1.5 Exchanging materials Flashcards
What is the primary function of exchange surfaces in multicellular organisms?
To facilitate the exchange of materials with the environment
Exchange surfaces are crucial for maintaining homeostasis by allowing the uptake of nutrients and the excretion of waste.
What are the key characteristics that exchange surfaces must have?
- Thin
- Moist
- Large surface area
- High concentration gradient
These characteristics enhance the efficiency of material exchange.
What is diffusion in the context of respiratory gases?
The passive movement of gases from a high concentration to a low concentration area until equilibrium is established
This process does not require energy and occurs across the cell membrane.
What materials do animals take in from their environment?
- Oxygen
- Water
- Carbohydrates
- Lipids
- Proteins
- Vitamins
- Minerals
These materials are essential for various biological functions.
What materials do animals release into their environment?
- Excess water
- Salts
- Toxic waste products (e.g., urea, carbon dioxide)
These materials must be excreted to maintain homeostasis.
What is the significance of a high surface-area-to-volume ratio in exchange surfaces?
It allows for more efficient exchange of materials
A higher ratio means more surface area is available for diffusion relative to the volume of the substance.
What role does moisture play in the exchange of materials?
Moisture assists the transport of materials across the exchange surface by allowing substances to diffuse as dissolved solutes
Without moisture, diffusion would be less efficient.
True or False: Diffusion requires energy input.
False
Diffusion is a passive process that does not require energy.
What is the primary role of capillaries in exchange surfaces?
To provide a rich blood supply that helps maintain a steep concentration gradient
This enhances the efficiency of material transport to and from the exchange surfaces.
Fill in the blank: The movement of substances across exchange surfaces occurs through the process of _______.
DIFFUSION
Diffusion is driven by concentration gradients.
What substances are exchanged at the alveoli?
- Carbon dioxide
- Oxygen
- Water
The alveoli facilitate gas exchange in the respiratory system.
What substances are exchanged at the villi?
- Water
- Amino acids
- Sugar
- Fatty acids
- Glycerol
Villi are specialized for nutrient absorption in the digestive system.
What substances are exchanged in the nephrons?
- Urea
- Water
- Salts
Nephrons are part of the excretory system and help in waste removal.
What is the consequence of a large cell volume on diffusion?
It results in a lower surface area to volume ratio, slowing the diffusion of oxygen, nutrients, and waste
Larger cells may require additional transport mechanisms for efficient exchange.
Describe the structure of alveoli that facilitates gas exchange.
- Thin walls (one cell thick)
- Moist surface
- Rich network of capillaries
These adaptations maximize the surface area for gas exchange.
What is the function of microvilli in the villi?
To increase surface area and enhance nutrient absorption
Microvilli are tiny projections that further improve the efficiency of exchange.
What is the function of the glomerulus in the nephron?
To aid in the absorption of substances into the blood
The glomerulus is a cluster of capillaries crucial for filtration.
