Chapter 5 Flashcards
__________ is the main energy carrier in all living cells.
Adenosine triphosphate
_____ store and retrieve energy when they convert one molecule to another.
Cells
JOBS OF THE PLASMA MEMBRANE ARE TO….
- Isolate the cytoplasm from the external environment
- Regulate the exchange of substances
- Communicate with other cells
- Semi-permeable
- Protects
The plasma membrane is composed of how many layers?
2 (bilayer)
Composed of ______ molecules
Phospholipid
Phosphate groups are _____ in water and are _____.
Soluble, polar
“Water loving”
Hydrophilic
“Water hating”
Hydrophobic
Fatty acid chains are _____ in water because they are _______.
Insoluble, nonpolar
What is the fluid mosaic model?
Property of the plasma membrane where in many similar molecules are free to move sideways within the lipid bilayer.
_______ molecules embedded in the membrane makes it stronger and less fluid. It also prevents the fatty acid chains from sticking together.
Cholesterol
Regulate movement of particles/substance
Transport proteins
Form small openings for molecules to diffuse through
Channel proteins
Binding site on protein surface “grabs” certain molecules and pulls them into the cell.
Carrier proteins
Similar to carrier proteins, not always “open”
Gated channels
Molecular triggers that set off cell responses (such as release of hormones or opening proteins)
Receptor proteins
______ determines how substances move within cells and their membranes
Diffusion
Movement of particles across membranes by diffusion. Requires no energy.
Passive transport
Movement of particles across membranes from areas of lower concentrations (the environment) to higher concentrations (in the cell); moves against a concentration gradient. Requires energy.
Active transport
EX of passive transport
Diffusion, osmosis, facilitated diffusion
EX of active transport
Endocytosis, exocytosis, sodium potassium pump
Process by which a cell surrounds & takes in material from its environment.
Endocytosis
Expulsion or secretion of materials from a cell.
Exocytosis
Is the diffusion of water molecules through a selectively permeable membrane from an area of higher water concentration to an area of lower water concentration
Osmosis
Is when the concentration of dissolved substances (solute) in the solution is the same as the concentration of dissolved substances inside the cell. Cells in an isotonic solution do NOT experience osmosis and they retain their normal shape.
Isotonic solution
