exchange surfaces Flashcards
which makes for more efficient diffusion: a large surface area:volume or a small surface area:volume
a large surface area to volume ratio
do large organisms or small organisms have a higher surface area to volume ratio
small organisms
why does a large surface area overcome a decrease in the surface area to volume ratio
a large surface area allows more efficient diffusion, this is found in prokaryotic cells which their large surface area allows them to meet the cells energy requirements without respiration like in eukaryotic cells which have to use mitochondria to respire
why does a thin membrane overcome a decrease in the surface area to volume ratio
it makes a short diffusion pathway
why do transport systems overcome a decrease in the surface area to volume ratio
transport systems allow for a higher concentration gradient to be maintained, transport systems also allow substances to move closer to the cells where exchange is needed
how does heat transfer overcome a decrease in the surface area to volume ratio
some large animals have adaptations that allow heat to be transferred efficiently, animals in cold climates have to conserve heat and animals in warmer climates have to be able to transfer the heat to outside of their body so that they dont overheat, eg elephants have large vascularised ears that allow for heat to be easily transferred to outside of the body
why do single celled organisms need to exchange substances
they need substances for processes inside the cell such as oxygen for respiration, waste products also need to be able to leave the cell to avoid harming the cell
is the diffusion rate in a single celled organism high or low
high-it is extremely fast
gas exchange in insects
insects use a tracheal system, a network of small tubes which pump oxygen around the body, spiracles to tracheoles to trachae which have tracheal fluid, during an active period this will move by osmosis into the cell allowing for direct diffusion of oxygen
what is the most efficient gas exchange system
the tracheal system
gas exchange in fish
when the mouth opens the water enters into the bucal cavity due to it being a lower pressure than the environment, when the mouth closes the oeperculum are opened and water is forced across the gills, oxygen from the water diffuses into the blood vessels
how is the fish gas exchange system adapted for efficient diffusion
fish use counter current flow to maintain a high concentration gradient, the gill filliaments also increase the surface area which means that gas exchange is more efficient, the gills are also covered with lamellae which increases the surface area
how is the mammilian gas exchange system structured
the air travels through a highly branched system where there is a large surface area for efficient gas exchange
how is the trachea adapted for gas exchange
rings of cartilage provide protection and structure, these are c shaped so that they do not constrict the oesophagus
what do the bronchi consist of
cartilage and smooth muscle
