B2.2.1 - Exchange And Transport Flashcards
What is the surface area to volume ratio?
The surface area per unit volume of an object
Why is surface area to volume ratio important?
It can help with diffusion
If an organism is large, will the surface area volume ratio be higher or lower?
Lower
If an organism is small, will the surface area volume ratio be higher or lower?
Higher
Why can most multicellular organisms not use simple diffusion to survive?
It can not occur fast enough to meet the cells’ demands
What do lungs have to help with gas exchange?
Alveoli
Why are alveoli important to lungs?
It maximises the rate of diffusion into the bloodstream as it increases the surface area
What are exchange surfaces?
A process where an organism exchanges something in need of something else
What do intestines contain to help with diffusion?
Villi
What does villi do to help the intestines?
It increases the surface area of the intestines
Why is it good for the intestines to have a high surface area?
It increase the rate of diffusion of digested food molecules
What do you call the villi which are on the villi that are very small?
Microvilli
What tubes carry water and mineral ions around in a plant?
Xylem tubes
What tubes can transport sugars and amino acids in plants?
Phloem tubes
How are alveoli adapted for gas exchange?
Spherical shape gives relatively large surface area
Very thin walls mean shorter distance for diffusion
Ventilation moves air in and out and helps maintain a steep diffusion gradient
Good blood supply maintains concentration gradient for diffusion by removing oxygen and bringing lots of carbon dioxide
