BIOL 1201 EXAMS: LATEST A+ GUIDE WITH ESSENTIAL
QUESTIONS AND ANSWERS
Plasma membrane
the boundary that separates the living cell from its surroundings
the plasma membrane is
selectively permeable
what are responsible for controlling passage across cellular membranes
transport proteins
fluid mosaic model
The membrane is a mosaic of protein molecules bobbing in a fluid bilayer of phospholipids
membranes are held together by
weak hydrophobic interactions
what can move sideways within the membrane
most lipids and some proteins
peripheral proteins
bound to the surface of the membrane
what penetrate the hydrophobic core
integral proteins
integral proteins that span the membrane are called
transmembrane proteins
cell-surface membrane functions
transport
enzymatic activity
signal transduction
cell-cell recognition
intercellular joining
attachment to the cytoskeleton and extracellular matrix
cells recognize each other by
, binding to molecules, often containing carbohydrates, on the extracellular surface of the
plasma membrane
Membrane carbohydrates may be covalently bonded to what (forming what) or to what
(forming what)
lipids (forming glycolipids)
or
proteins (forming glycoproteins) (more common)
A cell must exchange materials with its surroundings, a process controlled by
the plasma membrane
what are selectively permeable, regulating the cells molecular traffic
plasma membranes
What can dissolve in the lipid bilayer and pass through the membrane rapidly?
hydrophobic (nonpolar) molecules
(Ex. hydrocarbons)
What allow passage of hydrophilic substances across the membrane
Transport proteins
other transport proteins, called carrier proteins do what
bind to molecules and change shape to shuttle them across the membrane
A transport protein is specific for what
the substance it moves
the tendency for molecules to spread out evenly into the available space
diffusion
although each molecule moves randomly, diffusion of a population of molecules may be
directional
substances diffuse down their
concentration gradient
the diffusion of a substance across a biological membrane is ? because no energy is expended
by the cell to make it happen
passive transport
QUESTIONS AND ANSWERS
Plasma membrane
the boundary that separates the living cell from its surroundings
the plasma membrane is
selectively permeable
what are responsible for controlling passage across cellular membranes
transport proteins
fluid mosaic model
The membrane is a mosaic of protein molecules bobbing in a fluid bilayer of phospholipids
membranes are held together by
weak hydrophobic interactions
what can move sideways within the membrane
most lipids and some proteins
peripheral proteins
bound to the surface of the membrane
what penetrate the hydrophobic core
integral proteins
integral proteins that span the membrane are called
transmembrane proteins
cell-surface membrane functions
transport
enzymatic activity
signal transduction
cell-cell recognition
intercellular joining
attachment to the cytoskeleton and extracellular matrix
cells recognize each other by
, binding to molecules, often containing carbohydrates, on the extracellular surface of the
plasma membrane
Membrane carbohydrates may be covalently bonded to what (forming what) or to what
(forming what)
lipids (forming glycolipids)
or
proteins (forming glycoproteins) (more common)
A cell must exchange materials with its surroundings, a process controlled by
the plasma membrane
what are selectively permeable, regulating the cells molecular traffic
plasma membranes
What can dissolve in the lipid bilayer and pass through the membrane rapidly?
hydrophobic (nonpolar) molecules
(Ex. hydrocarbons)
What allow passage of hydrophilic substances across the membrane
Transport proteins
other transport proteins, called carrier proteins do what
bind to molecules and change shape to shuttle them across the membrane
A transport protein is specific for what
the substance it moves
the tendency for molecules to spread out evenly into the available space
diffusion
although each molecule moves randomly, diffusion of a population of molecules may be
directional
substances diffuse down their
concentration gradient
the diffusion of a substance across a biological membrane is ? because no energy is expended
by the cell to make it happen
passive transport
