Lab 1: Simple Molecular Movement

Unidirectional

________- only operates in one direction.

Saturation

________- substrate concentration at which all binding sites are constantly occupied.

Competition

________- molecules seem to compete for space, but one with greater concentration gradietn will be transported at greater rate.

Simple

not using a protein, molecule can pass between phospholipids or through another medium such as air or water

Cell mediated

using a protein to cross the cell membrane

Passive

driven by concentration gradient, no energy input by cell required for movement, gradient not required

Brownian motion

random movement of particles in liquid or gas, no change in concentration over time

Simple diffusion

movement of molecules from area of high concentration to area of low concentration leading to change in concentration over time

Concentration gradient

difference in concentration between two areas

molarity (M or mM)

concentration of solute in solution, moles/L or millimoles/L

Temperature

average kinetic energy of the sample

Molecular size (dalton, amu)

size of the molecule

Electrochemical gradient

gradient consisting of both charge and concentration

Eq potential

charge gradient equal and opposite to concentration gradient in force

Osmosis

net movement of water across a semi-permeable membrane

Osmolarity (OsM, mOsM)

concentration of active particles in solution in osmoles or millisosmoles

Osmotic gradient

difference in osmolarity across a semipermeable membrane

Osmotic pressure

pressure generated when water pushes toward the side with higher osmolarity in a system with a fixed volume (or the pressure required to prevent osmosis)

Tonicity

describes the effect of a solution on the volume or tension of a cell

Isotonic

no net osmosis, no effect on cell volume or tension

Hypertonic

net osmosis out of cell, decreases cell volume and tension → crenation of cell

Hypotonic

net osmosis into cell, increases cell volume and tension → swell and lyse of cell

Uniporter

moves one type of molecule

Cotransporter

moves more than one type of molecule

Symporter

same direction

Antiporter

oppsite directions to each other

Unidirectional

only operates in one direction

Bidirectional

operates in either direction depending on conditons

Conformational change

change in the 3D shape of a protein

Specificity

specific based on size, shape, charge of substrate

Competition

molecules seem to compete for space, but one with greater concentration gradietn will be transported at greater rate

Saturation

substrate concentration at which all binding sites are constantly occupied

Vmax/Tmax

highest rate of transport possible without adding more proteins, at or above saturation concentration

Facilitated diffusion

passive movement of molecules across a cell membrane from high concentration to low concentration via a transmembrane protein, leading to a change in concentration over time

Primary active transport

movement of molecules across a cell membrane via a transmembrane protein using ATP as the energy source

Secondary active transport

movement of one molecule from low concentration to high concentration coupled with the movement of another molecule from high concentration to low concentration using the concentration gradient of the second molecule as the energy source

What is simple?

not using a protein, molecule can pass between phospholipids or through another medium such as air or water

What is cell mediated?

using a protein to cross the cell membrane

What is passive?

driven by concentration gradient, no energy input by cell required for movement, gradient not required

What is Brownian Motion?

random movement of particles in liquid or gas, no change in concentration over time

What is simple diffusion?

movement of molecules from area of high concentration to area of low concentration leading to cahnge in concentration over time

What is concentration gradient?

difference in concentration between two areas

What is molarity?

cocentration of solute in solution, moles/L or millimoles/L

What is temperature?

average kinetic energy of the sample

What is molecular size?

size of the molecule, measured in dalton or amu

What effects membrane permeability?

thickness, resistance, and surface area of membrane

What is electrochemical gradient?

gradient consisting of both charge and concentration

What is Eq potential?

charge gradient equal and opposite to concentration gradient in force

What is osmosis?

net movement of water across a semi-permeable membrane

What is osmolarity?

cocentration of active particles in solution in osmoles or milliosomoles

True or False: Size and type of particle is important in osmolarity.

False - only requirement is particle is water soluble

How is osmolarity calculated?

molarity X number of particles from each molecule

What is osmotic gradient?

difference in osmolarity across a semipermeable membrane

What is osmotic pressure?

pressure generated when water pushes toward the side with higher osmolarity in a system witha fixed volume (or pressure required to prevent osmosis)

What is tonicity?

describes the effect of a solution on the volume or tension of a cell

What is isotonic?

no net osmosis, no effect on cell volume or tension

What is hypertonic?

net osmosis out of cell, decreases cell volume and tension causing crenation of cell

What is hypotonic?

net osmosis into cell, increases cell volume and tension causing cell to swell and eventually lyse

What are examples of transport proteins?

transporters, channels, ATP powered pumps

What is a uniporter?

moves one type of molecule

What is a cotransporter?

moves more than one type of molecule

What is a symporter?

moves more than one type of molecule in same direction

What is an antiporter?

moves more than one type of molecule in opposite directions to each other

What is unidirectional?

only operates in one direction

What is bidirectional?

operates in either direction depending on conditions

What is conformational change?

change in the 3D shape of a protein

What is specificity?

specific based on size, shape, charge of substrate

What is competition?

molecules seem to compete for space, but one with greater concentration gradient will be transported at greater rate

What is saturation?

substrate concentration at which all binding sites are constantly occupied

What is Vmax/Tmax?

highest rate of transport possible without adding more proteins, at or above saturation concentration

What is facilitated diffusion?

passive movement of molecules across a cell membrane from high concentration to low concentration via a transmembrane protein, leading to a change in concentration over time

Binding of a substrate causes what to occur during facilitated diffusion?

conformational change

What is primary active transport?

movement of molecules across a cell membrane via a transmembrane protein using ATP as the energy source

What causes conformational change in primary active transport?

phosphorylation & dephosphorylation

Na+/K+ pump is an example of what type of transport?

primary active; moves 3 Na+ out, 2 K+ in, and uses 1 ATP

What is secondary active transport?

movement of one molecule from low concentration to high concentration coupled with the movement of another molecule from high concentration to low concentration using the concentration gradient of the second molecule as the energy source

Ca2+/Na+ antiporter is an example of what transport?

secondary active transport; 1 Na+ in and 1 Ca2+ out