Exchange And Transport In Animals - TOPIC 8 Flashcards
Learn about topic 8
what is the need to transport oxygen and carbon dioxide into and out of cells
cells need oxygen for aerobic respiration which produces carbon dioxide as a waste product and so it needs to leave the cell both by DIFFUSION
what is the need to transport urea out of the body
urea is a waste product produced by animals and it diffuses from cells into the blood plasma for removal from the body by the kidneys
volume =
length x width x height
area =
length x width
why are exchange surfaces needed in multicellular organisms
they have a smaller surface area compared to their volume, which makes it difficult to exchange enough substances to supply their entire volume across their outside surface alone
they need it for efficient diffusion
why do multicellular organisms need a transport system
to move substances between the exchange surface and the rest of the body
what factors affect the rate of diffusion
surface area
concentration gradient
diffusion distance
what is the need to transport urea out of the body
urea is a waste product produced by animals and it diffuses from cells into the blood plasma for removal from the body by the kidneys
volume =
length x width x height
area =
length x width
why are exchange surfaces needed in multicellular organisms
they have a smaller surface area compared to their volume, which makes it difficult to exchange enough substances to supply their entire volume across their outside surface alone
they need it for efficient diffusion
why do multicellular organisms need a transport system
to move substances between the exchange surface and the rest of the body
how does surface area affect the rate of diffusion
the more surface area there is available for molecules to move across, the faster they can get from one side to the other
how does concentration gradient affect the rate of diffusion
substances diffuse faster if there is a big difference in concentration between the area they are diffusing from and the area they are diffusing to
how does diffusion distance affect the rate of diffusion
substances diffuse more quickly when they have not as far to move, so the thinner the exchange surface the shorter the distance substance have to diffuse across it so thew faster the rate of diffusion
what is ficks law
rate of diffusion is proportional to :
SA x concentration difference / thickness of membrane
according to Fick’s law, what will happen to the rate of diffusion if the SA doubles
rate of diffusion will double
according to Fick’s law, what will happen to the rate of diffusion if the thickness of the membrane halves
rate of diffusion will double
what are the adaptations of alveoli which maximise the diffusion of oxygen and carbon dioxide
they have an enormous SA
A moist lining for dissolving gases
very thin walls
a good blood supply to maintain the concentration gradients of oxygen and carbon dioxide
what is blood made up of
red blood cells
white blood cells
platelets
what is the function of red blood cells
to transport oxygen around the body
what are the adaptations of red blood cells
they have a bioconcave disc shape to give them a large SA for absorbing oxygen
they contain haemoglobin which carries the oxygen
they don’t have a nucleus which allows more room for haemoglobin which means they can carry more oxygen
what is the function of white blood cells
they help to defend against microorganism s that cause disease
what are phagocytes
a type of white blood cell which changes shape to engulf unwelcome microorganisms