Surface area to Volume ratio Flashcards
What is the surface area to volume ratio of a small organism such as an amoeba?
Very large surface area in comparison to their volume. Thus, they have a large surface for exchange of substances. But they have a small distance from the outside to the middle of it. As a result, they can simply exchange substances across their surface.
What is the surface area to volume ratio of a larger organism?
Smaller surface area to volume ratio. The distance from the outside to the middle is larger. They’ll typically have a higher metabolic rate.
What is the metabolic rate?
Amount of energy used up by an organism within a given period of time.
What does having a higher metabolic rate mean?
It demands efficient transport of waste out of cells.
6 Examples of adaptations that increase surface area to volume ratio?
Villi and Microvilli
Thin Leaves on a plant
Alveoli and Bronchioles
Spiracles and Tracheoles
Many Capillaries
Gill Filaments and Lamellae
How are villi an adaptation to increase surface area to volume ratio?
They’re covered in microvilli which increases the surface area to volume ratio. Thus they have more efficient absorption for the digestion of food.
How are alveoli and bronchioles an adaptation to increase surface area to volume ratio?
Millions of alveoli and branches of bronchioles increase the surface area. Beneficial for gas exchange.
How are leaves on plants an adaptation to increase surface area to volume ratio?
Leaves are very broad and thin which increases the surface area to maximise gas exchange.
How are capillaries an adaptation to increase surface area to volume ratio?
Capillaries occur as capillary network meaning there is a very large number of capillaries providing a large surface area for gas exchange.
What is metabolic rate measured by?
Oxygen uptake as used in aerobic respiration to make ATP for energy release.
Explain the relationship between SA:V and metabolic rate.
As SA:V increases (in smaller organisms), metabolic rate increases because the rate of heat loss increases so organisms need a higher rate of respiration to release enough heat to maintain a constant body temperature.
Explain how the body of a single-celled organism is adapted for gas exchange.
Thin, flat shape and large SA:V ratio. Short diffusion distance to all parts of cell. Rapid diffusion of O2 and CO2.
