Chapter 12: Respiration Flashcards
How is energy used in the body?
Muscle contraction - for movement
Protein synthesis - making proteins
Cell division - making cells for growth and repair
Active transport - moving molecules across a cell membrane against a concentration gradient
Conduction of nerve impulses
Maintaining constant body temperature
Where does respiration take place?
In the mitochondria of cells and is controlled by many different enzymes.
Define aerobic respiration.
Aerobic respiration is defined as the chemical reactions in cells that use oxygen to break down nutrient molecules to release energy.
What does aerobic mean?
Means that oxygen is required for the chemical reaction to occur.
Write the equation for aerobic respiration.
glucose + oxygen —–> carbon dioxide + water + energy
C6H12O6 + 6O2 —–> 6CO2 + 6H2O + ATP
Define anaerobic respiration.
Anaerobic respiration is defined as the chemical reactions in cells that break down nutrient molecules to release energy without oxygen.
What does anaerobic mean?
absence of oxygen
Where does anaerobic respiration occur?
It takes place in plant cells and some microorganisms.
What is anaerobic respiration in yeast used for?
brewing
bread-making
Write the equation for anaerobic respiration in yeast.
glucose —-> ethanol + carbon dioxide
C6H12O6 —-> 2C2H5OH + 2CO2
When does anaerobic respiration take place in muscles?
During vigorous or prolonged exercise where muscle cells do not receive sufficient oxygen to maintain aerobic respiration.
This leads to the incomplete breakdown of glucose into lactic acid.
Write the word equation for the anaerobic respiration in muscles.
glucose —–> lactic acid
Why is anaerobic respiration less efficient?
Because it releases much less energy per glucose molecule that is broken down.
Aerobic respiration releases 19 times more energy than anaerobic respiration from the same amount of glucose.
Explain oxygen debt.
Vigorous exercise leads to a build-up of lactic acid which is toxic to the cells.
To be removed, the lactic acid needs to be oxidised to carbon dioxide and water.
This creates an oxygen debt that needs to be repaid once exercise has stopped.
What does accumulation of lactic acid result in?
Muscular fatigue, leading to cramps.
