Structure and Function of Cells

I.         Development of Cell Theory

II.        Robert Hooke (1665)

            A.        First to describe cells

            B.        Viewed plant tissue at 30x

            C.        Saw little boxes, called them cells

            D.        Did not describe living cells

III.       Antoni van Leeuwenhoek (1675)

            A.        Designed and built own microscopes

            B.        First drawings and descriptions of living cells(protozoa)

            C.        Called them animalcules (little animals)

            D.        Discovered bacteria in 1683

IV.      Theodor Schwann and Matthias Schleiden (1839)

            A.        First statement that all living things are made of cells

V.        Louis Pasteur (1860)

            A.        Conclusive proof life must come from preexisting cells

VI.      Cell Theory

            A.        All living things are composed of one or more cells

            B.        Cells are the basic unit of structure and function in an organism

            C.        Cells come only from the reproduction of existing cells

VII.     Cell Diversity

            A.        Size

            B.        Shape

            C.        Internal organization

VIII.    Size

            A.        Most visible only with microscope

            B.        Size limited by ability of nutrients to enter cell

            C.        Volume grows faster than surface area

            D.        Surface area determines rate of entry to cell

            E.        At some point surface area unable to supply volume

IX.      Shape

            A.        Shape determined by function

            B.        Nerves: central body with long wire like extensions

            C.        Skin: flat to act as cover

            D.        Blood: shaped to move through small vessels

X.        Internal organization

            A.        Organelles: cell component with a specific function

            B.        Cell membrane: outer cover of cell

            C.        Protoplasm: gel-sol filling cell

            D.        Procaryote: no nucleus, no membranes around organelles

            E.        Eucaryote: nucleus, membrane bound organelles

XI.      The Generalized Cell

XII.     Cell Membrane

            A.        Barrier, isolates interior of cell

            B.        Semi-permeable (selectively permeable)

            C.        Bi-layer of lipids between protein membrane

                        1.         Hydrophilic head outward

                        2.         Hydrophobic tail (carboxyl group) inward

                        3.         Isolate cell from environment

                        4.         Controlled flow across membrane

            D.        Proteins

                        1.         Peripheral proteins

                                    a.         On outer surfaces

                                    b.         Binding sites for chemical messengers

                        2.         Integral proteins

                                    a.         Within membrane

                                    b.         May pass through

                                    c.         Active in transport across and within membrane

                                    d.         Bind with carbohydrates on outside of cell

                                                (1)       binding site for viruses

                                                (2)       binding site for chemical messengers

                                                (3)       binding site for hormones

XIII.    Cytoplasm

            A.        Aqueous colloid (cytosol)

            B.        Dissolves salts, minerals, and organic molecules

            C.        Contains cell organelles (table on overhead)

XIV.   Mitochondria

            A.        Power plant of cell

            B.        Double membrane, inner membrane folded to increase surface area

            C.        Transfer energy to ATP from organic molecules

            D.        Site of Krebs Citric Acid Cycle

            E.        Have own DNA, from mother only

XV.     Ribosome

            A.        No membrane

            B.        Combination of proteins and RNA

            C.        Made in nucleus and transported to cytosol

            D.        Free ribosomes make protein for cell

            E.        Ribosomes in ER make proteins for export

XVI.   Endoplasmic Reticulum

            A.        Membranes and sacs in cytoplasm

            B.        Act as cell’s highway

            C.        Rough endoplasmic reticulum contains ribosomes

            D.        Smooth Endoplasmic reticulum

                        1.         No ribosomes

                        2.         Synthesis of steroids

                        3.         Regulation of calcium in muscles

                        4.         Breakdown of toxic materials in liver

XVII.  Golgi Apparatus

            A.        A series of flattened sacs in cytosol

            B.        Processing, packaging, and secreting organelle

            C.        Modifies proteins for export from cell

XVIII. Lysosomes

            A.        Enclose hydrolytic enzymes

            B.        Enzymes digest polymers

            C.        Digest bacteria and viruses

            D.        Development: spaces between fingers

XIX.   Cytoskeleton

            A.        Protein strands supporting cell structure

            B.        Microfilament

                        1.         Actin polymers

                        2.         Smallest fibers in skeleton

                        3.         Cell movement and contraction of muscle fiber

            C.        Microtubules

                        1.         Extend from nucleus to cell membrane

                        2.         Form spindle fibers during cell division

XX.     Cilia and Flagella

            A.        Extend from surface, assist in movement

            B.        Internal structure of both similar

            C.        Cilia

                        1.         Short

                        2.         In large numbers

                        3.         Propel organisms

                        4.         Move foreign bodies

            D.        Flagella

                        1.         Long

                        2.         Few in number

                        3.         Propel cells

XXI.   Nucleus

            A.        Nuclear envelope: membrane

            B.        Nuclear matrix: skeleton

            C.        Chromatin

                        1.         Strands of DNA and protein

                        2.         Form chromosomes during cell division

            D.        Stores DNA

            E.        RNA copies DNA

            F.        Nucleolus: ribosomes built

XXII.  Plant Cells

            A.        Cell wall

            B.        Vacuoles

            C.        Plastids

XXIII. Cell Wall

            A.        Cellulose in proteins

            B.        Form rigid wall to support and protect

            C.        Primary: flexible allows growth

            D.        Secondary: woody, forms at full growth

XXIV. Vacuoles

            A.        Store enzymes

            B.        Store toxic wastes

XXV.  Plastids

            A.        Dual membranes

            B.        Store starches and fats

            C.        Chloroplast

                        1.         Thylakoids: Site of photosynthesis

                        2.         Convert sunlight to chemical energy

XXVI. Multicellular Organization

            A.        Tissues: cells carrying out specific function

            B.        Organs: interacting tissues

            C.        Organ System: interacting organs

            D.        Organism: interacting organ systems

XXVII.           Colonial Organizations

            A.        Groups of unicellular eukaryotes

            B.        Link between individual cells and multicellular organism

            C.        Some cells specialized (e.g. Volvox)

            D.        Suspected evolved into multicellular organisms