Ch 3 Flashcards
Define Cell
the smallest unit of life
Define Phospholipid
chief component of cell membranes / help transport lipids in blood / ha 2 fatty acid chains and 1 phosphate group with an attached nitrogen containing group
Define cholesterol
Stiffens membrane / Further decreases water solubility of membrane
Define hydrophobic
attracted to water
Define hydrophilic
avoid water
Define amphipathic
(of a molecule, especially a protein) having both hydrophilic and hydrophobic parts
Define semipermeable
determines which substances enter or exit the cell
Define kinetic energy
energy that is being used to move something
Define diffusion
the movement of molecules or ions from an area where they are in higher concentration to an area where they are in lower concentration
Define gradient
movement from high to low concentration is also called movement down
Define polarized
Define voltage
Define receptor
Define polypeptide
Define globular
Define fibrous
Define denature
Define active site
Define intracellular
Define extracellular
Define lipid bilyaer
Define colloid
Define absorption
Describe the cell theory
the cell is the smallest unit of life
all organisms are made of one or more cells
cells only arise from other cells
List and describe the 3 major parts of a cell seen under the microscope
- the plasma membrane; the outer boundary of the cell
- the cytoplasm; the intracellular fluid packed with the organelles
- the nucleus; an organelle that controls cellular activity
Define plasma membrane. State its function
the outer boundry of the cell; it acts as a permeable barrier that allows certain things in
Describe the structure of the fluid mosaic model
rows of phospholipids with some proteins and carbohydrates every now and then
Identify the 3 lipid components of the plasma membrane. State their function
phospholipids: form the structure of the membrane and keep water-soluble substances form coming in
enzymes: determines what functions the membrane can perform
carbohydrates: acts as identity molecules, allows cells to know ‘who is who’
Identify the protein populations of the plasma membrane
Integral proteins; firmly inserted into membrane
Peripheral proteins; not imbedded into lipid bilayer
Understand fluidity of the phospholipid bilayer
What is a lipid raft? State the importance
Describe the Glycocalyx and state it functions
fuzzy, sticky, carbohydrate-rich area at the cell surface created by sugars of glycoproteins and glycolipids
it provides identity for the cell
Know the 6 functions of membrane proteins
Transporters receptors enzymatic activity cell-cell recognition attachment to the cytoskeleton and extracellular matrix cell-to-cell joining
What are microvilli and where would you find them? State their function
Microvilli are thin finger-like membrane protrusions that are found on the surface of a wide variety of cell types
Identify the 3 types of membrane junctions and state their functions
tight junctions: prevent molecules from passing between cells
gap junctions: allows small molecules to pass from cell to cell
desmosomes: anchoring junctions / helps keep cells from tearing apart
Identify the substances surrounding cells. Know how it is produced and name the basic components
Define selective permeability. How does this affect the components of interstitial fluid
Describe the difference between Active and Passive forms of transport across the plasma membrane
Define the following:
a. Diffusion
b. Concentration gradient
the movement of molecules or ions from an area where they are in higher concentration to an area where they are in lower concentration
movement from high to low concentration is also called movement down
Identify 2 factors that influence the speed of diffusion
concentration
molecular size
temperature
Identify substances transported by simple diffusion
gases, steroid hormones, and fatty acids
Describe facilitated diffusion. Identify substances transported by facilitated diffusion
the transported substance either ‘binds to carrier proteins in the membrane and is ferried across’ or ‘moves through water-filled channel proteins’
How do the following proteins function in facilitated diffusion?
Carriers –
Channels -
transmembrane proteins that are specific for transporting certain polar molecules or classes of molecules, such as sugars and amino acids, that are too large to pass though membrane channels
transmembrane proteins that transport substance, usually ions or water, through aqueous channels from one side of the membrane to the other
How is facilitate diffusion regulated
How is osmosis different from diffusion
Define the following:
a. Osmolarity
b. Tonicity c. Isotonic d. Hypertonic e. Hypotonic
- the total concentration of all solute particles in a solution
- the ability of a solution to change the shape of cells by altering the cells internal water volume
- the same tonicity
- a higher concentration of nonpenetrating solutes than seen in the cell
- a lower concentration of nonpenetrating solutes than seen in the cell.
How is primary active transport different from facilitated diffusion
expends its own energy, and moves against the gradient current