Exam 2 - Chapter 7 Flashcards
cell vs plasma membrane
cell membrane is any membrane of the cell.
plasma membrane is the outermost membrane of the cell
Fluid Mosaic Model
- The “fluid” part refers to the fluidity of the membrane
* The “mosaic” part refers to the various components that make up the membrane
Peripheral proteins
associated with one side of the membrane
Integral proteins
embedded within the membrane
Transmembrane proteins
integral proteins that fully span the membrane
Transport proteins
move specific solutes into or out of the cell
Enzymes
catalyze a chemical reaction
Signal transduction
relay cellular messages
Cell-cell recognition
attach two adjacent cells together, recognize “self cells”
Intercellular joining
connection between adjacent cells
Attachment
to cytoskeleton and extracellular matrix, maintains cellshape and stabilizes the location of membrane proteins
Extracellular Matrix
- composed of proteins, other macromolecules, and fluids secreted by the cells
- Functions to stabilizes the structure of tissues and protects and supports the plasma membrane
Selective Permeability
- Some molecules can pass the plasma membrane freely if they are small,uncharged, non-polar, and/or hydrophobic
- Gases like O2 and CO2
- Hydrophobic lipids
- Water (less freely)
- But ions, most polar molecules, and large molecules cannot
Passive Transport
- fueled by kinetic energy
- molecules move down their concentration gradient
- concentration gradient serves as a form of potential energy
Diffusion
spontaneous spreading of molecules down their concentration gradient from an area of higher concentration to an area of lower concentration, fueled by kinetic energy
Diffusion Factors
- Mass – heavier molecules tend to diffuse more slowly, lighter molecules tend to diffuse more quickly •Temperature – higher temperatures increase diffusion rate, lower temperatures decrease diffusion rate
- Extent of the concentration gradient – the greater the difference in concentration the greater the diffusion rate, the smaller the difference in concentration the slower the diffusion rate
- Density of solvent, solubility of solute, distance molecules must travel
Osmosis
diffusion of water across a selectively permeable membrane, water moves down its concentration gradient from an area of higher free water to an area of lower free water, fueled by kinetic energy
Osmosis Factors
•Osmosis occurs when there is a concentration gradient of water across a semipermeable membrane •Water moves down its concentration gradient equalizing water and solute concentrations on either side of the membrane
Tonicity
the ability of an extracellular solution to cause a cell to gain orlose wate
Osmolarity
a solutions total solute concentration
Isotonic
equal solute concentrations in ECF and ICF, no net movement of water
Hypotonic
solute concentration of ECF is lower than solute concentration of ICF, water moves into cell
Hypertonic
solute concentration of ECF is higher than solute concentration of ICF, watermoves out of cell
Facilitated diffusion
solute binds to transport protein and moves across membrane down its concentration gradient from an area of higher concentration to an area of lower concentration, fueled by kinetic energy
Channel proteins
always open or gated, like a “door” that opens only to specific molecules
Carrier proteins
pick up specific moleculeson one side of the membrane and releases it onto the other side of the membrane
Aquaporins
water based channels that allow access across the membrane
Active transport
Diffusion (small molecules), osmosis (water), facilitated diffusion (ions, polar molecules, smaller biomolecules)
movement of molecules against their concentration gradient from an area of lower concentration to an area of higher concentration, fueled by ATP
Protein Mediated Active Transport
transport protein (carrier protein) pumps a solute against its concentration gradient, from an area of lower concentration to an area of higher concentration, fueled by ATP
Vesicle Transport
use of a vesicle to transport large particles or bulk substances into or out of the cell without actually passing through the membrane, requires ATP
Exocytosis
use of a vesicle to move materials out of the cell
Endocytosis
use of a vesicle to move materials into the cell
Phagocytosis
movement of solids
Pinocytosis
movement of fluids
Receptor mediated endocytosis
targeted endocytosis
Passive transport
Protein mediated active transport, vesicle transport
