Final Flashcards
what is Diffusion
how molecules passively move from a region of high concentration to low concentration
what is Osmosis
a special type of diffusion that describes the movement of WATER from a region of higher concentration to low
What is the law of diffusion
As cells become larger, they become less efficient at taking in and releasing molecules
What is the surface area of a cell
the area of the cell that is in direct contact with the environment
What is a cell’s volume
everything inside the cell
what is the volume of a cube
(length of one side)^3
what is the surface area of a cube
(# of sides)(length of one side)^2
What is the definition of selective permeability
the cell membrane’s ability to “select” what molecules enter and exit based on size and chemical composition
What happens to the cell’s surface area and volume as it grows larger
the surface area does not increase proportionally with volume
Isotonic definiton
solutions that cause cells to gain or lose water at the same rate; they do not expand or shrink
Hypotonic defintion
Solutions that cause a cell to gain water; cell expands or bursts
Hypertonic definiton
Solutions that cause a cell to lose water; cell shrinks
What happens as a cell grows larger
The bigger the cell the slower the rate at which nutrients move into
all parts of the cell and waste moves out.
what is a dialysis tube & how does it relate to selective permeabilty
Dialysis tubing is a plastic tube with tiny pores in it. Some molecules are small and can pass through the pores. While other molecules are too large to pass through the pores. This is acting as a semipermeable membrane
Surface area to volume ratio determines
The rate of diffusion of solutes in and out of the cell
* The higher surface area to lower volume ratio the greater the rate of
diffusion of nutrients into the cell and waste out of the cell.
increases as the surface area to volume ratio increases.
What is concentration gradient
The greater the difference in concentration, the more rapid the diffusion.
* The closer the distribution of the material gets to equilibrium, the slower the rate of diffusion
becomes.
How does temperature affect rate of diffusion
Higher temperatures increase the energy and therefore the movement of the molecules,
increasing the rate of diffusion.
* Lower temperatures decrease the energy of the molecules, thus decreasing the rate of diffusion.
What are enzymes
Molecules (usually proteins) that aid in anabolic (combining molecules) or catabolic (separating molecules) reactions
How do enzymes function
as a catalyst
