Chp 5 Cell function Flashcards
What property do cells have that allows phospholipids to form a stable bilayer?
Its in water
What role do each of the following play in cell membranes? Lipids, Protein, Carbohydrates
Lipids: form a flexible bilayer
Protein: embedded in the plasma membrane and aid in transport
Carbs: Cell ID tags on the surface of the plasma membrane
How does cholesterol act as a fluidity buffer in the phospho bilayer?
in warm temps, it retains movement of phospholipids
at cool temperatures, it maintains fluidity by preventing tight packing of phospholipids
What makes the membrane selectively permeable?
Transport proteins
each protein is specific to a solute
What is diffusion? is it active or passive? is energy required?
high concentration to low concentration = passive
energy is not required
What is osmosis? is it passive or active?
diffusion of water across a selectively permeable membrane. from a low concentration to a hih concentration
Which kind of solution are plant cells happiest in?
Hypotonic solutions, because it prevents the cell wall from rupturing
What kind of molecules can diffuse freely through the phospholipid bilayer?
small non-polar molecules (O2, CO2, H2O)
What is facilitated diffusion? does it require energy?
Substances moving down concentration gradient with the help of transport proteins. does not require energy
What is an important example of active transport?
Na+/K+ pump
What is exocytosis? how does it work?
Movement of large molecules to the outside of cell. a membrane bound vesicle fuses with membrane and expels it contents
What is endocytosis?
The opposite of exocytosis. large molecules brought into cell when membrane folds inward, trapping material
What are the two main forms of energy?
- Kinetic energy
- Potential/ chemical energy
Where is potential energy stored?
In chemical bonds
What is the first law about energy?
Energy can be changed from one form to another, but it cannot be created or destroyed
