POB ch 4 Flashcards
why is the plasma membrane the fluid mosaic model?
Because there are a bunch of different parts to the plasma membrane (mosaic) and most of the proteins and phospholipids are able to drift slightly from side to side, which gives it a somewhat (fluid) structure.
Proteins=Mosaic
Lipids=Fluid
what is selectively permeable ?
it means that some substances cross more easily than others.
- Small, Nonpolar, and soluble in lipids pass easily
- Large and charged molecules do not move easily through the phospholipid bilayer
what is the phospholipid and what does it form?
lipid thats found in the cell membrane,
- glycerol molecule with a phosphate group at one end and 2 fatty acids at the other
- has a hydrophobic non polar head (fatty acids)
- has a hydrophilic polar tail (phosphate group)
Proteins in the Plasma Membrane?
- channel proteins
- carrier proteins
- cell recognition proteins
- receptor proteins
- enzymatic proteins
Chennel Proteins
allows molecules to move through a membrane through space provided by the protein
-move across freely
Carrier Proteins
interacts and binds to a molecule to help it move across the membrane, usually requiring a change in protein shape
Cell Recognition Proteins
glycoproteins that recognize pathogens/ determine if a cell belongs in your body or is an invader
Receptor Proteins
Shape that allows specific molecules to bind to it ,
-binds to a specific extracellular molecule to bring about a change within the cell
Enzymatic Protein
carry out metabolic reactions
Isotonic
water concentration both inside and outside of the cell are equal!!!
Hypertonic
water rushes out of the cell, causing the cell to shrink
Hypotonic
water rushes into the cell, causing the cell to expand
_________ is extremely important to the maintenance of the plants erect position
Turgor Pressure
the swelling of a plant cell in a hypotonic solution creates _______
Turgor Pressure
Diffusion
movement of molecules from a higher to a lower concentration
-does NOT require energy
Osmosis
diffusion of water across a selectively permeable membrane due to concentration differences
-lower to higher concentration
(diffusion of water)
Osmotic Pressure
Pressure that develops in a system due to osmosis, the greater the osmotic pressure, the more likely it will diffuse in that direction
Facilitated Transport
- toward lower concentration
- down concentration gradient
- requires a carrier
- does NOT require energy
Active Transport
- toward higher concentration
- against gradient
- REQUIRES energy
- needs a carrier
Exocytosis
- big molecules go outside the cell
- REQUIRES energy
- vesicles fuse with plasma membrane
Endocytosis
- big molecules go inside the cell
- REQUIRES energy
- vesicle formation
Phagocytosis
- type of endocytosis
- when the particles taken in in endocytosis is large, such as food particles or another cell
Pinocytosis
-liquids and small particles
receptor Mediated
- from of pinocytosis that uses a receptor (signal) so that a specific molecule will bind to it
- involves coated pit
Diabetes
- high blood sugar over a long period of time
- frequent urination, increased thirst, etc.
- symptoms have to do with homeostasis; getting back to equilibrium (isotonic state)
- insulin receptors on muscle and liver cells
- GLUT4 (carrier protein) embedded in membrane
- vesicle merges with the cell membrane
- glucose enters by Facilitated Diffusion
