Cell Biology - Cell transport Flashcards
What is diffusion?
The spreading out of particles resulting in a net movement from an area of high to low concentration.
What is a concentration gradient?
The difference in concentration between 2 areas.
What factors affect the rate of diffusion?
- The concentration gradient = the steeper concentration gradient, the faster the rate of diffusion.
- The membrane surface area = the larger the membrane surface area, the faster the rate of diffusion.
- The temperature = the higher the temp, the faster the rate of diffusion.
What is osmosis?
The diffusion of water from a dilute solution to a concentrated through a partially permeable membrane.
Where does the water molecules move from and to?
Lower solute concentration area to an area of higher solute concentration.
Does diffusion require energy?
No its a passive process.
Does osmosis require energy?
No its a passive process.
What is active transport?
The movement of particles from a dilute solution to a more concentrated solution using energy from respiration.
How do the particles in active transport move?
Against the concentration gradient from an area of low to high concentration.
Does active transport require energy?
Yes - using energy released from respiration.
What are 2 examples of diffusion in humans?
- Urea diffuses from cells into the blood for excretion by the kidney.
- Nutrients in small intestine diffuse into blood in the capillaries through the villi.
What are examples of diffusion in fish?
- Oxygen from water passing over the gills diffuses into the blood in the gill filaments.
- Carbon dioxide diffuses from blood in the gill filaments into the water.
What are examples of diffusion in plants?
- Carbon dioxide and oxygen diffuse into the leaves through the stomata.
What is an example of osmosis in fish?
Water moves from a dilute solution in the soil to a concentrated solution in the root hair cell.
What is an example of active transport in humans?
It allows sugar molecules to be absorbed from the small intestine when the sugar concentration is higher in the blood than in the small intestine.
What is an example of active transport in plants?
Used to absorb mineral ions into the root hair cells from more dilute solutions in the soil.
Why is the villi in the small intestine adapted?
To absorb nutrients.
What are the adaptations of the villi?
- Network of capillaries.
- Large surface area.
- Thin wall + one cell think.
- Good blood supply.
Why is the alveoli in the lungs adapted?
For gas exchange.
What are the adaptations of the alveoli?
- Network of capillaries provides a good blood supply.
- Large surface area.
- Moist.
- One cell thick.
Why are fish gills adapted?
For gas exchange.
What are the adaptations of fish gills?
Made of stacks of thin filaments with:
- Large surface area.
- A network of capillaries.
Why are root hair cells adapted?
For the uptake of water and minerals.
What are the adaptations of root hair cells?
- Lots of mitochondria to take in mineral ions by active transport.
- Large surface area.
