Biological Membranes and Cell Division in Eukaryotic Cells Flashcards
the common feature found in all cells
the plasma membrane
what is the plasma membrane composed of
a phospholipid bilayer
is embedded with proteins and is referred to as the fluid mosaic model of cell membrane structure
phospholipid bilayer
the model of the membrane that shows the membrane is composed of proteins
fluid mosaic model
the spaces in between the proteins are filled with
phospholipids
The phospholipid consists of these and it points toward the outside environment of the cytoplasm
hydrophilic heads
repels the water and points in
hydrophobic tails
forms a bilayer that acts like a barrier between the cell and its environment
the phospholipids
regulates the entry and exit of specific molecules through the cells
the plasma membrane
why is the plasma membrane considered to be selectively-permeable
because it allows the passage of some substances but not others
what is the cytoplasm of cells made of
75 to 85 % water
most substances entering the cells are
dissolved in water
What is water considered
the solvent of life
solutes are
substances dissolved in water
solvents are
a solution consists of solutes dissolved
if the solvent is water, then what is the solution referred to as
an aqueous solution
the most common method by which solutes enter the cells by is called
diffusion
define diffusion
diffusion is the movement of substances from a region of high concentration to a region of low concentration.
the movement of substances from a region of high concentration to a region of low concentration is known as
diffusion
once inside the cell, solutes move by
diffusion through the cytoplasm
why doesn’t diffusion require the input of energy
because molecules naturally tend to move in this fashion
does not require the input of energy because molecules naturally tend to move in this fashion
diffusion
besides diffusion what is another type of movement that occurs across the plasma membrane
osmosis
define osmosis
the movement of water across a membrane and it occurs from a region of high water concentration to a region of low water concentration
the movement of water across a membrane and it occurs from a region of high water concentration to a region of low water concentration.
osmosis
both occur until the cell has reached equilibrium
diffusion and osmosis
both occurs until the cell has reached a point at which the substance or water is uniformly distributed throughout the cell
both diffusion and osmosis
the point at which the substance or water is uniformly distributed throughout the cell
equilibrium
________ is the movement of molecules from high concentration to low concentration. The rate at which _______ occurs is ___________
Diffusion, diffusion occurs is influenced by many factors such as weight. The larger a molecule the slower the rate of diffusion
The movement of water across the plasma membrane is called
osmosis
the movement of water from a region of high water concentration to a region of low water concentration
osmosis
the universal solvent of life since a good majority of substances dissolve in this solvent
water
The substance that can dissolve in water is known as the
solute