneration oxaloacetate


METABOLISM


THE MALATE SHUTTLE


D. ELECTRON TRANSPORT System of REDOX reactions Series of membrane electron carriers Ubiquinone (quinone molecule)

Cytochromes (contain Fe++)OXYGEN is final electron acceptorWater is final product (two H+)

attach to oxygen


METABOLISM


METABOLISMD. ELECTRON TRANSPORT:The movement of electrons down the concentration gradient to O2 as the final acceptor releases protons (H+) to the intermembrane spaceProtons move thru ATP synthase making ATP from ADP (oxidative phosphorylation)


METABOLISM

Four majorcomponents of electron trans-

port system


METABOLISM


Malate-Aspartate Shuttle


METABOLISM


METABOLISMENERGY (ATP) YIELD per GLUCOSE Glycolysis: 2ATP by substrate level

phosphorylation Oxidation Pyruvate: 2 NADH (3 ATP per) Krebs Cycle: 6 NADH (3 ATP per)

2 FADH2 (1-2 ATP per)2 ATP via GTP

Electron Transport: 32 ATP oxidativephosphorylation


METABOLISM


Oxidation of Fatty Acids in Mitochomdria & Peroxisomes


METABOLISMAlternative Energy Sources

FOOD

complex carbohydrates

simple sugars

pyruvate

acetyl-CoA

glycogenfats proteins

amino acids

carbon backbones

fatty acids

glycerol

NH3

PGAL

glucose-6-phosphate

GLYCOLYSIS

KREBS CYCLE

urea

Figure 8.11Page 145


METABOLISMControl of Glucose Catabolism Feedback inhibition

Phosphofructokinase inhibited by: ATP levels Citrate levelsPhosphofructokinase stimulated by ADP levels AMP levels


ControlOf

Metabolism


There is a mutualistic symbioticrelationship between the productsof glycolysis and the requirementsfor photosynthesis. This is an interrelationship between the cell’smitochondria and chloroplast.


Processes Are Linked

sunlight energy

water+

carbondioxide

PHOTOSYNTHESIS

AEROBICRESPIRATION

sugarmolecules

oxygen

In-text figurePage 146


METABOLISM


METABOLISMPHOTOSYNTHESIS: LIGHT DEPENDENT REACTIONS

1. Captures energy2. Makes ATP & NADPH

LIGHT INDEPENDENT REACTIONS

3. Use ATP & NADPH for synthesis organic compound


METABOLISM

Copyright © 2005 Brooks/Cole — Thomson Learning

Biology, Seventh Edition CHAPTER 8 Photosynthesis: Capturing Energy

Overview of photosynthesis


METABOLISMPHOTOSYNTHESIS:A process whereby radiant

electromagnetic energy (light) is transformed by a specific photochemical system located in the thylakoid to yield chemical energy in the form of reducing potential (NADPH) and ATP.


METABOLISM


CHLOROPLAST Double membrane, DNA containing

organelle Internal membrane formed into:

Thylakoids (contain photosystem)Grana (stacks of thylakoids)

Stroma in internal compartment


PHOTOSYSTEM OVERVIEW: Acts as an antenna, i.e. absorbs

light energy Energy passed via chlorophyll Förster resonance energy transfer Energy transfer @ Reaction Center Membrane Proteins move energy Forms ATP and NADPH


METABOLISM


METABOLISMPHOTOSYSTEM OVERVIEW:

THE PROCESS OF TRANSDUCTION OF LIGHT ENERGY INTO CHEMICAL NRG,THE PHOTOCHEMICAL EVENT, IS THE ESSENCE OF PHOTOSYNTHESIS.


ELECTROMAGNETIC SPECTRUM Visible Light Spectrum

Range from 400nm-750nmGamma rays to Radio WavesMeasured in cps (Hertz)λ is symbol for wavelength


Absorption Spectrum ofChlorophyll a


METABOLISM


METABOLISMOVERALL Rx OF PHOTOSYNTHESIS: 6CO2+12H2O→C6H12O6+6O2+6H2OReactions of Photosynthesis are divided into:“Photo”, i.e. light dependent in thylakoid“Synthesis”, i.e. carbon fixation; light

independent, occurs in the stroma


METABOLISMLIGHT DEPENDENT REACTIONS 1. Primary Photo Event 2. Electron Transport 3. Chemiosmosis

May be Cyclic or NoncyclicLIGHT INDEPENDENT REACTION 1. Calvin-Benson Cycle

CO2 FixationOrganic Synthesis


PHOTOSYSTEMS: a network of Chlorophyll a and accessory pigments held within a proteinmatrix on the surface of the photo-synthetic membrane.


METABOLISM


METABOLISM PHOTOSYSTEMS CONSIST OF: 1. Antenna Complex 2. Reaction Center

PHOTOSYSTEM I: Absorption peak of 700nm. (P700) PHOTOSYSTEM II: Absorption peak of 680nm. (P680)


NONCYCLIC ELECTRON TRANSPORT

Begins with Photosystem IIPheophytin (1o electron acceptor)Electron Transport ChainPhotolysis (splitting water): This is the MOST IMPORTANT chemical reaction on earth.


METABOLISM


Formation of Oxygen duringNon-Cyclic photosynthesis


Cyclic Electron Transport


Cyclic Photosynthesis


LIGHT INDEPENDENT REACTION

Utilizes the materials from the light dependent reactions, i.e.

Energy (ATP from Photo 2) Reducing Power (NADPH from Photo 1)

PHOTOSYNTHESISCALVIN CYCLE

3CO2 + 9ATP + 6NADPH + water

reacts to yield

3-PGA + 8Pi + 9ADP + 6 NADP+


METABOLISM


Terminal Events of Calvin Cycle … Synthesis of SucroseIn cytoplasm of cell


CRASSULACEAN ACID PATHWAYPresent in warmer climatesAllows stomata to close during

day (Preserve H2O)Characterized by:

CactusPineapple

“Temporal” separation of steps


C4 PATHWAY (Hatch-Slack Pathway)

Allows stomata to close duringday

Characterized by:Grasses, Sugar Cane, Corn

“Spatial” Separation of steps


C4 Pathway


C3 Leaf C4 Leaf

Chloroplast


Anatomy of the Vascular SheathIn C4 Leaves


METABOLISM


METABOLISMFACTORS AFFECTING PHOTOSYNTHESIS

1.Water Shortage2.Temperature3.Light Intensity


PHOTORESPIRATION

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BIO 101, 102 ENERGY & METABOLISM

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