Transport,Movement+Passage

Question 1

saturation

Answer 1

characteristic feature of protein mediated transport processes – by increasing the concentration of the molecules to be transported, increase of the transport speed increases less and less as most of the transporter molecules tend to be occupied after a certain concentration

Question 2

endocytosis

Answer 2

entrance of substances into the cell by membrane invagination to form an internal vesicle

Question 3

exocytosis

Answer 3

transport of substances stored in internal vesicles from the cell to the surroundings by fusion of the vesicle with the cell membrane


Question 4

vesicle

Answer 4

small, spherical compartment in the cell surrounded by a membrane (e.g. synaptic vesicle)

Question 5

filtration

Answer 5

movement of water and small molecules through a membrane (capillary wall) because of the pressure difference


Question 6

ion channel (leakage, voltage-dependent, ligand-dependent)

Answer 6

pore enabling passage of ions through the membrane; it is formed by intrinsic membrane proteins and is either continuously open (leakage) or opened by a change of membrane potential or by the binding of a ligand (signal) molecule

Question 7

permeability

Answer 7

ability of a compound to cross the membrane; it depends on the characteristics of the compound and of the membrane


Question 8

fluid mosaic model

Answer 8

according to this model, biological membranes are built up of a lipid bilayer in which protein molecules can easily move (float) in the horizontal direction


Question 9

electrical synapse

Answer 9

alternate name for gap junctions between excitable cells through which small molecules, thus ions carrying excitation can pass


Question 10

convection

Answer 10

bulk flow, movement of substances caused by pressure differences

Question 11

Poiseuille’s law

Answer 11

equation describing the laminar flow of fluids in rigid tubes as the function of pressure difference, tube diameter and length, and viscosity

Question 12

laminar flow

Answer 12

movement of a fluid or air, during which layers are sliding smoothly on each other


Question 13

turbulent flow

Answer 13

a flow pattern in which particles of the fluid move irregularly in all directions of the space

Question 14

viscosity

Answer 14

physical property of fluids that determines the ease with which the layers of a fluid move past ach other


Question 15

active transport

Answer 15

energy-requiring translocation of a substance across a membrane against its electrochemical gradient


Question 16

ion pump

Answer 16

active transport process moving ions through the membrane using energy stored in ATP molecules

Question 17

ATP

Answer 17

adenosine-triphosphate, energy-rich nucleotide used as a common energy source by all cells

Question 18

GTP

Answer 18

guanosine triphosphate, energy-rich nucleotide, like ATP


Question 19

nucleotide

Answer 19

building block of nucleic acids formed by purine or pyrimidine base, a ribose or deoxyribose sugar, and phosphate group

Question 20

nucleoside

Answer 20

similar to nucleotide, but contains no phosphate group

Question 21

facilitated diffusion

Answer 21

passive transport of a molecule across a membrane along the concentration gradient thus not using energy, but requiring a transporter to help the passage of the molecule


Question 22

concentration gradient

Answer 22

change in the concentration of a substance depending on distance (dc/dx)

Question 23

blood-brain-barrier

Answer 23

mechanism controlling the transport of materials from the blood to the extracellular space of the brain

Question 24

phagocytosis, pinocytosis

Answer 24

forms of endocytosis to take up solid particles or fluid into the cell

Question 25

tight junction

Answer 25

area of membrane fusion between adjoining cells that prevents the passage of extracellular material between the cells


Question 26

osmosis

Answer 26

diffusion of water; water is moving through the membrane from the more diluted solution toward the more concentrated solution following its concentration gradient


Question 27

axonal transport (anterograde, retrograde)

Answer 27

transport mechanism in neurons providing relatively fast movement of substances toward the axon terminals (forward) and toward the cell body (retrograde)

Question 28

diffusion

Answer 28

random thermal movement of atoms, molecules and ions from sites with higher concentration toward sites with lower concentration