Exercise 4Exercise 4
The Cell—Anatomy & The Cell—Anatomy & DivisionDivision
What is a cell?What is a cell?
Structural & functional unit of ALLLLLL Structural & functional unit of ALLLLLL living thingsliving things
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) Separates cell’s contents from outside Separates cell’s contents from outside
environmentenvironment Controls what goes in and out of the cellControls what goes in and out of the cell
NucleusNucleus ““control center” of cellcontrol center” of cell DNADNA
Cytoplasm Cytoplasm Fluid AND other contents Fluid AND other contents outsideoutside the the
nucleusnucleus
PLASMA PLASMA MEMBRANEMEMBRANE
NUCLEUSNUCLEUS
CYTOPLASMCYTOPLASM
Lab Fig. 4-3Lab Fig. 4-3
Cytoplasmic OrganellesCytoplasmic Organelles
Chromatin (in nucleus)Chromatin (in nucleus) DNA + proteins—when not replicating, DNA is DNA + proteins—when not replicating, DNA is
in this threadlike form all over the nucleusin this threadlike form all over the nucleus Chromosome (in nucleus)Chromosome (in nucleus)
When DNA replicates, chromatin becomes When DNA replicates, chromatin becomes tightly coiled, short, rod-shapedtightly coiled, short, rod-shaped
Nucleolus Nucleolus Dense protein & RNA mass in nucleusDense protein & RNA mass in nucleus Forms ribosomes which are then transported Forms ribosomes which are then transported
to cytoplasmto cytoplasm
CHROMATINCHROMATINNUCLEOLUSNUCLEOLUS
Lab Fig. 4-3Lab Fig. 4-3
Lecture Fig. 3-14Lecture Fig. 3-14
Cytoplasmic OrganellesCytoplasmic Organelles
RibosomeRibosome RNARNA Where proteins are madeWhere proteins are made
Cytoskeleton (“support beams”)Cytoskeleton (“support beams”) Protein fibersProtein fibers Centrioles: paired cylinders at right angles Centrioles: paired cylinders at right angles
(important in cell division, makes (important in cell division, makes microtubules)microtubules)
Microtubules: thin hollow tubes (transport Microtubules: thin hollow tubes (transport things in the cell, rigidity)things in the cell, rigidity)
Mitotic spindleMitotic spindle of microtubules forms of microtubules forms between centrioles during cell divisionbetween centrioles during cell division
RIBOSOMESRIBOSOMESMICROTUBULESMICROTUBULES
CENTRIOLESCENTRIOLES
Lab Fig. 4-3Lab Fig. 4-3
Cytoplasmic OrganellesCytoplasmic Organelles
Cytoskeleton (“support beams”)Cytoskeleton (“support beams”) Microfilaments: proteins, important in Microfilaments: proteins, important in
muscle cells; cell-shapemuscle cells; cell-shape Intermediate filaments: proteins, cell-Intermediate filaments: proteins, cell-
stabilizers—resist pulling forcesstabilizers—resist pulling forces
INTERMEDIATE INTERMEDIATE FILAMENTSFILAMENTS
MICROFILAMENTSMICROFILAMENTS
Lab Fig. 4-3Lab Fig. 4-3
Cytoplasmic Organelles with Cytoplasmic Organelles with MembranesMembranes
Nuclear membrane (envelope)Nuclear membrane (envelope) 2-layered2-layered Porous: materials moving to/from Porous: materials moving to/from
nucleus & cytoplasmnucleus & cytoplasm Mitochondria Mitochondria
2-layered membrane with inner folds2-layered membrane with inner folds Powerhouse of cellPowerhouse of cell Transforms energy from food into a form Transforms energy from food into a form
usable by the cell…aerobic respiration usable by the cell…aerobic respiration ATPATP
MITOCHONDRIAMITOCHONDRIA
NUCLEAR NUCLEAR MEMBRANEMEMBRANE
Lab Fig. 4-3Lab Fig. 4-3
Cytoplasmic Organelles with Cytoplasmic Organelles with MembranesMembranes
ER: Canal network continuous with nuclear membraneER: Canal network continuous with nuclear membrane
Smooth endoplasmic reticulum (ER) Smooth endoplasmic reticulum (ER) Synthesizes lipidsSynthesizes lipids
Rough endoplasmic reticulum (ER)Rough endoplasmic reticulum (ER) 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 with Cytoplasmic Organelles with MembranesMembranes
Golgi apparatusGolgi apparatus Cluster of flattened sacs near rough ERCluster of flattened sacs near rough ER Proteins made in ER come here to get Proteins made in ER come here to get
packaged and shipped out of the cell or to packaged and shipped out of the cell or to the cell’s cytoplasmthe cell’s cytoplasm
SecretSecretory vesicles: pinch off the golgi, to ory vesicles: pinch off the golgi, to plasma membrane, release contents from the plasma membrane, release contents from the cellcell
Lysosome: sack with Lysosome: sack with digestive enzymesdigestive enzymes ((digest digest foreign material, old cell parts)foreign material, old cell parts)
Peroxisome: sack with oxidase enzymes (use Peroxisome: sack with oxidase enzymes (use oxygenoxygen to to detoxifydetoxify—free radicals, kidney, —free radicals, kidney, liver)liver)
SECRETORY SECRETORY VESICLESVESICLES
GOLGI GOLGI APPARATUSAPPARATUS
Lab Fig. 4-3Lab Fig. 4-3
Cell MembraneCell Membrane
Phospholipid bilayerPhospholipid bilayer PhospholipidsPhospholipids
Hydrophobic tailsHydrophobic tails Hydrophilic headsHydrophilic heads
CholesterolCholesterol Lipid, helps stabilize cell membraneLipid, helps stabilize cell membrane
ProteinsProteins Move 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
Cell Division: MITOSISCell Division: MITOSIS
InterphaseInterphase ProphaseProphase MetaphaseMetaphase AnaphaseAnaphase TelophaseTelophase CytokinesisCytokinesis
Cell Division: MITOSISCell Division: MITOSIS
InterphaseInterphase Normal cell activities Normal cell activities
PRIOR to divisionPRIOR to division
Lab Fig. 4-4Lab Fig. 4-4
Cell Division: MITOSISCell Division: MITOSIS
ProphaseProphase Chromosomes Chromosomes
form as sister form as sister chromatidschromatids
Centrioles Centrioles separate, mitotic separate, mitotic spindle formsspindle forms
Nuclear Nuclear membrane & membrane & nucleolus break nucleolus break downdown
Lab Fig. 4-4Lab Fig. 4-4
Cell Division: MITOSISCell Division: MITOSIS
MetaphaseMetaphase Chromatids Chromatids
migrate along migrate along spindle to the spindle to the middle----middle----metaphase metaphase plateplate
Lab Fig. 4-4Lab Fig. 4-4
Cell Division: MITOSISCell Division: MITOSIS
AnaphaseAnaphase Centromeres Centromeres
split & split & chromosomes chromosomes split into 2 split into 2 chromosomes chromosomes which migrate which migrate to opposite to opposite ends of the ends of the cellcell
Lab Fig. 4-4Lab Fig. 4-4
Cell Division: MITOSISCell Division: MITOSIS
TelophaseTelophase Reverse of prophaseReverse of prophase Chromosomes uncoil Chromosomes uncoil
into chromatininto chromatin Spindle breaks downSpindle breaks down Nuclear membranes Nuclear membranes
form @ each endform @ each end Nucleoli appear in Nucleoli appear in
each nucleuseach nucleus
Lab Fig. 4-4Lab Fig. 4-4
Cell Division: MITOSISCell Division: MITOSIS
CytokinesisCytokinesis Division of cytoplasmDivision of cytoplasm Starts at end of telophaseStarts at end of telophase 2 new cells are formed, 2 new cells are formed, each genetically each genetically
IDENTICAL to the “mother” cellIDENTICAL to the “mother” cell
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