cell structure and func PROKARYOTIC CELLS

similarities

1. nucleoid/nucleus where DNA is located

2. cytoplasm

3. ribosomes

4. plasma membrane

cytoplasm

semifluid matrix of organelles and cytosol

ribosomes

synthesize proteins

plasma membrane

phospholipid bilayer

prokaryotic cells

• simplest organisms

• 2 domains:

  • archaea

  • bacteria

• lack of membrane bound nucleus

• has DNA in the nucleoid

• cell wall outside of plasma membrane

• has ribosomes

organelles

• no organelles common to all prokaryotes

• some contain organelles w/ specific functions

• may also have infoldings of the plasma membrane that aggregate reactions

bacterial microcompartments

• cellular compartments bounded by a semipermeable protein shell

• 40 to 400 nm

• isolate specific metabolic processes

• storage

• functional but not structural analogs of eukaryotic organelles

cytoskeletons

• prokaryotes possess molecules related to actin and tubulin

• influence shape of cell wall

• shape and strength of the cell is determined by cell wall

bacterial cell wall

• composed of peptidoglycan

• most bacterial cells are encased by cell wall

• plants, fungi, and most protist cell walls differ

• protect the cell, maintain its shape, and prevent excessive uptake/loss of water

• susceptibility of bacteria to antibiotics depends on structure of cell walls

archaean cell walls

• cell walls lack peptidoglycan

• greater diversity in components

archaean cell membrane

• membrane lipids structure helps distinguish archaea from bacteria

• contains saturated hydrocarbons attached to glycerol @ both ends

flagella

• present in some prokaryotic cells

• may be more than one if present

• used for locomotion

• rotary motion PROPELS the cell