3.3 (cellular) respiration (ppt 3.3; 7.1)

define respiration

the process by which organisms release energy in the form of ATP by consuming molecules like glucose and breaking them down

state the diff between breathing and respiration

breathing involves movement of air in and out of the lungs

respiration refers to release of energy in the form of ATP when cells break down glucose 

define aerobic respiration in human cells

the release of energy in the form of ATP by the breakdown of glucose in the presence of oxygen

state the word and chemical equation of aerobic respiration

glucose (C₆H₁₂O₂) + oxygen (6O₂) → carbon dioxide (6CO₂) + water (H₂O)

define anaerobic respiration in human cells

the release of energy in the form of ATP by the breakdown of glucose in the absence of oxygen

state the word equation of anaerobic respiration

glucose → lactic acid

compare aerobic and anaerobic respiration (S+D)

similarities:

• both involve breakdown of glucose

• both releases energy in the form of ATP

differences:

• O₂

  • present in aerobic

  • absent in anaerobic

• energy in the form of ATP

  • aerobic releases large amount

  • anaerobic releases relatively small amount

• product

  • aerobic — carbon dioxide + water

  • anaerobic — lactic acid

• location

  • aerobic — mitochondria in cells

  • anaerobic — muscle cells

why do muscle cells need more energy during vigorous activity/exercise?

because muscle cells contract continuously, increasing their energy demand for movement

how do muscles get more energy to contract (increased energy demand) during vigorous activity/exercise?

aerobic respiration in muscle cells increase

• increased breathing to obtain oxygen

• increase heart rate to supply oxygen

why do cells switch to anaerobic respiration during vigorous activity/exercise?

when continuous muscle contraction occurs, aerobic respiration alone is not fast enough to supply the increase in energy demand, so anaerobic respiration takes place to meet the increased energy demand (as they do not require oxygen)

define oxygen debt

amount of oxygen required to remove lactic acid

how is the build up of lactic acid in muscles removed?

• continued fast / high heart rate

• continued deeper and faster breathing

why does the heart rate remain fast / high after exercise?

• to transport lactic acid to liver via blood for removal

• to transport oxygen to liver

why does deeper and faster deep breathing continue after vigorous exercise?

to obtain oxygen for supply to liver

when is oxygen debt considered repaid?

when all lactic acid has been removed from the body