III. Metabolism
A. Catabolism
B. Anabolism
C. ATP
D. Enzymes
Properties
Factors that influence activity
Temperature
pH
Substrate concentration
Inhibitors
E. Energy production
Redox
Catabolism
Fermentation
Aerobic respiration
Anaerobic respiration
 

The Big Picture- Catabolism of Glucose

•    Understand 6 carbon glucose is oxidized
    to CO2 releasing the energy to form ATP
•    Know electron/energy transfers
•    Oxidation and reduction processes
•    Know ATP production/phosphorylation
•    Understand glycolysis is the first step for most cells
•    Metabolic steps prevent over heating of cell
 
Example aerobic respirers
Example fermenters
Example anaerobic respirer
 

Nicotinamide Adenine Dinucleotide

    Important coenzyme
    Electron carriers
Shuttle e- from one reaction to another
NAD+ = oxidized can accept 2 electrons
NADH = reduced donates 2 electrons
 
Structure of glucose
    Hydrogens = electrons = energy
    Getting energy through catabolism
 

Metabolism roadmap

    Glycolysis FIG 5.11
 
Glycolysis (split)
Part I Spliting glucose
Fig. 5.12

Glucose prepared for ox.

• 2 ATP used – E investment
    Glycolysis (redox)
    Part II Redox
2 3C compounds oxidized to
    pyruvate
• 2 NAD+ used
• 4 ATP formed
NET: 4 ATP - 2 ATP = 2 ATP
 

Glycolysis Summary

•    First step in catabolism for most cells
•    Can work with or without oxygen
•    2 ATP generated
•    Substrate level Phosphorylation
•    2 NAD+ reduced to give NADH
•    Glucose 6 carbon to pyruvate 3 carbon
•    Only energy in fermentation produced in glycolysis
•    In cytoplasm
 

Metabolism roadmap Fig 5.11

Fermentation
 

Glycolysis & Fermentation

Fig. 5.18
Re-oxidize NAD
Dump reduced waste products
 

Lactic acid or alcohol fermentation

 

Acetaldehyde dehydrogenase requires NAD. Hangover

NAD is a coenzyme.

 

Fermentation products and organisms
Fig. 5.17
    Homolactic = Lactic acid only
    Heterolactic = Other acids or alcohols (waste)
 

Points to remember! Fermentation

    2 ATP from Glycolysis only
    Fermentation reoxidizes NADH to NAD +
    Reduced waste products are dumped
    Acids or alcohols are produced
    Organic final electrons acceptor
 
Metabolism roadmap
    Krebs Cycle
Pyruvate converted to acetyl CoA
   which enters Krebs Cycle
• 5 redox reactions (per pyruvate)
   e- extracted by oxidizing C
• ATP produced (1 per pyruvate)
 

Important points! Krebs Cycle!

    Each pyruvate gives 1 ATP
    Substrate phosphorylation
    AcetylCoA starts cycle
    Loss of 3 CO2 = 3 carbon pyruvate (oxidized)
    5 Redox per pyruvate
    Reduced carriers “store” electrons
    In membranes
 

Metabolism roadmap

    Electron transport
Electron Transport Chain
Fig. 5.14
e- transferred from NADH and FADH2 to a final e- acceptor
• Results in a buildup of H+ ions across membrane
e- transferred from NADH and FADH2 to a final e- acceptor
• Results in a buildup of H+ ions across membrane
    1 NADH = 3 ATP
    1 FADH2 = 2 ATP