biology 12 - respiration. cellular respiration provides energy for the cell occurs in all cells net...
TRANSCRIPT
Biology 12 - respiration
Cellular respirationProvides energy for the cell
Occurs in all cells
Net equation:
glucose + oxygen carbon dioxide + water + energy (ATP)
Occurs as a series of reactions, involving many different enzymes
Involves anaerobic and aerobic reactions
ATP and ADP
• Act as chemical batteries
• Carry and release small amounts of energy
energy
adenosine
phosphateadenosine
ATP
ADP
Anaerobic respiration
• Occurs in the cytoplasm
• Does not need oxygen
• Involves 2 processes – glycolysis and fermentation
Glycolysis
• Glucose is broken down into 2 pyruvate (pyruvic acid) molecules
• Reactions use 2 ATP
• Reactions make 4 ATP
• Net ATP = 2/glucose molecule
FermentationIn animals:
Pyruvate is converted to lactic acid
In plants and fungi:
Pyruvate is converted to ethanol and carbon dioxide
Aerobic respiration
• Occurs in the mitochondrion
• Needs oxygen
• Involves Transition reaction, Krebs cycle and Electron transport chain
• Involves many reactions and enzymes
• Produces 36 ATP
• Waste products are carbon dioxide and water
Structure of mitochondrion
Transition reaction
• Pyruvate attaches to Coenzyme A to form Acetyl Coenzyme A
• Acetyl Coenzyme A enters mitochondrion and releases the pyruvate into the Krebs cycle
• Coenzyme A can also pick up fatty acids and take them into the Krebs cycle
Transition reaction
Krebs cycle
• Occurs in the matrix of the mitochondrion
• A cycle of reactions generates ATP and hydrogen ions (carried by NAD and FAD carriers to electron transport chain)
• Waste product is carbon dioxide
• Produces 2 ATP/glucose molecule
Krebs cycle
Carrier proteins
Carry hydrogen ions to electron transport chains
NAD NADH + H+
FAD FADH2 + H+
Electron transport chain
• Found in the cristae (inner membranes) of the mitochondrion
• ATP is generated as hydrogen ions are passed down the chain
• Oxygen is used up
• Waste product is water
• Produces 34 ATP/glucose molecule
Electron transport chain
Summary of reactions
Comparison of aerobic and anaerobic respiration
Anaerobic Aerobic
Site it occurs cytoplasm mitochondrion
Need for oxygen no yes
Waste products Animals – lactic acid
Plants – carbon dioxide and alcohol
Carbon dioxide and water
Amount of ATP 2/glucose molecule 36 – 38/glucose molecule
Reactions involved
Glycolysis
Fermentation
Glycolysis
Transition reaction
Krebs cycle
Electron transport chain