Cell Membrane, Diffusion, Osmosis, Active Transport Flashcards
Thin, flexible barrier
Cell Membrane
What is the function of the cell membrane?
Regulates what enters and leaves the cell
Provides protection and support
What does it mean for the membrane to be selectively permeable?
It decides what can or can’t pass through
Only some things can pass through
List the composition of the cell membrane
Double layered sheet (lipid bilayer)
Held together by phosphate
Stabilized by cholesterol
- *Protein** channels (large openings)
- *Carbohydrate** chains for sensors (antennae)
Most of the functions of the membrane are carried out by which type of molecule?
Proteins
Brownian Motion states that
Particles in a solution are constantly and randomly moving
Does any type of diffusion ever take energy?
NO
Movement of particles from high concentration to low concentration
Diffusion
When particles move through the lipid bilayer without using energy they are doing
Diffusion
Dynamic equilibrium is
When the concentration of particles is EQUAL both inside and outside of the cell but the particles continue to move
The movement of WATER across the cell membrane from high concentration to low concentration
Osmosis
Water will move into the cell in a _____ solution
Hypotonic
(more water outside than inside)
When there is less what inside than outside of the cell, the cell is in a ______ solution
Hypotonic
A hypertonic solution is one in which _____
There is less water outside the cell than inside the cell
(water moves out)
Equal amounts of water both inside and outside
Isotonic solution
What will happen if a cell is placed in a VERY hypotonic solution
It will fill up with too much water and burst (lyse)
True or False: Facilitated diffusion requires energy.
False
Movement of VERY large particles from high concentration to low concentration
Facilitated diffusion
How do particles move across the membrane in facilitated diffusion?
Through protein channels in the cell membrane
Movement of particles against the concentration gradient (from low concentration to high concentration)
Active Transport
How do particles move across the membrane during active transport
Through channel and carrier proteins
Active transport that brings substances INTO the cell
Endocytosis
Releasing of materials from the cell (cell poop)
Exocytosis
Cell “eating”
Phagocytosis