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
If 2% of K+ leaks out of the cells, _______.
the pt can die
How is the patch clamp technique performed?
A glass pipette touches a cell - gentle suction draws membrane into the mouth of the pipette to form a seal- channel gate opens- record the electric current through the channel
What is the extracellular fluid comprised of?
1) plasma 2) lymph 3) interstitial fluid
The ability of the membrane to withstand the imposed electric force with a strength of about ________ is due to its lipid composition.
100,000 volts/cm
What is the total volume of the extracellular fluid?
13 liters
What is the boundary btw the intra- and extracellular fluids?
the plasma membrane
The excess ____ create an electrical potential difference between the inside and the outside of the cell, called the membrane potential.
anions
Where is the concentration of Cl- higher?
in the ECF
The cytoplasm of nearly all cells is electrically _____compared to the ECF.
negative
Cells contain a few more _____ ions than _____ ions.
negative; positive
Most channels are _______ for particular ions.
selective
What is the total volume of the intracellular fluid?
27 liters
It is estimated that ____ of the energy we expend at rest is used to pump ions across membranes.
50%
Name 2 general kinds of proteins that mediate transmembrane movement of charged substances.
1) channels 2) transporters
Secondary active transport also depends on ______.
metabolism
Where is the concentration of protein higher?
in the ICF
