A2 Biology - ATP and Energy

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  • Created by: dom
  • Created on: 03-01-15 12:04

ENERGY

ENERGY - THE ABILITY TO DO WORK

  • ENERGY TAKES A VARIETY OF FORMS - LIGHT, HEAT, SOUND, ELECTRICAL, MAGNETIC ETC.
  • IT CAN BE CHANGED FROM ONE FORM TO ANOTHER 
  • IT CANNOT BE CREATED NOR DESTROYED 
  • MEASURED IN JOULES 

ORGANISMS REQUIRE ENERGY TO STAY ALIVE 

ENERGY INITIALLY COMES FROM THE SUN 


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WHY DO ORGANISMS NEED ENERGY

  • METABOLISM - ALL REACTIONS REQUIRE ENERGY 
  • MOVEMENT - WITHIN (BLOOD) AND OF THE ORGANIMS ITSELF
  • ACTIVE TRANSPORT - IONS AND MOLECULES AGAINST A CONCENTRATION GRADIENT
  • MAINTENANCE - REPAIR - DIVISION OF CELLS -
  • PRODUCTION OF SUBSTANCES - E.G. ENZYMES 
  • MAINTENANCE OF BODY TEMP - MAMMALS AND BIRDS ANIMALS - ENDOTHERMIC - NEED TO REPLACE LOST HEAT 
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ENERGY AND METABOLISM

LIGHT ENERGY FROM THE SUN IS CONVERTED INTO CHEMICAL ENERGY THROUGH PHOTOSYNTHESIS 

CHEMICAL ENERGY, IN THE FORM OF MOLECULES, CONVERTED TO ATP DURING RESPIRATION IN CELLS

ATP IS USED BY CELLS TO PERFORM USEFUL WORK 

ATP IS MADE UP OF ADENINE, RIBOSE SUGAR AND 3 PHOSPHATES 

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HOW ATP STORES ENERGY

ADENOSINE TRIPHOSPHATE

IT HAS 3 PHOSPHATE GROUPS 

BONDS BETWEEN THESE PHOSPHATES ARE UNSTABLE - THEY HAVE A LOW ACTIVATION ENERGY 

EASILY BROKEN 

WHEN THEY BREAK THEY RELEASE A LOT OF ENERGY 

WATER IS USED TO CONVERT ATP TO ADP - HYDROLYSIS REACTION 


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SYNTHESIS OF ATP

ENERGY CAN BE USED TO ADD PHOSPHATE TO ADP TO FORM ATP

KNOWN AS CONDENSATION REACTION - WATER IS REMOVED 

IT OCCUR IN THREE WAYS 

  • PHOTOPHOSPHORYLATION - TAKES PLACE IN CHLORPHYLL DURING PHOTOSYNTHESIS 
  • OXIDATIVE PHOSPHORYLATION - OCCURS IN THE MITOCHONDRIA DURING RESPIRATION IN ELECTRON TRANSPORT CHAIN 
  • SUBSTRATE LEVEL PHOSPHORYLATION - WHEN PHOSPHATE GROUPS ARE TRANSFERRED FROM DONOR MOLECULES TO ADP TO MAKE ATP.
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ROLES OF ATP

ATP IS A GOOD ENERGY DONOR BECAUSE INSTABLE PHOSPHATE BONDS - THIS ALSO MEANS ITS NOT A GOOD LONG TERM ENERGY SOURCE 

FATS AND CARBOHYDRATES - ARE A MUCH BETTER LONG TERM ENERGY SOURCE 

ATP IS THEREFORE AN IMMEDIATE ENERGY SOURCE 

AS A RESULT THEY DONT NEED A LARGE SUPPLY OF ATP, ONLY A FEW SECONDS SUPPLY - BECAUSE IT IS RAPIDLY REFORMED 

ATP IS A BETTER IMMEDIATE ENERGY SOURCE THAN GLUCOSE BECASUE....

  • ATP RELEASES LESS ENERGY - SMALLER MORE MANAGEBLE QUANTITIES 
  • SINGLE REACTION - HYROLYSIS - GLUCOSE IS A LONG SERIES OF REACTIONS.

ATP CANNOT BE STORED SO HAS TO BE CONTINOUSLY MADE IN MITOCHOINRIA E.G. CELLS IN SMALL INTESTINE - REQUIRE ENERGY FOR MOVEMENT HAVE ALOT OF ENERGY FOR MOVEMENT 

ATP IS SOURCE OF ENERGY FOR 

  • METABOLIC PROCESSES - PROVIDES ENERGY TO BUILD UP MACROMOLECULES 
  • MOVEMENT - MUSCLE CONTRACTIONS 
  • ACTIVE TRANSPORT - PROVIDES ENERGY TO CHANGE SHAPE OF IONS GOING AGASINT GRADIENT 
  • SECRETION - FORMS LYSOSOMES FOR SECRETION OF CELL PRODUCTS 
  • ACTIVATION OF MOLECULES 
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