Cellular Process ✅ Flashcards
receptor mediated endocytosis
what is a solvent?
the liquid doing the dissolving this is usually water.
what is a solute?
the dissolved material (particles or gas)
what is concentration?
amount of solute in a given amount of solvent
what is the concentration gradient?
the difference in concentration between 2 areas of solution (from the inside to the outside of the plasma membrane)
what fluid is the body most made up of?
intracellular (ICF) which is within cells. makeup about 2/3 of the total (around 67%) . found in the cytosol of the cell.
what is the extracellular fluid (ECF)?
The fluid which is outside of the cell
where can ECF be located?
- between cells = interstitial
- in blood vessels = plasms
- in lymphatic vessel = lymphatic fluid (lymph)
- within the brain and spinal cord - cerebrospinal fluid
the = are what the fluid is known as for where it is located.
what does the molecule movement across the membrane depend upon?
the gradient across the plasms membrane.
what does selective permeability allow?
allows a living cell to maintain different concentrations of substances on either side of the plasma membrane.
what is an electrical gradient?
the difference in electrical charges between two regions.
where are any ions or molecules most concentrated in?
cytosol
or extracellular fluid.
what charge is the outer surface of the plasma membrane
positively charged
what charge is the inner surface of the plasma membrane
negatively
where does the electrical gradient occur? and what is the charge difference known as?
plasma membrane
known as membrane potential
why is the concentration gradient and the electrical gradient important?
help move substances across the plasa membrane.
what is the electrochemical gradient?
the combined influence of conc gradient and electrical gradient on movement of a particular ion
where do negatively charged ions typically move to?
to a positively charged area to reach equilibrium and vise verse with positively charged ions.
in which direction of the gradient does passive transport occur?
down the concentration gradient across the membrane using its own energy
e.g. simple diffusion
what is endocytosis?
where the vesicles from the plasma membrane detach while bringing material into a cell
what is exocytosis?
merging of vesicles from the plasma membrane to release material.
what does endocytosis include?
phagocytosis
fluid endocytosis
receptor-mediated endocytosis
how does diffusion take place?
random micing of particles in solution which occur due to the kinetic energy of the particles.
what factors affect the rate of diffusion?
-the steepness of the concentration gradient,
-temp
- mass of the diffusing substance - larger mass slower rate
- surface area - larger the membrane surface area available for diffusion, faster the rate.
- diffusion distance
simple diffusion?
a passive process in which substances move freely through the lipid bilayer of the plasma membranes of the cells without the help of membrane transport proteins.
is energy required for simple diffusion?
no
why do substances move for simple diffusion?
move due to gradient
difference in conc, pressure, charge
how do non polar hydrophobic molecules move across the lipid bilayer?
simple diffusion
what is facilitated diffusion?
a passive process where an integral membrane protein assists the substances across the membrane. the membrane protein can either be a membrane channel or a carrier.
why might facilitated diffusion occur?
if the solute is too polar or highly charged to move across the lipid bilayer by simple diffusion, then facilitated diffusion may occur to pass the plasma membrane.