cells all cells have two characteristics in common surrounded by a cell membrane surrounded by a...
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CellsCells All cells have All cells have twotwo
characteristics in characteristics in commoncommon Surrounded by a cell Surrounded by a cell
membranemembrane At some point contain At some point contain
DNADNA Two TypesTwo Types
Prokaryotic and Prokaryotic and EukaryoticEukaryotic
ProkaryotesProkaryotes
Generally smaller and Generally smaller and simplersimpler
Genetic material is Genetic material is not contained in a not contained in a nucleusnucleus
Grow, reproduce, Grow, reproduce, respond to the respond to the environmentenvironment
ExampleExample: Bacteria: Bacteria
EukaryotesEukaryotes
Generally larger and more Generally larger and more complexcomplex
Contain dozens of structures Contain dozens of structures and internal membranesand internal membranes
Highly specialized cellsHighly specialized cells Genetic material is contained Genetic material is contained
in a nucleusin a nucleus May be single celled May be single celled
organisms, or part of a large organisms, or part of a large multi-cellular organismmulti-cellular organism
Diversity of Cellular LifeDiversity of Cellular Life
Unicellular OrganismsUnicellular Organisms Made of a single cellMade of a single cell Majority of life on Majority of life on
EarthEarth
Multi-cellular Multi-cellular OrganismsOrganisms Made of many cellsMade of many cells Depend on Depend on
cooperation and cooperation and communication among communication among specialized cellsspecialized cells
Cell specializationCell specialization: cells : cells develop in different ways to develop in different ways to perform different tasksperform different tasks Animal cellsAnimal cells: red blood cells : red blood cells
(transport oxygen), (transport oxygen), pancreas (protein pancreas (protein production), muscle cells production), muscle cells (movement)(movement)
Plant cellsPlant cells: guard cells : guard cells (regulate exchange in (regulate exchange in leaves)leaves)
Levels of OrganizationLevels of Organization Individual CellsIndividual Cells
TissuesTissues Cells grouped togetherCells grouped together A group of similar cells that perform a particular A group of similar cells that perform a particular
functionfunction
OrgansOrgans Tissues work togetherTissues work together
Organ SystemsOrgan Systems Group of organs that work together to perform a Group of organs that work together to perform a
specific functionspecific function
Osmosis and DiffusionOsmosis and Diffusion
Chapter 7.3Chapter 7.3
Cell BoundariesCell Boundaries
Cell MembraneCell Membrane Thin flexible barrier that surrounds a cellThin flexible barrier that surrounds a cell Regulates what enters and leaves the cell, Regulates what enters and leaves the cell,
provides protection and supportprovides protection and support Cell WallCell Wall
Strong supporting layer around the cell Strong supporting layer around the cell membranemembrane
Gives protection and support to a plant cellGives protection and support to a plant cell
Cell Membrane StructureCell Membrane Structure
Made of two layers Made of two layers (lipid bilayer)(lipid bilayer) Gives cell membranes Gives cell membranes
a flexible structure that a flexible structure that forms a strong barrierforms a strong barrier
Contains protein and Contains protein and carbohydrate carbohydrate moleculesmolecules Helps materials cross Helps materials cross
the membranethe membrane
Cell Wall Cell Wall StructureStructure
Found outside Found outside the cell the cell membrane membrane (plants)(plants) Main function to Main function to
provide support provide support and protectionand protection
Allows water, Allows water, oxygen, carbon oxygen, carbon dioxide to pass dioxide to pass throughthrough
Made from Made from carbohydrates carbohydrates and proteinand protein
DiffusionDiffusion Movement of dissolved Movement of dissolved
molecules from one side molecules from one side of cell membrane to of cell membrane to anotheranother
Particles move from an Particles move from an area where they are more area where they are more concentrated to an area concentrated to an area where they are less where they are less concentratedconcentrated
Substances diffuse across Substances diffuse across a membrane without the a membrane without the cell using any energycell using any energy
OsmosisOsmosis Diffusion of waterDiffusion of water across a selectively across a selectively permeable permeable membranemembrane
Most membranes Most membranes selectively selectively permeablepermeable
• some substances some substances can pass through can pass through and others cannotand others cannot
• Water passes easily Water passes easily across most across most membranesmembranes
OsmosisOsmosis How Osmosis works…How Osmosis works…
Water will move across Water will move across the membrane until the membrane until equilibriumequilibrium is reached is reached
• Moves from high to low Moves from high to low concentrationconcentration
Osmotic pressureOsmotic pressure: : pressure on the pressure on the hypertonic side of a hypertonic side of a selectively permeable selectively permeable membranemembrane
SolutionsSolutions HypertonicHypertonic: side of the : side of the membrane with more membrane with more molecules; “above molecules; “above strength”strength”
HypotonicHypotonic: the side of the : the side of the membrane with less membrane with less molecules; “below molecules; “below strength”strength”
IsotonicIsotonic: concentrations : concentrations the same on both sides of the same on both sides of the membrane; “same the membrane; “same strength”strength”
Facilitated DiffusionFacilitated Diffusion
Cell membrane has Cell membrane has certain channels certain channels (proteins) that make it (proteins) that make it easy for certain easy for certain molecules to cross molecules to cross the membranethe membrane Will only occur if there Will only occur if there
is a higher is a higher concentration on one concentration on one side of the membraneside of the membrane
Active TransportActive Transport
Small molecules and ions are carried across Small molecules and ions are carried across membranes by proteinsmembranes by proteins Requires energy, cells use majority of their energy for Requires energy, cells use majority of their energy for
transporttransport
EndocytosisEndocytosis Process of taking material into the cell by folding of Process of taking material into the cell by folding of
cell membranecell membrane
ExocytosisExocytosis Membrane of vacuole fuses with cell membrane Membrane of vacuole fuses with cell membrane
forcing contents out of cellforcing contents out of cell