Exchange Surfaces Flashcards
How do singular celled organisms exchange substances?
Singular celled organisms like Amoeba use diffusion for gas exchange.
They can diffuse substances directly in and out across the cell surface membrane.
What are the three ways that absorption can be done?
- Diffusion
- Osmosis
- Active transport
What does diffusion do?
Exchange gases such as Oxygen and Carbon Dioxide
What does Osmosis do?
Exchanges liquid such as water
What does Active Transport do?
Exchange glucose and proteins
Smaller organisms have a smaller/larger surface area to volume ratio
larger
Larger organisms have a smaller/larger surface area to volume ratio
smaller
Larger organisms require ________ exchange systems
specialised
What are 4 examples of specialised exchange surfaces?
- Alveoli in lungs
- Villi in small intensines
- Leaves & root hair cells of plants
- Gills on fish
What is the villi’s adaptation?
Large surface area for absorption
What is the blood supply in the small intestines adaptation?
Good blood supply - speeds up absorption
What is the concentration gradient’s adaptation in the small intenstines?
Large (good blood supply) - speeds up diffusion and osmosis
Why do villi have a single layer of cells?
Short distance to diffuse across
Villi have ________ permeable membranes with ___________ molecules in them
Partially & transport
What does the villi’s partially permeable membrane allow?
Allows osmosis of water and active transport of glucose, amino acids, fatty acids and glycerol to occur
