Cells

The Structure and Function of Cells The History of the CellThe CellThe basic unit of an organismDiscovery made possible by the invention of the microscope

MicroscopesA microscope is an optical instrument used for viewing very small objects, such as mineral samples or animal or plant cells, typically magnified several hundred times. The Eye PieceAlso called the ocularThe part of the microscope you look throughThe eye piece magnifies what you are looking at 10xArm and BaseThe arm and the base are used to hold the microscopeYou should always use two hands when carrying the microscope. One on the arm and one on the base.Coarse AdjustmentThe course adjustment knob is used to focus the objectOnly used under low power. Fine AdjustmentThe fine adjustment knob refocuses the object.Only use under high powerObjectivesThe objectives are used to magnify what you are looking atDiaphragm Used to adjust the amount of light

Microscopes and Cells1600s.Anton van Leeuwenhoek first described living cells as seen through a simple microscope.

Microscopes and Cells1830s.Mathias Schleiden identified the first plant cells and concluded that all plants made of cells.Thomas Schwann made the same conclusion about animal cells.

Cell TheoryAll organisms are made up of one or more cells.The cell is the basic unit of organization of all organisms.All cells come from other cells all ready in existence.

Two Basic Cell Types1) ProkaryoteLacks internal compartments.No true nucleus.Most are single-celled (unicellular) organisms.Examples: bacteria

Two Basic Cell Types2) EukaryoteHas several internal structures (organelles).True nucleus.Either unicellular or multicellular. unicellular example: yeast multicellular examples: plants and animals

The Parts of The Eukaryotic CellBoundariesA) Plasma Membrane -- Serves as a boundary between the cell and its external environment. -- Allows materials to pass in and out of the cell.

The Parts of The Eukaryotic CellB) Cell Wall-- Surrounds the plasma membrane of the cells of plants, bacteria, and fungi.-- Plant cell walls contain cellulose while fungi cell walls contain chitin.

The Parts of The Eukaryotic Cell2) ControlsA) NucleusRegulates cell function.Surrounded by a double-layered membrane (nuclear enveloped) with large pores that allow materials to pass in and out of the nucleus.Contains chromatin long tangles of DNA.

The Parts of The Eukaryotic Cell2) ControlsB) NucleolusFound in the nucleus and responsible for ribosome production. Ribosomes are the sites of protein production.

The Parts of The Eukaryotic Cell3) AssemblyCytoplasmThe jelly-like material that surrounds the organelles.

The Parts of The Eukaryotic Cell4) TransportA) Endoplasmic reticulumFolded membrane that acts as the cells delivery system.Smooth E.R. contains enzymes for lipid synthesis.Rough E.R. is studded with ribosomes for protein synthesis.

The Parts of The Eukaryotic Cell4) TransportB) Golgi apparatus (or Golgi body)A series of flattened sacs where newly made lipids and proteins from the E.R. are repackaged and shipped to the plasma membrane.

The Parts of The Eukaryotic Cell5) StorageA) VacuolesA sac of fluid surrounded by a membrane used to store food, fluid, or waste products.

The Parts of The Eukaryotic Cell5) StorageB) LysosomesContain a digestive enzyme.Can fuse with vacuoles to digest food, or can digest worn cell parts.Also known as suicide sacs because they can also destroy the whole cell.

The Parts of The Eukaryotic Cell 6) Energy TransformersA) MitochondriaProduce the energy for the cell.Also known as the powerhouse of the cell.Has a highly folded inner membrane (cristae).

The Parts of The Eukaryotic Cell6) Energy TransformersB) Chloroplasts-- Found in plant cells and some protists.-- Transforms light energy into chemical energy which is stored in food molecules.-- Contain chlorophyll a green pigment that traps light energy and gives plants their green color.

The Parts of The Eukaryotic Cell7) SupportCytoskeletonA network of thin, fibrous materials that act as a scaffold and support the organelles.Microtubules hollow filaments of protein.Microfilaments solid filaments of protein.

The Parts of The Eukaryotic Cell 8) LocomotionA) CiliaShort, numerous, hair-like projections from the plasma membrane.Move with a coordinated beating action.

The Parts of The Eukaryotic Cell8) LocomotionB) FlagellaLonger, less numerous projections from the plasma membrane.Move with a whip-like action.

The Parts of The Eukaryotic Cell9) Cell DivisionA)Centriolesmade of protein.play a role in the splitting of the cell into two cells.found in animal and fungi cells.

Composite Animal Cell32Teachers: you may want to print out this diagram, photocopy it for each student and have them fill in the blanks as you go through this presentation.Cellular OrganizationCellTissue group of cells functioning together.Organ group of tissues functioning together.Organ System group of organs functioning together.Organism group of organ systems functioning together.

Cellular FunctionsAll the different parts of the cell are important to the life of the cell. Cellular activities require energy. All cells are able to release energy from complex molecules. The energy in a sugar molecule is released by the mitochondria in small steps.After a cell has taken in energy-rich molecules, the molecules are used by the mitochondria and energy is released. MetabolismMetabolism is the sum of all the chemical reactions in a in a cell or organism. Important molecules, like sugar, are processed and energy is transformed to ATP and waste materials. Not all energy is used immediately. Some cells, for example, those in green plants that contain chloroplasts, store energy in complex molecules such as sugars. Homeostasis and TransportAtoms, molecules and small particles are in constant motion. Molecules tend to move from an area where they are more concentrated to an area where they are less concentrated, until their concentration is the same everywhere. The concentrations of molecules at various points between the high and low areas form what is called the concentration gradient. Molecules are said to move down the concentration gradient. Homeostasis and TransportWater moves in and out of cells and diffuses down its concentration gradient in the same manner as other substances.Passive TransportThe diffusion of water is called the osmosis. Molecules move across a semipermeable membrane, from an area of high concentration to low concentration. Hypertonic: If concentration of water is higher inside the cell, water diffuses out of the cell and the cell will shrink.Salt solutionPlasmolysis is a loss of turgor pressure and the cell will shrink. Hypotonic: If concentration of water is higher outside the cell, water diffuses into the cell and the cell will expand (burst). Provides the plant cell with turgor pressure.In an animal cell, it may result in cytolysis (bursting of the cell) Contractile vacuoles are used to remove excess water in protozoa. Animals use lungs and kidneys. Isotonic: The concentration is the same inside and outside of the cell. Saline solution

Active TransportMovement of molecules up the concentration gradient.Requires energyCarrier proteins can also serve as pumps during active transport.Sodium Potassium Pump works to maintain a higher concentration of sodium (Na) ions inside the cell and a higher concentration of postassium (K) ions outside the cell. Requires energy to do so.Creates and electrical gradient across the cell membrane which is essential for nerve impulses.