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CellsCells
Chapter 7Chapter 7
How many cells do humans have?How many cells do humans have?
About 10 TRILLION cells!About 10 TRILLION cells!
If you tried counting them at a rate of If you tried counting them at a rate of 1cell/sec, it would take over 2000 years to 1cell/sec, it would take over 2000 years to do it.do it.
Discovery of CellsDiscovery of Cells
Robert Hooke (1665)Robert Hooke (1665)
Used microscope to look at thin slice of cork Used microscope to look at thin slice of cork treetree
Named structures “cells” like the small Named structures “cells” like the small rooms monks lived in.rooms monks lived in.
Anton van LeeuwenhoekAnton van Leeuwenhoek
1673- Used a simple microscope to 1673- Used a simple microscope to observe pond scum & discovered observe pond scum & discovered livingliving single-celled organismssingle-celled organisms
He called them “animalcules”He called them “animalcules”
1838- Matthias Schleiden- all plant parts are made 1838- Matthias Schleiden- all plant parts are made of cellsof cells
1839- Theodor Schwann- all animal tissues are 1839- Theodor Schwann- all animal tissues are composed of cells.composed of cells.
Development of Cell TheoryDevelopment of Cell Theory
1858- Rudolf Virchow, concluded that cells must 1858- Rudolf Virchow, concluded that cells must arise from preexisting cells.arise from preexisting cells.
The Cell Theory The Cell Theory
1. All living things are composed of one or more 1. All living things are composed of one or more cells. cells.
2. The cell is the basic unit of structure and function 2. The cell is the basic unit of structure and function in all living things. in all living things.
3. All cells are produced from pre-existing cells. 3. All cells are produced from pre-existing cells.
88
Sizes of Living ThingsSizes of Living Things
10 m1 m0.1 m1 cm1 mm100 nm10 nm1 nm0.1 nm
mousefrog egg
human eggmost bacteria
virus
protein
atomant
electron microscope
light microscope
human eye
humanblue whale
chloroplastrose
1 km100 m100 m10 m1 m
plant and animal
cellsaminoacid
ostrichegg
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Types of MicroscopesTypes of Microscopes
1. Compound light 1. Compound light microscopemicroscope
Light passes Light passes through lenses to through lenses to magnify image up magnify image up to 1000Xto 1000X
Can observe Can observe living cells living cells
Types of MicroscopesTypes of Microscopes
2. 2. Electron Electron microscopemicroscope
Uses a beam of Uses a beam of electrons to electrons to magnify image magnify image
> 1000X> 1000X Kills cells being Kills cells being
observed observed
Scanning Electron MicroscopeScanning Electron Microscope
Produces 3-dimensional images of cell Produces 3-dimensional images of cell surfacesurface
Transmission Electron MicroscopeTransmission Electron Microscope
Electrons pass through only thin samples Electrons pass through only thin samples
Explores cell internal structures and large Explores cell internal structures and large proteinsproteins
Prokaryotes and EukaryotesProkaryotes and Eukaryotes
ProkaryotesProkaryotes
Prokaryotes: Prokaryotes: ((pro-pro- means means beforebefore, and , and
karyotekaryote means means nucleusnucleus));first type of cells to ;first type of cells to evolve evolve Very small, the size of mitochondriaVery small, the size of mitochondria UnicellularUnicellular Kingdoms: Archaea and BacteriaKingdoms: Archaea and Bacteria Reproduce asexually via Binary FissionReproduce asexually via Binary Fission
ProkaryotesProkaryotes
Structures:cell membranecell wallribosomesflagella or cilianucleoidcytoplasmcapsuleNo membrane bound organelles - only eukaryotes have
A day in the life of BacteriaA day in the life of Bacteria
Can only move in two directions forward Can only move in two directions forward (swimming) and tumbling, and at one speed.(swimming) and tumbling, and at one speed.
Divide every 20 minutesDivide every 20 minutes
Long family history….. 3.5 billion years ago to be Long family history….. 3.5 billion years ago to be exact (The earth formed 4.6 billion years ago)exact (The earth formed 4.6 billion years ago)
From Prokaryotes to From Prokaryotes to EukaryotesEukaryotes
EUKARYOTESEUKARYOTES
Emerged 1.6-2.1 Billion years agoEmerged 1.6-2.1 Billion years ago
Kingdoms: Animals, Plants, Fungi, and Kingdoms: Animals, Plants, Fungi, and ProtistsProtists
Characteristics: Characteristics: Complex structure with Nucleus and Membrane-Complex structure with Nucleus and Membrane-
Bound OrganellesBound Organelles
Unicellular and MulticellularUnicellular and Multicellular
If all cells originate from other If all cells originate from other cells, how do you think cells, how do you think
eukaryotes came about?eukaryotes came about?
EndosymbiosisEndosymbiosis Endosymbiotic theoryEndosymbiotic theory - -
states that some states that some eukaryotic organelles eukaryotic organelles evolved from evolved from prokaryotes.prokaryotes.
The host and prokaryotic The host and prokaryotic cells benefited from cells benefited from each other and each other and eventually resulted in eventually resulted in this evolutionary change this evolutionary change of eukaryote cells.of eukaryote cells.
Plant and Animal CellsPlant and Animal Cells• Plant CellPlant Cell
Cell WallCell Wall ChloroplastsChloroplasts Rigid Shape (Cell Wall)Rigid Shape (Cell Wall) Large Central VacuoleLarge Central Vacuole
•Animal Cell•No Cell Wall•Irregular/ round shape
Plant and Animal Cell Structures: Plant and Animal Cell Structures: Nucleus, Nucleolus, Nuclear EnvelopeNucleus, Nucleolus, Nuclear Envelope
NucleusNucleus - stores - stores genetic informationgenetic information
NucleolusNucleolus - - ribosome productionribosome production
Nuclear envelopeNuclear envelope - - protective layer protective layer controlling what controlling what enters and leavesenters and leaves
Plant and Animal Cell Structures: Plant and Animal Cell Structures: Cytoplasm and CytosolCytoplasm and Cytosol
CytoplasmCytoplasm – everything – everything inside cell membraneinside cell membraneCytosolCytosol - gel like material - gel like material within the cell, includes within the cell, includes proteins, dissolved proteins, dissolved molecules, water, etc.molecules, water, etc.
Cell MembraneCell MembranePhosphoPhospholipidlipid bibilayerlayer
FlexibileFlexibile
Regulates what goesRegulates what goes
in and out of cellin and out of cell
Cell WallCell WallLocated outside Located outside membrane in membrane in plantplant and and prokaryoticprokaryotic cells, cells, NOT in animal cells.NOT in animal cells.
Rigid, porousRigid, porous
Plant and Animal Cell Structures: Plant and Animal Cell Structures: RibosomesRibosomes
Also found in ProkaryotesAlso found in Prokaryotes
Protein synthesisProtein synthesis (makes proteins) (makes proteins)
Plant and Animal Cell Structures: Plant and Animal Cell Structures: CytoskeletonCytoskeleton
MicrofilamentsMicrofilaments: : carry out cellular movements carry out cellular movements including including gliding, contraction, and cytokinesis.gliding, contraction, and cytokinesis.
MicrotubulesMicrotubules: : Cell shapeCell shape
• Helps move things within the cell (tracks)Helps move things within the cell (tracks)• Form the spindle fibers for separating Form the spindle fibers for separating
chromosomes during mitosischromosomes during mitosis
Plant and Animal Cell Plant and Animal Cell Structures: Flagella and CiliaStructures: Flagella and Cilia
Hairlike structures that aid Hairlike structures that aid in movement (motility) of in movement (motility) of the cellthe cell
ORGANELLESORGANELLES
Endoplasmic ReticulumEndoplasmic ReticulumStructure: network of interconnected Structure: network of interconnected
membranes forming channels within cellmembranes forming channels within cellRough Endoplasmic Rough Endoplasmic Reticulum (RER)Reticulum (RER)
Covered with ribosomes which Covered with ribosomes which synthesize proteinsynthesize protein
Smooth Endoplasmic Smooth Endoplasmic Reticulum (SER)Reticulum (SER)
A site for synthesis and A site for synthesis and metabolism of lipids (fats).metabolism of lipids (fats).
roughendoplasmic
reticulum
smoothendoplasmic
reticulum
ribosomes
Golgi ApparatusGolgi ApparatusPurpose: Process, Package, SecretePurpose: Process, Package, Secrete
StructureStructure a series of stacked membranesa series of stacked membranes
FunctionFunction Modifies and packages Modifies and packages
macromolecules for transport macromolecules for transport elsewhere in the cell in vesicleselsewhere in the cell in vesicles
transportvesicle
Nucleus
Golgi apparatus
transportvesicle
ER
MitochondriaMitochondriaPurpose: Energy ProductionPurpose: Energy Production
StructureStructure::• Double membrane with a series of Double membrane with a series of
folds called cristae.folds called cristae.
FunctionFunction: : • Cellular respirationCellular respiration- chemical energy - chemical energy
from food converted into usable energy from food converted into usable energy for cellfor cell
• Contains its own DNA Contains its own DNA ““Powerhouse of the cell”Powerhouse of the cell”
Lysosomes (Animals Mostly)Lysosomes (Animals Mostly)
Garbage disposal of Garbage disposal of the cellthe cell
Contain digestive Contain digestive enzymes that break enzymes that break down lipids, down lipids, carbohydrates, carbohydrates, proteins, invaders and proteins, invaders and wasteswastes
Animal Cells Only: Animal Cells Only: CentriolesCentrioles
Organelles used in cell Organelles used in cell reproductionreproduction
Produce microtubulesProduce microtubules
Plants Mostly: VacuolePlants Mostly: Vacuole
Membrane surrounded Membrane surrounded "bags" that contain "bags" that contain water, enzymes and water, enzymes and storage materials in storage materials in plants. plants.
smaller vacuoles in animal cells
Plants Only: ChloroplastsPlants Only: ChloroplastsPhotosynthesis: capture Photosynthesis: capture light energy to produce light energy to produce sugarssugarsDouble outer membraneDouble outer membrane
Human Cell TypesHuman Cell Types
4040
Endomembrane System: A Visual SummaryEndomembrane System: A Visual Summary
lipid
secretion
ribosome
lysosomecontains digestive enzymesthat break down worn-outcell parts or substancesentering the cell at theplasma membrane
transport vesicleshuttles lipids to variouslocations such as theGolgi apparatus
smooth endoplasmicreticulumsynthesizes lipids andalso performs variousother functions
incoming vesiclebrings substances into thecell that are digested whenthe vesicle fuses with alysosome
transport vesicleshuttles proteins tovarious locations such asthe Golgi apparatus
Golgi apparatusmodifies lipids and proteinsfrom the ER; sorts themand packages them invesicles
secretory vesiclefuses with the plasmamembrane as secretionoccurs
RER synthesizes proteins andpackages them in vesicles;vesicles commonly go tothe Golgi apparatus
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Fluid Mosaic ModelFluid Mosaic ModelProteins, carbohydrates are floating among Proteins, carbohydrates are floating among the lipid bilayerthe lipid bilayer
Allows SOME things to enter/exit cell Allows SOME things to enter/exit cell (selectively permeable)(selectively permeable)
Quick ReviewQuick ReviewWhich organelle is the control center of the cell? Which organelle is the control center of the cell? NucleusNucleus
Which organelle holds the cell together?Which organelle holds the cell together?Cell membraneCell membrane
Which organelles are not found in animal cells?Which organelles are not found in animal cells?Cell wall, central vacuole, chloroplastsCell wall, central vacuole, chloroplasts
Which organelle helps plant cells make food?Which organelle helps plant cells make food?ChloroplastsChloroplasts
What does E.R. stand for?What does E.R. stand for?Endoplasmic reticulumEndoplasmic reticulum