Transport in Cells Flashcards
Diffusion
What is diffusion?
The net movement of particles from an area of high concentration to an area of low concentration.
Diffusion
What three main factors affect the rate of diffusion?
- Concetration gradient- larger gradient, faster diffusion
- Temperature- higher temperature, faster diffusion
- Surface area- larger surface area, faster diffusion
Diffusion
Give examples of substances transported by diffusion in the lungs and kidneys.
- Lungs- oxygen diffuses into the blood from the lungs and carbon dioxide diffuses into the lungs from the lungs, both down their concentration gradient.
- Kidney- urea diffuses from cells into blood plasma so it can be excreted in urine.
Diffusion
How is surface area to volume calculated?
Surface area = Number of sides x (Side length x Side width)
Volume = length x width x depth
Ratio = Surface area:Volume
Osmosis
What is Osmosis?
The movement of water from a high concentrated solution to a low concentrated solution through a partially permeable membrane.
Osmosis
What is meant when a solution in isotonic to a cell?
The concentrations of the external and internal solutions are the same.
Osmosis
What is meant when a solution is hypertonic to a cell?
The concentration of the external solution is higher than that of the internal solution
Osmosis
What is meant when a solution is hypotonic to a cell?
The concentration of the external solution is lower than that of the internal solution
Osmosis
What may happen if an animal cell is placed in a hyoptonic solution?
Water moves in the cell, causing it to burst
Osmosis
What may happen when an animal cell is placed in a very hypertonic solution?
What moves out of the cell, causing it to shrivel up
Osmosis
What may happen when a plant cell is placed in a very hypertonic solution?
Water moves out of the cell by osmosis and the vacuole and the cytoplasm decrease in size. The cell membrane may pull away from the cell wall, causing the cell to become plasmolysed.
Active Transport
What is Active Transport?
The movement of molecules from an area of low concentrationg to an area of high concentration, against the concentration gradient, using energy from respiration in the form ATP
Active Transport
How do root hair cells use active transport?
To take up mineral ions from a more dilute solution in soils.
Active Transport
How is active trasport used to absorb the products of digestion?
It is used to transport glucose in a low concentration in the gut to a high concentration in the blood. Glucose is then transported to the tissues where it can be used for respiration.
