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Welcome back! There's something I need to tell you... I'm pregnant.
Nah, It's just that I left off some information in the last video.
You see, there are two basic types of cells: prokaryotic and
eukaryotic. Prokaryotic cells are cells that don't have a nucleus.
Eukaryotic cells do and are generally more complex. Since
eukaryotic cells are the more complex ones, we are going to do them first. What's
going on everybody! My name is Jack Jenkins and this is Academy of One.
Today we are going to talk about eukaryotic cells.
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[Music] The word eukaryotic means true
nuclease and the nuclease is the main differentiation between
eukaryotic and prokaryotic. Eukaryotic cells make up the body of
animals, plants, fungus and more. The variety of eukaryotic
cells is very diverse, thus why this video is so much longer than the
prokaryotic one. Another difference between eukaryotic and
prokaryotic is that eukaryotic are bigger. The
cytoplasm, which remember from the last video is all the stuff inside of the plasma
membrane, includes organelles. An organelle
are membrane-enclosed structures. This includes
mitochondria and the nucleus, two things I will talk about
later. So What gives the cytoplasm it's structure? Well the
cytoskeleton is the answer. A network of protein fibers that give a
eukaryotic cell it's shape. There are three types of protein fibers.
Micro-filaments are the thinnest of the three. Micro-filaments are linear polymers
of actin. Micro-filaments are highly versatile, aiding in
cellular movement. Intermediate filaments are the
medium-size protein fibers. These fibers consist of a wide variety
of protein and maintain the cell shape and rigidity.
Intermediate filaments are also invoked in creating the nuclear lamina,
which is mesh-work that lines the inner nuclear membrane.
Lastly are the micro-tubules. These big polymers of tubalin help aid
n cell division. The micro-tubes also make up cilia
and flagella. These two are extensions of the cell membrane, anchored onto
it by the Basel body. These three protein fibers, which are the
micro-filaments, intermediate filaments and the micro-tubules make up
the cytoskeleton. So let's bring up this picture. This is the
map of the animal cell. You see animal and plant cells differ in a number of ways
and we will explore the plant cell later. For now let's give this tour
of the anatomy of animal cells.
The first one is the pinocytotic vesicle. The
pinocytotic vesicles aids in the process of pinocytosis.
Pinocytosis is a mode of endocytosis. Endocytosis is the
process by which cells absorb molecules. The process of pinocytosis
is simple. A small molecule get trapped in the pinocytotic
vesicles and the vesicles will use lysosomes to hydrolyze the molecule.
This process uses a lot of energy in the form of adenosine
triphosphate or ATP. Remember, hydrolyze is to break down with
water and a lysosomes is another organelle in a cell. The process of
pinocytosis is how a cell absorbs fluids called
extracellular fluids or ECF. Think of the pinocytotic vesicle
as your mouth and the process of pinocytosis as the process of digestion.
The outside of the cell is the cell membrane. The cell membrane. This is what
separates the cell from the outside environment. The cell membrane will be the topic for
videos 5.4 through 5.6. Next up is the
golgi apparatus or golgi body. This is the organelle that is
responsible for packaging proteins inside of the cell.
The golgi apparatus is the colon of the organelle world.
The golgi apparatus is also involved in the creation of
lysosomes and delivery of protein. Inside of the golgi apparatus is
the golgi vesicles. The Golgi vessel contain the enzymes or whatever
other compounds that have been transported through the golgi
apparatus. Connected to the nucleus is the endoplasmic
reticulum. The ER is a series of membranes that form a labyrinth that
synthesis proteins. There are two types of endoplasmic
reticulum: Smooth and rough. Smooth reticulum doest have
ribosomes where as rough does have ribosomes. Funny enough
ribosomes are the next organelle. A ribosome is a particle of
RNA and proteins that aid in synthesization of protein.
The ribosomes are created in the nuclease. We already talked
about how a nucleus is the main difference between a
eukaryotic and a prokaryotic cell. The nuclease is the largest
organelle in the organ and consists of three parts: the
nucleus envelope, chromatin and the nucleolus.
The nuclear envelope is a double membrane that protects the nucleus. The
membrane contain protein called the nuclear pore complex. These protein are the
bouncer of the nucleus club. They allow only certain molecules to come in, such as
water and certain proteins. The envelope is also covered with ribosomes
just like the rough endoplasmic reticulum. Inside the nucleus is where
the second part is found, called chromatin. Chromatin consists of DNA
and proteins. Long strands of chromatin are called chromosomes.
Chromosomes play a key role in genetics. The last part is the
nucleus which is where ribosomes are made. It also holds the DNA
information on coding for RNA. We went over a bunch of different organelles
but we really don't know how they work together. To understand
this we will take a look at how a cell creates and exports a protein.
This particular protein is called an antibody. An antibody
is a glycoprotein that attack and destroy invaders such as
bacteria. Antibodies are synthesis from the rough
endoplasmic reticulum. They are then packed into vesicles and travel to the
golgi apparatus. In the golgi apparatus, carbohydrates join the
protein and then repacked into another vesicle. It then
goes out to the plasma membrane. The membrane unpackages it and
releases it outside the cell. The antibody will then fight
out all the bacteria... How heroic. The next organelle
is lysosomes. Lysosomes are membrane organelle that break down
biomolecules. The pinocytotic vesicle will trap outside
molecules. It will then form a membrane around the molecule, called a food
vacuole and the lysosomes will eat them. The last thing we're going to talk about
in an animal cell is the mitochondria. The mitochondria is known as
the cellular power house because its function is to take food and
turn it into energy. This energy comes in the form of ATP.
Cells digest food in two different ways,: Aerobic and
anaerobic. Aerobatic is the metabolism done in the
mitochondria. This type of metabolism produces the most ATP but uses
the most oxygen. Anaerobic is used when the cell doesn't have a lot
of oxygen. This metabolism is done inside the cytoplasmic
fluid and produces very little ATP. Let's get away from the animal
cells and move into plants. As you can see, pant cells are very close to
animal cells, with a few changes. First thing is that most plants cells
\have a cellular wall. This wall is
usually made by cellulose that is secreted from the plasma membrane.
The purpose of the cell wall is to protect the delicate plasma membrane.
The big white thing in the middle of a plant cell is the central vacuole. The
Central vacuole is mostly filled with water that helps keep the cells water balance.
Some plants, such as the Californian red wood,
Californian red wood, stores poison in the central vacuole.
This is to make sure those dang animals don't eat it. A cool thing plants do that animals don't is that they
get energy from photosynthesis. Photosynthesis is the process of turning
light into energy a plant can use. Photosynthesis occurs in the
chloroplasts. Chloroplasts are double membrane organelles that turns sunlight into
ATP. Chloroplast have a few different parts. The inside of a
chloroplast is filled with liquid called the stroma. Within the liquid are
hollow sacs called thylakoids.
Stacks of sacs are known as granum. Within the thylakoid are
molecules chlorophyll. This chlorophyll is the reason why plants are
green. There are many different types of chlorophyll but the main one is chlorophyll
a with a molecular formula of, this is a long one,
C55H72O5N4
MG... Yeah... Gotta love nature. During photosynthesis,
the chlorophyll will capture the energy of the sunlight and other molecules
within the thylakoids will turn the energy into ATP. The molecules
will then diffuse into the stroma and the ATP will be used for the various
synthesis plants preform. Ok, now that we understand both plant and animal cells
we can move on the prokaryotic cells... Which is the
topic of the next video. If you want to see that video early, as well as hundreds of
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amazing day. [Music]
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