The Cell Membrane Flashcards
The membrane is made up of two sheets made up of what?
Phospholipids placed on top of eachother.
The cell membrane acts as what to the cell?
As a barrier to keep foreign objects out and holds the mechanics of the cell together.
The arrangement of two phospholipids placed on too of eachother is called?
the phospholipid bilayer.
What makes up the tail of the phospholipids?
Carbon and hydrogen
Carbon and hydrogen tails of the phospholipids are said to be water…
Fearing, or hydrophobic.
The heads of the phospholipid molecule faces what part if the structure?
The inside and outside, due to water preference in the heads.
What type of protein floats in the phospholipid bilayer?
Membrane proteins.
The membranes fluidity keeps the cell from:
Fracturing under strain
An important function of the cell is selective…
Permeability.
What two types of molecules can pass freely through the membrane?
Small and non polar (hydrophobic) molecules.
What allows the composition of the cel to maintain it’s composure?
The cell membranes permeability.
What are the three main types of passive transport?
Diffusion, facilitated diffusion and osmosis.
Osmosis is…
The diffusion of water.
In absence of other forces, substances diffused in water naturally move to…
Areas where they are scarce.
Water is defined on a molecular level as…
A small polar molecule.
Water moved to places of low concentrations with many dissolved substances called…
Solutes.
Therefore water moves from where there are fewer dissolved substances (called _______) to places where there are many dissolved substances (called ______)
A. Hypotonic
B. hypertonic
An isotonic solution is…
Is one in which the concentration is the same both inside and outside of the cell, meaning osmotic pressure is the same on both sides.
Immersing cells in unusually hypotonic and hypertonic solution can be…
Disastrous. Water will even rush into a cell in hypotonic conditions causing the cell to burst.
Tho combat the possibility of bursting, freshwater molecules posses…
Small vacuoles that pump out excess water.
Certain compounds such as _____ cannot enter the cell through simple diffusion because…
Ions. They cannot pass through the membrane.
The cell has protein channels through the…
Phospholipid layer.
Protein channels can open and close based on…
The protein membranes.
Exocytosis is…
When a cell removes waste product.
