Anatomy & Physiology Bio 168 Chapter 3 Exam Questions With Correct Expert
Answers | Latest New 2025 Update
revealed plasma membrane, nucleus, and cytoplasm (fluid
Light microscope (LM)
between nucleus and surface)
Transmission electron improved resolution (ability to reveal detail)
microscope (TEM)
Scanning electron microscope improved resolution further, but only for surface features
(SEM)
Basic components of a cell Plasma, Cytoplasm, Extracellular fluid
Surrounds cell, defines
Plasma Cell
boundaries Made of
proteins and lipids
Cytoplasm Consists of organelles, cytoskeleton, and cytosol
The fluid outside the
Extracellular fluid (ECF
body's cells includes
tissue
Plasma membrane Boundary of cell. Holds things together and controls entry and exit
of substances.
98% of membrane molecules are lipids
A molecule that is a constituent of the inner bilayer of
Phospholipids
biological membranes, having a polar, hydrophilic head
and a nonpolar, hydrophobic tail.
20% of the membrane lipids
Cholesterol
Holds phospholipids still and can stiffen membrane
Are complexes of
Glycolipids
carbohydrates and lipids 5% of
the membrane lipids
Membrane proteins 2% of the molecules but 50% of the weight of membrane
penetrate the hydrophobic core of the lipid bilayer, often
Integral proteins
completely spanning the membrane (as transmembrane
proteins).
Are proteins that are attached to the surface
Peripheral proteins of the membrane. does not penetrate
tethered to the cytoskeleton
, Receptors, second-messenger systems, enzymes, channels,
Functions of membrane proteins
include: carriers, cell-identity markers, cell-adhesion molecules
Receptors bind chemical signals
Second messenger systems communicate within cell receiving chemical message
catalyze reactions including digestion of molecules,
Enzymes
production of second messengers
allow hydrophilic solutes and water to pass
Channel proteins
through membrane some are always open,
some are gated
Ligand-gated channels respond to chemical messengers
Voltage-gated channels respond to charge changes
Mechanically-gated channels respond to physical stress on cell
Carriers bind solutes and transfer them across membrane
Cell-identity markers glycoproteins acting as identification tags
Cell-adhesion molecules mechanically link cell to extracellular material
Chemical first messenger (epinephrine) binds to a surface recepto
relays signal to adenylate cyclase which converts ATP to
G protein
cAMP (second messenger) cAMP activates cytoplasmic
kinases
Kinases Add a phosphate group to a molecule
Answers | Latest New 2025 Update
revealed plasma membrane, nucleus, and cytoplasm (fluid
Light microscope (LM)
between nucleus and surface)
Transmission electron improved resolution (ability to reveal detail)
microscope (TEM)
Scanning electron microscope improved resolution further, but only for surface features
(SEM)
Basic components of a cell Plasma, Cytoplasm, Extracellular fluid
Surrounds cell, defines
Plasma Cell
boundaries Made of
proteins and lipids
Cytoplasm Consists of organelles, cytoskeleton, and cytosol
The fluid outside the
Extracellular fluid (ECF
body's cells includes
tissue
Plasma membrane Boundary of cell. Holds things together and controls entry and exit
of substances.
98% of membrane molecules are lipids
A molecule that is a constituent of the inner bilayer of
Phospholipids
biological membranes, having a polar, hydrophilic head
and a nonpolar, hydrophobic tail.
20% of the membrane lipids
Cholesterol
Holds phospholipids still and can stiffen membrane
Are complexes of
Glycolipids
carbohydrates and lipids 5% of
the membrane lipids
Membrane proteins 2% of the molecules but 50% of the weight of membrane
penetrate the hydrophobic core of the lipid bilayer, often
Integral proteins
completely spanning the membrane (as transmembrane
proteins).
Are proteins that are attached to the surface
Peripheral proteins of the membrane. does not penetrate
tethered to the cytoskeleton
, Receptors, second-messenger systems, enzymes, channels,
Functions of membrane proteins
include: carriers, cell-identity markers, cell-adhesion molecules
Receptors bind chemical signals
Second messenger systems communicate within cell receiving chemical message
catalyze reactions including digestion of molecules,
Enzymes
production of second messengers
allow hydrophilic solutes and water to pass
Channel proteins
through membrane some are always open,
some are gated
Ligand-gated channels respond to chemical messengers
Voltage-gated channels respond to charge changes
Mechanically-gated channels respond to physical stress on cell
Carriers bind solutes and transfer them across membrane
Cell-identity markers glycoproteins acting as identification tags
Cell-adhesion molecules mechanically link cell to extracellular material
Chemical first messenger (epinephrine) binds to a surface recepto
relays signal to adenylate cyclase which converts ATP to
G protein
cAMP (second messenger) cAMP activates cytoplasmic
kinases
Kinases Add a phosphate group to a molecule
