Exchange Surfaces Flashcards
Cell Biology (18 cards)
What process do cells use to take in substances and remove waste products?
Diffusion
Which gases are transferred between cells and the environment during gas exchange?
Oxygen and carbon dioxide
What is urea?
A waste product produced from the breakdown of proteins
How does urea leave the cells in humans?
It diffuses from cells into the blood plasma for removal by the kidneys
What does the surface area to volume ratio (SA : V) indicate?
How easily an organism can exchange substances with its environment
What happens to the surface area to volume ratio as an organism increases in size?
The surface area becomes smaller compared to the volume
How is the surface area of a block calculated?
Length x Width
What is the total surface area of a hippo represented as a 2 cm x 4 cm x 4 cm block?
84 cm²
How is the volume of a block calculated?
Length x Width x Height
What is the volume of the hippo block?
32 cm³
What is the surface area to volume ratio of the hippo?
84 : 32 or simplified to 2 : 1
What is the surface area of a mouse represented as a 1 cm x 1 cm x 1 cm block?
8 cm²
What is the volume of the mouse block?
1 cm³
What is the surface area to volume ratio of the mouse?
8 : 1
How do single-celled organisms exchange gases and dissolved substances?
Directly across the cell membrane
Why do multicellular organisms need exchange surfaces?
They have a smaller surface area compared to their volume, which is insufficient for diffusion
What adaptations do exchange surfaces have to maximize effectiveness?
- Thin membrane
- Large surface area
- Lots of blood vessels
Why are exchange surfaces in animals often ventilated?
To ensure air moves in and out
