METABOLISM

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METABOLISM
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YOU MUST KNOW

• THE KEY ROLE OF ATP IN ENERGY COUPLING
• THAT ENZYMES WORK BY LOWERING THE ENERGY OF
  ACTIVATION
• THE CATALYTIC CYCLE OF AN ENZYME THAT RESULTS IN
  THE PRODUCTION OF A FINAL PRODUCT
• THE FACTORS THAT INFLUENCE THE EFFICIENCY OF
  ENZYMES

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CONCEPT 8.1

• AN ORGANISMS METABOLISM TRANSFORMS MATTER AND
  ENERGY, SUBJECT TO THE LAWS OF THERMODYNAMICS

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METABOLISM

• THE TOTALITY OF AN ORGANISMS CHEMICAL REACTIONS
• MANAGES THE MATERIAL AND ENERGY RESOURCES OF THE
  CELL

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CATABOLIC PATHWAY

• LEADS TO THE RELEASE OF ENERGY BY THE BREAKDOWN
  OF COMPLEX MOLECULES
• TO SIMPLER
• COMPOUNDS
• EX. BREAKDOWN
• OF FOOD

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ANABOLIC PATHWAY

• CONSUME ENERGY TO BUILD COMPLICATED MOLECULES
  FROM SIMPLER ONES
• EX. LINKING a.a.
• TO FORM MUSCLE
• PROTEIN IN
• RESPONSE
• TO PHYSICAL
• EXERCISE

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ENERGY

• THE CAPACITY TO DO WORK
• KINETIC ENERGY ENERGY DURING MOVEMENT
• POTENTIAL ENERGY STORED ENERGY
• CHEMICAL ENERGY A FORM OF POTENTIAL ENERGY
  WHERE ENERGY IS STORED IN MOLECULES AND THE
  AMOUNT DEPENDS ON ITS CHEMICAL BONDS

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THERMODYNAMICS

• STUDY OF ENERGY TRANSFORMATIONS THAT OCCUR IN
  MATTER
• FIRST LAW OF THERMODYNAMICS THE ENERGY OF THE
  UNIVERSE IS CONSTANT AND THAT ENERGY CAN BE
  TRANSFERRED AND TRANSFORMED, BUT CANNOT BE
  CREATED OR DESTROYED

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THERMODYNAMICS

• SECOND LAW OF THERMODYNAMICS EVERY ENERGY
  TRANSFER, OR TRANSFORMATION INCREASES THE ENTROPY
  OR THE AMOUNT OF DISORDER OR RANDOMNESS, IN THE
  UNIVERSE

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CONCEPT 8.2

• THE FREE-ENERGY CHANGE OF A REACTION TELLS US
  WHETHER THE REACTION OCCURS SPONTANEOUSLY

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FREE ENERGY

• THE PART OF A SYSTEMS ENERGY THAT IS ABLE TO
  PERFORM WORK WHEN THE TEMPERATURE OF A SYSTEM IS
  UNIFORM
• INCLUDES EXERGONIC AND ENDERGONIC REACTIONS

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EXERGONIC REACTION

• ENERGY IS RELEASED
• OCCURS SPONTANEOUSLY (THAT DOESNT NECESSARILY
  MEAN QUICKLY) AND RELEASE FREE ENERGY TO THE
  SYSTEM

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ENDERGONIC REACION

• REQUIRES ENERGY IN ORDER TO PROCEED
• ABSORB FREE ENERGY
• THEY REQUIRE FREE ENERGY FROM THE SYSTEM

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CONCEPT 8.3

• ATP POWERS CELLULAR WORK BY COUPLING EXERGONIC
  REACTIONS TO ENDERGONIC REACTIONS

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ENERGY COUPLING

• THE WAY CELLS MANAGE THEIR ENERGY RESOURCES TO DO
  CELL WORK
• THE USE OF AN EXERGONIC PROCESS TO DRIVE AN
  ENDERGONIC ONE

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ATP

• THE PRIMARY SOURCE OF ENERGY FOR CELL IN ENERGY
  COUPLING
• MADE UP OF THE NITROGENOUS BASE ADENINE, RIBOSE,
  AND A CHAIN OF 3 PHOSPHATE GROUPS
• WHEN A PHOSPHATE GROUP IS HYDROLYZED, ENERGY IS
  RELEASED IN AN EXERGONIC REACTION

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RELEASE OF ATP

• WORK IN THE CELL IS DONE BY THE RELEASE OF A
  PHOSPHATE GROUP FROM ATP
• THE EXERGONIC RELEASE OF THE PHOSPHATE GROUP IS
  USED TO DO THE ENDERGONIC WORK OF THE CELL
• WHEN ATP TRANSFERS ONE PHOSPHATE GROUP THROUGH
  HYDROLYSIS, IT BECOMES ADP

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CONCEPT 8.4

• ENZYMES SPEED UP METABOLIC REACTIONS BY LOWERING
  ENERGY BARRIERS

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CATALYSTS

• SUBSTANCES THAT CAN CHANGE THE RATE OF REACTION
  WITHOUT BEING ALTERED IN THE PROCESS
• ENZYMES ARE MACROMOLECULES THAT ARE BIOLOGICAL
  CATALYSTS

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ACTIVATION ENERGY

• THE AMOUNT OF ENERGY IT TAKES TO START A REACTION
• THE AMOUNT OF ENERGY IT TAKES TO BREAK THE BONDS
  OF THE REACTANT MOLECULES
• ENZYMES SPEED UP REACTIONS BY LOWERING THE
  ACTIVATION ENERGY OF THE REACTION BUT WITHOUT
  CHANGING THE FREE ENERGY CHANGE OF THE REACTION
• THE ENZYME ACTS ON A SUBSTRATE

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ACTIVE SITE

• THE PART OF THE ENZYME THAT BINDS TO THE
  SUBSTRATE
• FORMS AN ENZYME-SUBSTRATE COMPLEX THAT IS HELD
  TOGETHER BY WEAK INTERACTIONS
• SUBSTRATE IS THEN CONVERTED INTO PRODUCTS THAT
  ARE RELEASED FROM THE ENZYME

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WHAT AFFECTS ENZYME ACTIVITY?

• CHANGES IN pH AND TEMPERATURE
• 3-D SHAPE IS CHANGED SO THE ENZYME WILL NOT
• BE AS EFFECTIVE
• (DENATURES)

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• MANY ENZYMES REQUIRE NONPROTEIN HELPERS CALLED
  COFACTORS TO FUNCTION PROPERLY
• ORGANIC COFACTORS ARE REFERRED TO AS COENZYMES

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COMPETITIVE INHIBITORS

• REVERSIBLE INHIBITORS THAT COMPETE WITH THE
  SUBSTRATE FOR THE ACTIVE SITE ON THE ENZYME
• SIMILAR CHEMICALLY TO THE SUBSTRATE
• REDUCE THE EFFICIENCY OF THE ENZYME AS IT
  COMPETES FOR THE ACTIVE SITE

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NONCOMPETITIVE INHIBITORS

• DO NOT DIRECTLY COMPETE WITH THE SUBSTRATE
• IMPEDE ENZYME ACTIVITY BY BINDING TO ANOTHER PART
  OF THE ENZYME
• CAUSES ENZYME TO
• CHANGE SHAPE MAKING
• THE ACTIVE SITE
• NONFUNCTIONAL

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CONCEPT 8.5

• REGULATION OF ENZYME ACTIVITY HELPS CONTROL
  METABOLISM

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ALLOSTERIC SITE

• A SPECIFIC BINDING SITE BUT NOT THE ACTIVE SITE
• ONCE BOUND, THE SHAPE OF THE ENZYME IS CHANGED
  AND IT CAN EITHER STIMULATE OR INHIBIT ENZYME
  ACTIVITY

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FEEDBACK INHIBITION

• A TYPE OF
• ALLOSTERIC
• INHIBITION
• IT INCREASES THE EFFICIENCY OF THE PATHWAY BY
  TURNING IT OFF WHEN THE END PRODUCT ACCUMULATES
  IN THE CELL