Active transport, Diffusion and Osmosis Flashcards
1
Q
What is active transport?
A
- moving substances against a concentration gradient
- from a more dilute solution to a more concentrated solution
2
Q
How does active transport work?
A
- using carrier proteins in cell membrane
- uses energy from respiration
- moves substances into/ out of cell
3
Q
Give an example of active transport in plants
A
- root hair cells absorb mineral ions from dilute solution from soil
- needs mineral ions for healthy growth
4
Q
Give an example of active transport in animals
A
- absorbing sugar from intestine into blood
- lower concentration in gut than blood stream
5
Q
What is diffusion?
A
- net movement of particles from an area of higher concentration to lower concentration
down the concentration gradient
6
Q
Give an example of diffusion in animals
A
- oxygen and digested food molecules moving into cells
- carbon dioxide + urea moving out of cells
7
Q
What are the 4 factors that affect rate of diffusion?
A
- concentration gradient - steep so that chance of particles moving from high -> low is higher
- temperature - increases kinetic energy of particles = moves faster
- surface area - more membrane for particles to move across
- diffusion distance
smaller organism = larger SA to volume ratio
8
Q
Explain how the small intestine is adapted to increase the rate of diffusion
A
- villi + microvilli increase SA
- wall of villi= thin, shorter diffusion distance
- well supplied with blood in capillaries = larger conc. grad.
9
Q
Explain how the lungs are adapted to increase the rate of diffusion
A
- capillaries surrounding alveoi + good ventilation = higher conc. grad.
- alveoi wall + capillary wall = 1 cell thick = small diffusion distance
- folded surfaces = larger SA
10
Q
Explain how fish gills are adapted to increase the rate of diffusion
A
- gill filaments = increase SA
- filamentes well supplied with blood = higher conc. grad.
- thin walled = shorter diffusion pathway
- floor of mouth moves down to draw water in and moves it up to push water out of gill slits- ventilates gills
11
Q
What is osmosis?
A
- diffusion of water from a dilute solution to more concentrated solution through a partially permeable membrane
- no energy needed
- does not allow solute to diffuse through
12
Q
What happens when the cell is in a dilute solution?
A
- mass and volume increase
- water moves into cell
13
Q
What happens when the cell is in a concentrated solution?
A
- volume + mass decrease
- water moves out of cell
14
Q
what happens when the cell is in a solution of same concentration?
A
- no net movement of water
- volume + mass stay the same
