Cell transport Mechanism Flashcards
What forms the cell’s flexible outer surface, separating the cell’s
internal environment from the external environment that is also a selective barrier that regulates the flow of materials into and out of a cell.
The cell membrane/ Plasma membrane.
Who proposed the most widely accepted model of the cell membrane, popularly known as the fluid mosaic model?
S.J Singer and Garth L. Nicolson in 1972
The basic structural framework of the plasma membrane is the lipid bilayer. What is a lipid bilayer
Two back-to-back
layers made up of 3 types of lipid molecules: phospholipids, cholesterol, and glycolipids
The lipids are amphipathic molecules. What are amphipatic molecules?
Amphipathic molecules are chemical compounds that have both polar and non-polar parts
Describe the polar part of phospholipids.
It’s the phosphate that has the hydrophilic head.
Describe the non-polar parts of the phospholipids.
They are two long fatty acid “tails” that are hydrophobic hydrocarbon chains
What is the primary role of the Cell Membrane?
Is responsible for controlling what goes in the cell and what does not. (small uncharged molecules ✅)
(Charged ions and large molecules ❌)
Enumerate at least 2 small uncharged molecules, charged ions and 1 large molecule.
small uncharged molecules - oxygen, carbon dioxide, and water
Charged Ions - sodium, potassium, and calcium.
Large molecules - amino
acid and carbohydrates
What are the two transport mechanisms in a cell
Passive Transport - Transportation of molecules that uses no energy.
Active Transport. - Transportation of substances that require cellular energy in the form of ATP.
- transports polar or charged solutes.
What type of Passive Transport is the movement of nonpolar, hydrophobic solutes from a region of higher concentration to a region of lower concentration without the help of membrane transport proteins?
Simple Diffusion
Enumerate 3 nonpolar, hydrophobic solutes that Simple diffusion transports.
oxygen, carbon dioxide, and nitrogen
gases; polar molecules such as water, urea and
small alcohols
What type of Passive Transport does not require energy but does require cell membrane proteins which are called carrier proteins to carry polar or charged solutes across the cell membrane from a higher concentration to an area of lower concentration?
Facilitated Diffusion
Enumerate 3 polar or charged solutes that Facilitated Diffusion transports.
glucose, fructose, galactose, ions such as K,
Cl, Na, and Ca2
What type of Passive Transport is the movement of water molecules across a selectively permeable membrane from areas of high water concentration to areas of lower water concentration.
Osmosis.
What is Tonicity?
It is the measure of a effective osmolarity in cell biology.
It is a property of a solution in reference to a particular membrane, and is equal to the sum of the concentrations of the solutes which have the capacity to exert an osmotic force across the membrane.
