C7- A View of the CellC7- A View of the Cell
A View of the CellA View of the Cell
7-1 Discovery of Cells7-1 Discovery of Cells 7-2 7-2 Plasma MembranePlasma Membrane 7-37-3
Discovery of CellsDiscovery of Cells
Anton van Anton van Leeuwenhoek used Leeuwenhoek used the first microscope the first microscope early in the 1600s.early in the 1600s.
It revealed the world It revealed the world of microorganisms of microorganisms and cells which are and cells which are the basic unit of an the basic unit of an organism.organism.
Discovery of CellsDiscovery of Cells
Robert Hooke coined Robert Hooke coined the term cell after the term cell after observing cork under observing cork under a microscope.a microscope.
Hooke’s illustration of cork
Discovery of CellsDiscovery of Cells
1838 Matthias 1838 Matthias Schleiden observed Schleiden observed plant cells.plant cells.
Theodor Schwann Theodor Schwann studied animal cells.studied animal cells.
Ideas were Ideas were summarized in the summarized in the Cell Theory.Cell Theory.
Cell TheoryCell Theory
1. All organisms are made of one or more 1. All organisms are made of one or more cells.cells.
2. The cell is the basic unit of structure 2. The cell is the basic unit of structure and organization in organisms.and organization in organisms.
3. All cells come from preexisting cells.3. All cells come from preexisting cells.
Electron MicroscopesElectron Microscopes
Light Microscopes Light Microscopes 1500X1500X
Dev new EM in 1930s Dev new EM in 1930s & 40s& 40s
Uses beam of Uses beam of electrons to multiply electrons to multiply image 500,000Ximage 500,000X
Lets us see internal Lets us see internal cell structurecell structure
Scanning vs. Transmission EMScanning vs. Transmission EM
Scan surface of cell Scan surface of cell for 3D imagefor 3D image
Study internal Study internal structure of cellstructure of cell
Two Basic Cell TypesTwo Basic Cell Types
All cells contain All cells contain specialized structures specialized structures called called organelles.organelles.
Eukaryotes have Eukaryotes have membrane-bound membrane-bound organellesorganelles
Prokaryotes do notProkaryotes do not Some eukaryotes are Some eukaryotes are
unicellular like unicellular like amoebas.amoebas.
Two Basic Cell TypesTwo Basic Cell Types
Robert Brown Robert Brown observed eukaryotes observed eukaryotes had a prominent had a prominent structure.structure.
Rudolf Virchow said it Rudolf Virchow said it was responsible for was responsible for cell division.cell division.
Eventually the Eventually the structure was called structure was called the nucleus or cell’s the nucleus or cell’s control center.control center.
7.2 Plasma Membrane7.2 Plasma Membrane
Responsible for controlling what goes in and out Responsible for controlling what goes in and out of the cell.of the cell.
Plasma MembranePlasma Membrane
Maintains Maintains homeostasis by homeostasis by selective selective permeability permeability keeping keeping some things in and some things in and keeping others outkeeping others out
Plasma Membrane StructurePlasma Membrane Structure
Phospholipid BilayerPhospholipid Bilayer Glycerol backbone, 2 Glycerol backbone, 2
fatty acids & a fatty acids & a phosphate group phosphate group make a phospholipid.make a phospholipid.
Water is attracted to Water is attracted to the head but not to the head but not to the lipid fatty acids.the lipid fatty acids.
Plasma Membrane StructurePlasma Membrane Structure
Fluid Mosaic Model Fluid Mosaic Model because because phospholipids ripple phospholipids ripple like water with the like water with the currents.currents.
Protein molecules Protein molecules float like boats on the float like boats on the surface in a mosaic surface in a mosaic pattern.pattern.
FlexibleFlexible
Other componentsOther components
CholesterolCholesterol stabilizes the stabilizes the phospholipids by phospholipids by keeping the the tails keeping the the tails from sticking togetherfrom sticking together
Transport proteins Transport proteins span the membrane span the membrane to move needed to move needed substances in and substances in and wastes out of the cell.wastes out of the cell.
7.3 Eukaryotic Cell Structure7.3 Eukaryotic Cell Structure
Each component has Each component has a specific function.a specific function.
They work together to They work together to help the cell survive.help the cell survive.
Cell wall Cell wall fairly rigid fairly rigid part of plant cells, part of plant cells, bacteria & protists bacteria & protists made of cellulose.made of cellulose.
Eukaryotic Cell StructureEukaryotic Cell Structure
NucleusNucleus Cell ControlCell Control Contains directions Contains directions
for making proteins in for making proteins in chromatin.chromatin.
Strands of genetic Strands of genetic material, DNAmaterial, DNA
Chromatin condenses Chromatin condenses to chromosomes to chromosomes before cell divisionbefore cell division
Eukaryotic Cell StructureEukaryotic Cell Structure
NucleolusNucleolus Makes ribosomesMakes ribosomes Ribosomes Ribosomes are are
production site of production site of proteins made by proteins made by direction of DNAdirection of DNA
They’re made of RNA They’re made of RNA and must travel to the and must travel to the cytoplasmcytoplasm to build to build proteins.proteins.
The nucleolus makesThe nucleolus makes ribosomes ribosomes which are which are the site of protein the site of protein synthesis.synthesis.
Ribosomes must Ribosomes must travel out of the travel out of the nucleus to the nucleus to the Cytoplasm Cytoplasm where they where they build the proteins build the proteins according to DNAs according to DNAs direction.direction.
Eukaryotic Cell StructureEukaryotic Cell Structure
CytoplasmCytoplasm Clear, gelatinous fluid Clear, gelatinous fluid
inside a cellinside a cell Ribosomes and RNA Ribosomes and RNA
pass through nuclear pass through nuclear pores in the pores in the nuclear nuclear envelopeenvelope to enter the to enter the cytoplasmcytoplasm
Eukaryotic Cell StructureEukaryotic Cell Structure
Assembly, transport & Assembly, transport & storagestorage
Endoplasmic Endoplasmic reticulum reticulum site of site of cellular chemical cellular chemical reactionsreactions
Highly folded Highly folded membrane which membrane which ribosomes attach to ribosomes attach to (Rough ER) do (Rough ER) do protein synthesisprotein synthesis
Eukaryotic Cell StructureEukaryotic Cell Structure
Each protein has a Each protein has a specific function.specific function.
Smooth ER has no Smooth ER has no ribosomes but makes ribosomes but makes and stores lipids.and stores lipids.
After proteins are After proteins are made they’re sent to made they’re sent to the the Golgi ApparatusGolgi Apparatus
Eukaryotic Cell StructureEukaryotic Cell Structure
Golgi ApparatusGolgi Apparatus Modifies proteins & Modifies proteins &
sorts them into sorts them into packages (packages (vesiclesvesicles) ) for transport to their for transport to their destinationdestination
Eukaryotic Cell StructureEukaryotic Cell Structure
Vacuoles Vacuoles membrane membrane bound compartment bound compartment for temporary storagefor temporary storage
Stores food, enzymes Stores food, enzymes & other needed & other needed materials.materials.
Animal cells may also Animal cells may also have vacuoles usually have vacuoles usually smaller.smaller.
Eukaryotic Cell StructureEukaryotic Cell Structure
Lysosomes Lysosomes contain contain digestive enzymes.digestive enzymes.
Used to digest worn Used to digest worn out organelles, food out organelles, food particles or engulfed particles or engulfed viruses or bacteria.viruses or bacteria.
The membrane The membrane prevents enzymes prevents enzymes from destroying the from destroying the cell.cell.
Eukaryotic Cell StructureEukaryotic Cell Structure
Energy TransformersEnergy Transformers Chloroplasts Chloroplasts capture capture
light energy & convert light energy & convert it to chemical energy.it to chemical energy.
Eukaryotic Cell StructureEukaryotic Cell Structure