Chapter 3-Cell Structure of Prokaryotes Flashcards
How do Prokaryotes differ from Eukaryotes?
in size and simplicity
most prokaryotes lack a _____________
internal membrane system
prokaryotes are divided into _____________
bacteria and archaea
describes cell shape
morphology
what are the 3 major cell morphologies? (there are variations from the main 3)
coccus (cocci), bacillus (bacilli), spirillium
2 cocci
diplococcus
chains of cocci
streptococcus
4 cocci
tetrad
8 cocci
sarcinae
many cocci
staphylococcus
diplobacilli
2 bacilli
chains of bacilli
streptobacilli
several parallel cells along long axis
pallisade
rods
bacilli
very short rods
coccobacilli
resemble rods, comma shaped
vibrios
rigid helices
spirilla
flexible helices
spirochetes
network of long, multinucleate filamentous cells
mycelium
organisms that are variable in shape
pleomorphic
Why is it advantageous for a cell to be small?
small cells have a higher SA to volume ratio than large cells, allows for greater nutrient exchange per unit of cell volume
what makes up the cell envelope?
(1) structures exterior to the cell wall
(2) cell wall
(3) cell membrane
What are the functions of the cell membrane?
maintain cell integrity, regulate transport, protein attachment, receptors for detection of/response to chemicals in surroundings, energy metabolism in prokaryotes
describes the cell membrane as somewhat fluid, somewhat solid, lipid bilayer with floating proteins
fluid mosaic model
phospholipid bilayer with proteins, no sterols, but contains hopanoids (both hydrophobic and hydrophilic components), many variations to glycerol backbone
composition of cytoplasmic membrane
loosely connected membrane protein on cytoplasmic side, easily removed
peripheral protein
embedded with membrane, project outward and inward, amphipathic, control important functions and microdomains
integral proteins
completely cross membrane
transmembrane protein
What are two cell membrane strengthening agents?
(1) sterols
(2) hopanoids
rigid and planar, found in eukaryotic membranes, strengthen membrane, only found in a very few prokaryotes
sterols
structurally similar to sterols, present in membranes of many Bacteria
hopanoids
liquid crystal, rigid and temperature dependent
cell membrane
What happens when the cell membrane gets too cold?
solidification occurs, gelling, Van der Waals forces pull tails together
What happens when the cell membrane gets too warm?
thermal lysis, cell death
How is the correct fluidity of a cell membrane obtained?
adjust fatty acid composition
if cold: more unsaturated fatty acids, minimize VDW forces
if hot: more saturated fatty acids, minimize VDW forces
transport which does not require ATP or other cellular energy to be used by the cell
passive transport
transport which require the cell to extend its own energy in the form of ATP
active transport
transport that doesn’t require a transport protein
simple transport
transport which requires a transport protein
facilitated transport
the movement of a molecule due to inherent kinetic energy from high concentration to low concentration
diffusion