The document explains the differences between prokaryotic and eukaryotic cells, highlighting that prokaryotes are unicellular, simpler in structure, and were the first form of life, while eukaryotes can be unicellular or multicellular and have more complex structures with membrane-bound organelles. It discusses their reproductive processes, with prokaryotes reproducing via binary fission and eukaryotes through mitosis and meiosis, and ends with the endosymbiotic theory explaining the origin of eukaryotic cells as a result of symbiotic relationships with prokaryotes. Additionally, it touches upon the metabolic pathways of both cell types, noting that while eukaryotes primarily utilize aerobic respiration, prokaryotes exhibit diverse metabolic modes.

1. Cell Biology:
Prokarotic vs
ekaryotic cells

2. Cells have evolved into 2
different architectures

3. Prokaryote “style”: all unicelular
organisms
Eukaryotic “style”: uni and
multicelular organisms
Cells have evolved into two different
architectures:
Prokaryotes
Eukaryotes

4. Who was here
first?
Prokaryotic cells were here first and for billions of years they were the only form of
life on Earth. They are all unicellular, and their inner structure is less organized.
Eukaryotic cells appeared on earth long after prokaryotes,evolving from complex
associations of primitive cells, but they are much more advanced. Eukaryotic
organisms can be unicellular or multicellular.

5. Prokaryotes
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6. Characteristics of Prokaryotes

7. Characteristics of Prokaryotes

8. ● Cocci: spherical or round
● Bacillus: rod-shaped
● Spirilla: helical spiral
Do you know examples of each of these types of organisms?
Shapes of
prokaryotes

9. Shapes of prokaryotes

10. Cell structure
A primitive form of the lipid bi-
layer
External limit of the cell, made up of
carbohydrates and/or proteins.
The inner medium of the cell, full of
molecules of metabolic importance.
Like flagellae or pili, used to
interact with surroundings
Membrane
Cytoplasm
Wall
Extensions

11. Cell structure

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2
Eukaryotes

13. Characteristics of Eukaryotes

14. Structures unique to eukaryotes
Membrane
More advanced structure and
components, very selective, and
contains more components.
Nucleus
Contains and protects the genetic
material, which is replicated and
read in there.
Golgi
Responsible for the post-
processing and distribution of
proteins.
Mitochondria
The metabolic activity of cell
respiration takes place in this
organelle.
Endomembrane
system
The compartment where RNA is
translated to manufacture
proteins.

15. Cell structure

16. ● Organelles lack a membrane
● Ribosomes are almost always the only
organelles.
● Genetic material (circular DNA and RNA)
floats in a central part of the cytoplasm.
● Circular DNA
● Unicellular, but can associate
● Has larger number of organisms
● Appeared 4 billion years ago
Differences
● Organelles covered by a membrane.
● Multiple organelles including ribosomes.
● Genetic material is covered by a nuclear
membrane. Linear DNA
● Organisms can be multicellular or
unicellular.
● Larger in size.
● Appeared around 1 billion years ago

17. Prokaryotic organisms are predominantly
unicellular, however they can interact
with neighbouring cells forming
associations. A prokaryote can be found:
• In a unicellular state;
• Forming a colony;
• Forming a filament.
What’s the difference between this and
being a multicellular organism?

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Processes

19. They reproduce by a process called Binary Fission,
a form of asexual reproduction. It consists of the
duplication of DNA and the division of the
cytoplasm simultaneously, giving rise to two
identical daughter cells.
This process begins with DNA replication, which
creates two new identical strands of DNA (unless a
mutation or error has occurred during replication).
After replication, the mother cell grows, creating
enough space for both DNA molecules to migrate
towards the poles of the cell, each one being
located at an opposite pole.
Prokaryote
reproduciton

20. In contrast, eukaryotic reproduction involve mitosis and meiosis. During mitosis, a eukaryotic cell
replicates its DNA, which is then tightly packed forming chromosomes, followed by nuclear division and
cytokinesis, resulting in two genetically identical daughter cells. Mitosis is essential for growth and
development in multicellular organisms.
Meiosis, specific to eukaryotes, is a specialized form of cell division that produces gametes with half the
chromosome number of the parent cell. Meiosis involves two rounds of division, resulting in four haploid
daughter cells, each genetically unique due to genetic recombination.
Eukaryotic reproduciton

21. Eukaryotes are primarily aerobic, meaning they turn glucose
into energy (ATP). They predominantly generate energy through
aerobic respiration, which occurs in the mitochondria. This
process involves the complete oxidation of glucose to produce
ATP, with oxygen serving as the final electron acceptor. Some
eukaryotic cells, such as certain yeast species, can also perform
anaerobic respiration or fermentation under low-oxygen
conditions.
Prokaryotes, on the other hand, have varying metabolic
pathways, therefore, can either be aerobic (like Eukaryotes) or
anaerobic, like fermentation. Anaerobic metabolism implies
obtaining energy through the combustion of carbs with a lack of
oxygen. They may utilize various electron acceptors and donors,
including oxygen, nitrate, sulfate, and carbon dioxide.
Metabolism

22. How did Eukaryotes
come to be?
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23. Endosymbiosis
By Kelvinsong, CC BY-SA 3.0,
https://commons.wikimedia.org/w/index.php?curid=25295406
This theory proposes that eukaryotic cells originated from
symbiotic relationships between prokaryotic cells billions of
years ago. An ancestral eukaryotic cell engulfed a prokaryotic
cell capable of aerobic respiration, forming a symbiotic
relationship where the engulfed cell became a
mitochondrion. This event provided the host cell with
increased energy production efficiency.
Subsequently, another endosymbiotic event occurred where a
photosynthetic prokaryote was engulfed, giving rise to
chloroplasts in photosynthetic eukaryotes. Evidence
supporting this theory includes similarities between
organelles (mitochondria and chloroplasts) and free-living
bacteria, such as circular DNA, ribosomes, and similar size
and structure. Endosymbiosis theory provides a plausible
explanation for the origin of eukaryotic cells and the
evolutionary development of complex cellular structures.

24. This website has complete and accurate content
about prokaryotes and their differences with
eukaryotes, and some review questions and exercises.
Learn more

25. Physiology chart
Phase Description
Prophase Initiation of the assembly of the mitotic spindle
Metaphase
The microtubules start pulling the chromosomes with equal
force
Anaphase The chromosomes are then pulled towards the pole by the fibres
Telophase The chromosomes that cluster at the two poles start coalescing
Cytokinesis Denotes the division of the cytoplasm to form two daughter cells