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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!