about the eukaryotic cell. Last time we were able to discuss the different parts and structure of the prokaryotic cell and today's discussion we're going to revolve on the different parts and structure of the eukaryotic cell. So you have to realize that last time when we discussed prokaryotic cell there are only few components because prokaryotic cell have less parts also day. are smaller and there are more simple compared or simpler compared to eukaryotic cell. So today, let us just recall some of the things that we have discussed last meeting.
These are our objectives for today. So number one, describe the structure and function of the prokaryotic cell where we were able to achieve that last meeting. Second is to describe the structure and function of the major and subcellular organelles of the eukaryotic cell. Third is to distinguish prokaryotic and eukaryotic cell according to general characteristics. And number four, compare and contrast the animal and plant cell which are all eukaryotic in nature.
So also before we proceed with our topic, we also discussed the difference of prokaryotic and eukaryotic cell. And all of those can be located in the presentation. We are already done with the discussion regarding that. And let us more or let us focus on the eukaryotic cell.
So last time, we have mentioned that eukaryotic cells have these different characteristics. Number one, DNA in the nucleus that is bounded by a membranous nuclear envelope. So this just simply means that DNA is encapsulated or located inside the nucleus.
It has a nuclear envelope that encapsulates the genetic material of the eukaryotic cell. Second, it has a membrane-bound organelle. So literally, the organelle inside the eukaryotic cell have their own membrane or they are membranous it needs to not for the different processes to commence or happen. Unlike prokaryotic cell, some of the metabolic processes happen in the cytoplasm alone.
But in eukaryotic cell, since they are more complex, they need compartmentalization wherein different processes happen. Cytoplasm in the region between the plasma membrane and the nucleus. So if you're going to look at the screen, we have here the nucleus which is located in the upper right part, the nucleus that you can see here in the upper left of a protist. And then this just simply means that the region or the cytoplasm is the region wherein this is in the middle of the plasma membrane and the nucleus.
The karyotic cell again really much larger than prokaryotic cell. We have discussed this last time. Now let's proceed on the different parts and structure of the cell.
So first and foremost, we have the cell membrane. When we talk about cell membrane, the primary function is for protection. That is a no-brainer already because since cell membrane is located in the outermost part of the animal cell, its primary function is for protection.
One of the things that we need to consider is that the function also of the cell membrane is for maintaining homeostasis. Last time we discussed that the term homeostasis came from two words, homeo means same and stasis or stasis means standing. So literally, when we talk about homeostasis, the cell wants to balance the internal and external part of the cell.
So we are not just referring to temperature, we also refer to the different substance and molecules that wants to enter or exit the cell. For example, there is a There's a lot of water outside of the cell. So, what is the tendency of the water?
Since water is a fluid and the cell wants to achieve homeostasis, there are tendencies wherein water will enter the cell so that balance or we can achieve homeostasis from the internal and external. For example, carbon dioxide is concentrated inside the animal cell. What do you think will happen? Let's say that carbon dioxide is concentrated inside of the cell. and carbon dioxide is nowhere to be found outside of the cell.
So to maintain the balance or homeostasis, carbon dioxide needs to exit the cell through cell membrane. Another function of the cell membrane is providing protection and support. Just like what I have mentioned, protection because it is located in the outermost part and support to support the different mechanisms like transport mechanism in the cell in the cell okay so just like what i've mentioned there are molecules that wants to enter and exit the cell and not all of those things can enter the cell or exit the cell.
So what are the criteria? There are criteria that the cell wall considers to happen. Hence, we call it selective permeability.
The permeability class allows the passing through of any molecule. When it says selective, it means it is choosing. Not all that wants to enter the cell will be allowed to enter. Because if that happens, bacteria or virus that wants to hijack the cell can easily penetrate.
So there are different things that the cell need to consider, hence we call it selective permeability. That is the characteristic of the cell membrane. Next one, it gives the cell their shape and flexibility.
You have to realize that the cell membrane is not a fixed in a certain position. They They behave like fluid. Also, we refer to it as fluid music.
Now, when we talk about fluid in physics and in chemistry, we're referring to two types of matter, namely the liquid and gas. So if you can imagine the cell membrane, they are constantly moving. They are moving depending on the need or what will happen to the cell. So they are not fixed in that position. They are not still.
They are moving to cater the cell. And lastly, we have the communication between... among other cells.
So you have to realize that in eukaryotic cells that are multicellular in nature, they have to communicate with other cells. So for example in tissue level, again tissue is just an congregation or pinagsama-sama cell. So you have to realize that for example sugar scars in cell number two. So we have two cells, cell one in the left side, cell two in the right side. For example, sugar or glucose is scarce at cell number two.
So what are the tendencies? It needs to communicate to the neighboring cell that it needs sugar for its different metabolic processes to happen. So what will happen?
Cell number two from the left side will give sugar molecule to the right side. It enters the cell membrane and then the sugar now goes to the mitochondria. So, that's what's possible to happen. And we also want to talk about cell-to-cell communication. There are junctions.
There are spaces between them to help them communicate even further and much more faster. So, now let us proceed on the chemical composition of the cell membrane. But before we proceed with that, let's look at the structure of the cell membrane. If you're going to look at it in... using electron microscope compound, you can see it, kagaya na sa picture natin sa upper part.
Ano lang talaga siya, cluster cell membrane looks like an outline in any cell. Ganoon lang talaga siya. So, Mark, paano po natin alaman na meron po siyang iba't-ibang chemical composition that is flush on the screen, kagaya po naka-flush the screen?
You have to realize that there are different types of microscope. We can use TEM or transmission electron microscope and scanning electron microscope to see the different species or organism in molecular or structural level. Ibig sabihin, although they are line lang, because they are microscopic nga, although they are line and compound microscope, using advanced technology or TEM, transmission electron microscope, you can see the different component or structure of the cell membrane just like what is flush on your screen. So you have to realize that when we zoom the cell membrane, it looks like this one. So there are two components in the cell membrane.
We have the head and the tail. Also realize that the cell membrane is also referred to as the phospholipid bilayer. So let's start with the bilayer.
It is called a bilayer because it is composed of bi or two layers. So, remark, but what about phospholipid? Realize that one layer is composed of phospholipid. Literally, it is composed of phosphorus and lipid or in other term is fat.
So, one layer of the phospholipid has two components again. It has a head and a tail. So, the head or the red one is uh also referred to as hydrophilic hemp. When we talk about hydrophilic, the term hydro means water and philic or philia means labbing.
So literally The hydrophilic head is water-loving or they are attracted to water, meaning they can form bonds with water because they are polar in nature. Next one, you also have the hydrophobic tail. Hydrophobic means hydro means water, phobic means or phobia means fear. So hydrophobic tail literally means they are water-fearing.
With that being said, they repel water or they do not want to form bond. with water. So as you can see at the arrangement of the phospholipid, sir Mark, why is the hydrophilic head oriented outward of the membrane, of the cell membrane? To answer that question, you have to realize that the cell component is also made up of water. Same with the outside of the cell.
Our body is composed of 50 to 60 percent water, therefore our cell, which is the basic unit of life, is made up of water also. So if we're going to look at the lower right picture, inside the cell, also known as the intracellular or the cytosolic fluid, it composed or it is made up of water. On the other hand, outside of the cell, we call it extracellular part of the cell or interstitial fluid, it is made up of water.
Hence, the hydrophilic head is oriented outside and inside of the cell. That's why we have two layers. And then the hydrophobic tail can form band with other hydrophobic tail.
Hence, you have the orientation like that one. You have to realize that the lipid is composed of carbon, hydrogen, and oxygen. Next one, you have the cytoplasm.
If you're going to look at the diagram in the right part, you can see the color pink one. So that ping to pitch. Pigmentation is the cytoplasm.
Last time, I have told you that cytoplasm used to hold all of the organelles intact inside the cell. They are a gel-like structure that used to maintain the position of the different organelles inside the cell. In addition to that, there is this term called cytosol.
Again, cytosol is a fluid membrane component of the cytoplasm. So if we have gel-like structure in the form of cytoplasm, cytoplasm has watery substance or fluid substance in there, and we call it cytosol. Again, we discussed cytoplasm in prokaryotic cell, and I believe you already know what cytoplasm is.
But again, for reiteration, cytoplasm is a gel-like fluid structure that can be found inside the cell. So imagine, if there's no cytoplasm, all of the organelle component inside the cell will be associated with each other or will stick together and it can hinder the whole process of the cell. For example, the lysosome is attached to the nucleus or mitochondria.
The lysosome can digest different parts of the cell and that is not beneficial for the growth and development of the cell. cell. Hence, we have cytoplasm that makes the cell organelle intact or in their places.
So next one we have cytoskeleton. The term cytoskeleton came from the word cyto. Cyto means cell. Skeleton means framework. So literally cytoskeleton serves as a framework inside the cell.
So cytoplasm alone cannot help withstand the shape of the cell. You have to understand and realize that just like any other building structure we need beams, reinforcement like hollow blocks, and iron for maintaining the structural integrity of the building. Same with a cell, okay? Cytoskeleton acts as a reinforcement and it helps in support and keeping the shape of the cell.
So as you can see in the picture. If you're going to zoom in here, class, you have to realize that the blue one is the nucleus and the red one is the cell membrane. The green that you can see in the picture are the cytoskeleton. They are the one that helps in keeping the structure of the cell and also support the whole cell. We're going to look at this one.
This is the look or overview on how Thus, the different cytoskeletons are integrated within the cell. So, the gap between that is filled by cytoplasm. But also, you have to realize that there are...
different cytoskeleton that is located inside the cell. They are there for support. So there are three types of cytoskeleton namely the microtubules, the microfilament, and the intermediate filament.
So microtubules are the hollow tubes made up of subunits of tubulin or protein. So let's go back. All of the cytoskeleton are made up of protein but my question is, where is the protein made up of? You have to realize that protein is made up of amino acid because amino acid is the building block of protein.
In analogy, if we have a rosary, the rosary itself is a protein. And for you to create a protein or a rosary, you need a beads. The beads serves as amino acid that makes up the rosary. Hence, the amino acid is the building block of the protein.
For those students that like to go to gym or in the bulking season, more often than not, your diet is composed of lots of protein because it helps in muscle building. Now, to realize that protein building blocks is what we know as amino acid. If there is a whey protein, whey protein component includes lots of amino acid or different amino acid. Hence, it helps in muscle building.
Going back to the three types of cytoskeleton, we have the microtubule, the bead. If you can again go back, the beads are the amino acid and the primary function of microtubule is for cell division or movement also. It is used in cilia, flagella, central and basal body of the eukaryotic cell.
For movement, usually the microtubule. Next one, we have the microfilaments. It is a rod like structure consisting of actin. protein.
They are solid in nature and usually this one is responsible in cell division and also in muscle movement. When you have your muscle flexed, for example, your bicep, you flex your bicep, your muscle bulge because the microfilament moves and contract with each other. Therefore, your muscle moves. Now when you relax your muscle or your bicep, the microfilament will go to its original state or phase.
Hence, you have a normal muscle shape. So we have microfilament. Next one, we have the intermediate filament.
It is a tough fiber that, again, is made up of protein. It helps in stabilizing the shape of the cell. Okay, we have the cytoskeleton.
Next one, we have the nucleus. Nucleus is known as the control center of the cell. Again, let us debunk that nucleus is always located in the middle or in the center. You have to realize that not all nucleus is located in the center of the cell.
It is known as the control center, not the center of the cell. So, it is the control center. Therefore, it serves as the brain of the cell.
It navigates what will happen inside the cell. Because again, last time you have realized that the DNA or the deoxyribonucleic acid is located in the nucleus. So there are three different parts of the nucleus, namely the nuclear membrane or the nuclear envelope, which we can see in this part, the chromatin and the nucleus. Now let us zoom on the nuclear envelope. So you have to understand that the nuclear envelope or the nuclear membrane is divided into three.
We have the inner membrane, which is facing toward the nucleus, the outer membrane, which is facing towards the cytoplasm and the nuclear pore. you have to realize that nuclear pores are there for a reason. Just like any other transport mechanism and just like cell membrane, there are material that needs to exit and enter the nucleus. So one of the material that needs to exit the nuclear pore is the ribosome that has been manufactured by the nucleus. Again, the ribosome is essential in creating protein.
Hence, it is needed outside of the nucleus, particularly in the cytoplasm. or in the endoplasmic reticulum. So we have ribosome that exits the nucleus and passes through the nuclear pore.
Next one, you also have the RNA or ribonucleic acid. It is a single stranded molecule that is essential for protein synthesis or protein creation. So you have to to realize that when transcription happens, DNA create an mRNA or messenger RNA. that messenger RNA, a single strand molecule, exits the nucleus to the nuclear pore.
Hence, we have the nuclear pore. So we have that one. How about the thing that wants to enter the nucleus.
So there are proteins that are essential also inside the nucleus because DNA needs to be organized. And for the DNA to be organized, we need a protein called histones to make the DNA inside the cell organized. So if you can imagine, it's not just a single piece of spaghetti that's being put together.
They are organized in nature. And as you can see in here, class, we have the chromatin. That is the look of the chromatin. They are bounded.
The chromatin is the second tense DNA, and they are bounded by the histone. Histone is a type of protein for the DNA to be organized. And next one, we have the nucleolus, which is located in the center of the nucleus.
Usually, this is where our... DNA. So nucleolus is also a granular body within the nucleus, consists of RNA and proteins, and it is the site for our asynthesis.
So this is where the creation or making of mRNA happens. So if we're going to zoom in this one class, you have to realize that the nuclear envelope, particularly the nuclear pore complexes, is made up of protein. So we can see here that it's like a flower class.
yung mga part na yan, 1, 2, 3, 4, 5, 6, all of those are made up of protein. And the nuclear envelope inner and outer membrane is made up again of phospholipid. So almost similar lang din ng composition sa cell membrane natin. So we have the nucleus, the nuclear envelope, the nucleolus, and also the chromatin.
Next one, we have the ribosome. So ribosome is very essential because it helps in creating protein inside the cell. So protein is very essential inside the cell because it constitutes almost all of the parts and structure of the cell.
So without the help of ribosome, there are no protein inside the cell. And without the help of the protein, we don't have any different structure within the cell. So if you're going to look at the diagram in the lower part, we have here the example of the ribosome.
which is composed of large subunit and small subunit. The unit of measurement that we use for ribosome is S, or we can refer to it as a Svenberg unit. Again, the instruction that came from the DNA after it manufactured an mRNA, the ribosome are being...
the ribosome we'll go to the mRNA, it will now synthesize or create protein. So this is the whole process of how to create protein. Actually, a central dogma is the process from transcription to translation.
But if we're going to look at this one, let us trace how all of these things happen. If we're going to look at that one, you have to realize that for the ribosome to create a protein, it needs a message first. It needs a message, an instruction that came from the DNA or inside the nucleus.
If we're going to look at the diagram, the blue one or the dark blue one, the DNA, now starts to transcribe an mRNA or create an mRNA. So what happens is the creation of Nucleolus. When mRNA or a single-stranded molecule, as you can see in the picture, the blue-green one, exits the nucleus through the nuclear pore, what happens next?
it will now go to the cytoplasm where it is deposited. Okay? So, in our example in here, the ribosome are attached into endoplasmic reticulum.
But sometimes, protein synthesis can also happen in the cytoplasm. So, ribosome can be free-flowing in the cytoplasm. Also, ribosome can be attached to endoplasmic reticulum. Okay? So in the cytoplasm, the mRNA and the ribosomal subunit joins together and form or started to synthesize polypeptide.
So we have to look at the second picture. If we're going to look at the picture, the ribosomal small and large unit start to sandwich the mRNA. And as you can see, there are beads that you can see on the picture.
These are the amino acid. When amino acid is squeezed together, we call it a protein. But you also have to realize that peptide is the bond that is located within the amino acid. We call it polypeptide because there are lots of peptide bonds that can be located in two. the protein.
For the next step, if a ribosome attached to a receptor on the ER, the polypeptide enters the lumen of the ER. So as you can see in here, kapag naka-attach yung receptor ng ribosome, the polypeptide will go in the ER. But there are instances, just like what I have mentioned, that cytoplasm is the site of the protein synthesis.
Hence, the protein is not being given to ER but it is in cytoplasm only, free-flowing. So, there can be such instances. And for the last one, when the ribosome is done reading the message of the mRNA, the termination phase now commenced.
So, what happens in the termination phase? The small and large unit will start to disengage or disperse alongside with the mRNA and the protein. The byproduct of this is a protein, of course. And then the small subunit and the large subunit can again be reused by the cell after creation of protein.
So that is the process of protein synthesis. Next one, we have the endoplasmic reticulum. The endoplasmic reticulum or other referred to as ER, primary function is for synthesis of lipid and modification of many protein inside the cell.
Okay, so as you can see in here. There are two types of ER or endoplasmic reticulum. They need a rough endoplasmic reticulum and smooth endoplasmic reticulum.
As you can see, the very difference lie on their surface. So rough ER has a ribosome attachment while smooth ER do not have a ribosome attachment. So that is the difference when it comes to structure.
Now let us try to look on the difference of the smooth and rough ER. So one of the distinct differences of the rough and smooth ER or endoplasmic reticulum aside from the surface is that they differ in function also. For the rough endoplasmic reticulum, they carry a ribosome wherein it helps in the creation of protein. And we explained the mechanism or slide earlier.
It also helps in distributing transport vesicle for the protein surrounded by the membrane. So earlier we have mentioned that ribosome creates protein. And there are ribosomes that is integrated within the rough ER.
When protein has been manufactured, the ER will process it even further, modify if there is a need of modification, and the protein undergo or gets through the transport vesicle. If we say transport, it used to transport different materials. among inside the cell so technically if protein has been manufactured by the ribosome and modified by the smooth er it can now be used in transport vesicles. Sir Mark where will the transport vesicle go? Transport vesicle will go to the different site of the cell wherein protein is needed.
That is how basic it is. It is also known as a membrane factory for the cell because you you have to realize that different membrane inside the cell For example, the membrane of the mitochondria, our cell membrane, they have protein in there, inside of them. Therefore, the membrane factory of the cell is called RAF-ER because all of the membranes have protein.
Also, the nuclear pore earlier we have mentioned is made up of protein. Therefore, we call RAF-ER or RAF-ANAPLASIC RITICULUM membrane factory of the cell. Next one, we have the smooth ER.
It helps in lipid synthesis or creation of lipid. What is the essence of lipid inside the cell? Last time, we also have discussed that the cell membrane is made up of phospholipid bilayer.
Therefore, lipid synthesis is essential for cell membrane to be possible to occur. the cell membrane to be synthesized or created. Similar with the nuclear envelope, the inner and outer membrane is made up of lipid.
Therefore, the cell needs to make lipid. Next one, it also helps in metabolizing carbohydrates. So, realize also that metabolism has two components, namely the catabolism and anabolism that we have discussed in the introduction to biology. Pag katabol is same, it just simply means the breaking down of sugar or carbohydrates. So, remark, when we break down sugar, di ba nangyari ito sa mitochondria?
Yes, that happens inside the mitochondria for ATP. synthesis or creation of ATP, but there are also modification that needs to happen with the help of the smooth endoplasmic reticulum. So we have catabolism wherein sugar is being breakdown. And another is anabolism wherein sugar is being added to other protein.
Let's look at it. Anabolism is creation or putting things together. So for example, breakdown of sugar or carbohydrates There are modifications that need to be done.
For example, the protein needs another sugar or glucose. We already have glycoprotein when we combine sugar and protein. Lipid and sugar can also be combined inside the cell, hence we call it anabolism or putting things together.
Next one, detoxification of poison. You have to realize that There are varieties of elements and chemicals inside the cell since there are different metabolic processes. So this includes carbon dioxide that is not beneficial for the plant or eukaryotic cell growth.
So therefore, this poison needs to be eliminated inside the cell. Next one, we also have stores calcium. Smooth ER stores calcium because calcium is known as a neurotransmitter. A neurotransmitter is any chemical signal that is essential for passing down of information.
So usually calcium serves as a neurotransmitter in sending different signal from cell to cell communication. Next one we have the Golgi apparatus. Other book refer to it as Golgi complex or Golgi bodies. They are stocks of flat membranous structure looks like a smooth ERO because they are smooth in nature. But you have to realize that the function of the Golgi apparatus has something to do with the sorting and modification of protein.
Ito yung mga, kumbaga sa parcel, ito yung mga sorting center, yung Shenzhen sorting center. For the parcel to reach your home, kailangan mo nang ipak, nang maayos, at isort kung saan talaga siya papunta. So technically, there are two phases.
of the Golgi apparatus, namely the cis phase, wherein it is the receiving phase of the Golgi apparatus and the trans phase or the shipping side or phase of the Golgi apparatus. So, remarks, saan po galing yung receiving or saan po galing yung molecule na na-receive ni Golgi apparatus? It came from the rough ER or smooth ER after they have manufactured the protein.
So, just like what I have said earlier, After a modification of ERs, a modification of Golgi apparatus is needed. As you can see, there are different flat stacks of membrane. While it is being passed through the glass, there will be a modification.
Until there is such time that it goes to the transphase wherein it is ready for transportation. So, this is a vehicle. It can be two.
It can be a transport vesicle or a secretory vesicle. Transport vesicle when the protein or other molecule like protein, sugar, and lipid is transported inside the cell. But when the protein, molecule, or any other chemical is transported outside of the cell, it will ride or go to the secretory vesicle. Secretory vesicle used to secrete molecule outside of the cell. Hence, we call it secretory vesicle.
So again, there are two phases of the Golgi apparatus, the receiving end called the cis phase and the transferring phase or sorry the shipping phase known as the trans phase. So, this is what we call the cis-terrinary flat structure that we see in the Golgi apparatus. So, this is the view of the Golgi apparatus in transmission electron microscope. As you can see, we can see the varieties of structure series or stacks of cisternae.
Overall, we have this system called an endomembrane system. This is located inside the cell, kaya nga endo, inside of the cell. So there are organelles that are responsible in containing or having the endomembrane system. So we only have five. So we have the nucleus, we have the smooth endoplasmic reticulum, the rough endoplasmic reticulum, the Golgi apparatus or Golgi complex or Golgi bodies, and next one we have the plasma membrane.
So to summarize it, That is how the production of protein or lipid happens. The signal to the nucleus begins. The nucleus will create an mRNA.
mRNA will be read by the ribosome that is attached to the rough ER. The ribosome from the rough ER will create a protein. The protein is being sorted and packed in the rough ER. The rough ER will send the package to the Golgi apparatus in this phase part of the Golgi apparatus. The Golgi apparatus will modify and further sort the molecule or material and then there will come a time that when the protein is modified and sorted properly it goes to the the transface of the Golgi complex ready for shipping outside of the cell or inside of the cell, depending on where it is needed.
So next one we have the mitochondria. This is familiar to others. Mitochondria is known as the powerhouse of the cell because it is the one that is responsible in creating or synthesizing of ATP or creation of ATP.
You have to realize that the mitochondria also contain DNA. Quick trivia, did you know that your mitochondria is from your mother. Let's say your mitochondria came from your mother.
Therefore, the athleticism of your mother is passed down to you as a child. Meaning, when we talk about athleticism, we can associate this to ability to produce ATP, to supply your cell or your body. So, if you want to have athletic sons and daughters in the future, try to consider having an athletic wife or mother. So that is linked or the ATP sorry or the DNA of the mitochondria is related to your mother.
We are very much aware of the mitochondria because it helps in releasing of energy from the sugar. So when sugar enters the cell, sugar goes to the mitochondria or mitochondrion. Mitochondrion then processes the sugar and makes an ATP or adenosine triphosphate.
The ATP or adenosine triphosphate is the energy expenditure of the cell. Therefore, for the different mechanism to happen or metabolic processes to commence and happen inside the cell, ATP is essential and needed. If we're going to look at the compartment or parts of the mitochondria or mitochondrion in the picture, it doesn't outer membrane and an inner membrane and again that is made up of the PID.
It has a matrix inside it where DNA is located and also the matrix is the site where cellular respiration happens or creation of ATP. Cisternae are the flat flap that you can see that helps in creating the surface area among or inside the mitochondria. So we have here the mitochondria. Next one, we have the lysosome. Lysosomes are known as the garbage collector inside the cell because they are the one that breaks down the different waste products inside the cell.
You have to realize that the lysosome is made up of plasma membrane again known as a lipid bilayer. So we have to realize that lipid is synthesized in the smooth ER. Therefore, lipid is very essential.
inside the cell. Aside from nuclear envelope, aside from mitochondria, aside from cell membrane, meron din tayong lysosome that needs lipid because doon may kita sa loob ng lysosome yung hydrolytic enzyme. Usually the pH of the hydrolytic enzyme is from 4.5 to 5 so these are acidic in nature okay so for it to digest and process different uh ways inside the cell, kailangan acidic ito para matunaw yung mga different substance that is no longer serving its purpose inside the cell. Another thing that we need to know about lysosome, it serves as a pore protection inside the cell. If there are foreign invaders like bacteria and virus that wants to hijack the cell, lysosome are there to support our cellular function by engulfing or eating the foreign substance.
other or sometimes like as a self-disloc device for the cell. So there are moments wherein kapag sobrang the cell is worn off, there is a process called apoptosis. A-P-O-P-T-O-S-I-S Apoptosis, wherein the cell started to lyse, or it means it is popping.
Because sometimes, when the cell is not functioning, in a tissue level, it needs to kill itself so that it will not have a direct grip on another or neighboring cell. So that's what happened. So there are two processes.
We have the phagocytosis and autophagy. Phagocytosis, if you are familiar with Pac-Man game, the yellow one, everything that goes on its way will be engulfed or eaten. Same with phagocytosis.
But again, in the Lysozoon class, you have to realize that they are selective. Not all of them can be seen. Number one, this should be a foreign invader. pangalawa It should be a waste product or number three, it should be needed by the cell for further digestion. So, in our example, the lysosome or the color purple one in image A helps the food molecule digestion.
So, it just brings down or has a catabolism in the food molecule vesicle. On the next one, we have the autophagy or autophagy. We have the mitochondrion.
that is integrated within the vesicle and alongside with peroxisome. So what happened in here, class? Lysosome helps in breaking down the mitochondrion and peroxisome because it has or have a low pH level or acidic nature.
Therefore, it helps in breaking down. So, Mark, why do you need to break down the mitochondrion? Isn't this what causes ATP?
Just like what I have mentioned, there are moments wherein some organelles also experience cell growth or were worn off. It means that the normal process that mitochondrion have is no longer able to make the mitochondrion that we have there. So the tendency is the cell needs to digest it and it needs to be replaced by a new mitochondrion.
So that's what you're doing. For example, at work, if a worker can't do it, This is something. Parang ganun din ang nangyari dito.
At maghahanap ng panibang. So we have lysosome. Next one, we also have peroxisome.
It is a site for many metabolic processes or reactions. So you have to realize that peroxisome function inside the cell is converting hydrogen peroxide, H2O2, into usable water or H2O and O2 oxygen gas. So there are moments wherein when our body contains lots of alcohol, instead of throwing those alcohols because alcohol can make our cell dehydrated, what does peroxisome do? It converts hydrogen peroxide or alcohol H2O2 into usable H2O water and O2 oxygen gas inside the cell.
That is why very... essential ang peroxisome sa ating katawan. And usually, peroxisome is concentrated on our kidney and liver. Kaya nga diba kapag tayo ay umiinom or if you meron tayong kailangan na lagi umiinom or umiinom frequently, we associate them having their kidney being damaged because peroxisome are the one that process the alcohol inside the cell. Hence, peroxisome is concentrated in the kidney and the liver.
So when... If your liver is damaged, it means that peroxisome can no longer do its function or very hindered its function of converting hydrogen peroxide into water and oxygen, which is useful for the cell. Next one, we have the vacuole. Animal cell and plant cell have this mechanism in if they have extra water or sugar they will store it enough they will store it in a form called vacuole. So vacuole is very specific to, or prominent rather to plant cell.
So in plant cell class, they have a larger central vacuole because they need water for the different process to happen in the plant. So that is the vacuole. So if we have an analogy here, if we have a refrigerator inside our house, it's like a vacuole. It stores the water inside the house and also it stores food inside the house. Plant cell and animal cell do contain vacuole but the difference is the plant cell have a large central vacuole while the animal cell have a small vacuum.
When plants are completely filled with water, the cell are pumped and plant is firm. If it loses water, the plant will wilt. So that's the class. If the water is too dry for the plant, they will have a firm structure when it comes to cellular level.
But if the water is not enough for the plant cell or the plant in general, yung vacuole din nila class lumiliit hence they will become wilt or nalalanta sila nagkakaroon nabewither sila okay so we have vacuole next one we have the chloroplast which is located in the plant cell it is a large oval shape it is a double membranous organelle that is only can be found on plant cell okay the chloroplast serves as a site for photosynthesis wherein carbon dioxide, water, and sometimes with the help of sunlight, helps in a process called photosynthesis. And the byproduct is O2 or oxygen, gas, and sugar. So imagine your class, the very reason why plants can function well is with the help of chloroplasts.
They are there for photosynthesis. In our last meeting for GenBio1, we will discuss cellular respiration, which happens in the animal cell, and also photosynthesis which happens in the chloroplast of that plant set. Next one we also have the centrosome. Centrosome is found in the cytoplasm and usually close to nucleus. So the very reason why it is closed in the nucleus because these are the one that is responsible for cell division.
So you have to realize that centrosome is close to the nucleus because it is responsible for cell division, mitosis, and meiosis. So centrosomes are made up of microtubules and earlier we have mentioned that microtubules are made up of protein. So the function of the centrosome are they are the one responsible organizing the center of the cell specifically when there is a division that will happen, no, somatosis and meiosis. Centrosome produces a filament that used to pull the different DNA or chromosome to the opposite part of the cell.
In the cell cycle or cell reproduction metastasiosis, we will appreciate how centrosome works even further. It also directs the movement of the microstribule, other cytoskeleton structure, and protein along the change of the shape of the animal membrane. Again, centrosome is very beneficial for the plant cell and animals in animal cell because of It is essential in cell reproduction, particularly in mitosis and meopsis. So, if we can see here, class, this is the process from single cell organism up until giving a two offspring.
That is what Centrosome does. Centrosome produces spindle fiber and the spindle fiber is attached to the kinetochore. of the chromosome.
So kinetochore class that is a protein that is integrated or attached to the chromosome. So there will come a time that the chromosome needs to migrate to the opposite centrosome or opposite pole therefore it pulls on a different direction. As you can see in the diagram also in the right side from center, you can see the color blue class, the center that is is the centrosome.
The centrosome is pulled with the help of the cent... Sorry, the chromosome rather, the blue one, is located in the middle. And with the help of centrosome and spindle fiber, it is pulled into an opposite pole.
So, we can see the color blue, which is the chromosome, and it is pulled into the opposite part of the cell. And there will come a time that there is a new, there is a new offspring that has been produced. So, we have centrosome. Next one, we have the cell wall. Cell wall in the eukaryotic cell.
correction lang ito class, is made up of cellulose and chitin. Wala pong peptidoglycan because again in our discussion, peptidoglycan cell wall is only located and can be found in prokaryotic cell. So the primary function of cell wall is for structural support.
We are very much aware of that. Protection of plant from the diseases. So before you hijack the plant cell, you need to undergo first or pass through the cell wall and plasma membrane.
Also, it prevents the plant cell from bursting due to the increased hydrostatic pressure. So just like we have mentioned earlier, when there's a lots of water inside the vacuole, there's a pressure inside the So to prevent it from bursting and for prevention of bursting of the plant cell, meron tayong cellulose, that is rigid in nature because it is made up of cellulose and it protects the plant cell. So next one, we have the plasmodesmata. It is a membrane channel that cross the wall of the adjacent plant cell.
it is also the linking It also links the cytoplasm and plasma membrane of the cell. So, the function of the netoclast, it helps in cytoplasmic cell division. If the plant cell, I'm sorry, if the animal cell has mitosis meiosis, the plant cell, in order to have mitosis, it also needs plasmodesmata. It helps in communication or junction from one cell to the another. We have plasmodesmata.
Next one, appendages. We have cilia and flagella. So the cilia is a hair-like structure, flagella is a whip-like structure, and they are used for locomotion or movement of the different cell.
In animal cell, we have sperm cell that has a flagella, and the movement is up-down motion. So there is a movement of flagella. On the other hand, the flagella in the prokaryotic cell move in circular direction. Last one, we have the surface structure. Some eukaryotic cells do contain a glycocalyx, which is made up of sugar and protein.
They are integrated within the cell membrane for signal reception. For example, there are signal-passing surface structures like glycocalyx, which is located in the extracellular part of the cell membrane, are the ones that receive the signal okay we have surface structure. So that will be all for the function and parts of the cell. So you have to realize that this is an animal cell on the left side and also we have the plant cell on the right side. These are the difference of the plant cell and animal cell.
So plant cell have plasmid like chloroplast. Animal cell do not have a chloroplast. Plant cell cell wall is made up cell you lose while animal cells do not have a cell wall. Third, plant cells have a large central vacuole while animals do not have a large central vacuole.
Instead, it has a small and temporary vacuole. Plants have plasmodesmata while animals do not have a plasmodesmata. Sorry.
Plants have plasmodesmata while animals do not have a plasmodesmata. plants do not have a sentry hole they do not also have a cholesterol in the cell membrane but animal have a cholesterol in the cell membrane and they have a centriole with centrosome. The form of storage in plant is called a starch while in animal we call it glycogen and plants usually has a fixed regular shape while animal have a amorphous shape or irregular shape.
So that would be about the difference so we have here a video. So, differentiate plants and animals. This video will be sent to you just so you know. But to end our discussion for today, let me just share this quote to you. So, according to Eric Lander, suddenly it was clear to me that all of the beautiful complexity of the life had simplicity as its core.
So, you have to realize that all... Though eukaryotic cell is complex in nature because they have different components like organelles or membrane-bound organelles, you have to realize the simplicity lies within its nucleus or core. Ganon din tayo bilang isang tao. Although we may sometimes look complex, but if you're going to look at the heart of each and every one of us, kindness is the universal language that we all speak. Tama ba?
So you have to look at the core. ng bawat isang. So that would be all for today and I hope you learned something in our lesson. Thank you.