Cell: the smallest unit of life
Discovery of Cells Robert Hooke was the first to identify and name cells Anton van Leeuwenhoek made better lenses and observed cells in greater detail Mathias Schleiden noted that plants are made of cells Theodor Schwann concluded that all living things are made of cells Rudolf Virchow proposed that all cells come from other cells
Cell Theory All organisms are made of cells All existing cells are produced by other living cells. The cell is the most basic unit of life.
Prokaryotic cells Simple cells No nucleus Ex: bacteria Staphylococcus aureus
Prokaryotic Cell
E Coli Bacteria Enterococcus faecalis Bacteria
Eukaryotic Cells More complex Have a true nucleus Make up all living cells other than bacteria
Eukaryotic Cell
Nerve cell Nerve Cell Hair Cell Fingernail White and Red Blood Cells
Similarities and differences between the Prokaryotic and Eukaryotic Cells Prokaryotic cellsEukaryotic cells Cell size1-10 micrometers micrometers Cell membrane?Yes Membrane-bound organelles? NoYes Have nucleus?NoYes Have cytoplasm?Yes Have DNAYes, in cytoplasmYes, in nucleus ExamplesBacteriaFungi, plants, animals
Cells use three different methods to move themselves or debris
Flagella: long hairlike filaments used by some prokaryotes to move
Flagellum
Cilia: short hairlike projections that some cells use for movement
Pseudopod: false foot
Picture Quiz Identify the cells as prokaryotic or eukaryotic.
Eukaryotic- Mushroom Cell
Eukaryotic- Red blood cells
Prokaryotic- Lactobacilli bacteria
Eukaryotic- fish egg cell
Prokaryotic- MRSA
Prokaryotic- Streptococcus pneumoniae bacteria
Eukaryotic- Fern leaf cell
Eukaryotic- taste bud cell
Eukaryotic- Osteocyte (bone cell)
Eukaryotic- cartilage cells
Cell Organelles Specialized cell parts that carry out many different processes and functions.
Cell membrane Barrier around the cell that controls what goes in and out Security Guard
Nucleus Controls most of the cell’s processes Stores DNA Control center or ‘brain’ Nuclear Membrane Separates the nucleus from the rest of the cell
Nucleolus Darker portion inside the nucleus that produces ribosomes
Cytoplasm (cytosol) Jelly-like fluid inside the cell where metabolic processes occur
Ribosome Small organelles that float in the cytoplasm or on the ER that build proteins Cell workers
Endoplasmic Reticulum Produces and transports materials such as proteins Assembly line
Golgi Apparatus (Golgi body) Packages and distributes proteins and lipids Shipping and handling department
Lysosome Stores enzymes and removes worn- out organelles. Mainly in animal cells. Waste disposal unit
Mitochondria Provides energy for the cell Powerhouse or powerplant
Cytoskeleton Thin protein fibers that helps keep the cell’s shape
Centrioles Only found in animal cells that are important for cell division
Cell wall Found only in plant and fungus cells. Provides extra shape, support and protection.
Chloroplast Found only in plant cell. They contain chlorophyll used for photosynthesis
Vacuole Stores water, salts, and wastes. Plants have larger ones Storage unit
Differences Between Plant and Animal Cells Plant CellsAnimal Cells Have a Cell Membrane, Nucleus, Mitochondria, Ribosomes, Golgi apparatus, and Endoplasmic Reticulum? YES Have a Cell Wall? YESNO Have Lysosomes? NO (rarely)YES Have Vacuoles? YESNone or Small Have Chloroplasts? YESNO
Cellular Differentiation 250 different kinds of cells in the human body Through cellular differentiation, different types of cells are created to carry out specific tasks or functions. In animals the “starter” cells that differentiate are called stem cells In plants those cells are called meristematic cells
Cellular Organization Cells Tissues Organs Organ Systems Organisms
Image References /characteristics-of-prokaryotic-cells / 59/characteristics-of-prokaryotic-cells /