Biology: Cell Structure, Function, PDF

Okay, here's the conversion of the image/document into a structured markdown format: # Le Cellule * Contain water and biomolecules necessary for survival, approximately 10,000 types of diverse molecules. * Can be minuscule or large: the diameter can vary between 1-100 nm. * The volume determ...

Okay, here's the conversion of the image/document into a structured markdown format: # Le Cellule * Contain water and biomolecules necessary for survival, approximately 10,000 types of diverse molecules. * Can be minuscule or large: the diameter can vary between 1-100 nm. * The volume determines the level of functionality of a cell (the larger, the more activity it performs), while the surface determines the quantity of substances it can exchange with the exterior. * The relationship between surface area and volume is adequate but non-linear; in effect, if the volume increases, the surface area does not increase at the same ratio (small cells are more efficient because they have more surface area). The basic structure of the cellular membrane is called the **FLUID MOSAIC MODEL**, formed by a double layer of phospholipids into which several proteins are immersed. **Phospholipids:** * **Hydrophilic Region:** bound to polar molecules by water. * **Hydrophobic Region:** made of nonpolar tails interact with other nonpolar, are insolube in water and do not bind hydrofilic substances. In an aqueous environment, they arrange themselves in a double layer with the hydrophobic tails inside and the hydrophilic heads outside in contact of the water. **Two Types of Membrane Proteins:** * **INTEGRAL:** Immersed in the double layer of phospholipids, with both hydrophobic and hydrophilic parts. * **PERIPHERAL:** Located on one side of the membrane, with neutral polar portions that interact with other polar molecules. Carbohydrates are present on the outer surface for cell identification and adhesion: * Glycolipids * Glycoproteins Lipids confer stability and fluidity. The membranes can have different compositions even within the same cell because if they come into contact with a specific organelle, they undergo chemical modifications. ## Cellula Procariote * Archaea and Bacteria **Possesses:** * A plasma membrane that encloses the cytoplasm (cytosol + insoluble particles), where, in a precise area, there is the nucleoid where DNA is found, and ribosomes where protein synthesis occurs. Some prokaryotes have **SPECIALIZED STRUCTURES** (developed during evolution): * **Cell Wall:** support and shape of the cell * **Capsule:** preserves the cell and protects bacteria from attacks by the immune system. * **Internal Membranes:** cyanobacteria, to contain. * **Chloroplasts:** Plastids are the site of photosynthesis, of various shapes and sizes, 2 external membranes, a molecule of circular DNA, internal membranes called grana formed by thylakoids, which contain chlorophyll, are suspended in a liquid called stroma (DNA and ribosomes). * **Cytoskeleton:** (protein filaments) cellular division of maintenance of 3D structure of the cell * **Flagella:** movement of the cell * **Pili:** adhesion of bacteria to each other or to animal cells. ## Cellula Eucariote * Fungi, animals, plants, protists **Possesses:** * Plasma membrane and cytoplasm * Nucleus where the DNA replicates, enclosed by the nuclear envelop, a double membrane separated by 10-20 nm, has about 3500 pore which alow molecules (ions and some proteins with short amino acid sequence to label them), Contains several molecules of DNA joined to proteins forming chromatin (-> chromosomes) and the nucleolus (assembly of ribosomes). * Ribosomes contain rRNA(ribosomal rna), are assemblied in the nucleus and then exit to synthesize the proteins based on the information of the dna (translation) thanks to the mRNA (RNA messanger) * Organelles: internal compartments delimited by the membranes, contain enzymes (biological catalyst) Different types of organelles: * Golgi apparatus : elaborate the proteins * Vacuole: water reserve * Mitocondria: Energetic station * Cytoskeleton: moves and sustains * Endoplasmic reticulum: Protein Synthesis * Smooth Endoplamic Reticulum : Lipids Synthesis | | | | ----------- | ----------- | | ANIMALS | VEGETABLE | | centrioli: cellular division | Cell Walls | | Lysosmes: substance degradation | Chloroplasts | * **Mitochondria:** Cellular respiration occurs here, a process that uses oxygen to completely break down nutrients and produce ATP (adenosine triphosphate), the main source of cellular energy. It is made up of adenine, ribose, and three phosphate groups, and its hydrolysis releases energy usable for cellular reactions. They have two membranes: the outer one is smooth and protective, the inner one is folded into cristae, regulating the passage of substances. The mitochondrial matrix houses enzymes, DNA (information to produce proteins necessary for respiration and diverse RNAs) and ribosomes. Inherited from the mother. * **Membrane Interne:** Reticolo Endoplasmatico Set of connected internal membranes, internal space called the lumen. * **Rough (RER):** Regions with ribosomes on the outer wall, which synthesize and chemically modify the proteins that must exit the cell (secretion proteins). * **Smooth (REL):** More tubular structure and activities due to enzymes inside the membrane: synthesizes lipids, degrades toxic substances, drugs and pesticides, hydrolyzes glycogen and accumulates calcium ions (Ca2+). * **Golgi Apparatus:** From Camillo Golgi, receives and modifies the proteins of the RER, labels them, and sorts them based on their destination, and synthesizes polysaccharides for plant cells. The cisternae have three zones: entrance (near the nucleus and the RER) where vesicles containing proteins enter, which proceed inside transport vesicles in the intermediate area up to the exit where they are packaged to be expelled or integrated into the membrane (also of other organelles). * **Lisosmi:** Vesicles of about 1 μm with and single membrane enzymes fromd by the ER in Golgi's apparatus where nutrive and estranes body degrade from the cell in fagocitosi Cell englobing cells forming Vacuole that forms the secondari where is the digestion, primary substrate is spreaded and the extraneus are expulled. The compartment isolats the ezimes of the cytoplasm * **Perossimosi:** Little cellular Organels with enzimes tha degrade toriscs perodsits. * **Vacuoli:** compartimenti cellulari pieni di soluzioni acquose, circondati da membrana Nella cellula vegetali immagazzinano sostanze di scarto, regolano la pressione interna per dare sostegno alla cellula,contengono pigmenti per attirare impollinatori e rilasciano enzimi per digerire le riserve nutritive (accumulo,sostegno,riproduzione,digestione) * **Citoscheletro:** Compartments cellular with solutions aqueous, sorround by membrana Three type of fribres | | | | | ----------- | ----------- | ----------- | | Microfilamentis | Filamenti Intermedi | Microtobuls | | Palimorees Proreim | Fibrose Proteins | Moleculs of Proteins | | Actina mantain the cells form, they form move and determins contracture. | Orgànizée robuste cordas strutture Stabilizing the cellule for and aiting a teners unite 2 cells vince | Tubalins the terminating lingths forminigs interno rigs that the | | | |Motrice Proreion and cells | * **Ciglia e Flagelli:** Apperndix tha make the cellule costistuitée made in Microtubules cilgila made in gran number flagelli are solo in. Cuoia * **Desmosomi:** Made in proteis unishing membrane to one cells tha perimeters permettono il passaggio di sostanze attraverso lo spazio intercellulare e garantiscono grande resistenza. Interno é una Struttura chiatama pacche, con ligando e proteina ### Adhesion to the Extracellular and Cell Structure That's a reunion of cell in Tessuti, avvienes through il riconosciment cellulare cell that connect so quelle dello steso tipo of adeisione that celle che rinforza le connesioni tra di esse. And is based on the memranes proteing and lead at the creation with the Union chiamates Giunzione cellular | | | | | ----------- | ----------- | ----------- | | Giuntione Occludenti | | | | League than proreins specificella | | Giuntioni Communicanti | | Membrana Plasmatica Sigilindo | | Canali Proteici tha Atravesano | | Spazi Tra le cellule impendeondo ao | | Le Membrane Plasmatiche de 2 | | Aleun sostanze oi penetrare the cellulae L altrs e delimitano le parti Bella Members, a tha hano | |Cellulae Ricin Consento no of | | Funzione Oiverse. | | Comunicación e is veloce spostamento and iomi micromolecole ca un la cellula altra. | * **Parete Cellulate:** Struttura Semi rigida di fibre di cellulosa, a immersioni in Protein e police cardid complessa * **Matrix Extracellalure:** Proteic collagene matrice di glicoproteine + proteogli canni (catene Gelatinose) proteic ta tiene ilsiame circonda a il cellule filtea a i Material tra Tessuto