Transport Flashcards
Diffusion
Spreading out of particles resulting in a net movement from area of high concentration to low concentration
Where does diffusion take place?
In and out of the cell membrane
Examples of diffusion (gas exchange in cells)
Oxygen from blood (high concentration from lungs) into body cells (low concentration)
For aerobic respiration
But then have high concentration of co2 in cell
So co2 moves out via diffusion into bloodstream
Urea
Waste product produced in cells from broken down ammonia
Diffuses out into the blood plasma then excreted
Example of diffusion
Urea from breakdown of ammonia in cells (high concentration)
To blood plasma (low concentration)
Factors affecting diffusion
Concentration gradient
Temperature
Surface area of membrane
How does concentration gradient affect diffusion?
Concentration gradient (difference in concentration)
Quicker rate = larger concentration gradient
How does temperature affect diffusion?
Quicker rate = warmer because have particles move faster with more energy thus quicker net movement of particles
How does surface area affect diffusion?
Greater surface area = higher rate of diffusion
As more particles can diffuse at once
Ósmosis
Diffusion of water from a dilute solution (lots of water) to a concentrated solution (little water)
Through partially permeable membrane
What is the concentration gradient in osmosis?
Follows the concentration gradient
From many water particles to low water particles
Partially permeable membrane
Allows some molecules to pass through
Such as water as they are smaller
Ósmosis in animal cells by putting it in water
Low amount of water (concentrated) in the cytoplasm
Placing it in water = water will move into the cell by osmosis
Then expand
What happens if an animal cell has too much water diffuse into it by osmosis?
It will expand then burst
As it contains to much water
Ósmosis in animal cells by putting it in a concentrated solution
Water moves from the cell into the solution as the cell contains more water
Thus shrink
Placing a plant cell in water
Will expand
But WONT burst as it becomes swollen instead = turgid
Because the cell all protects it from doing so
Placing a plant cell in a concentrated solution
Will shrink
Because more water in the cell than the solution so ósmosis of particles out of the cell
Thus becomes flaccid
When does active transport occur?
When a cell needs to bring a molecule into it that already has a high concentration of it inside the cell
Active transport
The net movement of substances from a low concentration to a higher concentration
Thus going against the concentration gradient
What does active transport require?
Energy from respiration
Does diffusion require energy?
No
Examples of active transport
Sugars From the small intestine to the bloodstream
Mineral ions from soil into root hair cells
Active transport of sugars in small intestine
After digestion enters the lumen of small intestine
Moves into the blood stream through cells
Said cells contain many mitochondria for energy
Active transport of mineral ions into root hair cells
Root hair cells contain many mitochondria for respiration
As concentration of ions in soil is lower than in the root hair cell
