Composition of Cells Flashcards
_________ are composed of lipids.
Membranes
The two major fluid compartments are the _____ and _____.
intracellular; extracellular
Where is the concentration of Na+ higher?
in the ECF
Where is the concentration of water higher?
it’s the same in the ICF and ECF
Membranes are composed of _____.
lipids
What are the principal inorganic ions in the cell?
Na+, K+, and Cl-
Name the 5 components of ICF or ECF.
1) Na+ 2) K+ 3) Cl- 4) proteins 5) water
The excess anions create an _______ potential difference between the inside and the outside of the cell, called the ______.
electrical; membrane potential
Stimuli for gated channels include _____, ______, ______, or _______,
1) electricity (voltage gated) 2) mechanical 3) chemicals 4) temperature
What components can pass through the membrane?
K+, Cl-, H2O
It is estimated that 50% of the energy we expend at rest is used to _____.
pump ions across membranes
What is an example of a primary active transporter?
the Na+/Cl- pump
The ability of the membrane to withstand the imposed electric force with a strength of about 100,000 volts/cm is due to its __________.
lipid composition
Channels behave as _____ or _____ in the membrane.
passive pores; tunnels
What is the intracellular fluid comprised of?
mitochondrial, vesicular, nuclear, and other subcompartments
The patch clamp technique allows one to see ______.
individual ion channels at work
If the energy for transport comes directly from metabolism (usually splitting ATP), the transport is called _________. transport.
primary active
Some channels contain molecular ______.
gates
Where is the concentration of K+ higher?
in the ICF
______ work thousands of times slower than channels.
Transporters
Some charged/polar substances cross membranes by passing through _____, which behave as passive pores, or tunnels, in the membrane.
channels
Some substances cross membranes by binding to _____ and being escorted (‘carried’) across.
proteins
Transporters are also needed in order to _____ to concentrate them on one side against ______.
pump molecules across a membrane; their energy gradient
If the transport energy comes from other sources and not ATP, it is called ______.
secondary active transport
