Biology test #2 Flashcards
All cells have:
Plasma membrane, semifluid substance (cytosol), genetic material (chromosomes & DNA), & ribosomes
Compare and Contrast the structures of prokaryotic cells and eukaryotic cells
Prokaryotic cell structure has bacterial chromosomes, nucleoid, Ribosomes, plasma membrane cell wall, glycocalyx, and some have fimbriea and/or flagella. Eukaryotic cell structure has DNA in a nucleus that is bounded by a double membrane, membrane-bound organelles, and cytoplasm in the regions between the plasma membrane and nucleus
Bacterial Chromosomes
Bacterial Chromosomes
Nucleoid
contains the bacterial chromosomes (the genetic makeup)
Cell wall
A rigid structure that surrounds the plasma membrane and provides support to the cell
Glycocalyx
a bacterial capsule that protects the prokaryote
Fimbriae
finger or fringe like projections at the end of the fallopian tubes
Flagella
A long, whip-like filament that helps in cell motility
Plasma Membrane
A selectively-permeable phospholipid bilayer forming the boundary of the cells
vesicles
small membrane sacs that specialize in moving products into, out of, and within a cell
Exocytosis
Process by which a cell releases large amounts of material
Endocytosis
process by which a cell takes material into the cell by infolding of the cell membrane
Membrane proteins
Embedded proteins that perform specific functions for the cell membrane.
Peripheral proteins
a protein loosely bond to the surface of a membrane or to part of an integral protein and not embedded in the lipid bilayer
Integral proteins (transmembrane protein)
a transmembrane protein with hydrophobic regions that extend into and often completely span the hydrophobic interior of the membrane and with both hydrophilic regions in contact with the aqueous solution on one or both sides of the membrane (or lining the channel in the case of a channel protein)
Factors that affect Membrane fluidity
Temperature (Cools, membrane becomes less fluid; Heats up, membrane becomes more fluid), Phospholipids (more saturated fatty acids decrease fluidity, due to saturated tails being packed close together; more unsaturated fatty acids increases fluidity, due to kink in unsaturated tails that prevents packing together), and Cholesterol (moderates shifts in fluidity depending on temp; reduces phospholipid movement, but hinders solidification at low temps by disrupting packing)
How do hydrophobic (non polar) molecules pass through the plasma membrane?
they dissolve in the lipid bilayer and pass through the membrane rapidly
Diffusion
the movement of particles of any substance so that they spread out into the available space
Osmosis
the diffusion of free water across a selectively permeable membrane; artificial or cellular
concentration gradient
the region along which density of a chemical substance increases or decreases
Tonicity
the ability of a surrounding solution to cause a cell to gain or lose water
Isotonic
referring to a solution that, when surrounding a cell, causes no net movement of water into or out of the cell
how does isotonic affect an animal blood cell?
The blood cell is flat and normal