Comparing Prokaryotic and Eukaryotic Cells

1. TOPIC: Prokaryotic Cells

2. Ecoli - BacteriaEcoli - Bacteria
• E. coli are coliform bacteria that normally
live in the intestines of humans and
animals. Although most strains are
harmless, several are known to produce
toxins that can cause diarrhea. One
particular E. coli strain called 0157:H7 can
cause severe diarrhea and kidney
damage.
Ecoli under TEM

3. Structures of ProkaryotesStructures of Prokaryotes
• Cell Wall: is made of protein, peptidoglycan,
protects the cell and prevents it from
bursting, maintains its shape, and is always
present.
• Plasma Membrane: thin layer mainly
composed of phospholipids which is
selectively permeable, but can pump
substances in or out by active transport

4. Structures of ProkaryotesStructures of Prokaryotes
• Cytoplasm: watery fluid filled space within
the plasma membrane which contains
enzymes that control metabolic and contains
the organelles of the cell
• Pili: thin protein filaments protruding from the
cell wall that are used for cell to cell
adhesion
– Attachment pili – contains a sticky section
– Conjugation pili – less, longer, used to build a
bridge b/t the cytoplasm of another bacterium

5. • Flagella: long thread like structures made
up of protein whose base in embedded in
the cell wall and allow the bacterium to
move in a fluid environment.
• Ribosome: small granular structures which
consist of RNA and proteins and play a
key role in protein synthesis.

6. • Nucleoid Region
• Contains the DNA which contains the
genetic material
• The DNA molecule is circular

7. Binary FissionBinary Fission
• Prokaryotic cells divide by binary fission
• Begins with DNA replication which is followed
by the separation of the two circular strands to
either side of the cell.
• Cytokinesis occurs, where the cell divides in
two. Each new cell recieves about half of the
cytoplasm.
• Division is followed by growth back to full size.

8. The Eukaryotic CellThe Eukaryotic Cell

9. Eukaryotic CellsEukaryotic Cells
• Have much more complicated internal
structure than prokaryotic cells.
Plant Cell
Animal Cell

10. StructuresStructures
• Free Ribosomes – made of two subunits, protein
and RNA – site of protein synthesis
• Rough ER – membrane with ribosomes attached
– makes proteins that are exported (via
exocytosis) in order to be used outside the cell.
• Smooth ER – No ribosomes, Builds lipids, such
as cholesterol and steroid hormones in the
testes and ovaries, Abundant in kidney and liver
cells because it help detoxify drugs and poisons,
Releases calcium in skeletal and heart muscle

11. StructuresStructures
• Lysosome – contains hydrolytic enzymes
which can break down substances in the
cell – by fusing then digesting (also breaks
down old organelles)
• Golgi Apparatus – stack of flattened,
membrane bound sacs which aid in
intracellular transport, processing &
packaging of proteins

12. StructuresStructures
• Mitochondrion – the link reaction & krebs’
cycle occur in the matrix; electron
transport chain is in the cristae of the inner
membrane – releases energy from organic
molecules – “powerhouse of the cell”
• Nucleus – largest organelle – contains all
the genetic information – controls the
activity by transcribing certain genes and
not others.

13. Compare Prokaryotic toCompare Prokaryotic to
Eukaryotic CellsEukaryotic Cells
• Eukaryotic is larger, more complex
• Contain naked DNA vs. DNA associated
with protein
• DNA in cytoplasm vs. DNA enclosed in a
nuclear envelope
• No membrane-enclosed organelles vs.
membrane-enclosed organelles (e.g.,
mitochondria, chloroplasts)