Cell Biology PDF

CELL These are as fundamental to living systems as an atom to chemistry. ➔ All living organisms are composed of at least one cell. Basic structural and functional unit. Cellula in Latin ○ Robert Hooke in 1665 had first seen cell walls in cork. ➔ Kapag namatay yung...

CELL These are as fundamental to living systems as an atom to chemistry. ➔ All living organisms are composed of at least one cell. Basic structural and functional unit. Cellula in Latin ○ Robert Hooke in 1665 had first seen cell walls in cork. ➔ Kapag namatay yung plant cells, naiiwan yung sclerified cell walls or sclerenchyma, which is yung nakikita sa microscope. ○ Antoni van Leeuwenhoek in 1674 coined the term ‘animalcules’ MICROSCOPES REVEAL THE WORLD OF THE CELL ➔ To look into your cells, you always need to use the microscope. A variety of microscopes have been developed for a Image from: clearer view of cells and cellular structure. https://cdn.britannica.com/75/128775-050-D543844D/Phase-contrast- microscope.jpg The first microscopes were light microscopes. In a ➔ Due to the refraction of light, the image of the light microscope (LM), visible light passes through a specimen appears inverted. Example yung specimen, then through glass lenses, and finally is letter ‘e’ na nakainvert vertically and laterally. projected into the viewer’s eye. ➔ The LM is a series of lenses that are able to Magnification is the increase in an object’s image refract or deflect light, hence the deflection of size compared with its actual size. light causes the specimen to appear bigger ➔ Kung paano siya napeperceive than its actual as you look through the series of lenses. size. Using a microscope, an image can be ➔ So sa LM, depende kung concave or convex, magnified up to 1000 times. kung magmamagnify or lalaki yung organism. Resolution is a measure of the clarity of an image. In other words, it is the ability of an instrument to show Specimens can be magnified by up to 1,000 times. two nearby objects as separate. ➔ If the lens is curved, the light will be ➔ Example, kung pixelated or clear yung concentrated, so instead of going past directly, image. it will change its course. Macoconcentrate within the cylindrical tube yung light. Microscopes have limitations. ○ The human eye and the microscope have limits of resolution–the ability to distinguish between small structures. ➔ Limits of resolution depend on the depth of field. Fine adjustment can be used to determine whether the specimen is nasa taas or baba. Basically, how it appears on a  three-dimension, kung gaano kalapit yung object kapag nakapatong-patong. ○ Therefore, the light microscope cannot provide the details of a small cell’s structure. ➔ Our cell has multiple organelles that are freely-moving inside the cytoplasm, thus, it is far from possible to see all of them at once. Beginning in the 1950s, scientists started using a very powerful microscope called the electron microscope (EM) to view the ultrastructure of cells. ➔ Ultrastructure of cells are the large components or materials found within the cell, simply, the organelles. ➔ Our unaided eyes could only see around the Instead of lumens or light wavelengths, EM uses a size of the paramecium. beam of electrons. ➔ Electrons are smaller particles than atoms. It is similar to sonars, that when it is blasted on a surface, tapos mabilis bumalik yung electron, ibig sabihin mas malapit yung object doon. So EM could identify the image based on either the absorption of the material ng electrons or the return of the electric signal. Electron microscope can ○ resolve biological structures as small as 2 nanometers and ○ magnify up to 100,000 times Two Types of Electron Microscopes Scanning electron microscopes (SEMs) study the detailed architecture of cell surfaces. Transmission electron microscopes (TEMs) study the details of internal cell structure. ➔ Can identify the absorbed electron, so it can penetrate the organelles allowing it to identify what’s inside the organelle and its ➔ Plant and animal cells could be seen with shape. LM, whereas, Differential interference light microscopes amplify ➔ Plant and animal organelles could be seen differences in density so that structures in living cells with EM appear almost three-dimensional. Using light microscopes, scientists studied: ○ microorganisms ○ animal and plant cells, and ○ some structures within the cells ➔ Including yung reproduction ng cells, i.e., mitosis and meiosis.  ➔ And pwedeng maobserve din yung vacuole ➔ On the right figure, it has a total volume of ng well hydrated plant 9x3 = 27 units3. With a total surface area of 162 units2, 1 x 1 x 6 (faces) x 27 (cubes) = In the 1800s, these studies led to cell theory, which 162. And a surface-to-volume ratio of 6, by states that (2 tenets of cell theory): dividing 162 by 27 (162 ÷ 27). ○ all living things are composed of cells, and ➔ 6 faces ibig sabihin may 6 sides yung cube ○ all cells come from other cells (yun yung top, bottom, front, back, right, ➔ Or cells arise from preexisting cells left). ➔ Kung mas mataas yung surface-to-volume ratio, mas mabilis din dumating yung THE SMALL SIZE OF CELLS RELATES TO THE information from one cell to another. NEED TO EXCHANGE ACROSS THE PLASMA ➔ For example, kapag malaki yung dendrites MEMBRANE or nerve cells, mas mabagal magmove yung Cell size must information or impulse from one synapse to ○ Be large enough to house DNA, proteins, and another. Compared sa mas maliit na size, na structures needed to survive and reproduce, but mas mabilis dadaloy yung info. ○ Remain small enough to allow for a surface-to-volume ratio that will allow adequate The small size of cells relates to the need to exchange with the environment exchange across the plasma membrane ➔ Review: Programmed cell death occurs The plasma membrane forms a flexible boundary kapag may infection yung plant and kills the between the living cell and its surroundings surrounding cell na natamaan or ➔ It is very porous allowing the transfer of naapektuhan ng infection. material from one cell to another. ➔ Kapag sobrang laki ng cell, matagal ➔ Example, the lining of the stomach and the magtranscend yung information from one large and small intestine. The cells in these cell to another. So mas mabilis kakalat yung organs are able to absorb food for digestion, infection that even though the cell and transfer it to the bloodstream, to the underwent apoptosis, nakalusot na yung adjacent cells that will then transport to the bacteria / virus. That’s why maliit lang dapat whole body. yung cell. Phospholipids form a two-layer sheet called a phospholipid bilayer in which ○ Hydrophilic heads face outward, exposed to water, and ○ Hydrophobic tails point inward, shielded from water. Membrane proteins are embedded in the lipid bilayer. ➔ Important yung hydrophilic heads and hydrophobic tails because we have proteins that are embedded within the lipid bilayer. The hydrophilic head faces the outside and inside of the cell because the cytoplasm and outside environment of the cell contain ➔ On the left figure, A 3x3 unit will have a total water. volume of 27 units3. And the total surface area is 3x3=9, multiplied by 6 surfaces of the cube, so 9x6 = 54 units2. With a surface-to-volume ratio of 2, by dividing 54 to 27 (54 ÷ 27).  ➔ Eukaryotes have membrane bound nuclear region. ➔ Organelles are bound with bilipids separated spatially. ➔ Some eukaryotes are unicellular, and most are multicellular. Differences of Prokaryotes and Eukaryotes CELLULAR PROKARYOTIC EUKARYOTIC CHARACTERISTICS CELL CELL Size 1-10 μm 1-10 μm ➔ Hydrophobic tails are pushed towards each Genetic system Single, cellular Multiple, linear other. DNA DNA ➔ Channel proteins or membrane-bound proteins. Most of the proteins are Cell division and Binary fission; Mitosis and hydrophobic. If wala yung hydrophobic tails, reproduction reproduction by meiosis; sexual it would not be possible to let the proteins be conjugation reproduction embedded on the plasma membrane. Mode of Absorption; Absorption; nutrition photosynthesis in photosynthesis in Some proteins form channels (tunnels) that shield some some plants ions and other hydrophilic molecules as they pass through the hydrophobic center of the membrane. Nucleus No distinct nuclear Distinct nuclear Other proteins serve as pumps, using energy to membrane membrane actively transport molecules into or out of the cell ➔ Proton pumps -> active transport Endomembrane Absent Present system TYPES OF CELLS Cell movement Flagella Flagella, cilia, amoeboid projections Prokaryotic Eukaryotic Cell wall Made of Made of a - Non-membrane bound - Membrane bound peptidoglycan phospholipid nuclear region nuclear region bilayer; reinforced by cellulose in - Nucleoid - Nucleus plants - Absence of organelles - Presence of organelles Plasma Present Present membrane - Generally unicellular - Unicellular to multicellular Cytoplasm Absence of a Presence of a cytoskeleton cytoskeleton and ➔ Prokaryotic cells have a non-membrane cytoplasmic varions bound nuclear region, so its genetic material is freely floating within the cytoplasm, and Ribosomes 70S 80S only concentrates on the nuclear region. ➔ Prokaryotes also have non-membrane bound organelles,.e.g, ribosomes.  Cell division is not forever—once the telomeres are too short, cells either stop dividing or undergo programmed cell death. PROKARYOTES Prokaryotes, such as bacteria, have circular DNA. ○ Because their DNA is circular, theoretically, they can divide without showing signs of aging, unlike eukaryotes. ○ Bacteria can continue dividing multiple times without degradation in their DNA. ○ When culturing bacteria, this allows for continuous division. There is no significant damage to their genetic material during replication, which is a major difference between prokaryotes and eukaryotes. Prokaryotes are also much smaller in size. In terms of genetic structure, prokaryotes have circular DNA. Prokaryotic cells reproduce primarily by binary fission or through a process called conjugation. ○ Conjugation involves the formation of a structure, often referred to as a pilus, which is produced by the cytoplasm of one microorganism. Prokaryotes have circular genetic material. On the This pilus acts as a bridge to transfer genetic other hand, eukaryotes have linear genetic material material from one bacterium to another. because of the telomerases. ○ During conjugation, some of the circular DNA, ○ Telomerase is an enzyme that helps maintain the typically plasmids, are transferred between the length of telomeres, which are the protective caps cells. This exchange of genetic information at the ends of chromosomes. results in both bacteria having slightly different ○ Normally, during cell division, DNA is copied, but genetic material. a small portion of the telomeres is lost with each ○ After conjugation, when binary fission occurs, the division. daughter cells will have different genetic material ○ Telomerase helps replenish telomeres, from their parent cells due to this genetic particularly in certain cell types, like stem cells. exchange. However, in most somatic (non-reproductive) In prokaryotic cells, there is no distinct nucleus; the cells, telomerase activity is low or absent. As a genetic material is in a region called the nucleoid, result, telomeres gradually shorten as cells which is not membrane-bound. divide. Prokaryotes lack an endomembrane system, which ○ Over time, as telomeres shorten, the protective includes structures like the endoplasmic reticulum cap on chromosomes diminishes, which leads to (ER), Golgi apparatus, and vesicles that eukaryotic cellular aging and senescence. cells use for transporting and processing materials. Senescence refers to the state where cells ○ Prokaryotes do not require this system because no longer divide, and this is part of the they rely on simpler processes, like diffusion, to natural aging process. Eventually, when transport materials within the cytoplasm. telomeres become critically short, cells may ○ Prokaryotic cells also do not need an stop dividing, leading to chromosome endomembrane system to manage heat or instability and potential damage, which can enzymes. result in aging-related decline in cellular The enzymes they require are produced function. directly in the cytoplasm, and they can adapt  to environmental conditions, such as effectively. If they lost their distinct shape, their absorbing heat from their surroundings. functionality would be impaired. Similarly, Prokaryotic cells are more flexible and adaptive cuboidal cells in the gut are specialized for because they need to move and respond directly to absorbing nutrients, and their shape maximizes environmental stimuli. Their flexibility allows them to surface area for absorption. access food, escape predators, and survive in Eukaryotic ribosomes are 80S in size. dynamic environments. Prokaryotic ribosomes have a typical size of 70S. FUNCTIONAL COMPARTMENTS OF ○ Ribosomal differences can help identify the type EUKARYOTIC CELLS of infection caused by specific microorganisms. ○ Ribosomal RNA (rRNA) sequences, particularly from the 16S rRNA in prokaryotes, can be used NUCLEUS as "molecular barcodes" for the identification of The first compartment of the cell is responsible for microorganisms. genetic control and includes structures like the This technique allows for the precise nucleus and ribosomes. identification of bacterial strains and is The nucleus houses the cell's genetic material (DNA), commonly used in diagnostics, forensics, while the ribosomes are responsible for translating and molecular medicine. mature mRNA that exits the nucleus. For example, bacterial strains can be The most noticeable organelle in a cell. identified under a microscope and Separated by a nuclear envelope. through molecular techniques such as ○ This envelope is packed with proteins and fibers, 16S rRNA sequencing. including histones, which help organize and Once the microorganism is identified, this information compact the DNA. can be used to create targeted treatments, such as ○ DNA is packaged into chromatin fibers with designing specific antibodies or determining the best histone proteins. course of action for patient care based on the type of Histones are organized into octamers, infection. meaning they are made up of eight subunits. These histones wrap around DNA to form EUKARYOTIC CELLS structures called nucleosomes, which allow Eukaryotic cells have linear DNA, often contained in the DNA to supercoil and pack tightly multiple chromosomes. together in the nucleus. In eukaryotic cells, DNA is found in multiple locations: This compact organization is essential for in the nucleus, the mitochondria, and, in plant cells, DNA regulation and protection. also in the chloroplasts. Studded with nuclear pores for transport of DNA. Eukaryotes reproduce through processes like mitosis ○ Are composed of multiple proteins that form the and meiosis. nuclear pore complex. Eukaryotic cells have a distinct nucleus, which is ○ These pores allow the selective exchange of enclosed by a nuclear membrane that protects and materials between the nucleus and the organizes the genetic material. cytoplasm. In eukaryotic cells, the endomembrane system For example, mature mRNA exits the functions as the cell’s shipping machinery, facilitating nucleus through these pores to be translated the distribution of proteins, lipids, and other materials into proteins by ribosomes. to different parts of the cell and out of the cell as ○ Importantly, the nuclear pores prevent large needed. molecules from entering the nucleus from the In eukaryotic cells, the cytoskeleton provides cytoplasm. structure and support, ensuring that cells maintain Retroviruses, such as HIV (human their shape. immunodeficiency virus), can bypass these ○ For example, muscle cells are fusiform (tapered cellular defenses. at both ends), which helps them contract  Retroviruses integrate their genetic Ribosomes are involved in the cell’s protein material into the host's genome, synthesis. allowing them to replicate. ○ However, they do not directly create or produce This integration is why retroviruses are proteins. Instead, ribosomes are responsible for difficult to treat. Once the virus's DNA is assembling polypeptides, which later fold and embedded in the host genome, it is very modify to become functional proteins. challenging to remove. Ribosomes are the cellular components that Current technologies like CRISPR can be use instructions from the nucleus, written in used to gene-edit the viral DNA out of the mRNA, to build proteins. host cells, although this is still experimental. Ribosomes utilize instructional Another potential treatment option is stem information from messenger RNA cell therapy, which could involve replacing (mRNA). They read the mRNA infected cells with healthy ones. sequence and use the genetic code to ○ Under an electron microscope, the nucleus link together amino acids, creating the appears with visible nuclear pores, which allow polypeptide chain. the regulated entry and exit of molecules, such as Cells that make a lot of proteins have a large mRNA. number of ribosomes. A prime example of this would be prokaryotes. Prokaryotes contain many ribosomes compared to eukaryotes because they undergo polycistronic translation, which means multiple proteins can be synthesized from a single mRNA molecule. In contrast, eukaryotes follow a monocistronic model, where each mRNA typically codes for just one protein. Prokaryotes have circular DNA, and translation of mRNA can occur continuously as the DNA opens during transcription. ○ In prokaryotes, the mRNA is clustered closely, often organized in operons, allowing multiple ribosomes to bind to the mRNA at the same time. ○ This results in simultaneous synthesis of several polypeptide chains, leading to faster protein production. This rapid production is crucial for processes like lactose digestion, where enzymes are quickly synthesized to break down lactose and convert it into energy. RIBOSOMES MAKE PROTEINS FOR USE IN THE Some ribosomes are free ribosomes; others are CELL AND EXPORT bound. ○ Free ribosomes are suspended in the cytosol.  ○ Bound ribosomes are attached to the outside of Region between the plasma membrane and the the endoplasmic reticulum or nuclear envelope. nucleus. Those attached to the rough ER (named for Endomembrane components are suspended in the its "rough" appearance due to the presence cytosol. of ribosomes) help synthesize proteins that Region where the cell’s metabolic reactions occur. are typically exported out of the cell or integrated into cellular membranes. When mRNA exits the nucleus via nuclear pores, it can enter the rough ER, where ribosomes translate the mRNA into polypeptides. These polypeptides can then undergo further modifications and sorting within the ER before being transported to their destination. MANY ORGANELLES ARE CONNECTED IN THE ENDOMEMBRANE SYSTEM Many of the membranes within a eukaryotic cell are part of the endomembrane system. ○ Many of the membrane-bound organelles in eukaryotic cells are part of the endomembrane system. It is composed of the endoplasmic reticulum, Golgi apparatus, lysosomes, vacuoles, and various other components, but ribosomes are not part of the endomembrane system. ○ This system forms a network of pathways that allow materials, such as proteins, to be processed and transported to their final destinations. ○ For example, if a specific enzyme is needed for FUNCTIONAL COMPARTMENTS OF EUKARYOTIC chlorophyll function under stressful conditions, CELLS like high heat, the cell will produce the necessary The structures and organelles of eukaryotic cells proteins. These proteins are transported through perform four basic functions. the endomembrane system to where they are 1. The nucleus and ribosomes are involved in the needed, helping to maintain proper function and, genetic control of the cell. in some cases, to protect organelles from 2. The endoplasmic reticulum, Golgi apparatus, moisture loss. lysosomes, vacuoles, and peroxisomes are Some of these membranes are physically connected, involved in the manufacture, distribution, and and others are linked when tiny vesicles (sacs made breakdown of molecules. of membrane) transfer membrane segments between them. CYTOPLASM  ○ Many of the membrane-bound organelles in ○ Are primarily used for storage, such as storing eukaryotic cells are part of the endomembrane water in plant cells. system. 6. Plasma membrane - export of molecules ○ These vesicles are small membrane sacs that ○ Which controls the movement of substances in move freely within the cytoplasm, transporting and out of the cell. The plasma membrane is materials between organelles. flexible and made up of lipids and proteins, with Many organelles are connected in the structural support provided by the cytoskeleton. endomembrane system. The endomembrane system includes the: 1. Nuclear envelope – synthesis ○ In general, the nuclear envelope plays a key role in the synthesis of RNA. After RNA is produced, it becomes messenger RNA (mRNA) and exits the nucleus through the nuclear envelope. 2. Endoplasmic reticulum (ER) - distribution ○ Once outside the nucleus, the mRNA is captured by ribosomes on the rough endoplasmic reticulum (RER). ○ The RER is also involved in the process of glycosylation, where sugar molecules are attached to proteins. For example, it can add sugar molecules in different orientations, such as dextrorotatory (right-handed) or levorotatory (left-handed), depending on the position of the hydroxyl (OH) group. ○ The rough endoplasmic reticulum helps determine how many carbons the sugar molecule ENDOPLASMIC RETICULUM has and attaches the appropriate sugars to the protein. The largest component of the endomembrane system These sugars play a key role in directing the is the endoplasmic reticulum (ER), an extensive protein to its correct destination. network of flattened sacs and tubules. ○ By the time the protein reaches the Golgi There are two kinds of endoplasmic reticulum, which apparatus, it is already properly folded. differ in structure and function. 3. Golgi apparatus - distribution A. Smooth ER ○ The Golgi apparatus functions as the cell’s Lacks attached ribosomes. sorting and processing center. ○ Lacks ribosomes but is important to produce ○ It identifies proteins, processes them, and lipids, detoxification, and the transport of vesicles. finalizes the glycosylation. It also plays a role in the production of certain For instance, it may recognize patterns like enzymes. the arrangement of six sugars on one side of B. Rough ER the molecule, which helps determine where Has bound ribosomes that stud the outer surface of the protein should be sent next. the membrane. 4. Lysosomes - distribution ○ Has ribosomes attached to its surface, which are ○ Are vesicles that contain digestive enzymes, involved in protein synthesis. which break down macromolecules or recycle ○ The rough ER acts as a channel where proteins cellular waste. are synthesized and processed. It plays a key 5. Vacuoles - storage role in translating mRNA into polypeptides, which are the building blocks of proteins.  ○ As polypeptides are formed, they grow inside the Smooth ER the production of enzymes important in lumen of the endoplasmic reticulum. Some of the synthesis of various lipids and store calcium ions. these polypeptides become glycoproteins, ○ It helps in the production of membranes, both for meaning they are tagged with sugar molecules. itself and for secretory processes within the cell. This glycosylation process helps determine Rough ER makes additional membrane for itself and whether the protein will be exported out of the secretory proteins. cell. The sugar tags essentially act as a signal for ○ After mRNA exits the nucleus through the nuclear the protein’s destination. envelope, it binds to a ribosome on the rough ER. The ribosome translates the mRNA into a polypeptide, which enters the rough ER for folding and processing. Once inside, the polypeptide folds into its proper protein structure and may be tagged with sugars to become a glycoprotein. This glycoprotein can either be exported from the cell or transported to the Golgi apparatus for further modification and sorting. The Golgi apparatus is then responsible for distributing proteins and lipids to their proper destinations within or outside the cell. GOLGI APPARATUS Looks like a stack of discs, layered one on top of the other. Serves as a molecular warehouse and processing station for products manufactured by the ER. ○ As proteins or lipids move through these layers, the Golgi apparatus modifies and sorts them, determining their final destination. It also assesses whether enzymes are mature enough to digest food or recycle damaged mitochondria. Products travel in transport vesicles from the ER to the Golgi apparatus. ○ The multiple layers of the Golgi apparatus facilitate the maturation and proper packaging of proteins, which are then transported in vesicles. These vesicles contain the enzymes or other materials to be delivered to their target locations. One side of the Golgi stack serves as a receiving dock for transport vesicles produced by the ER. ○ For example, if the cell requires extra calcium ions, they might come from the smooth endoplasmic reticulum (ER) and be packaged in THE ENDOPLASMIC RETICULUM IS A vesicles for transport. BIOSYNTHETIC WORKSHOP ○ These vesicles, along with their contents, are delivered to the required locations, such as the  plasma membrane (not the cell wall, which is only found in plant cells). Calcium ions do not require nitrogen, but they play essential roles in signaling and other cellular processes. Interpretation From the plasma membrane it would be covered The food vacuole will be merging the lysosomes with digestive enzymes For digestion it can be released in the environment or to the blood stream (it can be distributed to the ketones (for the brain). Damaged vesicles (For example, mitochondria was teared due to lesion, lysosome would fuse and it will degrade mitochondria so that during the synthesis of LYSOSOMES another mitochondria meron silang materials to be used). A membrane-enclosed sac of digestive enzymes made by rough ER and proceeds in the golgi apparatus. VACUOLES Fuse with food vacuoles and digest food (when the Are large storage spaces. linings of intestine absorb the food, they are going to Some protists have a contractile vacuoles, which help digest and proceed to releasing it to the bloodstream to eliminate water from the protist. to cover all the movements). In plants vacuoles may Destroyed bacteria engulfed by white blood cells Have digestive functions Fuse with other vesicles containing damaged Contain pigments organelles or other materials to be recycled within a Contain poison that protects the plant. cell. (pag nasira ‘yong organelles, they are going to target ubiquitination. Therefore, it is going to be Different types of Vacuoles covered by a vesicle which will then fuse to another vesicle to recycle that form. All nutrients will be produced in the S-phase of mitosis).  1. Contractile vacuoles The polypeptide chain is found in ER, as it travels in ER, its going to be glycosylated to create glycoproteins for plotting and stacking ‘yong mga matured enough kapag dumating na sila sa golgi apparatus. The GA will identify the tag or the sugar, they are 2. Central Vacuole going to sort out and create vesicles containing specific polypeptides for proteins and bring it to wherever it is needed. This is only present in eukaryotes. NOTE Protists directly absorb materials from the environment, as they absorb materials hindi nawawala na mag-absorb sila ng moisture and if they continue on living like this, their body size will expand more because of water. If there is too much water, malaki rin ‘yong cytosol, the organelles found in the cytosol will have difficulty in interacting with other organelles since malaki na ‘yong space kung nasaan Interpretation sila suspended. Sometimes kapag sa labas siya need i-promote, some of the transport vesicles fuse with the plasma With contractile vacuole iipunin nila lahat ng membrane so that the materials/enzymes found moisture and they are going to expel it to maintain outside of the cell. the pressure and the proper size just enough for this the organelles and materials. ENDOMEMBRANE SYSTEM Interpretation From the nucleus magkakaroon tayo ng bmature RNA, going out in the nuclear pores The nuclear pores will then be translated by EUKARYOTIC CELLS ARE PARTITIONED INTO lysosomes if they are found in ER. They are going FUNCTIONAL COMPARTMENTS to be translated.  1. Mitochondria in all cells and chloroplasts in - Have increased surface area due to its stacking plants cells are involved in energy processing. structure called granum composed of individual 2. Structural support, movement, and thylakoid. communication between cells are functions of - Chloroplast is partitioned into compartments cytoskeleton, plasma membrane, and cell wall. - Inside the inner membrane is a thick fluid called stroma, and the network of interconnected sacs 3. Mitochondria and chloroplast have their own called thylakoids, where green chlorophyll sets of DNA which can be explained in molecules trap solar energy. endosymbiont theory. - In some regions, thylakoid is stacked like poker chips. Each stack is called granum. NOTE Photosystem 2 - collects the light, conical structures NOTE found in the cells , merong electron excitation Electron transport chain – photosystem 1 (dito magkakaroon ng ATP production) MITOCHONDRIA 1. Mitochondria are organelles that carry out cellular respiration in nearly all eukaryotic cells. It has bimembrane-bound organelle. Instead of having aflat surface, it has loops (cristae) have a lot of surface area due to its inner folded membrane that provides more space for energy production. 2. Cell respiration converts the chemical energy in food (sugar, carbohydrates) to chemical energy in ATP (adenosine triphosphate) ATP is more recognizable by the body for most of the functions. ATP is utilized by enzymes (e.g., Production of DNA, phosphorylation of nucleotide, and other In plants, chloroplast will form the carbohydrates, various catabolic and anabolic processes.) while mitochondria is responsible for P1 for the production of energy. Folds of the inner mitochondrial membrane, called From chloroplast we have a disc (which included cristae increase the membrane’s surface area, P2) cone-like structure. Chlorophyll is located enhancing the mitochondrion’s ability to produce under it, thus, the excitation will be converted into ATP. carbohydrates. Has its own extranuclear DNA The stock of discs are known as granum Granum CHLOROPLAST Has complex cells suspended in stroma Production of light energy to chemical energy in the form of carbohydrates. Stroma Photosynthesis is the energy conversion of the light Counterpart of matrix found in the organelle from the sun to the chemical energy of sugar molecules. Chloroplasts Chloroplasts are the photosynthesizing organelles of plants and algae.  Example: Muscle cells are fusiform; RBC is Are able to create carbohydrates (carbon source enucleated to have a larger surface area in connection by itself). Light energy – (chemical energy) carbohydrates with oxygen. Unlike humans, animals do not produce their The cytoskeleton includes: own carbohydrates. In which we consume 1. Microtubules – made of tubulin carbon sources that will be converted to our 2. Intermediate filaments – fibrous protein chemical energy to ATP. 3. Microfilaments – actin filaments This network of protein fibers provides the support and maintenance of the structure as ENDOSYMBIONT THEORY well as anchorage to other cells. The endosymbiont theory states that mitochondria and chloroplast were formerly small prokaryotes (archaea bacteria), and they began living within larger cells MICROTUBULES Shape and support for the cell. - Act as tracks along which organelles equipped with motor proteins move. - In animal cells, microtubules grow out from a region near the nucleus called the centrosome, which contains a pair of centrioles, each composed of a ring of microtubules. 25 nanometers in diameter. INTERMEDIATE FILAMENT Are found in the cells of most animals. Reinforce cell shape and anchor of some organelles NOTE and Communication is the signal transduction of one cell to Function in the retention of the cell shape as the cell another contracts. THE CELL’S INTERNAL SKELETON Are often more permanent fixtures in the cell - When IF was damaged it can’t be repaired by the new cells, instead they synthesize new cells. That Cells contains network of protein fibers, called the is why kapag nagkaka-sugat minsan nagiging cytoskeleton, which organize the structures and scar. activities of the cell 10nm in diameter. In Eukaryotes MICROFILAMENT - Specialized cells have fixed shape Supports the cell’s shape  - Motility – e.g. cilia and flagella; their arrangement helps in the movement of these fixtures. About 7nm in diameter (smallest and it is more mobile). CILIA AND FLAGELLA The short, numerous appendages that propel protists such as Paramecium are called cilia. Other protists may move using flagella, SUMMARY OF CELLULAR COMPONENTS which are longer than a cilia and usually limited to one or a few per cell. Both cilia and flagella are composed of microtubules wrapped in an extension of the plasma membrane. A ring of nine microtubules doublets surrounds a central pair of microtubules. - This arrangement is called the 9+2 pattern (9 pairs of microtubules and 2 central microtubules) - the central microtubule pair controls the outer ones surrounding it causing the flagella to move. Cross-linking proteins It can be cadherins depends from one cell to another. Dynein feet Cilia and flagella move by bending motor proteins called dynein feet. These feet attach to and exert a sliding force on an adjacent doublet This “walking” causes microtubules to bens. - Kada isang dynein feel na gumagalaw, 1 ATP is needed.