Chapter 3 Flashcards
Three basic human cells
Plasma membrane
Cytoplasm
Nucleus
Plasma membrane
flexible outer boundary
Cytoplasm
intracellular fluid outer organelles
Nucleus
DNA containing control center
What is the major component of the plasma membrane
phospholipid bilayer
Cell junctions
Tight
Desmosomes
Gap
Tight Junctions
impermeable, form continuous seals around the cell prevent molecules from passing between cells
Desmosomes
Anchoring, bind adjacent cells together like molecular Velcro and help keep cells from tearing apart
Gap Junctions
communicate, allow ions and small molecules to pass from cell to cell, in heart cells and embryonic cells
Passive transport
no energy is required
simple
very small molecules that can pass through membrane or channels, lipid-soluble and nonpolar substances
Facilitated
larger, non-lipid soluble or polar molecules can cross the membrane but only with assistance of carrier molecules
Osmosis
movement of solvent, not molecules
moving down a concentration gradient
natural movement of molecules from areas of high concentration to areas of low concentration
Osmolarity
measure the concentration of the total number of solute particles on solvent
Isotonic
has equal balance as osmolarity inside the cell, volume unchanged
Hypertonic
higher osmolarity resulting in cell shrinking
Hypotonic
lower osmolarity resulting in cell swelling
Hydrostatic pressure
outward pressure exerted on cell side of membrane caused by increased in volume of cell to osmosis
Osmotic pressure
inward pressure due to tendency water to be pulled into a cell with higher osmolarities
Active membrane transport
have Active transport and vascular transport both require ATP to move solutes across a plasma membrane:
Solute is too large for channels, or
Solute is not lipid soluble, or
Solute is not able to move down concentration gradient
Antiporter
Transport one substance into cell while transporting a different
substance out of cell
symporters
transport two different substances in the same direction
primary active transport
Required energy comes directly from ATP hydrolysis ->Energy from hydrolysis of ATP causes change in shape of transport protein->
Shape changes cause solutes (ions) bound to protein to be pumped across
membrane
secondary active transport
Required energy is obtained indirectly from ionic gradients created by primary active transport
Vesicular active transport
involves transport of large particles, macromolecules, and fluids across
membrane in membranous sacs called vesicles
Exocytosis
transport out of cell
Transcytosis
transport into, across, and out of cell
vesicular trafficking
transport from one area or organelle in cell to another
Endocytosis
involves protein-coated vesicles being pulled in must bind to its unique receptor once inside: fuse with lysosome or transcytosis
Phagocytosis
“Cell eating” pseudopods form and flow around solid particles being engulfed, forming a vesicle is pulled into cell
Pinocytosis
“Cell drinking” a fluid phase, plasma membrane enfolds bringing extracellular fluid and dissolved solutes inside cell membrane
Receptor- mediated endocytosis
involves endocytosis and transcytosis of specific molecules, bind to a membrane-bound receptor
Histones
have an effect on DNA can help regulate gene expression
Nucleus envelope
double membrane, separates nucleoplasm from cytoplasm
Nucleolus
Dense collection of RNA and proteins site of ribosome production
Chromatin
fibers of relaxed DNA and proteins, stores info for synthesis of proteins
Mitochondria
“Powerhouse” produces most of cell energy ATP cellular respiration. own DNA, RNA, and ribosomes
Free Ribosomes
free floating
Membrane-bound ribosomes
site of syntheses of proteins to be incorporated into membranes or lysosomes, exported from cell
peroxisomes
neutralize toxins, breakdown and synthesis of fatty acids
Lysosomes
digest old or unwanted cell sub, bacteria, viruses, and toxins
