Midterm 1 - Membranes and Transports Flashcards
1
Q
selective permeability
A
- membrane characteristic
- allows some substances through
2
Q
compartmentalization
A
- separation of cell interior
- distinct compartments , specific local conditions
- diverse metabolic reactions and processes
3
Q
energy transduction
A
- conversion of one form of energy into another
4
Q
membrane-bound receptor
A
- transmembrane receptor
- proteins found on the surface of cells
- span the plasma membrane
5
Q
phospholipid
A
- amphiphilic molecules
- hydrophobic fatty acid chains
- hydrophilic head
- occur naturally in living organisms
6
Q
sterol
A
- subgroup of steroids
- hydroxyl group at 3-position of A-ring
- amphipathic lipids
6
Q
peripheral membrane protein
A
- temporarily attached to the cell or mitochondrial membrane
7
Q
integral membrane protein
A
- integrated into membrane structure
- interacts with the membrane lipids’ hydrocarbon chains
- spans the membrane
7
Q
glycoprotein
A
- combo of carbs and proteins
8
Q
glycolipid
A
- combo of carbs and lipids
8
Q
phospholipid bilayer
A
- thin polar membrane
- 2 layers of lipid molecules
9
Q
self assembly
A
- components, either separate or linked, spontaneously form aggregates
10
Q
permeability levels
A
- high: oxygen, steroid hormones
- medium: water, ethanol
- low: large molecules, glucose
11
Q
osmosis
A
- transport of water through semipermeable membrane
- relates to water’s concentration gradient across the membrane
- results from presence of solute (can’t pass through membrane)
11
Q
simple diffusion
A
- molecules, atoms, or ions diffuse through semipermeable membrane down concentration gradient
- no assistance from transporter proteins
11
Q
hypotonic environment
A
- extracellular fluid has lower osmolarity than fluid inside the cell
- water moves into the cell
12
Q
isotonic environment
A
- extracellular fluid has same osmolarity as fluid inside the cell
- no net water movement in or out of cell
12
Q
facilitated diffusion
A
- passive movement of molecules along concentration gradient
13
Q
channel protein
A
- membrane protein
- allows a substance to pass through its hollow core across the plasma membrane
14
Q
gated channel
A
- integral membrane proteins
- allow regulated flow of selected ions across plasma membrane
14
Q
carrier protein
A
- membrane protein
- moves a substance across the plasma membrane by changing its own shape
15
Q
active transport
A
- method of transporting material
- requires energy
15
Q
chemical/concentration gradient
A
- difference in molecule concentrations across a cell membrane
- high to low concentration
16
Q
electrical gradient
A
- difference in charge across membrane
16
Q
electrochemical gradient
A
- combined electrical and chemical force that produces a gradient
17
Q
bulk transport
A
- moves particles
- endocytosis and exocytosis
17
Q
endocytosis
A
- active transport
- move substances (fluids and particles) into a cell
18
Q
phagocytosis
A
- endocytosis
- ingests and eliminates particles
- for homeostasis
- cyt = cell, phago = eating
19
Q
pinocytosis
A
- endocytosis
- imports macromolecules that the cell needs from the extracellular fluid
19
Q
receptor-mediated endocytosis
A
- endocytosis
- uses specific binding proteins in plasma membrane for specific molecules or particles
20
Q
exocytosis
A
- passing bulk material out of a cell
