Week 4 Flashcards
Plasma membrane
Border of the cell.
What does the plasma membrane look like?
It appears as pair of dark parallel lines when viewed with an electron microscope.
Does a plasma membrane have both intracellular and extracellular faces? True or false
True
What are the three functions of the plasma membrane?
Defines cell boundaires
Governs interactions with other cells
Controls passage of materials in and out of the cell
98% of membrane molecules are?
Lipids
The heads of phospholipids are?
Hydrophilic ( water-loving) Polar
The tails of phospholipids are?
Hydrophobic (water-fearing) nonpolar
Cholesterol
20% of the membrane lipids.
It holds phospholipids still and can stiffen the membrane.
Glycolipids
5% of the membrane lipids
Phospholipids with short carbohydrate chains on the extracellular face.
Contributes to glycocalyx- carbohydrate coating on the cell surface.
Membrane proteins
Are common protein molecules that are attached to, or associated with the membrane of a cell or an organelle.
Integral proteins
Is a protein that is permanently attached to the biological membrane.
Peripheral proteins
Adhere to one face of the membrane and usually tether to the cytoskeleton
Cilial
A short microscopic hair vibrating structure is found in large numbers on the surface of certain cells. 7-10um long
For example an eyelash
Multiple nonmotile cilia location
Found on sensory cells of the nose
Ciliopathies
Defects in structure and function of cilia
Motile cilia are found where?
Respiratory tract, uterine tubes, ventricles if the brain, ducts to testes.
How many Motile cilia are found on each cell
50-200
Axoneme
The core of motile cilium
How many structures of microtubules does the axoneme have?
9+2
Cilia beat freely within a saline layer located where?
The cells surface
Chloride pumps pump Cl- into what?
ECF
What follows after ECF
Na+ and H2O
Where does mucus float?
On top of the saline layer
What is the only functional flagellum in humans?
The tail of a sperm cell.
Pseudopods
Continually changing extensions of the cell that vary in shape and size.
Pseudopods can be used for what?
For cellular locomotion and capturing foreign particles.
Plasma membrane and organelle membranes are selectively permeable what does that mean?
They allow some things through but prevent others from passing.
Do passive mechanisms require ATP
No.
Passive Mechanisms
The random molecular motion of particles provides the necessary energy.
filtration, diffusion, osmosis
Active mechanisms
Consumes ATP.
And is used for two different types of transport Active and Vesicular
Carrier
Mediated mechanisms used a membrane protein to transport substances across the membrane
Filtration
Particles are driven through the membrane by physical pressure
Simple diffusion
The net movement of particles from a place of high concentration to a place of lower concentration
Substances diffuse down their concentration gradient do not require a membrane. True or false?
True
What are the factors that affect the diffusion rate through a membrane? for simple diffusion.
Temperature
Molecular weight
The steepness of the concentrated gradient
Membrane surface area
Membrane permeability
pH
Osmosis
The net flow of water through a selectively permeable membrane. Moves from higher to lower
Some examples of osmotic imbalance.
Diarrhea, constipation, edema
Channel proteins in membrane specialized for water passage?
Aquaporins
Water can be diffused through the phospholipid bilayer, but osmosis is enhanced by what?
Aquaporins
Osmotic pressure
Hydrostatic pressure is required to stop osmosis.
Increases the number of nonpermeating solutes
Reverse osmosis
The process of applying mechanical pressure to override osmotic pressure allows for water purification
Osmolarity
Number if osmoles per liter of solution
Tonicity
The ability of a surrounding solution (bath) to affect fluid volume and pressure in a cell.
Hypotonic solutions
Causes cells to absorb water and swell. if the cells stay in this solution too long it will cause them to explode and die
Has a lower concentration of nonpermeating solutes than intercellular fluid (ICF)
Hypotonic solutions
Hypertonic solutions
Causes the cell to lose water and shrivel (crenate)
Has a higher concentration of nonpermeating solutes than ICF
Hypertonic solutions
Isotonic solutions
Cause no change in the cell volume
The concentrations of nonpermeating solutes in the bath and ICF are the same.
Isotonic solution
