exchange surfaces Flashcards
what are the three main factors needed for an exchange system
size
activity level
sa;v ratio
why do multicellular organisms need specialised gas exchange surfaces
they have a smaller sa;v ratio, therefore diffusion distances are too long, substances cant easily enter the cells
what is sa;v ratio calculated
surface area/ volume
what are three features of a efficient gas exchange system
large sa
short diffusion distances
steep concentration gradient.
how are steep concentration gradients maintained
good blood supply or ventialtion
why is diffusion easier in single celled organism
because there cytoplasm is very close to the environment they live in- diffusion pathway is short
what size organism has a large surface area; vol ratio
small
why is a high level of activity a factor regarding exchange
metabolic activity uses energy from food and o2 to release atp in aerobic respiration.
therefore require a good supply of nutrients and oxygen to supply energy.
what other procces in mammals requires energy
thermoregulation
what features in the mitochondria increase surface area; volume ratio
folded membranes- cristae
