Organelles of the Cell
Summary
TLDRThis educational video script delves into the intricate components of a eukaryotic cell, emphasizing the plasma membrane, nucleus, and cytoplasm as the cell's foundational sections. It illustrates the cytoplasm's role as a medium for chemical reactions and the plasma membrane's selective permeability. The nucleus, often dubbed the 'control center,' houses DNA and directs protein synthesis. Ribosomes, ER, and the GOI body collaborate in protein production and modification. Mitochondria, known as the 'powerhouse,' generate energy through cellular respiration. The script also touches on the endosymbiosis theory, suggesting mitochondria and chloroplasts were once independent organisms. Lysosomes handle waste and food breakdown, while vacuoles store materials. The video concludes with a review of these concepts, encouraging viewer engagement.
Takeaways
- 🔬 Organelles are specialized structures within cells that perform specific functions, akin to organs in the body.
- 🌟 The plasma membrane, or cell membrane, is a lipid bilayer that selectively allows substances to pass in and out of the cell.
- 🧬 The nucleus acts as the cell's control center, housing DNA and directing the cell's activities through the production of proteins.
- 🍯 The cytoplasm is a gel-like substance that fills the cell and facilitates chemical reactions, including the dissolution of solutes like carbohydrates and proteins.
- 🏋️♂️ Ribosomes are the cellular structures responsible for protein synthesis, translating genetic information into functional proteins.
- 📦 The Golgi apparatus modifies, sorts, and packages proteins for transport within the cell or for secretion outside the cell.
- ⚡ Mitochondria are known as the 'powerhouses' of the cell, generating energy in the form of ATP through cellular respiration.
- 🔁 Endosymbiosis theory suggests that mitochondria and chloroplasts were once free-living organisms that became incorporated into larger cells.
- 🌱 Chloroplasts, found in plant cells, carry out photosynthesis, converting sunlight into glucose and oxygen using chlorophyll.
- 💧 Vacuoles store water, nutrients, waste products, and pigments, and can also regulate the cell's internal environment.
Q & A
What is meant by the term 'organelle' in the context of a eukaryotic cell?
-An organelle refers to the small specialized structures within a eukaryotic cell that perform specific functions necessary for the cell's survival and operation.
What are the three basic functions that all cells must perform?
-All cells must perform the functions of taking in food, getting rid of waste, and reproducing.
What is the primary role of the plasma membrane, also known as the cell membrane?
-The plasma membrane's primary role is to regulate the passage of materials into and out of the cell, acting as a selectively permeable barrier.
What is the cytoplasm and what does it do?
-The cytoplasm is a jellylike substance filling the cell, providing a medium for organelles to float within and facilitating various chemical reactions, including the dissolution of solutes like carbohydrates and proteins.
Why is the nucleus often referred to as the 'control center' of the cell?
-The nucleus is called the 'control center' because it contains DNA in the form of chromatin, which holds the genetic instructions for making proteins that perform most of the work within the cell.
What is the function of the nucleolus within the nucleus?
-The nucleolus is responsible for producing ribosomes, which are essential for protein synthesis within the cell.
How does the rough endoplasmic reticulum differ from the smooth endoplasmic reticulum?
-The rough endoplasmic reticulum is covered in ribosomes, which are involved in protein synthesis, while the smooth endoplasmic reticulum lacks ribosomes and is involved in lipid synthesis and toxin breakdown.
What is the role of ribosomes in the cell?
-Ribosomes are responsible for protein synthesis by linking amino acids together to form proteins, a process also known as translation.
What is the function of the Golgi apparatus in the cell?
-The Golgi apparatus receives proteins from ribosomes, modifies them, sorts, and packages them into vesicles for export from the cell.
What is the significance of the mitochondria being referred to as the 'powerhouse' of the cell?
-Mitochondria are called the 'powerhouse' because they generate ATP, the cell's primary energy molecule, through cellular respiration.
What is the endosymbiosis theory and how does it relate to the origin of mitochondria and chloroplasts?
-The endosymbiosis theory suggests that mitochondria and chloroplasts were once free-living organisms that were engulfed by a larger cell and eventually became integrated as organelles, surviving and reproducing within the host cell.
What is the primary role of lysosomes within a cell?
-Lysosomes contain digestive enzymes that break down various materials, including food particles, pathogens engulfed by immune cells, and even old or damaged cell components.
How do cilia and flagella differ in structure and function within cells?
-Cilia are short, hairlike extensions that aid in movement over short distances, while flagella are long, whip-like structures that can propel cells over greater distances, such as in the case of sperm cells.
What is the cell wall and what is its primary function?
-The cell wall is a tough, outermost layer found in plant, fungal, and bacterial cells, providing structural support and protection.
What is the role of chloroplasts in plant cells?
-Chloroplasts perform photosynthesis, converting sunlight, carbon dioxide, and water into glucose and oxygen, using the green pigment chlorophyll.
What is the function of the vacuole in both plant and animal cells?
-The vacuole serves as a storage area for food, water, waste, and pigments. In plant cells, it is often the largest organelle, pushing other structures to the cell's periphery.
Outlines
🌐 Overview of Eukaryotic Cell Organelles
The paragraph introduces the concept of organelles within eukaryotic cells, comparing them to organs in the body. It outlines the three fundamental sections of a cell: the plasma membrane, the nucleus, and the cytoplasm. The plasma membrane, also known as the cell membrane, is highlighted as a key part of the cell's structure. The nucleus is referred to as the 'control center' due to its role in housing DNA. The cytoplasm is described as a gel-like substance filling the cell, within which most organelles are suspended. The paragraph also mentions the importance of the cytoplasm in facilitating chemical reactions and providing support to the cell structure.
🧬 The Nucleus: Control Center and DNA Repository
This section delves into the nucleus, emphasizing its role as the 'headquarters' of the cell due to containing DNA. DNA is depicted as the cell's blueprint, with chromatin being the physical form of DNA within the nucleus. The nucleolus, a distinct structure within the nucleus, is introduced as the site of ribosome production. Ribosomes are then explained as the cellular machinery responsible for protein synthesis, which is central to the cell's functions. The paragraph also touches on the endoplasmic reticulum (ER), distinguishing between the rough ER, studded with ribosomes, and the smooth ER, which lacks ribosomes and is involved in lipid synthesis and toxin breakdown.
🔬 Ribosomes and Protein Synthesis
The focus shifts to ribosomes, which are described as the cellular structures responsible for protein synthesis. Ribosomes are shown to be composed of RNA and proteins, and their function is to link amino acids together to form proteins. The process of protein synthesis is mentioned as translation, a concept to be further explored. The paragraph also discusses the role of the Golgi apparatus in receiving proteins from ribosomes, modifying them, and packaging them into vesicles for export from the cell. This process is visualized through an animation that shows ribosomes moving through the ER and the Golgi apparatus processing and shipping out proteins.
🏋️♂️ Mitochondria: The Powerhouse of the Cell
This paragraph introduces mitochondria as the 'powerhouses' of the cell, responsible for generating ATP, the cell's energy currency, through cellular respiration. The theory of endosymbiosis is introduced to explain the origin of mitochondria as once free-living organisms that became integrated into cells. The paragraph discusses the unique characteristics of mitochondria, such as having their own DNA and ribosomes, allowing them to replicate independently. The historical context of cell theory development is also briefly touched upon, mentioning the contributions of Robert Hooke and his observations of cell walls in cork.
🌱 Plant Cells and Their Unique Organelles
The paragraph discusses the cell wall, a feature unique to plant, fungal, and bacterial cells, providing structural support and rigidity. It contrasts with animal cells, which lack a cell wall. The role of cellulose in forming the cell wall is highlighted, along with its toughness and indigestibility. Chloroplasts are introduced as the organelles responsible for photosynthesis in plant cells, containing chlorophyll, which converts sunlight, carbon dioxide, and water into glucose and oxygen. The endosymbiotic theory is also applied to chloroplasts, suggesting they were once free-living organisms that became part of plant cells. The paragraph concludes with a brief mention of vacuoles, which store food, water, waste, and pigments, and are often the largest organelle in plant cells.
🍄 The Role of Vacuoles and Cell Wall in Plant Cells
This final paragraph emphasizes the role of vacuoles in storing various substances within plant cells, including nutrients, water, and waste. It contrasts the large central vacuoles found in plant cells with the smaller, scattered vacuoles in animal cells. The paragraph also reiterates the importance of the cell wall in providing structural support to plant cells, mentioning the historical significance of Robert Hooke's observations of cell walls in cork. The paragraph serves as a conclusion, summarizing the key organelles and their functions within eukaryotic cells.
Mindmap
Keywords
💡Organelle
💡Plasma Membrane
💡Nucleus
💡Cytoplasm
💡Mitochondria
💡Endoplasmic Reticulum (ER)
💡Ribosomes
💡Golgi Apparatus
💡Cytoskeleton
💡Cell Wall
💡Chloroplasts
💡Vacuoles
Highlights
An organelle is a small part within a cell, akin to how organs are small parts within the body.
Cells have three main sections: the plasma membrane, the nucleus, and the cytoplasm.
The plasma membrane, also known as the cell membrane, regulates the entry and exit of materials.
The nucleus acts as the control center of the cell, containing DNA.
The cytoplasm is a jellylike substance within the cell where organelles float.
Cytoplasmic streaming is the movement of organelles within the cytoplasm.
The cytoplasm facilitates chemical reactions and dissolves particles like carbohydrates and proteins.
The plasma membrane is composed of a bilayer of lipids and proteins, and is selectively permeable.
The nucleus contains chromatin, which is DNA that provides instructions for protein synthesis.
The nucleolus within the nucleus is responsible for producing ribosomes.
Ribosomes, made by the nucleolus, are transported by the rough endoplasmic reticulum to make proteins.
The Golgi apparatus receives, modifies, sorts, and packages proteins for export from the cell.
Mitochondria are known as the powerhouse of the cell, generating energy through cellular respiration.
The theory of endosymbiosis suggests that mitochondria were once free-living organisms that became part of the cell.
Lysosomes contain digestive enzymes to break down food, pathogens, and even old cells through a process called autophagy.
Cilia and flagella are cell parts used for movement, with cilia being short and flagella being long and whip-like.
The cell wall is the outermost layer in plant, fungal, and bacterial cells, providing support and structure.
Chloroplasts, found in plant cells, perform photosynthesis using chlorophyll, a green chemical.
Like mitochondria, chloroplasts are thought to have evolved from free-living bacteria through endosymbiosis.
Vacuoles store food, water, waste, and color pigments, and are often the largest part in plant cells.
Transcripts
okay so in this video we're going to go
over some of the common organel of a
eukaryotic cell now an organel is simply
a word that means small part so just
like the body has small parts called
organs cells have small parts called
organel well there's a lot of them so
let's go ahead and get
started first thing I want to mention
are the three basic sections to the cell
and all cells need to take in food get
rid of waste and reproduce well cells
have three main sections to them and
inside of those three sections are parts
that allow them to take in food get rid
of waste and reproduce so the first
section you can see highlighted by the
flashing black line the plasma membrane
you might also hear the plasma membrane
simply called the cell membrane we'll
talk more about this in a little
bit pulsing in the picture you can see
the second main section the nucleus uh
you often hear the nucleus called the
control center we'll explain why in a
little
bit and lastly we have the cytoplasm now
the arrow in the picture looks like it's
kind of just pointing to empty space
well cells are not filled with empty
space they're filled with a part called
the cytoplasm we'll go into that in more
detail let's actually do the cytoplasm
first here we
go so the cytoplasm the first thing I
want to mention is that it's the
jellylike material on the inside of a
cell you know when you look at diagrams
sometimes in a diagram a cell might look
like it's empty or filled with Hollow
air Hollow air space and that's not true
cells are filled with a jellylike
liquidy material called the cytoplasm
and in that cytoplasm most organel float
within you can see here's a list of a a
few of the organel that are floating
around in the cytoplasm we're going to
go and talk about all of these
throughout this video we'll talk about
what mitochondria is what lomes
are and because the cytoplasm is a jelly
material and things are floating around
inside of it you often under a
microscope can actually see Parts
floating around in this animation here
you can see what's known as cytoplasmic
streaming the green circles that are
drifting around inside of the square
cells the rectangular shaped cells those
green circles are plant cell
chloroplasts you can see in every
rectangular shaped plant cell there's a
few dozen
chloroplasts in in each of these cells
here and this is known as cytoplasmic
streaming okay well what about the job
what does the cytoplasm actually do well
a lot of chemical reactions take place
within the cell and chemical reactions
take place in the cytoplasm so that's
kind of what the job of the cytoplasm is
it helps to facilitate chemical
reactions and it also helps to dissolve
uh solutes uh particles that are in the
cell carbohydrates proteins these are
all dissolved within the actual
cytoplasm of the cell so that's really
what the main function of the cytoplasm
is it also adds support to the cell a a
pressure a support for the
cell so the next part I want to mention
is called the plasma membrane also known
as the cell membrane and first of all
it's composition means what is it made
from it's a by layer of lipids and
proteins earlier in the school year uh
we we learned lipids lipid and this is a
drawing of a very simple lipid here the
round part represents the head two tails
are the fatty acids and what we mean by
a by layer it's not just one layer but
two layers on top of one another this is
a by layer of lipids right here in
between the by layer of lipids are also
proteins I've labeled this protein
Channel and you're going to see its
importance in a moment well the job of
the plasma membrane is to allow
materials to p uh to pass to enter and
exit you know small molecules like water
and oxygen H2O for water O2 for oxygen
small molecules like this can simply
pass through the lipid by layer however
larger molecules larger molecules like
glucose have to pass through these
protein channels and that's what you see
happening in the animation and so that's
really the job of the cell membrane but
the cell membrane is what we call
semi-permeable or selectively permeable
that means that it doesn't allow
everything in and out it only allows um
certain specific molecules and ions and
uh and and charged particles to enter or
exit through the plasma
membrane so when we come back to this
picture we saw earlier here we have the
next part I want to mention you can see
the black Square highlighting the
nucleus let's zoom on in for a closer
look when we zoom on in here we have the
nucleus and you've heard maybe in middle
school that the job of the nucleus is to
control the cell's activity you often
hear it given the nickname of the
headquarters what does that mean well
the reason we call the nucleus the
headquarters is because it contains DNA
and in the picture we see five uh
Twisted strands of what is called
chromatin chromatin are long strands of
DNA and DNA is the instructions the
blueprint the manual on how to make
proteins and this is why we call the
nucleus the control center is because
the chromatin will be sending out
information to make proteins and
proteins do a lot of the work the vast
majority of the work inside of our cells
inside of our bodies are performed by
proteins so this is why the nucleus gets
the nickname of the control
center also inside the nucleus there's a
round object known as the nucleolus and
the job of the nucleis is to make a
another part of a cell another organel
called the MIT excuse me called the
ribosome so the job of the nucleis is to
make ribosomes and we're going to see
what ribosomes do in just a
moment when we look at this picture
right here we can see a nice electron
microscope picture the overall round
object is the nucleus you can see the
dark spot is the nuclea a really nice
picture here of the nucleus and the
nucle
olis so we come back here we have the
box highlighting the rough ER and the
smooth ER let's zoom on in and take a
closer look at the endoplasmic
reticulum okay first of all there's two
kinds of er let's look at the rough ER
first the ER stands for endoplasmic
reticulum the rough ER the reason it's
called rough is that's covered in
ribosomes so we mentioned a moment ago
that the nucleolus makes ribosomes the
ribosomes then exit the nucleus and
travel along this tunnel system known as
the rough ER that's kind of the job of
the rough ER is to receive the ribosomes
and transport and carry around the
ribosomes from one part of the cell to
another as you can see we can uh we
finally see what the job of a ribosome
is protein making ribosomes so so that's
the job of a ribosome is to make a
protein so the rough ER will transport
the ribosomes as the ribosomes are
making a
protein well if we look at this picture
here we have the purple nucleus identify
part A in the nucleus I hope you know
that's the
nucleis the the the lines the purple
lines identified by letter B that's the
DNA I hope you remember the name of the
DNA that's called chromatin and then the
outside of the nucleus in picture C I
never mentioned the name earlier but
that's called the nuclear envelope
notice how the blue is the rough ER and
there's gray dots all over it well look
in the animation you see gray dots
exiting the nucleolus in the animation
and those gray dots are traveling
through the blue rough ER that means
those gray dots have to be the ribosomes
the job of ribosomes are to make
proteins we're going to go into more on
that in just a few moments
so what about the smooth ER well if the
rough ER is covered in ribosomes then a
little Common Sense the smooth ER is not
covered in ribosomes and you can see it
has a different job the job of the
smooth ER is to help make lipids and
fats and to help break down certain
toxins but the reason it gets its name
smooth ER is it's not covered in
ribosomes the rough ER is covered in
ribosomes and that's why it kind of has
a rough appearance to
it so let's talk a few moment a few
extra moments about those things called
ribosomes they're created by the nucleis
remember the nucleis is inside the
nucleus they're transported the
ribosomes are transported by the rough
ER and as the ribosomes are being
transported by the rough ER we now come
to their job their Duty their function
is to make proteins
and so if we highlight a few a few
ribosomes with that flashing Black Box
let's zoom on
into a ribosome that's attached to the
Ruff well here we have a ribosome and
the reason what what I mentioned a
moment ago is its job is to make a
protein and what it does is it will
gather individual amino acids and
earlier in the school year I hope you
learn you remember that amino acids are
the building blocks of protein
and so here we see a ribosome is
gathering and connecting a bunch of
amino acids into a long chain this long
chain of amino acids is what we call a
protein and that's the job of a ribosome
is to gather and build these amino acids
into a larger protein this process by
the way is known as translation we're
going to learn about it later in the
school year
though so if we come back back out here
to our diagram I've highlighted the
flashing box of the GOI body let's zoom
on in to the GOI body you might often
hear it called the GGI apparatus or the
GGI complex it's always going to be
called GOI because it's named after the
scientists with the last name of GOI who
discovered it and so the job of the GOI
body is to receive proteins that
ribosomes made receive proteins from
that ribosomes made modify them sort
them and package them so they can be
exported from the cell and the GOI body
will put the proteins into a protective
little envelope known as a vesicle and
so let's go ahead and review what we've
learned really
quick when we look at the process of
shipping out of protein in our animation
we can see the nucleolus is releasing a
black dot that black dot represents RI a
ribosome so the nucleis makes a ribosome
notice that ribosome then travels
through that rough ER that system of T
tubes and tunnels so the ribosome is
traveling through the rough ER making a
protein let's zoom on in for a closer
look so there's the
ribosome okay now that we can see the
ribosome remember what the job of a
ribosome is it it makes a protein and so
there you see the word protein now it's
spelled p r o t i n but it's not really
put together properly so this protein is
not quite finished even though the
ribosome made it well Watch What Happens
Next remember this is all happening at
the rough ER the protein is going to be
placed inside a of a protective vesicle
and travel away where is it going I hope
you know where it's
going it's going to a GGI body and so
the protein arrives at the gii body what
happens to the vesicle the vesicle fuses
and becomes a part of the gii body
well Watch What Happens the protein
moves through the gii body and is
eventually processed and modified and
ultimately is going to be released so
the GOI body kind of makes the final
changes to the protein well when the GOI
body releases the protein it also will
put it in a protective vesicle so the
vesicle is going to be a protective
little envelope watch this the protein
is put into a protective vesicle and
it's released the vesicle fuses with the
cell membrane and then the protein is
simply released from the cell goes where
it's
needed all right so if we were in class
I would have you turn to your neighbor
and try to work on these review
questions so we've kind of covered a lot
of information let's take a quick moment
you know pause the video pause the video
try to answer these seven questions I'm
going to go over the answers in three 2
one so which organel builds proteins I
hope you know that a ribosome which
organel stores DNA well that's the
that's the control center called the
nucleus which organel produces ribosomes
that's the nucleolus it's found inside
the
nucleus which organel creates fats and
breaks down toxins well that's the
smooth ER which organel number five
packages and releases proteins from a
cell that's the goldi body remember
they're put inside of a protective
vesicle number six which organel allows
material to enter and exit a cell that's
the cell membrane also called the plasma
membrane number seven which organel
links chains of amino acids together
that's the same thing as question number
one question number one and question
number seven it's the same question just
worded a little differently because
amino acids make proteins let's try this
one same thing in class I would have you
work on this with a neighbor for a
minute but pause the video try to put
these four step steps in order what
comes first second third fourth I'm
going to show the answer in 3 2 1
okay so the answer is I hope you chose
step C first the nucleolus makes
ribosomes and then I hope you chose D
ribosomes will exit the nucleus and then
I hope you chose B the ribosomes are
going to travel along the rough ER and
create proteins and then finally I hope
you chose a the gold body will package
and Export the finished protein inside
of a protective vesicle let's move
on so now we're back to our diagram and
I've highlighted the flashing box the
mitochondria let's zoom on in for a
closer look here we have the
mitochondria artist drawing on top
actual picture on the bottom and so the
job of the mitochondria you know in
middle school they give cute little
nicknames to cell parts in Middle School
you may have been told this is the
PowerHouse but you may never have told
why well it's the PowerHouse because its
job is to make an energy molecule by the
name of a Denine
triphosphate ATP so the mitochondria
does a very important process known as
cellular respiration and during the
process of cellular respiration it will
create an an energy molecule by the name
of ATP ATP is a molecule used by your
cells for energy so the analogy is the
mitochondria is kind of like the battery
of your cell
cells what's interesting about the
mitochondria is we're pretty certain the
mitochondria used to be a living
organism it used to be a basically a
bacteria cell but it has become part of
today's modern cells and this theory of
of how we think this happened is called
endosymbiosis I'll go over in more
detail in just a
moment well when we look at some of the
evidence for why we think the
mitochondria used to be its own living
organism is because it has its own DNA
it has its own ribosomes because it has
its own ribosomes it can manufacture its
own proteins and the mitochondria does
something very important to life the
mitochondria can reproduce and replicate
so when you look at this evidence it's
pretty C we're pretty certain the
mitochondria used to be a free living
organism a bacteria species but it's
become part of cells how did that happen
that's what endosymbiosis tries to
explain I hope I can visualize that on
the next
slide okay so I really want to try to
visualize the endosymbiosis Theory here
we have a large Predator cell in Orange
and it's going to devour that red
mitochondria ancestor Watch the watch
this so there it goes it just devoured
the mitochondria ancestor but the way we
think it were it happened is that red
mitochondria survived and divided and
multiplied it's just trapped inside of
the large Predator cell well as the two
go about their lives the large Predator
cell Al eventually is going to multiply
and divide as well and watch this when
cells divide they often grow and then
they split right down the middle and now
you have two Cells Two cells with the
mitochondria ancestors trapped inside of
them and then the process simply
continues so the the mitochondria
ancestors keep multiplying and then the
orange Predator cell divides in half and
over time over millions and millions of
years the two have become so dependent
on one another that they can't survive
without them so this is kind of what the
uh what the Endo symbiosis Theory uh it
tries to explain is how cells became
more complex how did we obtain certain
cell parts and this is the explanation
for how we think the mitochondria was
obtained
okay let's zoom on in Let's uh focus on
the lomes back in our diagram here and
let's zoom on in for a closer look at
the
lomes and so the lomes contain inside of
them very powerful digestive enzymes and
that's what my little animated scissors
here are showing so the blue circle is
the lome with the animated scissors
representing the enzymes
inside and so lomes have various jobs
number one is to break break down food
so here we have a protein molecule
that's being taken into the cell and the
protein is being broken down into
smaller parts I hope you know those
smaller parts are called amino
acids here we have an example of a white
blood cell you probably know white blood
cell's job is to fight off infections
like bacteria and viruses well that's
what we call pathogens things that cause
disease are called pathogens and so here
is a virus or a bacteria and and notice
how it just landed on a white blood cell
well what happens is the white blood
cell will swallow up that pathogen put
it inside of a lome and those powerful
digestive enzymes will destroy it so
that's one way that our immune system
Keeps Us
healthy and then there's the process
called autois where uh it's basically um
an aging cell will destroy itself and so
in our in the middle of our picture here
we have a group of cells and I have the
animated Scissors because what happens
is when cells are dying and aging they
will kind of self-destruct in a process
called autois where the lomes will
release all the digestive enzymes and
kill that cell it leaves behind a gap
but don't worry that Gap will simply be
filled in as cells multiply so you've
heard the expression out with the old in
with the new
another a couple other cell parts I want
to mention are used in movement and
that's the job of cyia and fella now not
all cells move so not all cells have
cyia and fagella but if cells move they
probably have either cyia or
fella so the picture on the left shows
the cyia short hairlike extensions
there's numerous hundreds and thousands
of them per cell way too many to count
very short stubby almost look like
eyelash ashes they're so short and
stubby the picture on the right shows a
sperm cell with a real long fella fella
is actually the plural version fum is
singular and so the difference is really
their length the cyia short stubby fella
are long and whip-like and usually
there's only a few of them maybe only
one flagellum maybe two maybe three
maybe four but not nearly as many as the
cyia
well in that picture on the right we
have a sperm cell about to penetrate a
female egg cell to create a fertilized
egg also known as a zygote let's have a
little fun with
this so after the fertili after the
sperm fertilizes the egg that fertilized
egg is going to grow into a fetus here
we have a nice little ultrasound showing
a child growing inside of a pregnant
woman well eventually 9 months later
that child's going to be born well let's
follow the life of this
child 17 years go by 17 years later hey
it's your first day at high school and
so here you go welcome to high
school and hopefully four years after
that you know you'll be celebrating your
graduation from high school so this all
started because of that flagella that
provided the swimming movement to
fertilize an egg
so we look at the next part I want to
mention is the cell wall and so this is
the outermost layer of plants fungus and
bacteria cells so from left to right we
have plants fungi and bacteria notice
animals like humans do not have a cell
wall well we also mentioned that the
cell wall is the outermost layer so when
we look at this picture we have a yellow
layer and a Green Layer so I hope you
know that yellow layer represents the
plasma membrane or the cell membrane and
the definition in the definition we see
that the outermost layer is the cell
wall so that's represented by the Green
Layer what about its job one of the jobs
of the cell wall is to add support it's
made from a real tough sturdy material
known as cellulose and so this adds some
of the support to plants and fungus and
bacteria cells that have
and so as I just mentioned the cell wall
is made from a real tough material by
the name of cellulose it's very hard to
digest the reason for the picture is
celery has a lot of cellulose in it and
I'm sure you've had bites of celery it's
a very tough very fibrous plant very
hard to digest well that's because
you're having to chew through a lot of
cellulose which is a main ingredient of
the cell
wall and the cell wall really started
our understanding of cells earlier in
another video we learned that Robert
Hook in 1665 again there's there's no
real good pictures of Robert Hook so
here we just have a a glass stained
glass picture in a cathedral Robert Hook
in 1665 examined
Cork and so he used a very primitive
microscope like this one in this picture
here and as I mentioned a moment ago he
examined cork now cork we might be
familiar with cork from you know wine
bottles
but cork is actually tree bark and he
examined a real thin slice of tree bark
called Cork and this is what he
saw in this picture
here is a drawing that he made it's kind
of shocking to believe that this picture
right here is a drawing made by hand but
that's how good of an artist he was and
what you see are hundreds of little tiny
cells but the outline of the cell is all
that's left he did a drawing of the cell
w there was no nucleus Cork and tree
bark is dead there was no nucleus when
he made the drawing there were no
mitochondria no vacul all that's left
and all you can see in the picture is
the drawing of the cell wall the cell
wall is very tough very strong and can
last for years and years after the cells
have
died so uh the next part I want to
mention is called the chloroplasts and
so you might might know the job of the
chloroplast is is to perform
photosynthesis well here are several
dozen plant cells taken with a
microscope let's zoom on in for a closer
look when we zoom on in we can see that
inside of every cell are dozens of those
green round shaped objects called
chloroplasts they're inside every single
cell there's dozens of them per
cell so you know that the job of the
chloroplast is to perform photosynthesis
well inside of the chloroplast is a
chemical A green chemical by the name of
chlorophyll the job of chlorophyll is to
actually perform photosynthesis it will
absorb sunlight absorb carbon dioxide
absorb water and turn those into oxygen
and sugar particularly in the form of
glucose so what photosynthesis does is
it uses three ingredients
water carbon dioxide sunlight and will
release two products oxygen and sugar
sugar called
glucose just like the mitochondria the
chloroplast is thought to have evolved
according and become a cell part
according to the endosymbiosis Theory we
think the chloroplast was also a free
living organism a bacteria in our
animation here we have a pred ether cell
devouring the chloroplast but not really
being digested that chloroplast ancestor
in green multiplies just like we saw a
moment ago with the mitochondria
ancestors and notice how the two are
just living together the green
chloroplast ancestors are just trapped
inside of the larger one well as time
goes by the larger cell divides and
splits into two and as years and go by
these two have become so dependent on
one another that they are now a part of
each other and the evidence to support
this is again the the chloroplasts just
like the mitochondria have their own DNA
and ribosomes they make their own
proteins they can replicate and multiply
and divide these are all real strong
indicators that the chloroplasts were
probably once a free living organism all
by itself but has become taken into the
cell and become part of mod
cells so the final one the last part I
want to mention is called the vacu the
job of the vacu is to store food store
Water waste color pigments and in the
picture here you can see it's the big
blue round object in the middle of the
cell often in plants that is it's often
the largest part of a plant
cell so in Plants it's often the largest
Central meaning in the middle so we
often think of the nucleus being in the
middle of a cell often the vacu is
because it's so big it pushes all the
other parts to the
edges when we look at this little
animation right here again I mentioned
cytoplasm ex streaming earlier here the
green circles represent chloroplasts but
they're all kind of revolving around the
Central vacu and so the central vacu is
often so big it will put the other
organel to the edge of the
cell so in Plants there tends to be a
large Central vacle but it's not like
that with animal cells here's a diagram
a drawing of animal cell of an animal
cell and the vacu are much smaller and
they're usually randomly scattered
throughout the cytoplasm but they still
serve the same purpose they still store
food store water store waste and so
that's really the job of the vacuo right
there well so there you have it I mean
there's a lot of cell parts that we
covered in this video here so try and
pause the video and work through these
questions if you're in my biology class
bring your answers to on a separate
sheet of paper I'd be happy to check
your accuracy either before school or
after school good luck
تصفح المزيد من مقاطع الفيديو ذات الصلة
5.0 / 5 (0 votes)