EXERCISE 4EXERCISE 4The Cell—Anatomy & The Cell—Anatomy & DivisionDivision

WHAT IS A CELL?WHAT IS A CELL?

Structural & functional unit of ALLLLLL living Structural & functional unit of ALLLLLL living thingsthings

Different sizes & shapesDifferent sizes & shapes Different functionsDifferent functions Components may vary but have many Components may vary but have many

common featurescommon features

CELL COMPARTMENTSCELL COMPARTMENTS

Plasma membrane (plasmalemma)Plasma membrane (plasmalemma)barrierbarrierin/out of cellin/out of cell

NucleusNucleus““control center” of cellcontrol center” of cell DNADNA

Cytoplasm Cytoplasm Fluid AND other organellesFluid AND other organelles

FIGURE 4.1A ANATOMY OF THE COMPOSITE ANIMAL CELL.

Nucleus

Cytoplasm

Plasmamembrane

FIGURE 4.1B ANATOMY OF THE COMPOSITE ANIMAL CELL.

Endoplasmicreticulum

Nuclear envelope Nucleus

NucleolusChromatinMitochondria

CYTOPLASMIC ORGANELLESCYTOPLASMIC ORGANELLES

Chromatin (in nucleus)Chromatin (in nucleus) DNA + proteins—threadlike form DNA + proteins—threadlike form

Chromosomes (in nucleus)Chromosomes (in nucleus) Before mitosis, chromatin becomes tightly coiled, rod-Before mitosis, chromatin becomes tightly coiled, rod-

shapedshaped Nucleolus Nucleolus

protein & RNA in nucleusprotein & RNA in nucleus

FIGURE 4.1B ANATOMY OF THE COMPOSITE ANIMAL CELL.

Endoplasmicreticulum

Nuclear envelope Nucleus

NucleolusChromatinMitochondria

CHROMATINCHROMATINNUCLEOLUSNUCLEOLUS

Lab Fig. 4-3Lab Fig. 4-3

Lecture Fig. 3-14Lecture Fig. 3-14

CYTOPLASMIC ORGANELLESCYTOPLASMIC ORGANELLES

RibosomeRibosome Made of RNAMade of RNA Protein synthesisProtein synthesis

Cytoskeleton (“support beams”)Cytoskeleton (“support beams”) Protein fibersProtein fibers Centrioles: paired cylinders near nucleusCentrioles: paired cylinders near nucleus Microtubules: thin hollow tubes (transport things in Microtubules: thin hollow tubes (transport things in

the cell, rigidity)the cell, rigidity) Mitotic spindleMitotic spindle forms between centrioles during mitosis forms between centrioles during mitosis

RIBOSOMESRIBOSOMESMICROTUBULESMICROTUBULES

CENTRIOLESCENTRIOLES

Lab Fig. 4-3Lab Fig. 4-3

CYTOPLASMIC ORGANELLESCYTOPLASMIC ORGANELLES

Cytoskeleton (“support beams”)Cytoskeleton (“support beams”)Microfilaments: tiny; cell shapeMicrofilaments: tiny; cell shapeIntermediate filaments: medium, cell-Intermediate filaments: medium, cell-

stabilizersstabilizers

INTERMEDIATE INTERMEDIATE FILAMENTSFILAMENTS

MICROFILAMENTSMICROFILAMENTS

Lab Fig. 4-3Lab Fig. 4-3

CYTOPLASMIC ORGANELLES CYTOPLASMIC ORGANELLES WITH MEMBRANESWITH MEMBRANES

Nuclear membrane (envelope)Nuclear membrane (envelope)2-layered2-layeredPorous: holes for in/outPorous: holes for in/out

Mitochondria Mitochondria 2-layered membrane with inner folds2-layered membrane with inner foldsPowerhouse of cellPowerhouse of cell

Food energy Food energy ATP energyATP energy

MITOCHONDRIAMITOCHONDRIA

NUCLEAR NUCLEAR MEMBRANEMEMBRANE

Lab Fig. 4-3Lab Fig. 4-3

CYTOPLASMIC ORGANELLES CYTOPLASMIC ORGANELLES WITH MEMBRANESWITH MEMBRANES

ER: Canal network ER: Canal network continuouscontinuous with nuclear membrane with nuclear membrane Smooth endoplasmic reticulum Smooth endoplasmic reticulum

Synthesizes lipidsSynthesizes lipids Rough endoplasmic reticulum Rough endoplasmic reticulum

Ribosomes attached to surfaceRibosomes attached to surface Protein synthesis and transportProtein synthesis and transport

Lab Fig. 4-3Lab Fig. 4-3

SMOOTH ERSMOOTH ER

ROUGH ERROUGH ER

CYTOPLASMIC ORGANELLES CYTOPLASMIC ORGANELLES WITH MEMBRANESWITH MEMBRANES

Golgi apparatusGolgi apparatusCluster of flattened sacs near rough ERCluster of flattened sacs near rough ER SecretSecretory vesicles ory vesicles

Secrete contents out of cellSecrete contents out of cellOrOrLysosome: Lysosome: digestive enzymesdigestive enzymes ( (digest digest foreign material, foreign material,

old cell parts)old cell parts)Peroxisome: oxidase enzymes (use Peroxisome: oxidase enzymes (use oxygenoxygen to to detoxifydetoxify

—free radicals, kidney, liver)—free radicals, kidney, liver)

SECRETORY SECRETORY VESICLESVESICLES

GOLGI GOLGI APPARATUSAPPARATUS

Lab Fig. 4-3Lab Fig. 4-3

FIGURE 4.3 STRUCTURE OF THE GENERALIZED CELL.

Chromatin

Nucleolus

Smooth endoplasmicreticulum

Cytosol

Mitochondrion

Lysosome

Centrioles

Centrosomematrix

Microvilli

Microfilament

Microtubule

Cytoskeletalelements

Intermediatefilaments

Peroxisome

Secretion being releasedfrom cell by exocytosis

Golgi apparatus

Ribosomes

Roughendoplasmicreticulum

Plasmamembrane

Nuclear pore

Nuclear envelopeNucleus

TABLE 4.1 SUMMARY OF STRUCTURE AND FUNCTION OF CYTOPLASMIC ORGANELLES

CELL MEMBRANECELL MEMBRANE

Phospholipid bilayerPhospholipid bilayer PhospholipidsPhospholipids

Hydrophobic tails Hydrophobic tails Hydrophilic headsHydrophilic heads

CholesterolCholesterolLipid, helps stabilize cell membraneLipid, helps stabilize cell membrane

ProteinsProteinsMove around, aid in transportMove around, aid in transport““fluid mosaic model”fluid mosaic model”

FLUID-MOSAIC MODELPHOSPHOLIPID PHOSPHOLIPID

BILAYERBILAYER

PROTEINSPROTEINS

CHOLESTEROLCHOLESTEROL

HYDROPHOBIC TAILSHYDROPHOBIC TAILS

HYDROPHILIC HEADSHYDROPHILIC HEADS

FIGURE 4.2 STRUCTURAL DETAILS OF THE PLASMA MEMBRANE.

Polar head ofphospholipidmolecule

Nonpolar tailof phospholipidmolecule

Cholesterol Glycolipid

Glycoprotein

Peripheralproteins

Filament ofcytoskeleton

Integralproteins

Inward-facing layerof phospholipids

Outward-facing layerof phospholipids

Lipid bilayercontaining proteins

Glycocalyx(carbohydrates)

Extracellular fluid(watery environmentoutside cell)

Cytoplasm(watery environmentinside cell)

CELL DIVISION: MITOSISCELL DIVISION: MITOSIS

InterphaseInterphase ProphaseProphase MetaphaseMetaphase AnaphaseAnaphase TelophaseTelophase CytokinesisCytokinesis

Microscope slides also

FIGURE 4.4 THE INTERPHASE CELL AND THE EVENTS OF CELL DIVISION. (1 OF 2)

Centrosomes (eachhas 2 centrioles)

Plasmamembrane

Nucleolus

Nuclearenvelope

Chromatin Chromosomeconsisting of twosister chromatids

Earlymitoticspindle

Aster

CentromereKinetochore Kinetochore

microtubule

Spindlepole

Polar microtubule

Fragments of nuclearenvelope

Interphase Early Prophase Late Prophase

FIGURE 4.4 THE INTERPHASE CELL AND THE EVENTS OF CELL DIVISION. (1 OF 2)

Centrosomes (eachhas 2 centrioles)

Plasmamembrane

Nucleolus

Nuclearenvelope

Chromatin Chromosomeconsisting of twosister chromatids

Earlymitoticspindle

Aster

CentromereKinetochore Kinetochore

microtubule

Spindlepole

Polar microtubule

Fragments of nuclearenvelope

Interphase Early Prophase Late Prophase

FIGURE 4.4 THE INTERPHASE CELL AND THE EVENTS OF CELL DIVISION. (2 OF 2)

Metaphase Anaphase Telophase Cytokinesis

Metaphaseplate

Spindle

Daughterchromosomes

Nuclearenvelopeforming

Nucleolus forming Contractilering atcleavagefurrow

CELL DIVISION: MITOSISCELL DIVISION: MITOSIS

InterphaseInterphaseNormal cell activities Normal cell activities

PRIOR to divisionPRIOR to divisionThen it gets the signal to Then it gets the signal to

dividedivideCopy DNACopy DNACopy organellesCopy organellesCopy centriolesCopy centrioles

Lab Fig. 4-4Lab Fig. 4-4

CELL DIVISION: MITOSISCELL DIVISION: MITOSIS ProphaseProphase

Chromosomes Chromosomes w/sister chromatidsw/sister chromatids

Centrioles Centrioles separated, spindleseparated, spindle

Nuclear membrane Nuclear membrane breaks downbreaks down

Lab Fig. 4-4Lab Fig. 4-4

CELL DIVISION: MITOSISCELL DIVISION: MITOSIS

MetaphaseMetaphaseChromatids @ Chromatids @

middlemiddle

Lab Fig. 4-4Lab Fig. 4-4

CELL DIVISION: MITOSISCELL DIVISION: MITOSIS

AnaphaseAnaphaseChromatids split, Chromatids split,

to opposite endsto opposite ends

Lab Fig. 4-4Lab Fig. 4-4

CELL DIVISION: MITOSISCELL DIVISION: MITOSIS

TelophaseTelophaseChromatin againChromatin againSpindle breaks downSpindle breaks downNuclear membraneNuclear membrane

Lab Fig. 4-4Lab Fig. 4-4

CELL DIVISION: MITOSISCELL DIVISION: MITOSIS

CytokinesisCytokinesisDivision of cytoplasmDivision of cytoplasm2 new cells 2 new cells each genetically IDENTICALeach genetically IDENTICAL

REVIEW FIGURE 4.1

REVIEW FIGURE 4.2