120 likes | 548 Views
Cellular Respiration Chemical Pathways Section 9-1. Flora Biology I. Chemical Energy and Food. Lots of energy present in food (glucose/other compounds) Ex: 1 gram glucose = 3811 calories Calorie – amount of energy required to raise one gram of water, one Celsius degree
E N D
Cellular RespirationChemical PathwaysSection 9-1 Flora Biology I
Chemical Energy and Food • Lots of energy present in food (glucose/other compounds) • Ex: 1 gram glucose = 3811 calories • Calorie – amount of energy required to raise one gram of water, one Celsius degree • Cells release the energy in glucose and other food compounds
Overview of Cellular Respiration • “reverse photosynthesis” • 6O2 + C6H12O6 → 6CO2 + 6H2O + energy • Cellular respiration – process of breaking down glucose and other food molecule in the presence of “oxygen” • Figure 9-2 (page 222)
Glycolysis • Glycolysis – one molecule of glucose is broken in half, producing two molecules of pyruvic acid and a 3-carbon compound • See figure 9-3(page 223)
Glycolysis • Key concepts: • Occurs in the cytoplasm of cell • No oxygen required for glycolysis to occur • Glucose is broken down into two 3-carbon pyruvates (pyruvic acid) • Net production of 2 ATP, 2 NADH, and 2 pyruvate molecules
Fermentation • Cellular respiration will NOT occur (Krebs and ETC) if oxygen is not present • If oxygen is not present, fermentation will occur • Fermentation – releasing of energy from food molecules by producing ATP in the absence of oxygen
2 Types of Fermentation • Alcoholic • Lactic acid
Alcoholic Fermentation • Pyruvic acid + NADH → alcohol + CO2 + NAD • Causes bread to rise • “anaerobic” – no oxygen present
Lactic Acid Fermentation • Pyruvic acid is converted into lactic acid • Pyruvic acid + NADH → lactic acid + NAD • Ex: muscle cells • Not enough ATP produced to lack of oxygen • Cells begin to produce ATP by lactic acid fermentation