SA to Vol ratio B4 Flashcards
What happens if the surface area is large? (Cell membrane)
The larger the SA of the membrane, the faster the diffusion rate because more particles can pass through at once
What happens if the volume of the cell is large? (Cytoplasm)
The larger the volume of the cell, the greater the demand for particles needed for the chemical reactions that are required to support the cell.
What needs to occur is you want efficient gas exchange?
The SA must be large compared to
its Volume.
How to calculate volume?
The volume of a block- Length x Width x Height
How do you calculate SA:Vol ratio?
Surface Area / Volume
Whatever number you get, put a :1 after it 💕
What happens when organism gets larger?
THE SA:VOL ratio decreases as organism gets larger ⬇️⬇️🤩🤩.
FO EXAMPLE:
As surface area to volume ratio decreases as an organism gets larger, a larger organism loses heat more slowly across its surface area than a smaller organism
How can a cell specialise to increase its surface to volume ratio?
Folded membranes increase Surface area.
Describe exchange in unicellular organisms
Gases and dissolved substances can diffuse directly in/out of cell across cell membrane.
They have LARGER SA COMPARED TO THEIR VOL so enough substances exchange across membrane to supply volume of cell.
Describe exchange in multi cellular organisms
*SMALLER SURFACE AREA TO VOLUME RATIO** not enough substances can diffuse from their outside surface to supply their entire volume 😔😔
Where can you find highly adapted exchange surfaces?
Lungs, intenstines and between bones
How are exchange surfaces adapted to maximize effectiveness?
-Thin membrane so short diffusion distance
-Large surface area so lots of substance can diffuse at once
-Ventilation to assist in gas exchange for animals.
