Biology Chapter 6 Notes
Biology Chapter 6 Notes BIOLOGY 108 - 0001
Popular in General Biology I
Popular in Biology
This 11 page Class Notes was uploaded by Koral Shah on Friday September 4, 2015. The Class Notes belongs to BIOLOGY 108 - 0001 at University of Missouri - Kansas City taught by Marilyn Yoder in Fall 2015. Since its upload, it has received 139 views. For similar materials see General Biology I in Biology at University of Missouri - Kansas City.
Reviews for Biology Chapter 6 Notes
Woah...are you an angel? Please tell me you're going to be posting these awesome notes all semester...
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 09/04/15
AP Biology 20122013 Unit 3 Chapter 6 A Tour of the Cell 61 Study of Cells Cytology study of cell structure Organelles membraneenclosed structures within eukaryotic cells Light Microscope shines visible light through specimen cannot view organelles Electron Microscope used to view organelles focuses beam of electrons through specimen Scanning Electron Microscope detailed study of topography of a specimen gives 3D image Transmission Electron Microscope internal structural study of cells Cell Fractionation cytology method taking cells apart separating major organelles from one another accomplished using a centrifuge 62 Membrane Function All Cells Pro and Eu Have Cytosol jellylike substances suspending organelles within a cell Chromosomes carry genes in form of DNA Ribsomes synthesize proteins Eukaryotic vs Prokaryotic Eukaryotic DNA in the double membrane bounded nucleus Prokaryotic DNA concentrated in nomembrane nucleoid much smaller Cytoplasm region between nucleus and plasma membrane Eukaryotic Cell Organelles Endoplasmic Reticulum ER network of membranous sacs contribute to membrane synthesis has rough and smooth regions Nucleus Nuclear Envelope double membrane enclosing nucleus Nucleolus production of ribosomes a nucleus may have more than one of these Chromatin consists of DNA and proteins dividing cell as individual chromasomes Plasma Membrane selective barrier allowing passage for oxygen nutrients and waste cell bouncer Ribosomes make proteins free in cytosol or bound to rough ER or nuclear envelope Golgi Apparatus synthesis modification sorting and secretion of cell products Lysosome digestive organelle not present in plants Mitochondrion where cellular respiration occurs and ATP is generated Peroxisome produces hydrogen peroxide then converts it to water Microvilli increase cell39s surface area Cytoskeleton functions in cell movement Plant Cell Organelles ones not present in animal cells Central Vacuole enlargement of this induces plant growth functions are storage breakdown of waste etc Chloroplast converts energy of sunlight to chemical energy Plasmodesmata channels through cell walls connect With adjacent cells Cell Wall outer layer that maintains cell shape made of cellulose polysaccharides and protein Smooth Rough endoplasmic W W Mn 39 Nucleus Flagellum Not in most plant cells M Centriole 39 Ribosomes Peroxisome l r r V 39 139 3 r u h f u apparatus Microtubule 1 v w Plasma membrane Cytoskeleton Intermediate lament Microfilament quot Mitochondrion Copyngnl 2003 Pearson Education Inc publishing as Beniamin Cummings 63 The Nucleus Nucleus contains most genes in eukaryotic cells Nuclear Envelope double membrane enclosing the nucleus Pore Complex regulates exit and entry of proteins and RNAs Nuclear Lamina lines nuclear side of envelope maintains shape and supports the nucleus aided by nuclear matrix Chromosomes condensed structures of genes containing one DNA molecule and associated proteins Chromatin complex of DNA and proteins making up chromosomes When cell is not dividing chromosomes are uncoiled messes When cell prepares to divide chromosomes coil up into condensed structures human cells have 46 chromosomes 23 in sex cells Nucleolus Where ribosomal RNA rRNA is synthesized proteins and rRNA are assembled into subunits of ribosomes Which Will leave the nucleus and assemble into ribosomes Ribosomes carry out protein synthesis Free Ribosomes suspended freely in cystosol synthesizes proteins that function in cytosol Bound Ribosomes connected to rough ER or nuclear envelope synthesize proteins to be inserted into membranes to be packaged for other organelles or export from the cell Nuclear Envelope Anatomy of the Nucleus Endoplasmic 39 39 Reticulum 39 Figure 1 Ribosomes 64 Endomembrane System Endomembrane System nuclear envelope endoplasmic reticulum Golgi lysosomes vesicles and plasma membrane all either physically continuous or by transfer of membrane segmentsvesicles Endoplasmic Reticulum ER network of membranes Smooth ER No Ribosomes synthesizes lipids metabolizes carbs detoxifies poisons and stores calcium Rough ER Has Ribosomes Glycoproteins proteins with carbs covalently bonded to them embedded in ER most secretory proteins transport vesicles will take these proteins from ER to transitional ER grows cell membrane by adding proteins and phospholipids to its own membrane Golgi Apparatus receives sorts and ships products of the ER manufactures some macromolecules consist of stacks of cisternae looks like stacked pita bread Cis Face side of the Golgi located near the ER vesicles can bind to it to add membrane so basicallyproducts are received here Trans Face side of the Golgi located away from the ER gives rise to vesicles that will separate and travel elsewhere in the cell so basicallyproducts are shipped from here products of ER are modified in transit from cis to trans faces The Process ER constructs proteins and phospholipids modified in the ER with polysaccharide chain vesicle brings it to the Golgi hydrolysis of polysaccharide occurs new ends of polysaccharides are constructed dictating the protein39s function Vesicle brings it to build on to cell membrane glycoproteins and glycolipids Vesicle becomes part of the membrane Membrane grows Ta da Lysosome sac of enzymes used by animal cells for digestion acidic environment around pH5 Phagocytosis eating process of protists by engulfing their food human white blood cells do this engulf and kill bacteria Digestion Products simple sugars amino acids other monomers Autophagy lysosome recycles cell39s organic material Vacuoles large vesicles derived from ER and Golgi Contractile Vacuoles pump excess water out of the cell found in freshwater protists Vacuoles in plants can store poisons to fend off carnivores can hold reserves of important organic materials can hold pigment to attract pollinating insects giving owers their color Central Vacuole contains cell sap plant39s main repository of inorganic ions potassium and chloride enlarges as it absorbs water allowing plant to grow Endomembrane System Summed Up Membrane moves from the ER to the Golgi then elsewhere Along the way its compositon and functions are modified Produces vesicles that allow for transport in and out of organelles and the cell itself 65 Mitochondria and Chloroplasts Endosymbiont Theory a eukaryotic cell engulfed a nonphotosynthetic prokaryotic cell becoming endosymbiont cell living within a cell this turned into a eukaryotic cell with a mitochondrion or chloroplast Characteristics of Mitochondria and Chloroplasts convert energy to forms cells can use for work two membranes surround them contain ribosomes and DNA within the organelle directs synthesis of proteins made by the innerorganelle ribosomes independent organelles grow and reproduce within the cell Mitochondria site of cellular respiration which uses oxygen to generate ATP using energy from sugars fats and other fuels found in all eukaryotes Double Membrane outer is smooth inner has infoldings Cristae inner membrane dividing the mitochondrion into two compartments gives membrane a large surface area enhancing productivity First Compartment intermembrane space Mitochondrial Matrix in the second compartment containing enzymes mitochondrial DNA and ribosomes enzymes within catalyze steps of cellular respiration Mitochondria Structural Features Figure 1 Chloroplast site of photosynthesis convert solar energy to chemical energy synthesizes sugars from C02 and water contains green pigment found in leaves of plants Thylakoids membranous sacs in addition to the double membrane arranged in stacks Granum each stack of thylakoids Stroma uid outside the thylakoids containing chloroplast DNA ribosomes and enzymes Three Compartments of Chloroplast intermembrane space stroma and thylakoid space Changeable shape grow reproduce and move around the cell Plastids family of closely related plant organelles Examples amyloplast stores starch or chromoplast giving fruits and owers color Plant Cell Chloroplast Structure Figure1 Granum Stack of Thylakolds Peroxisome removes hydrogen from substrates and transfers them to oxygen producing hydrogen peroxide toxic as a byproduct then converts that to water Functions breaks down fatty acids detoxifies alcohol Cooperates with chloroplasts and mitochondrion in metabolic functions 66 The Cytoskeleton Cytoskeleton networks of fibers extending through the cytoplasm Composed of microtubules microfilaments and intermediate filaments Function gives cell mechanical support to maintain shape interacts with motor proteins for cell movement Microtubules maintains cell shape thickest organelle and chromosome movement tracks motor protein can move on cell motility make up cillia and agella Centrosome region near nucleus from which microtubules grow organizes them Centrioles in a centrosome composed of sets of microtubules arranged in a ring Centriole Structure 2 Centriole Pair y g r 7 Microtubule Trlplet Figure1 Microfilaments maintains and changes cell shape thinnest contributes to muscle contraction cytoplasmic streaming acts like feet to move vesicles cell motility through pseudophodia cell division cleavage furrow formation Actin globular protein building blocks for microfilaments two twisted chains of actin Parallel to length of myosin muscle protein acts as motor and walks on microfilaments Actinmyosin groups responsible for contractions of cells muscle contractions Pseudophodia movement through cellular extension assembly of actin subunits Cytoplasmic Streaming circular ow of cytoplasm within cells brough about by actin myosin interactions Microfilament Structure and Assembly Filamentous Actln Globular Actin FActin 9 Q GActln polymerizemunMlmmamem 39 0 d Mame Other proteins bond to the actin chains branching off and creating a network Cortex a gellike outer cytoplasmic layer of the cell caused by the protein network Intermediate Filaments maintains cell shape and anchors important organelles forms nuclear lamina More permanent structures than other filaments Constructed of fibrous proteins coiled into thicker cables Cilia and Flagella microtubulecontaining extensions act as a movement mechanism Basal Body similar to a centriole anchors cilia and agella Dyneins large motor proteins responsible for bending movements of an organelle 67 Extracellular Components Cell Wall only in plant cells protects the cell maintains its shape and prevents excessive uptake of water much thicker than plasma membrane constructed of cellulose and bounded in a matrix of other polysaccharides and proteins deposited with the guidance of microtubules Primary Cell Wall exible wall secreted by a young plant cell Middle Lamella between primary walls of adjacent cells a thin layer of sticky polysaccharides called pectin used to thicken jam glues adjacent cells together Secondary Cell Wall added between plasma membrane and primary wall when plant stops growing Extracellular Matrix ECM in animals constructed of gylycoproteins secreted by cells Collagen most common glycoprotein in ECM glycoprotein covalently bonded carb Protoglycans small core protein with many carb chains attached embeds collagen in its network of chains Integrins receptor protein built into plasma membrane transmits signals between ECM and cytoskeleton Extracellular Matrix Basics network that signals to each other when changes occur in order to integrate these changes into necessary cell functions and coordinate those functions with other cells Plant Cell Junctions Plasmodesmata membranelined channels filled with cytoplasm that perforate the cell wall responsible for joining adjacent plant cells Animal Cell Junctions Tight Junctions plasma membranes of adjacent cells press tightly together bounded by proteins prevent leakage of extracellular uid ex tight junctions in skin cells prevent humans from leaking Desmosomes fastens cells together into strong sheets anchored by intermediate filaments attach muscle cells to each other Gap Junctions provide cystoplasmic channels from one cell to another through pores allows for communication between cells Specialized cell junctions Chapter 7 Membrane Structure and Function 71 Cellular Membranes Selective Permeability controls what can be transported in and out of the cell cell bouncer Basic Structure Phospholipids hydrophobic tails and hydrophilic heads make a bilayer Proteins hydrophobic and hydrophilic Rgroups Amphiapathic both polar and nonpolar regions water dictates positioning Fluid Mosaic Model uid nonrigid structure with various proteins embedded in or attached to the bilayer Fluidity phospholipids can move laterally more common or ip op sides of the bilayer less common held together by hydrophobic interactions much weaker than covalent bonds membrane remains uid until temperature is so low it solidifies plants can change from unsaturated fatty acid tails to saturated fatty acid tails depending on environment Unsaturated better for cold weather will still be liquid and allow for transport through organism as a a H quotr H 0 3 1 9 3 J i ii v l l i r a L it i quot7 39 1 i u 39ul u Saturated better for warm weather unsaturated would be too uid and could not support protein function l W 9 l i l i E i g 3 Elli 11 All Eli T i i i l Human Membranes Saturated regulated by cholesterol Cholesterol uidity buffer regulates uidity of membrane through environment changes Practice Question Would a cell need to increase or decrease its cholesterol level when temperature rises Answer Increase What about when temperature falls Answer Still Increase cholesterol is a regulator Protein Component Transport proteins allow very polar substances too polar to venture through the bilayer in and out of the cell Integral Proteins within the hydrophobic inner region of the phospholipid bilayer Peripheral Proteins sit outside membrane to communicate with other proteins Transmembrane Protein integral and spans the entire double bilayer some integral membranes are transmembrane but not all Protein Types Transport Proteins provides a hydrophilic channel across the membrane or shuttles a substance from one side to the other by changing shape Enzymatic Activity enzyme with an active site exposed to substances in adjacent solution Signal Transduction binding site that fits a chemical messenger example hormones CellCell Recognition quotidentification tagsquot recognized by membrane proteins of other cells shortlived bond cells recognize other cells by binding to carbohydrate molecules Glycolipids short carbohydrate chains bonded to lipids in the membrane Glycoproteins short carbohydrate chains bonded to proteins in the membrane Example Blood Types vary due to variation in carbohydrates in red blood cell membrane Intercellular Joining membrane proteins of adjacent cells hook together longlasting bond Attachments to the Cytoskeleton and Extracellular Matrix anchors membrane proteins and maintains cell shape Membrane Synthesis 1 Membrane proteins and lipids are synthesized in ER 2 Carbohydrates are added making them glycoproteins 3 Transported to the Golgi Apparatus 4 Glycoproteins undergo carb modification and carbs are added to lipids making glycolipids 5 Vesicles take them to the plasma membrane 6 Vesicles fuse with plasma membrane vesicle becoming part of the membrane 7 Exocytosis occurs secreting proteins from the cell and positions carbs on membrane 72 Membrane Selective Permeability GateKeeping System hydrophobic inner region of phospholipid bilayer makes polar molecules extremely slow to enter and exit the cell ex glucose or water Transport Proteins allow transport of hydrophilic substances inout of the cell Channel Proteins hydrophilic channel allowing certain molecules inout Aquaporins channels that allow passage of water Carrier Proteins shuttle passengers and change shape to bring them across the membrane vastly speeds up passage of molecules such as glucose Transport proteins are specific to the substance it transfers a glucose transporter will ONLY transport glucose 73 Passive Transport Diffusion movement of molecules so they spread evenly into all available space Concentration Gradient any substance will diffuse from where it is more concentrated to where it is less concentrated reaching an equilibrium Diffusion is spontaneous requiring no work Cell membrane traffic is caused by diffusion higher concentration on one side of the cell it39ll diffuse to the other side Passive Transport transport that does not requiring expending any energy concentration gradient represents potential energy driving diffusion Osmosis diffusion of free water molecules across selectively permeable membrane if there39s a higher concentration of something in water on one side than the other water will diffuse to the side of higher concentration until the concentrations of the substance are equal Tonicity ability of a surrounding solution to cause a cell to gainlose water Isotonic no net movement of water across plasma membrane Hypertonic higher concentration of nonpenetrating solutes in a solution a cell in a hypertonic environment will lose water shrivel and die in an effort to equal out concentrations of the solute Hypotonic lower concentration of nonpenetrating solutes in a solution a cell in a hypotonic environment will swell with water and burst Osmoregulation control of solute concentrations and water balance cells with cell walls such as plantscan tolerate being immersed in hypotonic environment plant cells still cannot tolerate hypertonic environment Turgid very firm state of a plant cell when it is saturated to capacity with rainwater Flaccid if plants are not immersed in isotonic uid plant cells go limp Plasmolysis a plant in a hypertonic environment will shrivel and membrane will pull away from the cell wallleads to plant death Facilitated Diffusion passage of polar molecules with the help of transport proteins Ion Channels transport proteins that transport ions gated channels can open or close in response to stimulus Animal Cell States In A Hypo Environment Lysed Bursts In An Iso Environment Normal In A Hyper Environment Shrivels Plant Cell States In A Hypo Environment Turgid Pressure ideal In An Iso Environment Flaccid In A Hyper Environment Plasmolysis 74 Active Transport Active Transport membrane traffic requiring work fueled by ATP pumping a solute across the membrane against its concentration gradient low to high concentration All carrier proteins not channel proteins Energy supplied by ATP transports terminal phosphate group directly to transport protein Cell Voltage Cytoplasmic side is negatively charged cations are favored to enter the cell Extracellular side is positively charged anions are favored to exit the cell Membrane Potential voltage across a membrane acts like a battery Electrochemical Gradient two driving forces of diffusion of ions chemical and electrical Electrogenic Pump transport protein that generates voltage across a membrane can store that voltage and be used for cellular work SodiumPotassium Pump exchanges Na for K the major electrogenic pump in animal cells Proton Pump actively transports protons out of plant cells major electrogenic pump in plants Cotransport a single ATP powered pump transports a specific solute this pumping across the membrane does work which drives cotransport Analogy water pumped uphill performs work as it ows downhill 75 Bulk Transport Exocytosis secretion of molecules by fusion of vesicles with plasma membrane vesicle binds to membrane dumps its contents out of the cell and becomes part of the membrane used in the export of products Exocytosis causes cell to increase in size example pancreas secretes insulin to extracellular uid Endocytosis cell takes in substances by forming new vesicles from plasma membrane basically the reverse of exocytosis gt Endocytosis causes cell to decrease in size Phagocytosis cell engulfs a particle in order to consume it packaged in a food vacuole Pinocytosis cell quotgulpsquot drops of extracellular uid into vesicles molecules dissolved in uid are needed by the cell ReceptorMediated Endocytosis enables cell to acquire substances in bulk receptor proteins are brought into coated pits of cell contents of those proteins are ingested then protein leaves the cell example taking in cholesterol for membrane synthesis Ligands any molecule that binds specifically to a receptor site on another molecule Water Potential Likelihood water will undergo osmosis Water Potential Solute Potential Pressure Potential Solute Potential icRT i ion constant ex NaCl 2 c molarity R 0831 T Temperature degrees celcius 273 Water always moves from high water potential to low water potential
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'