What does the body extract from food for energy?
The body extracts the chemical bond energy
How are elements released after bond energy is extracted?
The atoms are released back to the environment as carbon dioxide gas and water
How is excess energy stored if not immediately needed?
It is stored as fat
What is the main source of energy for muscles?
The breakdown of carbohydrates into glucose
What happens to muscle tissue during starvation?
It is broken down in a process called cannibalization
What are anabolic reactions?
Reactions involved in building molecules, such as protein synthesis and lipid synthesis/storage
What are catabolic reactions?
Reactions involved in breaking down molecules for energy, such as the breakdown of complex carbohydrates, proteins, or stored fat
Do muscles store excess ATP?
No, they do not.Energy is mainly stored as fat
How is quick energy stored in muscles?
As a molecule called creatine phosphate
How does creatine phosphate generate ATP for contraction?
When energy is needed, the enzyme creatine kinase transfers the phosphate group from creatine phosphate onto an ADP molecule to form ATP
How long can creatine phosphate supply ATP?
About ten seconds worth of ATP energy, enough for a short burst
What is muscle glycogen?
]Small amounts of glucose linked together to form a polysaccharide and stored within muscles
How long can muscle glycogen support activity?
Only enough to support short bursts of energy
What is the overall process where glucose is broken down into CO2 and H2O?
Aerobic respiration
Where is ATP released during substrate-level phosphorylation?
During glycolysis and the citric acid cycle (Krebs cycle)
Where is the majority of ATP formed?
By oxidative phosphorylation in the electron transport system
How is the energy transferred to form ATP in the final step?
Energy is released when hydrogen ions move down their concentration gradient across the mitochondrial membrane
What is the fate of the hydrogen ions after generating ATP?
They bond with inhaled oxygen to form water
What are the four main stages of aerobic respiration?
Glycolysis, Transformation of pyruvate into acetyl CoA, Krebs cycle, and Oxidative phosphorylation
What causes the aerobic system to “back up” like a traffic jam?
When oxygen levels are too low to bind up the hydrogen produced, typically when the rate of metabolism exceeds the person’s conditioning level
When oxygen levels are inadequate, what must cells rely on?
Anaerobic metabolism for energy
What happens to pyruvate when the aerobic pathway is backed up?
Pyruvate cannot enter the citric acid cycle.Instead, it retains hydrogen atoms to form lactic acid through a process called fermentation
How does lactic acid contribute to fatigue?
Lactic acid decreases muscle pH, which leads to pain and fatigue
What is the Cori cycle?
A process where liver cells regenerate glucose from lactic acid
