The Cell

Mr. RamosThe Cell1Introduction to CellsThe cell is lifes basic unit of structure and function. The cell is the smallest unit of living material that can carry out all the activities necessary for life. Two types of cells known: Eukaryotic and Prokaryotic

Plant Cell2The Cell TheoryAll living things are composed of cells.Cells are the basic unit of structure and function in living things.New cells are produced from existing cells.

Omnis Cellula e CellulaRudolf Virchow

3Pioneers of MicrobiologyAnton Van Leeuwenhoek: Father of microscopy and microbiologyBuilt first practical microscopeFirst to see & describe bacteria, yeast, & organisms in water.Robert Hooke:English father of microscopyLooked at a thin slice of cork under a microscope & noticed chambers, which he called cells.

4The Compound Light MicroscopeA compound light microscope uses multiple lensesThe nosepiece can holds 3 or 4objective lenses with the power4x, 10x, 40x, & 100xTotal magnification (power): ocular lens X objective lens. 10x X 40x = 400x

5Confocal Light MicroscopeConfocal Light Microscopes can observe living cells in 2D by scanning them with a laser beam.

6Electron MicroscopesElectron Microscopes use beams of electrons to see things smaller than cells, such as cell membranes, chromosomes, organelles, and more.Transmission Electron Microscope (TEM): can see the internal structure of cells (e.g. organelles)Scanning Electron Microscope (SEM): can see the full details of the 3D surface of a specimen

Only for nonliving, preserved cells and tissues7Eukaryotes vs. ProkaryotesEukaryotic CellsProkaryotic CellsNucleusYesNoOrganellesYesNoRibosomesYesYesDNAYesYesSizeGenerally bigger than prokaryotesGenerally smaller than eukaryotesExamplesAnimal cells, Plant cells, Fungi, ProtistsBacteria and Archaea

8ProkaryotesNo nucleusHave DNANo membrane bound organellesHave a plasma membraneMost have a cell wallHave ribosomesSmaller sizeBacteriaArchaea

9Eukaryotic Parts and FunctionsOrganelles are little organs.Nucleus: cells command center (home of DNA)Nucleolus: ribosomal RNA is assembled (rRNA)Cytoplasm: area outside of the nucleus where the organelles are foundPlasma Membrane: the cell membrane regulates what goes in and out of the cellRough Endoplasmic Reticulum (RER): contains ribosomes & synthesizes proteins for cells to exportSmooth Endoplasmic Reticulum (SER): does not contain ribosomes and is used to synthesize fats and detoxification of drugs

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Eukaryotic Parts and Functions11Eukaryotic Parts and FunctionsRibosomes: factories for making proteinsGolgi Apparatus: modify, sort, and package proteins made in the rough endoplasmic reticulum.Mitochondria: makes energy for the cell & contains its own DNALysosomes: digest old organelles, macromolecules, and remove junk from the cell.Vacuoles: store materials, such as water, salts, proteins, and carbohydrates. They are like a closet or kitchen cabinet. Chloroplasts: converts sunlight into chemical energy & contains its own DNA12Eukaryotic Parts and Functions

13Eukaryotic Cells: Plant Cell & Animal CellsPlant and animal cells are both eukaryotic cells.They contain a nucleus & most of the same organelles.

Differences:Plants have a cell wall.Plants have chloroplasts.Plants have a large vacuole.Plants do not have centrioles.

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Plant Cell vs. Animal Cell15Cell Membrane The cell membrane controls what goes into and out of a cell.All cells have a cell membrane.It is composed of two layers of phospholipids. phospholipid bilayerCell membranes may also contain proteins & carbohydrates.Fluid Mosaic Model

16Cell WallSome eukaryotic cells and some prokaryotic cells have cell walls. Plants, fungi, algae, and prokaryotes (bacteria & archaea) Cell walls provide support and protectionPlant cell walls are made of cellulose.Fungi cell walls are made of chitin.

17CytoskeletonThe cytoskeleton is the skeleton of the cellMicrotubules, Intermediate Filaments, & MicrofilamentsMicrotubules contain the protein tubulin & they participate in cell division & cell movementExamples: Centrioles, Cilia & FlagellaMicrofilaments contain the protein actin and are found in muscle cells. They also support cells & help them move.

18Cilia and FlagellaMicrotubules make up cilia and flagella.

19Cell TransportationCells need to get things in and outHow things get in and out:Semipermeability of the cell membraneThe size and charge of the particlesLipid molecules can easily go through the cell membraneWater may also go through the cell membrane, but not as easily as lipids.

20Passive Transport: DiffusionDiffusion is the movement of particles from an area of higher concentration to an area of lower concentration. Diffusion does not use energyPassive Transport

21Passive Transport: OsmosisOsmosis is the diffusion of water from an area of higher water concentration to an area of lower water concentration.In osmosis, it is water that moves, not the particles.Osmosis does not use energyPassive Transport

22Active TransportActive transport requires energy.Movement from a lower concentration to a higher concentrationNote: this is the opposite of diffusion & osmosis

23Endocytosis and ExocytosisEndocytosis involves bringing things into the cell.Phagocytosis: cell eatingPinocytosis: cell drinkingReceptor-mediated endocytosis: brings materials in along with cell receptors.

Exocytosis involves taking things out of the cell.

These terms are only used for larger molecules that cannot get in or out of the cell through diffusion or osmosis24

Endocytosis &Exocytosis

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