1. Enzymes and Cellular Respiration
Metabolism
Enzymes and Cellular Respiration

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3. Metabolism
Metabolism is the sum of all the chemical reactions in a cell
Anabolism – Chemical reactions that build molecules by using available energy to form bonds
Catabolism – Chemical reactions that break down larger molecules to release energy, making it available to do work

4. Enzymes Enzymes- Organic Catalysts Speed up reactions
Lower the energy of activation
Used but not used up
Specific to a chemical reaction or substrate
Substrates – the molecules acted on by enzymes
End Products – The products of chemical reactions involving enzymes
Names – “-ase” ending added to substrate or the reaction
Lipase – breaks down lipids
Deaminase – Removes an amine group
(not all enzymes end in “-ase” – like trypsin)

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7. Active sites
Certain critical areas of the enzyme that have a shape that matches the substrate of the reaction.
Shape dictates function – therefore, if the shape of the active site changes, the function is altered.
Enzymes are made of protein – therefore temperature and pH are critical conditions required for enzymatic functioning.

8. Energy and ATP Energy – the ability to do work
Kinetic – energy in motion or of movement
Potential – stored energy (gravitational, elastic, and chemical)
Exergonic – energy released as a product (heat released)
Endergonic – energy needed (a reactant in the chemical reaction) (heat absorbed)
ATP – Adenosine TriPhosphate - Nucleotide containing:
Adenine
Ribose
3 Phosphates
Calorie – unit of energy = amount of energy required to raise the temperature of 1 Kilogram of water 1° C. (nutritional Calorie = 1 Kilocalorie = 1000 calories). Capitalized C in Calorie – tells you that it is the Kilocalorie. When you say that a candy bar has 240 Calories, you are talking about the Kilocalorie.
ATPase – enzyme that breaks down ATP – ATP  ADP + P
ATP Synthase – enzyme that speeds up the production of ATP – ADP+P  ATP

9. Catabolism of Glucose
Respiration – a series of biochemical reactions in which energy is liberated – then used to synthesize ATP. The overall reaction is exergonic – not all energy released is used to make ATP.
Formula:
C6H12O6 + 6O2  6CO2 + 6H2O ATP

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ATP structure

12. Overall Aerobic Respiration Reaction
Steps:
Glycolysis
Transition
Kreb’s Cycle (Tricarboxylic Acid – TCA cycle) (Citric Acid Cycle)
Electron Transport Chain (Chemiosmosis)

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14. Glycolysis Location – Cytoplasm of both eukaryotic and Prokaryotic
Reactants – Glucose (6 C sugar) molecule + 2 ATP (to prime the pump)
Products:
2 NADH
4 ATP – therefore a Net of 2 ATP
2 Pyruvic Acid (3 C sugar)

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16. Fermentation
If no oxygen is available – then the cell goes into Fermentation and various products are produced:
Acids
Alcohol
Carbon dioxide

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19. Transition Transition – Considered part of the Kreb’s cycle
Location – Cytoplasm
Eukaryotic cells - it is transitioning into the mitochondria
Prokaryotic cells - it is in cytoplasm
Reactants – 2 Pyruvic Acid
Products –
2 NADH,
2 CO2,
2 Acetyl Co-A (2 C Sugar)

20. Kreb’s Cycle
Also called Tricarboxylic Acid and Citric Acid Cycle – for the recycled molecules in the cycle
Location
Matrix of mitochondria (Eukaryotic)
Cytoplasm (Prokaryotic Cells)
Reactants – 2 Acetyl Co-A
Products –
6 NADH
2 FADH2
4 CO2
2 ATP

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22. Electron Transport Chain
Also known as Chemiosmosis
Series of oxidation (loses electrons oxidation) and reduction (gains electrons reduction) reactions will pass the electrons from carrier molecules to proton pumps – powering the movement of protons across the membrane into the inner membrane space (or periplasmic space in prokaryotes).
Hydrogen ions build up in the “inner membrane space” – increasing the potential energy
Hydrogen ion will move across the membrane through ATP synthase molecule – Producing high energy phosphate bonds in ATP
Location – Inner membrane Space of Mitochondria (Eukaryotes) or Periplasmic Space (Prokaryotes)
Reactants
6 Oxygen molecules – end electron receptor
10 NADH - Each NADH has enough potential energy to produce 3 ATP (except the 2 NADH in Eukaryotic Cells produced during Glycolysis – which only produce 2 ATP/NADH)
2 FADH2 - Each FADH2 has enough potential energy to produce 2 ATP
Products
28-30 ATP produced from NADH and 4 ATP produced from FADH2
6 H2O

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26. Other Aspects of Catabolism
Catabolism of other Carbohydrates (ie Starch)
Hydrolysis – addition of water and specific enzymes for each carbohydrate (called hydrolases) will cause the decomposition of these carbohydrates
Catabolism of Proteins and Fats - Hydrolysis

27. Anabolism of Carbohydrates
Photosynthesis
Energy + 6CO2 + 6H2O  C6H12O6 + 6O2
Using light from the sun to synthesize carbohydrates

28. Anabolism of Proteins Protein Synthesis
Occurs in Ribosomes of Eukaryotics and Prokaryotics
Removing water to form peptide bonds between carboxyl group and amine group of two different amino acids
Transcription – making RNA from DNA code
Translation – making Proteins from RNA
Replication – making a copy of DNA for new cells during cell cycle