Chapter 3 Cell Transport Flashcards
What are the functions of the plasma membrane?
protection, selective permeability, recognition, adhesion
What is meant by “fluid mosaic model”?
the components of the plasma membrane, which fluidly change position: phospholipid bilayer, proteins, cholesterol, and glycocalyx
What does “hydrophilic” mean?
“water-loving”, attracts water (repels lipids)
What does “hyrophobic” mean?
“water-fearing”, repels water (attracts lipids)
Describe the structure of the plasma membrane.
polar head and non-polar tail, arranged tail-to-tail; gives cell ability to control movement of molecules in and out of the cell
What are the components and function of the glycocalyx?
glycoproteins and glycolipids: self recognition, determine blood type, immunity response, cell-to-cell interactions
What are the three main types of membrane junctions?
tight junction, desmosome, gap junction
Where would you find tight junctions?
between cells in lining of digestive tract
Where would you find desmosomes?
between skin cells
Where would you find gap juctions?
between heart cells and embryonic cells
What is a concentration gradient?
a difference in solute concentration on either side of a cell membrane
What are the six main functions of membrane proteins?
enzymes, receptors for hormones, cell recognition, cell adhesion, cytoskeleton attachment, transport (channels)
What is diffusion?
movement of substances from an area of high to low concentration (down concentration gradient)
What is osmosis?
movement of WATER across a membrane down its concentration gradient
What substances pass easily through the plasma membrane?
small, lipid-soluble molecules (tails are non-polar, hydrophobic)
What is facilitated diffusion?
diffusion of large molecules across a membrane using a protein carrier (channel protein); no energy is required
What are the types of passive transport?
diffusion, osmosis, facilitated diffusion, filtration
What are the types of active transport?
bulk transport, solute pumping (Na+/K+ pump), exocytosis, phagocytosis, bulk-phase endocytosis, receptor-mediated endocytosis
How does the flow of sodium and potassium ions in differ in passive and active transport?
passive-sodium diffuses in cell, potassium diffuses out; active- 3 sodium ions pumped out of cell, 2 potassium ions pumped in per ATP molecule
What would happen to a cell in a hypertonic solution?
A hypertonic solution contains more solutes than inside the cell; water moves out and cell crenates (shrinks)
What would happen to a cell in a hypotonic solution?
A hypotonic solution contains less solutes than inside the cell; water moves into the cell and cell swells or lyses
What would happen to a cell in an isotonic solution?
An isotonic solution contains the same amount of solutes on both sides of the cell membrane; no net water movement and cell stays the same
What is a pseudopod?
temporary projections of the plasma membrane used in movement and phagocytosis (macrophages)
