Cell Organelles | Biology PDF

12/09/2023 General Attributes of the Cell...

12/09/2023 General Attributes of the Cell 1. PLASMA phospholipid bilayer separating the cell from its environment The Cell MEMBRANE allows passage of oxygen, nutrients and wastes a semifluid substance where the organelles are suspended 2. CYTOSOL cytoplasm – region between the plasma membrane & nucleus CHROMOSOMES contain the genetic material in the form of 3. DNA DNA tiny organelles that make proteins using the instructions 4. RIBOSOMES contained in genes Reference: Urry LA et al. 2017. Essential Biology 11th Edition. New York, NY: Pearson Education, Inc. USA. Urry et al. 2017. Essential Biology 11th Edition 1 2 Prokaryotic vs. Eukaryotic Cells ANIMAL CELL PROKARYOTES EUKARYOTES Bacteria, Archaea Protists, Fungi, Plant, Animals Nucleoid, no membrane- Nucleus bound by a bound nucleus membrane Circular strand of DNA DNA in several linear Few organelles chromosomes Many specialized membrane- bound organelles Urry et al. 2017. Essential Biology 11th Edition Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings 3 4  12/09/2023 PLANT CELL NUCLEUS : Information Central contains the eukaryotic cell’s genetic library Separated from cytoplasm by a double membrane nuclear pore allows large macromolecules & particles to pass through Some genes are contained in MITOCHONDRIA and CHLOROPLASTS Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings 5 6 NUCLEAR LAMINA network of intermediate filaments maintain the shape of the nucleus mechanically support of the nuclear membrane DNA + HISTONES = CHROMATIN (appear as diffused mass) when cell prepares to divide, chromatin fibers coil up, seen as separate structures (CHROMOSOMES) NUCLEOLUS Site of ribosomal RNA (rRNA) synthesis rRNA combines with proteins in the cytoplasm to form ribosomal subunits Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings 7 8  12/09/2023 RIBOSOMES : Protein Factories THE ENDOMEMBRANE SYSTEM build a cell’s proteins (Translation) Many of the internal membranes in a eukaryotic cell are part of this system Direct contact or rRNA + proteins Connected via transfer of vesicles, sacs of membrane Site of protein synthesis Cell types that synthesize large quantities of proteins (e.g., Nuclear envelope Endoplasmic reticulum Golgi apparatus pancreas) have large numbers of ribosomes and prominent nucleoli Plasma Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Lysosomes Vacuoles/Vesicles membrane FREE ribosomes BOUND ribosomes Suspended in cytosol Attached to RER, Nuclear envelope Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Synthesize proteins that Plays a key role in the synthesis (& hydrolysis) of function in the cytosol Synthesize proteins included in macromolecules in the cell the membrane/for export from the cell Various components modify macromolecules for their various functions 9 10 ENDOPLASMIC RETICULUM : Biosynthetic Factory 2 ER regions manufactures membranes & performs many other biosynthetic functions Rough ER Smooth ER membranous TUBULES & With ribosomes No ribosomes fluid-filled sacs CISTERNAE Abundant in cells that Synthesis of lipids, oil, secrete proteins phospholipids & steroids Secretory proteins are Metabolism of carbohydrates ER membrane is continuous packaged into TRANSPORT Catalyzes key step in with the nuclear envelope VESICLES that carry them into mobilization of glucose from the next stage stored glycogen in the liver Synthesis of membrane Stores calcium ions esp in Cisternal lumen is continuous bound proteins muscle cells with the space between 2 Enzymes in RER synthesize membranes of nuclear Other enzymes in SER of the phospholipids from liver help detoxify drugs, envelope precursors in the cytosol poisons, alcohol Urry et al 2017. Essential Biology 11th Edition 11 12  12/09/2023 GOLGI APPARATUS : Shipping & Receiving Center finishes, sorts, & ships cell products Transport vesicles from ER travel to Golgi apparatus for modification Abundant in cells specialized for secretion of glycoproteins Flattened membranous sacs – CISTERNAE CIS SIDE – receives by fusing with vesicles TRANS SIDE – buds off vesicles Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Manufactures polysaccharides such as pectin 13 14 LYSOSOMES – Digestive Compartments Lysosomes can fuse with Membranous sac of hydrolytic food vacuoles, formed when a enzymes food item is brought into cell by phagocytosis Digests macromolecules other organelles or parts of the (proteins, fats, polysaccharides, cytosol & nucleic acids) Recycling process of autophagy renews the cell Enzymes work best at pH 5 Massive leakage from lysosomes can destroy an entire cell by Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings autodigestion Lysosomal enzymes & membrane are synthesized through RER then to Golgi Creates a space where the cell can digest macromolecules safely Arise from budding from Golgi Lysosome digesting food Lysosome breaking down damaged organelles Urry et al 2017. Essential Biology 11th Edition 15 16  12/09/2023 Tonoplast - membrane surrounding the central vacuole VACUOLES : Diverse Maintenance Compartments selective in its transport of solutes into the central vacuole contains glycolipids (instead of phospholipids) VESICLES & VACUOLES – membrane bound sacs with varied functions Functions of the central vacuole Stockpiling proteins or inorganic ions (K, Cl) Depositing metabolic by products Food From phagocytosis, fuse Storing pigments vacuoles with lysosomes http://www.cellimagelibrary.org/i Storing defensive compounds against herbivores mages/40986 Contractile In freshwater protists, pump vacuoles excess water out of the cell Major role in growth of plant cells: Cells enlarge as their vacuoles Central Found in many mature plant absorb water, with minimal vacuoles cells investment in new cytoplasm Urry et al 2017. Essential Biology 11th Edition Urry et al 2017. Essential Biology 11th Edition 17 18 Review organelle relationships Other Membranous Organelles Vesicle, Vacuole Lysosome Urry et al 2017. Essential Biology 11th Edition 19 20  12/09/2023 MITOCHONDRIA & CHLOROPASTS: Main Energy Transformers of Cells Convert energy to forms that cells can use for work Not part of the endomembrane system Mitochondria Chloroplast Proteins come from free ribosomes in the cytosol & a few from their own ribosomes Site of cellular In plants & eukaryotic respiration algae Have small quantities of DNA that direct synthesis Generates ATP from Site of photosynthesis of the polypeptides in these internal ribosomes catabolism of sugars, Convert solar energy to fats & other fuels in the Grow and reproduce as autonomous organelles chemical energy & presence of oxygen synthesize new organic compounds from CO2 & H 20 21 22 MITOCHONDRIA : Chemical Energy Conversion CHLOROPLAST : Capture of smooth outer membrane & highly folded inner membrane Light Energy – CRISTAE fluid filled space (intermembrane space) in between outer & inner One of the several members of a membrane generalized class of plant structures Cristae present ample surface area for enzymes that synthesize ATP called PLASTIDS AMYLOPLASTS – store starch Inner membrane encloses the mitochondrial matrix, a fluid CHROMOPLASTS – store filled space with DNA, ribosomes & enzymes pigments such as carotene Produces sugar via photosynthesis Found in leaves & other green structures Reproduce themselves by pinching into 2 Mitochondria and Chloroplasts are mobile & move around the cell along tracks in the cytoskeleton Urry et al 2017. Essential Biology 11th Edition Urry et al 2017. Essential Biology 11th Edition 23 24  12/09/2023 Process in chloroplast are separated from cytosol PEROXISOMES : Oxidation by 2 membranes generate & degrade hydrogen Inside the innermost membrane is a fluid-filled peroxide in performing various space, the stroma, in which float membranous metabolic functions sacs, the thylakoids Bound by a single membrane Stroma – contains DNA, ribosomes, enzymes Thylakoids – flattened sacs, stacked into grana, and are Formed by incorporation of proteins and lipids in the cytosol critical for converting light to chemical energy Splits into 2 upon reaching a certain size Contain enzymes that transfer H from various substrates to O2 (oxidation reactions) Thylakoid (flattened sac) Intermediate product is H2O2 but converted into H20 by catalase Grana (stack of thylakoids) Some break fatty acids to smaller molecules that are transported to mitochondria for fuel Stroma (fluid filled space) Some detoxify alcohol and other harmful compounds Urry et al 2017. Essential Biology 11th Edition Urry et al 2017. Essential Biology 11th Edition 25 26 The Cytoskeleton Roles of the Cytoskeleton: Network of fibers that organizes structures and activities in the cell MECHANICAL SUPPORT & cell shape MAINTENANCE ANCHORAGE for organelles & cytosolic enzymes DYNAMIC, dismantling in one part & Intermediate reassembling in another to change cell shape Microtubules Microfilaments Filaments 27 28  12/09/2023 Cytoskeleton : Role in Cell Motility MICROTUBULES Cilia & flagella, motor proteins pull components of cytoskeleton past each other alpha & beta tubulin dimers Interactions of motor proteins and the cytoskeleton circulates move chromosomes during cell division materials within a cell via streaming. grow out from a centrosome near the nucleus Also in muscle cells In animal cells, the centrosome has a pair of centrioles, each with nine triplets of microtubules arranged in a ring During cell division the centrioles replicate Urry et al 2017. Essential Biology 11th Edition Urry et al 2017. Essential Biology 11th Edition 29 30 MICROTUBULES MICROFILAMENTS central structural support in cilia & flagella thinnest among the 3 same ultrastructure - a core of microtubules sheathed by the plasma membrane solid rods of the globular protein actin 9 doublets of microtubules arranged around 1 pair at the center (9 + 2 pattern) resist tension form a 3D network with other proteins just inside the plasma membrane to support cell shape FLAGELLA – just one or few flagella in cell The shape of the microvilli in this CILIA – occur in large intestinal cell are supported by microfilaments, anchored to a network of numbers intermediate filaments. Urry et al 2017. Essential Biology 11th Edition Urry et al 2017. Essential Biology 11th Edition 31 32  12/09/2023 MICROFILAMENTS INTERMEDIATE FILAMENTS Keratin Motility Found only in the cells of in muscle cells some animals in amoeba – pseudopodia For bearing tension More permanent fixture of Cell division the cytoskeleton in animals – cleavage furrow Reinforce cell shape and fix organelle location Cytoplasmic streaming Plants Distribution of materials Urry et al 2017. Essential Biology 11th Edition 33 34 Cell Surfaces & Junctions extracellular components & connections between cells help coordinate cellular activities Urry et al 2017. Essential Biology 11th Edition 35 36  12/09/2023 CELL WALL – found in prokaryotes, fungi, Extracellular matrix (ECM) - animal cells some protists & plants functions in support, adhesion, movement, Protection, maintain shape, & and regulation prevent excessive uptake of H2O Thickness & chemical glycoproteins (collagen fibers) embedded in a network of composition differ from species proteoglycans to species & among cell types In many cells, fibronectins in Basic design – microfibrils of ECM connect to integrins, intrinsic membrane proteins cellulose embedded in a matrix of proteins & other Integrins connect ECM to the cytoskeleton polysaccharides Interconnections from ECM to Mature cell wall – Primary cell the cytoskeleton via the wall (cellulose), middle lamella fibronectin-integrin link with sticky polysaccharides permit the interaction of changes inside & outside the (pectin) that holds cell together, cell & layers of secondary wall Urry et al 2017. Essential Biology 11th Edition 37 38 INTRACELLULAR JUNCTIONS - help integrate Animals - 3 types of intercellular links cells into higher levels of structure & function TIGHT JUNCTIONS Fuse adjacent cells Neighboring cells in tissues adhere, interact, & prevents leakage of extracellular fluid communicate through direct physical contact DESMOSOMES Plant cells are perforated with PLASMODESMATA, channels (anchoring junctions) fasten cells allowing cytosol to pass between cells together into strong sheets Intermediate filaments reinforce desmosomes GAP JUNCTIONS – (or communicating junctions) provide cytoplasmic channels between adjacent cells Salt ions, sugar, amino acids, and other small molecules can pass In embryos, gap junctions facilitate chemical communication during development Urry et al 2017. Essential Biology 11th Edition Urry et al 2017. Essential Biology 11th Edition 39 40  12/09/2023 PLANT CRYSTALS - waste or excretory 2. Calcium oxalate products of the protoplasts Raphide encased in 1. Calcium carbonate carbohydrate Raphide Styloid Cystolith Lithocyst – cell containing cystolith Worm-like cystolith Prismatic Druse 41 42