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chapter 3: movement of substances into or out of cells - Coggle Diagram
chapter 3: movement of substances into or out of cells
diffusion (passive transport)
the net movement of particles from a region of their higher concentration to a region of their lower concentration
diffuse down a concentration gradient
concentration gradient between point A to B
can occur across a permeable membrane
factors affecting diffusion:
temperature
increase temperature will increases the kinetic energy ( increase rate of diffusion)
distance
how fast a substance travels depends on the distance, the shorter the distance the faster the rate of diffusion
surface area to volume ratio
rate of movement of a substance depends on how big the cell membrane area is, the greater the area of cell membrane per unit volume, the faster the rate of diffusion
only allow some substance pass through cell membrane, ex. carbon dioxide & oxygen can pass through membrane but proteins cannot
can also occur in solutes, ex. dissolved glucose enters the liver cells from the blood capillaries
osmosis
only involves in water
water potential used in connection with osmosis; move down a water potential gradient
is the net movement of WATER MOLECULES through a partially permeable membrane, from a region of higher water potential to a region of lower water potential
cell placed in higher water potential solution, the cell sap will have lower water potential
by osmosis, the water will enters through the partially permeable cell membrane
the cell will expands / swell / turgid
as water enters the cell, the vacuole increases in size and it exerted turgor pressure which pushes the cytoplasm against the cell wall
cell did not burst as it has a cell wall
if the cell was placed in lower water potential solution, by osmosis the water from the vacuole will leave the cell through the partially permeable cell membrane. The cell decrease in size and become flaccid, the cell is plasmolysed.
animal cell will burst as they don't have cell wall to protect
Crenation- if animal cell was placed in a concentrated solution ( more solute) the cell shrinks and little spikes will appear on the cell membrane. The animal cell will become dehydrated and die
add too much fertiliser around the roots will cause the soil solution become very concentrated and water will DIFFUSE out of the roots by osmosis
active transport
is the movement of particles through a cell membrane from a region of lower concentration to a region of higher concentration
against the concentration gradient
require energy from respiration
occurs in living cells only as living cells respire, ex. human body, uptake of glucose by the villi in the small intestine into the blood capillaries
requires protein molecules (carrier proteins) which carry the particles across the membrane