Diffusion, gas exchange and respiration Flashcards
Which substances do humans need to take in?
Oxygen, glucose, water, mineral ions, dissolved food molecules
Which substances do humans need to remove?
carbon dioxide, urea, excess mineral ions, excess water
What is the site of gas exchange in humans?
alveoli
How does surface area affect rate of diffusion?
larger surface area to volume ratio = faster diffusion
What is a concentration gradient?
Difference in concentration between two areas
How does concentration gradient affect rate of diffusion?
Larger/steeper concentration gradient = faster diffusion
How does diffusion distance affect rate of diffusion?
Further distance / thicker membrane = faster diffusion
How does temperature affect rate of diffusion?
Higher temperature = faster diffusion
Why does temperature affect rate of diffusion?
At higher temperatures molecules gain energy so move faster, speeding up diffusion
What is diffusion?
Movement of molecules from an area of high concentration to an area of low concentration down a concentration gradient
Name 3 features of alveoli which make them suitable for gas exchange
thin walls, good blood supply, large surface area:volume ratio
What is the word equation for aerobic respiration?
glucose + oxygen -> carbon dioxide + water
What is the word equation for anaerobic respiration?
Glucose -> lactic acid
What is the purpose of respiration?
To produce energy for life processes
When is anaerobic respiration used?
When the body cannot supply enough oxygen to cells, e.g. during intense exercise
