4.2 Respiration Flashcards
What is aerobic respiration?
An exothermic reaction in which glucose reacts with oxygen to release energy which can be used by cells
What are the equations for aerobic respiration? (word and symbol)
glucose + oxygen –> carbon dioxide + water (+ energy)
C6H12O6 + 6O2 –> 6CO2 + 6H2O (+ energy)
Where does aerobic respiration take place?
In the mitochondria
Why do organisms require the energy released by respiration?
● Synthesis of larger molecules
● Muscle contraction
● Maintenance of body temperature
● Active transport
What is anaerobic respiration?
An exothermic reaction in which glucose is broken down to release energy in the absence of oxygen
What is the word equation for anaerobic respiration?
glucose –> lactic acid (+ energy)
Why is anaerobic respiration less efficient than aerobic respiration?
Glucose is not completely broken down, so less energy is transferred
Why can anaerobic respiration lead to muscle fatigue?
Lactic acid (product of anaerobic respiration) builds up in muscles, preventing efficient contraction.
What is an oxygen debt?
The amount of oxygen needed to convert lactic acid back into glucose after anaerobic respiration
What is fermentation?
A type of anaerobic respiration that occurs in yeast cells
What is the word equation for fermentation?
Glucose –> ethanol + carbon dioxide (+ energy)
Why is the fermentation reaction important?
It is used in the production of bread and alcoholic drinks
What are the differences between aerobic and anaerobic respiration?
● Aerobic requires oxygen; anaerobic does not
● Aerobic produces CO2 and water; anaerobic produces lactic acid or ethanol + CO2
● Aerobic transfers a greater amount of energy
How do muscles store glucose?
As glycogen in their cells
What changes take place when muscular activity increases in the body?
● Heart rate increases and arteries dilate which increases the flow of oxygenated blood to muscles
● Breathing rate increases and breathing is deeper
which increases the rate of gaseous exchange
● Stored glycogen is
converted back into glucose
How is lactic acid transported away from the muscles? (Higher)
Blood flow through the muscles transports lactic acid to the liver, where it is oxidised back to glucose.
What is metabolism?
The sum of all the reactions that take place in a cell or an organism
How do cells use the energy transferred by energy?
To continuously carry out enzyme-controlled processes which lead to the synthesis of new molecules
Give examples of metabolic reactions
● Glucose into
starch/glycogen/ cellulose
● Glycerol and fatty acids into lipids
● Glucose and nitrate ions into amino acids
● Photosynthesis
● Respiration
● Breakdown of excess proteins into urea
