Download 3. Related Pathways

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Related Pathways
Organisms are able to metabolize nutrients other than carbohydrates during times of
starvation
Once broken down, these monomers are able to feed into various parts of glycolysis or the
Krebs cycle (Fig.1, p.117)
Protein Catabolism
 Through a process called deamination, proteins remove amino groups from the amino acids
converting the group to ammonia, NH3 (urea is expelled from the body in urine)
Lipid Catabolism
 Glycerol can be converted to glucose through a process called gluconeogenesis
 Fatty acids undergo beta-oxidation where 2-C acetyl groups are removed
 Fats can produce 20% more ATP than carbohydrates
Anaerobic Pathways (does not require oxygen)
 Mainly used by bacteria and protistans that live in oxygen-free settings, although lactate
fermentation can occur in multicellular organisms
1. Ethanol Fermentation (through glycolysis)
2 ADP
2 ATP
(Fig.2, p.119)
Glucose (6-C)
2 NAD+
2 NADH
(x2) Pyruvate (3-C)
CO2
(x2) acetaldehyde (2-C)
2 NADH
2 NAD+
(x2) ethanol (2-C)
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Ex/when yeast consumes sugar and releases CO2, it causes bread to rise)
2. Lactate Fermentation (through glycolysis)
2 ADP
2 ATP
Glucose (6-C)
2 NAD+
2 NADH
(x2) Pyruvate (3-C)
2 NADH
2 NAD+
(x2) Lactate (3-C)
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Ex 1/ Lactic acid builds up in muscle cells
Ex 2/ Producing yogurt from milk
(Fig.4, p.120)