Anatomy & Physiology Bio 168 Chapter 3 |
Questions and Answers
Cytology - -scientific study of cells
-Cell theory - -1) All living things made of cells
-Human cell size - -10-15um in diamete
-Limit on cell size - -an overly large cell cannot support itself, may rupture
For a given increase in diameter, volume increases more than surface area
-Light microscope (LM) - -revealed plasma membrane, nucleus, and cytoplasm (fluid
between nucleus and surface)
-Transmission electron microscope (TEM) - -improved resolution (ability to reveal detail)
-Scanning electron microscope (SEM) - -improved resolution further, but only for surface
features
-Basic components of a cell - -Plasma, Cytoplasm, Extracellular fluid
-Plasma Cell - -Surrounds cell, defines boundaries
Made of proteins and lipids
-Cytoplasm - -Consists of organelles, cytoskeleton, and cytosol
-Extracellular fluid (ECF - -The fluid outside the 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
-Phospholipids - -A molecule that is a constituent of the inner bilayer of biological
membranes, having a polar, hydrophilic head and a nonpolar, hydrophobic tail.
-Cholesterol - -20% of the membrane lipids
Holds phospholipids still and can stiffen membrane
-Glycolipids - -Are complexes of carbohydrates and lipids
5% of the membrane lipids
, -Membrane proteins - -2% of the molecules but 50% of the weight of membrane
-Integral proteins - -penetrate the hydrophobic core of the lipid bilayer, often completely
spanning the membrane (as transmembrane proteins).
-Peripheral proteins - -Are proteins that are attached to the surface of the membrane.
does not penetrate
tethered to the cytoskeleton
-Functions of membrane proteins include: - -Receptors, second-messenger systems,
enzymes, channels, carriers, cell-identity markers, cell-adhesion molecules
-Receptors - -bind chemical signals
-Second messenger systems - -communicate within cell receiving chemical message
-Enzymes - -catalyze reactions including digestion of molecules, production of second
messengers
-Channel proteins - -allow hydrophilic solutes and water to pass 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
-G protein - -relays signal to adenylate cyclase which converts ATP to cAMP (second
messenger)
cAMP activates cytoplasmic kinases
-Kinases - -Add a phosphate group to a molecule
-Glycocalyx - -A fuzzy sticky carbohydrate rich area at the cell surface
unique to everyone except identical twins
-Glycocalyx Functions - -Protection -
Questions and Answers
Cytology - -scientific study of cells
-Cell theory - -1) All living things made of cells
-Human cell size - -10-15um in diamete
-Limit on cell size - -an overly large cell cannot support itself, may rupture
For a given increase in diameter, volume increases more than surface area
-Light microscope (LM) - -revealed plasma membrane, nucleus, and cytoplasm (fluid
between nucleus and surface)
-Transmission electron microscope (TEM) - -improved resolution (ability to reveal detail)
-Scanning electron microscope (SEM) - -improved resolution further, but only for surface
features
-Basic components of a cell - -Plasma, Cytoplasm, Extracellular fluid
-Plasma Cell - -Surrounds cell, defines boundaries
Made of proteins and lipids
-Cytoplasm - -Consists of organelles, cytoskeleton, and cytosol
-Extracellular fluid (ECF - -The fluid outside the 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
-Phospholipids - -A molecule that is a constituent of the inner bilayer of biological
membranes, having a polar, hydrophilic head and a nonpolar, hydrophobic tail.
-Cholesterol - -20% of the membrane lipids
Holds phospholipids still and can stiffen membrane
-Glycolipids - -Are complexes of carbohydrates and lipids
5% of the membrane lipids
, -Membrane proteins - -2% of the molecules but 50% of the weight of membrane
-Integral proteins - -penetrate the hydrophobic core of the lipid bilayer, often completely
spanning the membrane (as transmembrane proteins).
-Peripheral proteins - -Are proteins that are attached to the surface of the membrane.
does not penetrate
tethered to the cytoskeleton
-Functions of membrane proteins include: - -Receptors, second-messenger systems,
enzymes, channels, carriers, cell-identity markers, cell-adhesion molecules
-Receptors - -bind chemical signals
-Second messenger systems - -communicate within cell receiving chemical message
-Enzymes - -catalyze reactions including digestion of molecules, production of second
messengers
-Channel proteins - -allow hydrophilic solutes and water to pass 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
-G protein - -relays signal to adenylate cyclase which converts ATP to cAMP (second
messenger)
cAMP activates cytoplasmic kinases
-Kinases - -Add a phosphate group to a molecule
-Glycocalyx - -A fuzzy sticky carbohydrate rich area at the cell surface
unique to everyone except identical twins
-Glycocalyx Functions - -Protection -
