transport through cell membrane: Biology Flashcards
revision
Transport through cell
membranes:
what is diffusion?
diffusion is the movement of the molecules of the region form a high concentration to a lower one
Transport through cell
membranes:
how does the difference in the concentration a factor in the rate of
diffusion?
the bigger the difference between the two sides of the membrane the quicker the rate of diffusion.
Transport through cell
membranes:
how is the temperature a factor in the rate of diffusion?
higher temperature gives molecules or ions more kinetic energy, molecules move around faster, so diffusion is faster.
Transport through cell
membranes:
how is the surface area a factor in the rate of diffusion
the bigger the surface area the faster the rate of the diffusion takes place, this occurs because the more molecules or ions can cross the membrane at any one moment.
Transport through cell
membranes:
how is the type of molecule or ion diffusing a factor in the rate of diffusion?
large molecules need more energy to get them to move soothes ten to diffuse more slowly, the non-polar molecules diffuse more easily than polar molecules because they are more soluble in the non polar phospholipid tails.
Transport through cell
membranes:
what is faciliated diffusion?
some molecules can’t diffuse across the phospholipid bilayer, e.g amino acids / sugars.
these molecules can pass through protein channels instead, diffusion through these channels is called facilitated diffusion.
Transport through cell
membranes:
what is osmosis?
the diffusion of water from a area of high concentration of water molecules to a area of low concentration across a permeable membrane.
Transport through cell
membranes:
what is active transport?
the movement of the molecules from a area of a low concentration to a high concentration
Transport through cell
membranes:
what is endocytosis andexocytosis?
endocytosis is the case when a molecule causes the cell membrane to bulge inward, forming a vesicle
