Prokaryotic vs. Eukaryotic Cells (Updated)

Captions are on! Click CC at bottom right to turn off. Get updates from @AmoebaSisters on Twitter and Facebook! I’ll never forget a circular red spot I
developed on my arm when I was in elementary school. It left a lasting memory in my mind, because
it was something called ringworm and, with my active imagination, I thought I was now
infected a ring-shaped worm. I learned you’ve got to be careful about
names, because ringworm isn’t caused by a worm at all. It’s actually a fungus which it turns out
is pretty common and can be carried by many things like pets or soil. And since up to that point, I was used to
antibiotics as a way to treat infections, I assumed I’d be given antibiotics. But I wasn’t. I was given an antifungal cream instead, and
it went away. So it made me wonder – what made it different
from the bacteria that had made me sick in the past? Why wasn’t I given antibiotics? Well antibiotics target bacteria. Antibiotics can destroy bacteria by affecting
their ability to reproduce, damaging their cell walls, or interfering with their ability
to make proteins that they need to survive. Just some examples. But it turns out bacterial cells and fungal
cells are very different cell types. In fact, fungal cells have more in common
with your cells- which are animal cells- than they have in common with bacterial cells. And that has a lot to do with the comparison
of prokaryotic cells with eukaryotic cells which is what we will focus on. First, just a refresher—recall that the
modern cell theory includes the statement that all living things are made of one or
more cells. All living things. In the three domains of life, prokaryotes
are organisms that can be bacteria and archaea. They are unicellular which means they are
single-celled organisms. Eukaryotes are organisms that all fit in this
last domain Eukarya—eukaryotes may be protists, plants, animals, or fungi. They can be unicellular or they can be multicellular,
which means they can be made up of many cells. Like you! By the way, just to clarify: the word “prokaryote”
is typically used to refer to the organism itself. When you are describing its cell, you are
describing a prokaryotic cell. Same for eukaryote- “eukaryote” typically
refers to the organism itself and when you describe its cells, those are eukaryotic cells. Prokaryotic cells and eukaryotic cells do
have a lot in common. Both have DNA. That’s critical because DNA is the cells’
genetic material. Both prokaryotic cells and eukaryotic cells
have ribosomes, which are small organelles—an organelle being like a “tiny” organ. The ribosomes have the important job of making
protein. Got to make protein. Both cell types have cytoplasm, the jelly
like fluid within cells. Both of them have a cell membrane- also known
as a plasma membrane- which is critical because it controls what goes in and out of the cell
and therefore maintaining homeostasis. All cells have a cell membrane! Now as for cell walls—most prokaryotic cells
have cell walls. Many eukaryotic cells— plant cells and fungus
cells for example—can have cell walls. But there are plenty of eukaryotic cells that
don’t have cell walls such as animal cells. What makes prokaryotic cells and eukaryotic
cells different is especially interesting. Eukaryotic cells are more complex than prokaryotic
cells. They tend to be larger than most prokaryotic
cells. And to help me remember some more differences
in this next part, I like to remember that “pro” in prokaryote rhymes with “no”
and “eu” in eukaryote rhymes with “do.” Prokaryotic cells have no nucleus to contain
their DNA. So you will find their DNA is not contained
within a nucleus; it’s a bit messy here. They have no membrane-bound organelles. Membrane-bound organelles are fancy organelles
that have their own membrane like the nucleus, mitochondria, the endoplasmic reticulum, and
the golgi apparatus. A big indicator of eukaryotic cells is this
nucleus- eukaryotic cells DO have a nucleus to contain their DNA. Depending on what type of eukaryotic cell
it is—it could have different types of membrane-bound organelles. For example, a plant cell is likely to have
chloroplasts while an animal cell would not. Wow, look at all this alphabetized vocabulary. If you want to try to practice your skills,
pause the video and see how many of these vocabulary words you can use to compare and
contrast prokaryotic cells with eukaryotic cells. It’s important to grasp that all cells of
living things fall in one of these two categories. And understanding the characteristics of these
two cell types can help us better understand the diversity of living things whether they
are archaea, bacteria, protists, fungi, plants, or animals. And in the case of my example- realizing whether
an infection you’re dealing with involves prokaryotic cells (such as bacteria) or eukaryotic
cells (such as the fungus). Well that’s it for the Amoeba Sisters, and
we remind you to stay curious!

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