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Cellular Organelles Nucleus: Nucleus: “control center” of the cell “control center” of the cell Surrounded by a nuclear envelope Surrounded by a nuclear envelope DNA DNA Nucleolus: site of ribosome synthesis Nucleolus: site of ribosome synthesis
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AP Exam ReviewAP Exam ReviewCellsCells
Prokaryotic vs. Eukaryotic Prokaryotic vs. Eukaryotic CellsCells
ProkaryoteProkaryote ““before” “nucleus”before” “nucleus” BacteriaBacteria DNA is concentrated in nucleoid (non DNA is concentrated in nucleoid (non
membrane-bound)membrane-bound) No membrane bound organellesNo membrane bound organelles
EukaryoteEukaryote ““true” “nucleus”true” “nucleus” Protists, plants, fungi, animalsProtists, plants, fungi, animals Nucleus holds DNANucleus holds DNA Membrane bound organellesMembrane bound organelles
Cellular OrganellesCellular Organelles Nucleus:Nucleus:
““control center” of control center” of the cellthe cell
Surrounded by a Surrounded by a nuclear envelopenuclear envelope
DNADNA Nucleolus: site of Nucleolus: site of
ribosome synthesisribosome synthesis
Cellular OrganellesCellular Organelles
RibosomesRibosomes Site of protein assemblySite of protein assembly Free and bound ribosomesFree and bound ribosomes
Cellular OrganellesCellular Organelles Endoplasmic Reticulum:Endoplasmic Reticulum:
Made up of membranous tubules and Made up of membranous tubules and cisternae (sacs)cisternae (sacs)
Smooth ER: NO ribosomes attachedSmooth ER: NO ribosomes attached Synthesis of lipidsSynthesis of lipids Metabolism of carbsMetabolism of carbs Detoxification of drugs and other poisonsDetoxification of drugs and other poisons
Rough ER: ribosomes attachedRough ER: ribosomes attached Protein assemblyProtein assembly
Cellular OrganellesCellular Organelles Smooth and Rough Smooth and Rough
ERER
Cellular OrganellesCellular Organelles Golgi Apparatus:Golgi Apparatus:
Products of the Products of the Endoplasmic Endoplasmic Reticulum are Reticulum are modified and stored modified and stored herehere
Cellular OrganellesCellular Organelles Lysosomes:Lysosomes:
Used by cells to Used by cells to digest digest macromoleculesmacromolecules
Sac of Sac of hydrolytichydrolytic enzymesenzymes
Apoptosis: Apoptosis: Programmed cell Programmed cell
deathdeath
Cellular OrganellesCellular Organelles Vacuoles:Vacuoles:
Food vacuoles Food vacuoles (storage)(storage)
Contractile vacuoles Contractile vacuoles (pump extra water (pump extra water out of cells in out of cells in freshwater protists)freshwater protists)
Central vacuole Central vacuole (plant cells)(plant cells)
Stores organic Stores organic compounds, compounds, inorganic ions (K+, inorganic ions (K+, Cl-), and waterCl-), and water
Cellular OrganellesCellular Organelles Peroxisomes:Peroxisomes:
Contain enzymes that transfer hydrogen Contain enzymes that transfer hydrogen from various substances to oxygen, from various substances to oxygen, producing Hproducing H22OO22 as a byproduct as a byproduct
Various functions:Various functions: Break fatty acids down into smaller Break fatty acids down into smaller
molecules for cellular respirationmolecules for cellular respiration Detoxify alcohol in liverDetoxify alcohol in liver
Cellular OrganellesCellular Organelles MitochondriaMitochondria
Site of cellular Site of cellular respirationrespiration
““powerhouse of the powerhouse of the cell”cell”
More metabolic More metabolic activity = more activity = more mitochondriamitochondria
Cellular OrganellesCellular Organelles Mitochondrial Mitochondrial
Structure:Structure: Outer membraneOuter membrane Inner membrane:Inner membrane:
Cristae = large Cristae = large surface areasurface area
Intermembrane Intermembrane spacespace
Mitochondrial Mitochondrial matrixmatrix
Cellular OrganellesCellular Organelles Chloroplasts:Chloroplasts:
Found in plants and Found in plants and eukaryotic algaeeukaryotic algae
Site of Site of photosynthesisphotosynthesis
Contain the green Contain the green pigment chlorophyllpigment chlorophyll
Cellular OrganellesCellular Organelles Chloroplast Chloroplast
StructureStructure ThylakoidsThylakoids
Grana = stacks of Grana = stacks of thylakoidsthylakoids
StromaStroma Fluid outside the Fluid outside the
thylakoidsthylakoids
Cellular OrganellesCellular Organelles CytoskeletonCytoskeleton
Maintains shape of Maintains shape of cellcell
Responsible for Responsible for movement of cell movement of cell and movement of and movement of organelles within organelles within cellcell
Railroad ideaRailroad idea
Cellular OrganellesCellular Organelles Components of Cytoskeleton:Components of Cytoskeleton:
Microtubules – 25 nm diameterMicrotubules – 25 nm diameter Intermediate Filaments – 8 – 12 nm Intermediate Filaments – 8 – 12 nm
diameterdiameter Microfilaments – 7 nm diameterMicrofilaments – 7 nm diameter
Cellular OrganellesCellular Organelles MicrotubulesMicrotubules
Hollow tubesHollow tubes Made up of A- and B-tubulinMade up of A- and B-tubulin Responsible for:Responsible for:
Cell motility (cilia/flagella)Cell motility (cilia/flagella) Chromosome movements (mitosis)Chromosome movements (mitosis) Movement of organellesMovement of organelles Maintenance of cell shapeMaintenance of cell shape
Cellular OrganellesCellular Organelles Intermediate FilamentsIntermediate Filaments
Made up of fibrous proteinsMade up of fibrous proteins Made up of keratinMade up of keratin Responsible for:Responsible for:
Structural supportStructural support Maintenance of cell shapeMaintenance of cell shape
Cellular OrganellesCellular Organelles MicrofilamentsMicrofilaments
Made up of 2 intertwined strands of actinMade up of 2 intertwined strands of actin Responsible for:Responsible for:
Muscle contractionMuscle contraction Cytoplasmic streamingCytoplasmic streaming Cell motility (pseudopodia)Cell motility (pseudopodia) Cell division (cleavage furrow)Cell division (cleavage furrow) Maintenance of/changes in cell shapeMaintenance of/changes in cell shape
Cellular OrganellesCellular Organelles Cell WallCell Wall
Found only in plant Found only in plant cellscells
Protects the cell wallProtects the cell wall Maintains cell shapeMaintains cell shape Prevents excessive Prevents excessive
uptake of wateruptake of water Hold plant up against Hold plant up against
gravitygravity
Cellular OrganellesCellular Organelles Extracellular Matrix:Extracellular Matrix:
Found in animal cellsFound in animal cells Made up of Made up of
glycoproteins glycoproteins (collagen) & (collagen) & proteoglycansproteoglycans
Proteins + carbohydratesProteins + carbohydrates Provides support and Provides support and
anchorage for cellsanchorage for cells Differs from one cell Differs from one cell
type to anothertype to another
Intercellular JunctionsIntercellular Junctions Neighboring cells Neighboring cells
are connected to are connected to one anotherone another
Plant cells:Plant cells: Plasmodesmata:Plasmodesmata:
Channels in the cell Channels in the cell wall through which wall through which strands of cytoplasm strands of cytoplasm pass through and pass through and connect the living connect the living contents of adjacent contents of adjacent cellscells
Intercellular JunctionsIntercellular Junctions Animal Cells:Animal Cells:
Tight junctionsTight junctions DesmosomesDesmosomes Gap junctionsGap junctions
Intercellular JunctionsIntercellular Junctions Tight junctions:Tight junctions:
Membranes of Membranes of neighboring cells neighboring cells are fusedare fused
Form a continuous Form a continuous “belt” around a cell“belt” around a cell
Example: digestive Example: digestive tracttract
Intercellular JunctionsIntercellular Junctions DesmosomesDesmosomes
Anchoring junctionsAnchoring junctions Act as rivetsAct as rivets
Intercellular JunctionsIntercellular Junctions Gap junctionsGap junctions
Communicating Communicating junctionsjunctions
Cytoplasmic Cytoplasmic channels between channels between adjacent cellsadjacent cells
Salts, sugars, AAs, Salts, sugars, AAs, etc. can pass etc. can pass throughthrough
Diffusion vs. OsmosisDiffusion vs. OsmosisDiffusion:Movement of molecules from
high to low concentration until equilibrium is reached.
Passive Transport= no energy required
What substances may diffuse across membrane? Nonpolar (non-charged) molecules; small polar molecules
Osmosis:The passive transport of water across a selectively permeable membraneHyper-, hypo-, iso- tonic
RELATIVE TERMS!!Always referring to solute concentration
Water moves from areas of lower concentration of solutes (hypotonic) to areas of higher solute concentration (hypertonic)
MitosisMitosis