Chapter 7 - Cell Membrane Flashcards
Cell Membrane
boundary between inside and outside of Cell
Phospholipid Bilayer
double layer of a molecule made of a phosphate group, glycerol, and 2 lipids
Amphipathic
A molecule with hydrophilic and hydrophobic ends
Which part of the phospholipid is hydrophobic and which is hydrophilic?
Lipid - hydrophobic (repells water)
Phosphate - Hydrophilic (attracted to water)
What method did we use to study and learn more about the cell membrane with?
Freeze-Fracture method
Fluid Mosaic Model
The Cell membrane is flexible and fluid while also being made up of many different parts
How does temperature impact the fluidity of the cell membrane?
Colder temps make the membrane more ridged
What is the role of cholesterol in the cell membrane?
Cholesterol functions as a buffer to the changes caused by temperature variation
What two general categories of proteins form on or through the cell membrane?
Integral Proteins - Through the membrane
Peripheral Proteins - attached to, but not full width of membrane
What are the 6 functions of cell membrane proteins we discussed in class?
- Transport
- Enzymatic Activity
- Signal Transfer (transduction)
- Cell-cell recognition
- Intercellular joining
- Attachment to cytoskeleton
Glycolipids and Glycoproteins
Lipid or protein with a carbohydrate chain attached; Used for cell to cell recognition
Selective Permeability
Allows for some substances to pass through while others are not allowed
Passive Transport
Movement of substances across the Cell membrane without energy
Diffusion
Movement of substances across the cell membrane from higher to lower concentrations (example CO2 and O2)
Facilitated Diffusion
Movement of substance across the cell membrane from higher to lower concentrations via a transport protein
Channel protein
tunnel though the cell membrane to assist in transport
Aquaporins
Channel proteins specifically to move water in and out of the cell
Carrier Protein
Transport protein that changes shape to allow substances to move across the membrane
Osmosis
Facilitated Diffusion of water molecules
Isotonic Solution
Solution with the same concentration of solutes as the cell (equilibrium)
Hypertonic Solution
Solution with a higher concentration of solutes than the cell (water leaves the cell)
Hypotonic Solution
Solution with a lower concentration of solutes than the cell (Water enters the cell)
Active Transport
movement of substance across the cell membrane from low to high concentrations, via carrier proteins, and with the help of ATP
Sodium-Potassium Pump
3 Sodium (Na) out of cell, 2 Potassium (K) into cell
Active Transport that creates a electric differential across cell membrane
Electrogenic Pump
Active transport that generates a voltage across the cell membrane (ie. NA-K pump and Proton pump)
Cotransport
An active transport run in part or whole by a separate active transport
Exocytosis
Releasing of substances out of cell by a vesicle fusing with the cell membrane then opening up
Endocytosis
Cell taking in substances by engulfing them
Phagocytosis
“eating” of large particles by being engulfed (white blood cells “eating” foreign substances in body.
Pinocytosis
“Drinking” from outside of cell by engulfing a liquid
Receptor-Mediated Endocytosis
Bulk consumption of specific substances that have bound to receptors; limiting the undesired substances
