... Flashcards
What are the most important company nests of the plasma membrane?
Phospholipids
Channel proteins
Carrier proteins
Cholesterol molecules
What is simple diffusion?
The movement of molecules from a higher concentration to a lower concentration (I.e. Down the concentration gradient)
What is facilitated diffusion?
Facilitated diffusion (also known as facilitated transport or passive-mediated transport) is the process of spontaneous passive transport (as opposed to active transport) of molecules or ions across a biological membrane via specific transmembrane integral proteins.
How does the size of a cell effect diffusion?
Diffusion is less efficient in cells with a small surface area to volume ratio than cells with a large SA:V ratio.
Single- called organisms
(Eg. Amoeba) are small and have a large SA:V ratio. The cells requirements can be met by the diffusion or active transport of materials into and out of the cell
Multicellular organisms
(Eg. Plant and animals) are often quite large and large organisms have a small SA:V ratio. They require specialised systems to transport the materials they need to and fro the cells and tissues in there body.
Osmosis
The diffusion of water molecules from a lower solute concentration to a higher solute concentration across a partially permeable membrane
Active transport
Uses energy to transport molecules against their concentration gradient across a partially permeable membrane.
What does a phospholipid contain
A polar head and non polar tails
What is a solvent
A solvent is a fluid in which a substance is dissolved.
What is a solute
A solute is a substance dissolved in a solvent
What is a solution
A solution is a combination of solute and solvent
What is absent in a prokaryotic cell
Cell bound organelles
Nucleus
The cell membrane is composed of…..?
Lipids and proteins
Endocytosis
Endocytosis is a form of active transport in which a cell transports molecules (such as proteins) into t
