2.8.1 The Requirement for Transport Systems Flashcards
In order for any organism to function properly, it needs what to exchange substances?
It needs substances such as food molecules and waste products, between itself and its environment
This exchange of substances occurs across what?
The cell membrane
What are the three transport processes that living organisms use for exchange?
diffusion, osmosis and active transport
Unicellular (single-celled) organisms like amoeba have very large surface areas (SA) in comparison to what?
Their volumes
How big is the distance between the surface of the organism to its centre?
Distance is very small.
Do unicellular organisms need to have specialist exchange surfaces or transport systems; as diffusion, osmosis and active transport through the cell membrane occur at a sufficient rate to meet the organisms needs?
No
Do large, multicellular organisms like humans have relatively small surface areas (SA) in comparison to their volumes?
Yes
What is the distance between the surface of the organism to its centre?
It’s relatively long
Why do larger organisms usually have exchange surfaces and transport systems?
Diffusion, osmosis and active transport cannot occur at a sufficient rate to meet the needs of the organism
What two exchange surfaces are there in animals?
The lungs and alveoli for gas exchange
The small intestines and villi for absorption of digested food
What are the Transport systems in animals?
The blood and circulatory system carries the necessary substances around the body
What two Exchange surfaces are there in plants?
Roots and root hairs where mineral ions and water are absorbed
The leaves for gas exchange
What are the two Transport systems in plants?
The xylem moves water and mineral ions from roots to shoots
The phloem moves sugars and amino acids to where they are needed in the plant
