Cellular Energy: ATP & Enzymes. What is it? Where do we get it? How do we use it?

Transcription

1 Cellular Energy: ATP & Enzymes What is it? Where do we get it? How do we use it?

2 Energy The capacity to perform work; ability to rearrange matter Energy is required to drive reactions 2 forms: Potential Energy (PE): stored energy, due to position of structure Kinetic Energy (KE): Energy of motion Heat is KE associated with the movement of molecules/atoms within matter

3 Energy is just transformed Total amount of Energy in Universe is constant (1 st Law) Nothing created or destroyed, only transformed One result of ALL energy transfers is the production of heat (2 nd Law) Heat = disordered, unharnessed KE. This KE is LOST; cannot be used to perform work

4 Energy is lost during rxns

5 Chemical Reactions Endergonic (energy input): Store Energy products have higher energy than reactants; Anabolic Exergonic (energy output): Release Energy products have lower energy; Catabolic

6 Endergonic/Anabolic Photosynthesis: Reactants = CO 2 & H 2 O + light energy Products = sugar molecules

7 Exergonic/Catabolic Bonfire Reactants: Cellulose (glucose), O 2 Products: light, heat, CO 2, H 2 O Cellular respiration burns glucose to harness energy for work

8 Anabolic and Catabolic Reactions ANABOLIC REACTIONS Glycogen Triglycerides Protein Uses energy Uses energy Uses energy Glucose + Glucose Glycerol + Fatty acids Amino acids + Amino acids CATABOLIC REACTIONS Glycogen Triglycerides Protein Glucose Glycerol Fatty acids Amino acids Yields energy Yields energy Yields energy Yields energy

9 Cellular metabolism The sum of all cellular endergonic and exergonic rxns. Energy coupling (transfer) = use of released energy to run cellular processes ATP provides coupling mechanism

10 ATP High energy bonds join negatively charged phosphate groups Energy in bonds + energy of magnetic repulsion (high PE!) Hydrolysis rxn frees trapped energy

11 ATP Some freed energy is lost as heat The rest is transferred via the phosphate group when it binds to another molecule (phosphorylation)

12 ATP fuels ALL cellular work

13 ATP is continually regenerated

14 Enzymes are also required to drive reactions

15 Enzymes lower Activation Energy Some energy (E A ) must be applied to begin a rxn Sometimes the energy barrier is prohibitively large Enzymes reduce that barrier, allowing rxn to proceed with LESS energy input

16 Enzyme cycle 1. Available enzyme w/ active site 2. Substrate binds 3. Conversion to products 4. Products released

17 Enzymes possess: Ideal temperature regimes Ideal ph ranges Cofactors (inorganic molecules & ions) and coenzymes (organic molecules)

18 What fuels our bodies? 1. Adenosine triphosphate (ATP) 2. Creatine Phosphate (CP) 3. Glucose 4. Fats

19 What fuels our bodies? Adenosine triphosphate (ATP) THE energy carrying molecule in the body Muscles store only enough ATP for 1 3 seconds of activity ATP must be generated continuously Usually via carbohydrate metabolism with or without O 2

20 ATP structure

21 Alternative Fuels After depleting ATP stores, muscles turn to other sources: Creatine phosphate (CP) stores energy that is used to make ATP Creatine phosphate stores enough energy for 3 to 15 seconds of maximal physical effort

22 CP transfers P to make ATP

23 Glucose After CP, Glucose is the next source of energy for production of ATP Metabolism of glucose Anaerobic breakdown of glucose yields 2 ATP molecules (no O 2 ) Aerobic breakdown of glucose yields molecules of ATP (with O 2 )

24 Glucose metabolism In cytoplasm In mitochondria

25 Fat as fuel Stored triglycerides can be metabolized to generate ATP For low intensity exercise For exercise of long duration Ex: 10 hr. car-to-car approach + climb Abundant energy source. Provides 2x more energy per gram as carbohydrate

26 Carbs. or Fats Use BOTH as energy sources for production of ATP Carbohydrates - high intensity activity Fats - low intensity exercise Proteins (amino acids) rarely used as a fuel source for exercise

27 Distribution Short duration, max. int. (0-3 sec) Short duration, high int. (10-12 sec) Short-Mid duration, high int. (4-6 min) Mid duration, moderate int. (32-40 min) Long duration, moderate int. (2.5-3 hr) Extended duration, low-mod int. (5.5-7 hr)

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