3Discovery of the CellRobert Hooke examines a thin slice of cork with a microscope.He observes “a great many little boxes.”The first man to see dead cells.Notices that these little boxes look like jail cells – thus the name: CELL.
4…more Discovery…1673 – Anton van Leeuwenhook observes first living cells; called them animalcules.First to develop a “modern day” microscope: more of a hand lens and he even used water as a magnifier.
5The Cell Theory The Cell Theory has three main parts. 1. All living things are composed of one or more cells.2. Cells are the basic units of structure and function in living organisms.3. Cells only come from the reproduction of existing cells.
6Spontaneous Generation The cell theory (#3) also helps disprove the idea of Spontaneous Generation: living things (insects) can come from non-living things.Francesco Redi’s meat jars and flies experiment.
7The Different CellsEukaryotic Cells – have a nucleus and specialized organelles.Prokaryotic Cells – cells that do NOT contain a nucleus nor do they have organelles. DNA is free floating.
8Prokaryotes Very primitive cells. DO NOT have a nucleus. All are bacteria.Use flagella/cilia for mobility and locomotion.DNA is free floating – gooey.First living things on earth.
9Prokaryotes Pieces and Parts Has a cell membrane.Some have cell walls.Prokaryotes are so unique that they are in their own kingdom: Monera
10Eukaryotic Cells and Their Size Why are cells so small?****Cells are small because of their surface area – HAVE to exchange “stuff” with their environment.****Cells take materials in and expel wastes – must be small or will starve or suffocate.ALL materials enter/exit through cell membrane.
12Eukaryotic CellsOrganelle – cell component that performs specific functions for the cell.Cell Membrane – entire cell is surrounded by a thin “layer” membrane….skin?The cell membrane is said to be selectively permeable - which means that some substances can cross easily, while others cannot cross the membrane at all.
13Mitochondria Produce ATP. ATP is a molecule cells use for energy. Contain their own DNA.Numerous in cell.AKA Powerhouse of the cell.
14Mitochondria Theory?Mitochondria are/were a key component to the Theory of Evolution.Evidence has led scientists to believe that a cell engulfed a mitochondria, didn’t digest it, and kept it inside of it.Cell then used mitochondria to make energy (ATP).
15Ribosomes Most numerous organelle in most cells. Some ribosomes are free floating.Others are attached to the Endoplasmic Reticulum – the Rough E.R.Synthesize (Make) proteins!!!!!!!Proteins used in cytoplasm – made by free ribos. – Proteins put into membranes – E.R
16Endoplasmic Reticulum AKA the E.RSystem of a series of membranes – an intracellular highway – molecules move from one part of cell to another.Rough E.R – ribosomes are attached to ER – in cells that make large amounts of proteins.Smooth E.R – no ribosomes on this E.R
20Cilia and FlagellaHair-like organelles that extend from surface of cell.Cilia are short – many.Flagellum are less numerous and longer…whipping mvmnt.Made of microtubules.
21LysosomesThese are small, spherical organelles that contain digestive enzymes.Lysosomes can digest proteins, carbohydrates, DNA and RNA.Common in animal, fungal and protists but not in plants.Digest old organelles, VIRUS and bacteria.
22Cytoskeleton Cytoskeleton maintains shape of cell just like Network of long protein strands – helps cell move.Two major componentsMicofilaments MFMicrotubules MT
23The Nucleus Usually the most visible. Surrounded by a membrane – nuclear envelope.Chromatin is found inside DNA + Proteins.Stores heredity – your genes DNA!!Nucleolus – dark spot – ribosomes are synthesized.
25The Plant Cell Very similar to the animal cells Plant cells have a cell wallCell wall provide support and protection for the internal organellesCell wall DOES have pores to allow for “stuff” to come in and out – cell membraneDistinguishing characteristic
26Vacuoles Fluid – filled organelles store enzymes and wastes Usually quite large, can take up 90% of cellSometimes stores toxic materials
27Chloroplasts Contain their own DNA Convert sunlight into chemical energyContain chlorophyllIs green
28Chloroplast Theory ?Scientists are convinced that chloroplasts, like mitochondria, were once free living organisms.Evidence: Make their own “food” and they have DNA inside could survive on their own.