Cell Structure and Function (.ppsx)

Chapter 4: Cell Structure & Function

Exam ProtocolsTake out your smartphone/tablet/laptop.Sign on and establish Wi-Fi.Open a browser and go to http://socrative.com.Select "Student Login" & provide the Room Number: "BIO156".Await the Instructor's Start of the exam. You will see a rotating hexagon until that happens.Enter your name as Last Name, First Name.You will have 30 minutes to complete the exam.

BIO156Paradise Valley Community College#Todays TopicsHow Cells Are StudiedProkaryotic CellsEukaryotic CellsThe Cell MembraneThe Endomembrane SystemDiffusion, Osmosis, TonicityPassive TransportActive TransportCell Structure & Function

Chapter 3

BIO156Paradise Valley Community College#

22/11/2017Paradise Valley Community CollegeCell Structure & Function

Cell StructureA plasma membrane surrounds the cell and controls which substances move in and out.Plasma membraneA cells outermost membrane,composed of a lipid bilayer (mostly phospholipids)Lipid bilayerStructural foundation of cellmembranes; mainly phospholipidsarranged tail-to-tail in a bilayer

Source: 2012books.lardbucket.org. 2015.

BIO156Paradise Valley Community College#3

Paradise Valley Community CollegeCell Structure & Function2/11/2017

Source: modified from Cengage. 2015.The Structure of Cell MembranesThe plasma membrane is basically a lipid bilayerballoon filled with fluid.The nonpolar tails of both layers are sandwiched between the polar heads.Intracellularmatrix

Extracellularmatrix




~5 nanometers (nm) or 5 x 10-9 meters

Source: teebioscience.blogspot.com. 2015.

Lipid BilayerThe Fluid Mosaic Model of the Cell Membrane

Source: Starr, C., Evers, C. A., & Starr, L. 2015.PhospholipidLayerPhospholipidLayer

BIO156Paradise Valley Community College#5Figure 2.15Phospholipids. (A) Each phospholipid has a hydrophilic head and two hydrophobic tails. (B) A double layer of phospholipids is the structural foundation of all cell membranes.Cell Structure & FunctionParadise Valley Community College2/11/2017

Membrane ProteinsProteins, lipids, and carbohydrates associated with a membrane carry out most membrane functions.Extracellular matrix

Intracellular matrixSource: Modified from britannica.com. 2017.

Source: Modified from pulpbits.com. 2017.

Source: Modified from es.wikipedia.org. 2017.



Fluid Mosaic Model

Source: modified from Cengage, 2015.



Cell theory is the fundamental theory of biology.Cell theory:All organisms consist of one or more cells.The cell is the smallest unit of life.Each new cell arises from another cell.A cell passes hereditary information to its offspring. Cell Theory



Source: Modified from commons.wikimedia.org. 2017.Cell metabolism occurs in the cytosol and internal compartments, including organelles.OrganelleStructure that carriesout a specialized metabolicfunction inside a cellCytoplasmEverything within thecell membraneOrganellesOrganelleslittle organs




Prokaryotes and EukaryotesCells are classified as prokaryotes or eukaryotes based on how DNAis housed in the cell.NucleoidRegion of cytoplasmwhere DNA isconcentrated in aprokaryotic cellNucleus Organelle that contains aeukaryotic cells DNA

Source: gettyimages.be. 2015.

Source: jennarever.weebly.com. 2017.




Measuring CellsMost cells are visible only with the help of microscopes.Different types of microscopes use light or electrons to reveal different details of cells.

Source: modified from Cengage, 2015.1 m40 m200 m



Animalcules and BeastiesNo one knew cells existed until the microscope was invented by van Leeuwenhoek (1632-1723).

Source: modified from micro.magnet.fsu.edu. 2015

Source: microscopy-uk.org.uk. 2015.

Source: modified from en.wikipedia.org. 2015.



Source: Modified from stevegallik.org. 2015Robert Hooke (1635-1703) improved the microscope and coined the term cell.Robert Hooke

Source: Modified from en.wikipedia.org/wiki/Cell_theory. 2015

lenslight source

specimen



Modern MicroscopesDifferent types of microscopes reveal different aspects of cell structure. (Cost: $25 to $1,000,000)Light Microscope (phase contrast)Light Microscope (reflected light)Fluorescence MicroscopeTransmission ElectronMicroscope (TEM)Scanning ElectronMicroscope (SEM)Atomic Force Microscope (AFM)

Source: Modified from azonano.com. 2015.

Source: phys.org. 2015.

Source: now.humboldt.edu. 2015Source: Modified from blog.lib.umn.edu. 2015

Source: Modified from binoculars.clutchot.com. 2015Source: en.wkipedia.org. 2015.

Source: Modified from meter8.com. 2015.

Source: Modified from www.olympus-lifescience.com. 2015.



A spectrum of Sizes

1m0.1nm1m10m100m1mm100mm10mm1nm100nm10nmNaked EyeLight MicroscopeElectron Microscope

Atom

CellMembrane

Protein

Virus

Mitochondrion

Bacterium

PlantCell

AnimalCell

HumanEgg

FrogEgg

ChickenEgg

OstrichEgg

HumanSource: modified from openstaxcollege.com. 2017.

BIO156Paradise Valley Community College#Prokaryote Body PlanProkaryote (e.g., bacteria)Similarities toeukaryotic cells:DNAcell membranecell wallribosomescell wallflagellumDistinguishing characteristicsnucleoid instead of nucleuspilus (pili) instead of cilia

Source: OpenStaxCollege.org. 2015flagellumribosomecellmembranecell wallcapsulepilusDNA(nucleoid)



Prokaryote Body PlanFlagellum (pl., flagella)Long, slender cellular structure used for mobilityPilus (pl., pili)A protein filament used to help cells cling to or move across surfaces, or for DNA plasmid transfer (biofilm)

Source: sabalolodge.com/20/flagella-animation. 2015.

Source: faculty.ccbcmd.edu. 2015.




carboxysomechlorosomeflagellummagnetosomenucleoidplasmidribosomethylakoidpilus lysosomemelanosomemitosomemyofibrilparenthesomeperoxisomeribosomevesicle(Major)chloroplast (plastid)endoplasmic reticulumGolgi apparatusmitochondriavacuolenucleolusnucleus(Minor)acrosomeautophagosomecentrioleciliumeyespotglycosomeglyoxysomehydrogenosome

OrganellesEukaryote Prokaryote


Source: Modified from Cengage, 2015.Common Organelleschloroplast (plastid)vacuoleendoplasmic reticulum (ER)nucleolusnucleusmitochondria Golgi apparatus



Source: modified from Cengage. 2015.The NucleusPores, receptors, and transport proteins in the nuclear envelope control the movement of molecules into and out of the nucleus.Nuclear envelopeMembrane that constitutesthe outer boundary ofthe nucleus

Source: Modified from commons.wikimedia.org. 2017.




The nucleolus (pl., nucleoli) is a non-membrane bound structure composed of proteins and nucleic acids found within the nucleus.Ribosomal RNA (rRNA) istranscribed and assembledwithin the nucleolus.Malfunction of nucleoli canbe the cause for severalhuman disorders.tumorgenesisHIV incorporationcancer

Source: Modified from Cengage. 2015.The Nucleolus

Source: Modified from en.Wikipedia,com. 2017.




Todays TopicsHow Cells Are StudiedProkaryotic CellsEukaryotic CellsThe Cell MembraneThe Endomembrane SystemDiffusion, Osmosis, TonicityPassive TransportActive TransportCell Structure & Function



The Endomembrane SystemNucleusNuclear poreRough endoplasmic reticulum (rER)Ribosomes on therough ERSmooth endoplasmic reticulum (sER)Golgi BodyTransport vesicles

Source: Modified from Slideshare.com. 2017.76543217654321rERExocytosisVesiclesGolgi BodyLysosomessER7




The Endoplasmic Reticulum

Source: Modified from commons.wikimedia.org. 2017.Ribosomes makethe difference.Rough ERSmooth ERNucleus


The Golgi Apparatus

Source: Modified from commons.wikimedia.org. 2017.Source: Modified from Britannica.com. 2017.The Post Officeof the cell

BIO156Paradise Valley Community College#The Golgi Apparatus

Source: Modified from fineartamerica.com. 2017.

Source: Modified from biology-pictures.blogspot.com. 2017.TEMSecretoryvesiclesVesicles arrivingfrom ER

BIO156Paradise Valley Community College#The Mitochondrion

The Powerhouseof the cellSource: Modified from commons.wikimedia.org. 2017.


Source: Modified from vestinet.rs. 2017.Structure of a MitochondrionCristaeIntermembranespaceOutermitochondrialmembraneInnermitochondrialmembraneribosomemtDNAMatrix



Mitochondria and ChloroplastsMitochondria and chloroplasts have their own DNA. They resemble bacteria and may have evolved by endosymbiosis.Mitochondrion (pl., mitochondria)Membrane-enclosed organelleproducing ATP and CO2ChloroplastMembrane-enclosed organelleof photosynthesis producingglucose and O2

Source: Modified from Cengage. 2015.




Endosymbiosis

ProkaryoteMembraneboundDNAmoderneukaryoteProto eukaryoteFreemitochondrion

2.7 million years

Evolution of themodern eukaryoteSource: Modified from study.com. 2017.


Cell Structure & FunctionParadise Valley Community College302/11/2017

The CytoskeletonDynamic network ofprotein filaments thatsupport,organize, andmove eukaryotic cellsThe cytoskeleton interacts with accessory proteins, such as motor proteins (kinesins).

Source: employees.csbsju.edu. 2015.




Cytoskeletal ElementsMicrotubulesCytoskeletal elements involved in movementHollow filaments of tubulin subunitsMicrofilamentsReinforcing cytoskeletal elementsFibers of actin subunitsIntermediate filamentsElements that lock cells and tissues together

25 nm

10 nm

7 nmSource: Modified from mhhe.com. 2015.




FlagellaEukaryotic flagella are whip-like structures that propel cells such as sperm through fluidFlagellumDifferent internal structure and motion than prokaryotic flagella

Source: Modified from everythingaboutstemcells.com. 2017.Motor proteins& mitochondriaAcrosomeDNA



CiliaCilia (sing., cilium)Short, hair-like structures projecting from the plasma membrane of some eukaryotic cellsCoordinated beating stirs fluid, propels motile cellsMoved by organized arrays of microtubules

Source en.wikipedia.org. 2015.

Source: embryology.med.unsw.edu.au. 2017.




False FeetPseudopod (false foot)Extendable lobe of membrane-enclosed cytoplasm for movementor to engulf preyMoved by motor proteins attached to microfilaments that drag the plasma membraneSource: Modified from vcharkarn.com. 2017.




PhagocytosisPhagocytosis cell eatingMembrane extends around food particle to form an internal compartment where food is digestedExamples:amoeba( pl., amoebae)white blood cells (WBC)WBC engulfing bacterium

Source: David Rogers, Vamderbilt University, 1953. 2017..

Source: imgur.com. 2017.Amoeba engulfing paramecia




The Inner Life of the Cell


Cell Structure & FunctionParadise Valley Community College372/11/2017

Tight JunctionsDesmosomesGap JunctionsWhat Holds Us Together?Tight JunctionsFibrous proteins that join epithelial cells and prevent fluids from leakingbetween themDesmosomesAnchoring junctions bind adjacent cells together to help form shock-absorber of fibers.Gap JunctionsForms a channel across plasma membranes of adjoining animal cells

Source: Modified from Pearson Education. 2017.





BIO156Paradise Valley Community College#Tight Junctions and Disease

Systemic SclerosisNormal Cell JunctionsSystemic Autoimmune DiseaseSource: en.wikipedia.org. 2015.

Source: cellntec.com. 2015.



Diffusion, Osmosis, and TonicityDiffusionNet movement of molecules or ions from a region ofhigher concentration to a region of lower concentrationOsmosisDiffusion of water molecules across a selectively permeable membrane between two fluids with different water concentrationsTonicity The relative concentrations of solvent & solutes in fluids separated by a selectively permeable membrane.



Osmosis and TonicitySemi-permeable membrane: Molecules larger than water cannot pass.

Semi-permeable membrane[Glucose]=1 g/L

[Glucose]=3 g/L [Glucose]=2 g/L [Glucose]=2 g/L HypertonicHypotonicIsotonicMolecules too big to pass through membranebut water camIsotonic



Isotonic?Hypotonic?Hypertonic?

Hypotonic?Hypertonic?

Osmosis and TonicityBag isHypertonicto beaker.Bag isHypotonicto beaker.

2% Sucrose2% SucroseWaterABC

2% Sucrose

Bag isIsotonicto Beaker.10% Sucrose

Science

Cell Structure and Function (.ppsx)